Complications and Management of DVT

Complications of DVT

Pulmonary Embolism
The most serious complication of DVT occurs when a clot becomes dislodged from a vein, travels to the lung, and blocks or partially blocks the pulmonary artery leading from the heart to the lungs. This condition is called pulmonary embolism.

This short-term complication is potentially life-threatening and occurs in about 10% of patients with acute DVT events.

If the clot is small, only one or more portions of the lung may be deprived of blood and damaged. This condition can result in:

• Shortness of breath

• Chest pain with breathing

• Bloody sputum (material coughed up from the lungs)

If a blood clot blocks the pulmonary artery, pulmonary embolism can be fatal due to the inability of blood to circulate through the lungs.
Vigorous treatment is immediately begun with blood-thinning drugs, oxygen and other medications depending on the situation.

Multiple and repeated emboli can lead to chronic impairment of blood circulation through the lungs and cause a form of heart failure.

Post-Thrombotic Syndrome
Post-thrombotic syndrome is the name used to describe the long-term effects that can occur after you have had a venous thrombosis of the deep veins of the leg. In many people who have had a DVT, the thrombus leaves scars within the vein. This scarring can damage the valves and narrow the diameter of the veins.

If the valves in the deep veins are damaged then blood runs in the wrong direction, towards the ankle. This puts extra pressure on the ankle's blood vessels which means the leg can swell. Many people with this problem of incompetent deep veins ( valves that do not work) have pain in their leg when they stand up. The pain can get worse as the day continues. They only get relief when the lie down again.

The scarring of the veins can narrow their diameter. This means the calf muscle can only pump small amounts of blood out of the leg. This makes it difficult to drain the blood from the leg.

When the incompetent valves and failed calf pump are combined, the leg can become increasingly swollen and painful.Skin of the affected area appears thickened and glossy as well. Another possibility is an ulcer of the skin which can occur months to years after the blood clot. This condition is the Post-Thrombotic or Post-Phlebitic Syndrome.

Post-thrombotic syndrome can cause serious long-term ill health, poor quality of life, and increased costs for the patient and the healthcare system. Post thrombotic syndrome is common in people who have had thrombosis, whether they are young or old. Generally, 1 out of 3 people who have had thrombosis in the legs will develop some post-thrombotic symptoms within 5 years. People who have thrombosis more than once (recurrent thrombosis) are at higher risk for post-thrombotic syndrome. Thrombosis can go unnoticed, so it is sometimes possible to have post-thrombotic syndrome without being diagnosed with thrombosis first.

How Is Deep Vein Thrombosis Treated?

Treatment of DVT is aimed at:

• Easing symptoms

• Preventing worsening of the clot

• Preventing the clot from traveling to the lungs

Treatment usually requires hospitalization, primarily to facilitate monitoring of medications. Because DVT occurs in post-surgical patients, however, the person might already be in the hospital when DVT is diagnosed.

Deep vein thrombosis must be treated promptly. Once the diagnosis is confirmed, the individual is kept in bed with the foot of the bed elevated.

Bed rest. Individuals with DVT usually require bed rest until symptoms are relieved. The leg should be elevated to a position above the heart to reduce swelling (the foot of the bed is elevated about six inches to achieve this). Moist heat may be applied to the affected region to relieve pain.

Compression stockings. Physicians frequently recommend that people who have DVT wear compression stockings (also called support hose) to reduce symptoms. Compression stockings improve circulation by providing a graduated pressure on the leg to help return the venous blood to the heart.

Blood-thinning drugs. Treatment with anticoagulants (commonly known as blood thinners) is required in most cases of DVT. The anticoagulant drugs heparin and warfarin are used primarily to prevent the formation of new clots, and, thus, reduce the chance of pulmonary embolism.

Heparin is the anticoagulant drug of first choice. It must be administered intravenously (an injection made directly into a vein).

Warfarin (also called coumarin) is taken by mouth.

Treatment with heparin normally lasts seven to 14 days. Treatment with warfarin is usually continued from two to six months, depending on the age of the person, the severity of the DVT, and whether risk factors are present.

Warfarin usually takes several days to become fully effective, so heparin is continued until the warfarin has been fully effective for at least 24 hours. In almost all circumstances, warfarin is started only after heparin has been stared.

Pregnant mother should not take warfarin as it can cross the placenta and cause birth defect.

Patient should also consult the doctor before taking other drug such as aspirin together with anticoagulant drug due to additive effect and can cause excessive bleeding.
Blood tests will check how well the medicine is working. You should call your doctor right away if you are taking warfarin or heparin and have easy bruising or bleeding.

Clot-busting medication. Drugs called thrombolytic agents (clot-dissolving medications) are used to help dissolve existing clots and reopen clogged veins. The most commonly used thrombolytic agents are urokinase, streptokinase, and recombinant tissue plasminogen activator (rt-PA).

The best results occur when this treatment is given to people who have had DVT for less than 48 hours.

When effective, the clot usually breaks up within 24 to 48 hours.

Thrombolytic agents can also cause internal and external bleeding, and require careful monitoring. Treatment with thrombolytic agents usually lasts for only 24 to 72 hours.

Surgery. If an embolus develops, surgery may be necessary to prevent the spread of the clot to the lung. Surgery, however, is performed only as a last resort.

Surgery for complications resulting from DVT involves the insertion of a filter into a large blood vessel to trap any blood clots headed toward the lungs. The filter allows blood to flow through it normally, but traps the traveling clots. The procedure is called vena cava interruption because the filter is placed in the inferior vena cava, the large vein in the pelvic area that receives the blood returning from the deep femoral (thigh) veins.

The most severe cases of DVT may require the surgical removal of the blood clot from the vein, a procedure known as venous thrombectomy. The patient is given anticoagulant therapy with heparin during the surgery, and warfarin for a period of at least six weeks to three months following the operation.


Reference:
http://www.ehealthmd.com/library/dvt/DVT_complications.html
http://www.venous-info.com/handbook/hbk02c.html
http://www.swindon-marlborough.nhs.uk/departments/anticoag/pts.htm
http://bdb.org.uk/Post%20thrombotic%20syndrome.htm
http://www.cardiosource.com/ExpertOpinions/Programhlts/interviewDetail.asp?interviewID=211
http://bdb.org.uk/Post%20thrombotic%20syndrome.htm

Video:
http://www.nhlbi.nih.gov/health/dci/Diseases/Dvt/DVT_WhatIs.html
http://www.legalpointer.com/displaymonograph.php?MID=148

Contributed by
Lawrence Oh

Thrombophilia Screen

Thrombophilia: A congenital or acquired predisposition to thrombosis.

Causes of thrombophilia

Inherited:
An inherited abnormality of one of the plasma proteins listed below:


* Factor V Leiden homozygous individuals have an 80 X risk of Venous
Thromboembolism (VTE).

Acquired Risk factors for thrombosis

Risk factors for arterial thrombosis include:
Hypertension
Smoking
Diabetes
Polycythaemia
Lupus anticoagulant

Risk factors for venous thrombosis include:
Conditions causing stasis e.g. advanced age, cardiac failure, oedema, nephritic syndrome, obesity, trauma, long distance travel, immobility, post-operative, pelvic obstruction, myocardial infarct, central venous catheter
Altered blood constituents that is acquired in oestrogen therapy, contraceptive pill, malignancy, pregnancy, antiphospholid syndrome, raised plasma homocysteine, or raised factors VIII, IX or XI.
Polycythaemia and thrombocythaemia.

Pathogenesis is multifactorial and relates to elevated levels of procoagulant, depressed levels of inhibitor proteins and physical factors (e.g. stasis, surgery).

What is thrombophilia screen used for?
It is used to investigate the cause of thrombophilia.

Who should be referred for a thrombophilia screen?
Patients with have the following:
- Spontaneous thrombosis, particularly at a young age, or associated with pregnancy
- Thrombosis at an unusual site e.g. sagittal sinus thrombosis
- Recurrent thrombosis
- Thrombosis in those with a VTE and a first degree relative with a history of VTE.

What is screened for in the patient’s blood sample?

Activated Protein C Resistance (APCR)
The APCR test is a sensitive screening test for Factor V mutations which may lead to an increased risk of thrombosis. APCR is the most common known hereditary predisposition to venous thrombosis. Activated protein C normally degrades activated factors V and VIII by proteolytic change to inhibit coagulation. Individuals with APCR have a mutated Factor V, which is resistant to degradation by activated Protein C.

Protein C
Heterozygous protein C deficiency increases the risk for venous thrombosis sevenfold. It is more likely to be of relevance in young (<>

Protein S
Protein S is a cofactor for activated Protein C mediated degradation of the coagulation factors Va and VIIIa.

Antithrombin
Antithrombin is a powerful physiological coagulation inhibitor, which inhibits the activity of thrombin and factor Xa and to a lesser degree on factors IXa, XIa and XIIa and Kallikrein.

Factor V Leiden and Prothombin Gene Mutation Testing
The Factor V Leiden mutation has been identified as a major cause of familial venous thrombosis and is inherited in an autosomal dominant fashion. Heterozygosity is associated with an 8-fold increased risk of venous thrombosis and homozygosity with an 80-100-fold increased risk.
The prothrombin mutation (G20210A) is linked to increased prothombin levels. It is inherited independently from the Leiden mutation in an autosomal dominant fashion and is associated with an approximate 3-fold increased risk of venous thrombosis.

Antiphospholipid Antibodies
Antiphospholipid antibodies are a family of autoantibodies that recognise various phospholipids and/or phospholipid-binding proteins. This antibody family includes lupus anticoagulants, anticardiolipin antibodies and anti-beta2-glycoprotein I antibodies. All confer an increased risk of thromboembolic .

The diagnosis of Antiphospholipid syndrome, which can occur in isolation, or in association with other systemic autoimmune disease, such as SLE, is made using clinical and laboratory criteria.

Clinical criteria
1. Thrombosis -arterial, venous or small vessel
2. Complications of pregnancy -recurrent miscarriage in the first trimester of pregnancy, foetal death in the 2nd or 3rd trimesters of pregnancy, and premature birth.

Laboratory criteria
1. Lupus anticoagulant detected on 2 or more occasions, at least 6 weeks apart.
2. Moderate or high levels of anticardiolipin antibodies detected on 2 or more occasions, at least 6 weeks apart.

To make a defintive diagnosis of antiphospholipid syndrome, patients must meet at least one of the clinical AND one of the laboratory criteria.

Important points to take note of before doing a thrombophilia screen:

- Patient needs to know nature and limitation of tests. Important to know what advice should be given if an abnormality is identified.
- Laboratory tests may be affected by other medical conditions and medication e.g. liver disease, pregnancy, anti-coagulants.
- Identification of a laboratory thrombophilic abnormality will not usually affect immediate treatment but may be of value in preventing further thrombosis and in counselling other family members so as to reduce their risk of a thrombosis.
- A person who develops spontaneous DVT may have a normal thrombophilia screen. This does not imply that the patient is normal and that the patient has no increased risk of thrombosis in the future or in the family member. There may be heritable defects that have yet to be discovered.
- As the clinical interpretation of a thrombophilia screen will depend upon each patient's circumstances it is sensible for patients to be referred to a specialist who has experience in counselling and testing such individuals and families (rather than just taking a blood sample and requesting thrombophilia investigations).


Sources:
Haematology at a Glance, 2nd Edition, Mehta & Hoffbrand
British Heart Foundation, Thrombophilia Factfile 02/2002, http://www.bhsoc.org/bhf_factfiles/bhf_factfile_feb_2002.pdf
Guidelines for Thrombophilia Screening in Patients Taking Oral Contraceptives,
http://www.gp-training.net/protocol/cardiovascular/thrombo.htm
ACT Pathology: Investigations for Thrombophilia
http://www.actpathology.act.gov.au/c/ap?a=da&amp;amp;did=1008510&pid=1059373329&sid=

Contributed by John Lee

baker's cyst

Baker’s cyst


Pathophysiology:

Posterior herniation of capsule of the knee joint leads to escape of synovial fluid into one of the posterior bursae, Baker's cysts arise between the tendons of the medial head of the gastrocnemius and the semimembranosus muscles. They are posterior to the medial femoral condyle.
When this bulge becomes large enough, it becomes palpable and cystic. Most Baker's cysts maintain this direct communication with the synovial cavity of the knee, but sometimes, the new cyst pinches off.
A Baker's cyst can rupture if patient is mobile, particularly on standing up quickly or climbing stairs. Fluid escapes into the soft tissue of the popliteal fossa and upper calf, causing sudden and severe pain, swelling and tenderness of the upper calf. Dependent oedema of the ankle develops, and the knee effusion reduces dramatically in size and maybe undetectable.

Investigations:

Ultrasound
Positive patellar tap sign


D/dx:

DVT(may co-exist)

Treatment:

Baker's cysts usually require no treatment unless they are symptomatic. Often rest and leg elevation are all that is needed. If necessary, the cyst can be aspirated to reduce its size, then injected with a corticosteroid to reduce inflammation. Surgical excision is reserved for cysts that cause a great amount of discomfort to the patient.
A ruptured cyst is treated with rest, leg elevation, and injection of a corticosteroid into the knee, patient maybe given analgesics or NSAIDS for pain relief and swelling.

Management:

Many activities can put strain on the knee, and cause pain in the case of Baker's cyst. Avoiding activities such as squatting, kneeling, heavy lifting, climbing, and even running can help prevent pain. Despite this, some exercises can help relieve pain, and a physiotherapist may instruct on stretching and strengthening the quadriceps

Deep Vein Thrombosis
Signs & Symptoms
- leg pain
- leg tenderness
- swelling of leg
- increased warmth of leg
- changes in skin colour of leg (redness & bluish skin discoloration)
*Keep in mind many of the signs and symptoms are similar to many other conditions
eg. Muscle strains, skin infections, inflammation of superficial veins, cardiac related diseases (heart attack), lung related diseases (pneumonia)
*Nice to know: deep vein thrombosis related to pregnancy is also known as phlegmasia alba dolens.

Many patients do not show the symptoms until the clot dislodges and travels to the lung and causes pulmonary embolism.
- rapid heart rate
- shortness of breath
- sharp chest pain which worsens with deep breathing
- coughs up blood

Sources:
http://www.medicinenet.com/deep_vein_thrombosis/article.htm
http://www.nhlbi.nih.gov/health/dci/Diseases/Dvt/DVT_WhatIs.html

(Posted by: Vivian)

Anticoagulants and your favourite Clotting cascade

Investigations of DVT

Investigations of DVT

1. Doppler Ultrasound examination
2. Exclude pulmonary embolus (caused by DVT)
3. Thrombophilia screen
4. Venogram (gold standard)
5. MRV (magnetic resonance venogram) or MRI (may be better than other non-invasive techniques in diagnosing DVT in calf, but too expensive, so not used widely)

Ultrasonography
- best non-invasive diagnostic method
- average sensitivity & specificity of 97% for proximal DVT
- cannot be relied on to diagnose calf vein thrombosis (sensitivity too low 75%)
- three common techniques:

Compression ultrasound:
- looks at non-compressibility of the vascular lumen under gentle probe pressure
- if no residual lumen observed, vein is considered to be fully compressible, hence absence of DVT

Duplex ultrasonography:
- similar to above, but
- blood flow characteristics evaluated using pulsed Doppler signal
- blood flow in normal veins is spontaneous & phasic with respiration; can be augmented by manual compression distal to the ultrasound transducer
- if no phasic pattern, flow is defined as continuous, hence presence of venous outflow obstruction

Colour flow duplex imaging (colour coded Doppler ultrasonography aka colour Doppler):
- identical to above
- pulsed Doppler signals is used to produce images
- when a Doppler shift is recognized, it is assigned a colour (red or blue) according to its direction towards or away from the probe
- flowing blood displayed as a colour overlay to the grey scale ultrasound image, hence, easier to identify the veins
Therefore, Doppler ultrasonography
- shows direction and velocity of blood flow
- detects turbulent flow due to narrowing or blockage of blood vessels
- shows different rates of blood flow in different colours

Focus on Doppler Ultrasonography

Why the test is performed
- alternative to arteriography or venography
- help diagnose a blood clot, venous insufficiency, arterial occlusion (closing), abnormalities in the carotid artery blood flow caused by a narrowing and to evaluate trauma to the arteries
- also used to monitor arterial reconstruction and bypass grafts

How the test is performed
- done in the ultrasound or radiology department or in a peripheral vascular lab
- clear jelly (water-soluble gel) is squirted onto the inside of one of the patient’s thighs to help the ultrasound sensor (a handheld device called a transducer) slide around easily
- gel may be alternatively placed on the device
- a technician/doctor places the sensor against the patient’s skin
- once it's in place, an image appears on a video screen, and the technician/doctor moves the sensor up and down along the leg - from the groin to the calf - to view the veins from different angles
- the examiner presses the sensor into the patient’s skin firmly every few inches to see if the veins change shape under pressure
- the examiner then checks the other leg in the same way
- as the machine measures the blood flowing through a vein, it makes a swishing noise in time with the rhythm of your heartbeat
- the test usually takes 15-30 minutes
- most people don't feel any discomfort, but if the patient’s leg was swollen and sensitive to the touch before the test, the pressure of the sensor might cause some tenderness

Note, to examine the arteries: Blood pressure cuffs may be put around different parts of the body, including the thigh, calf, ankle, and different points along the arm. A paste is applied to the skin over the arteries being examined. Images are created as the transducer is moved over each area.

How to prepare for the test
The patient will need to remove clothing from the extremity being examined

How the test will feel
There is little or no discomfort associated with this test

Normal Values
- the vessels show no evidence of narrowing or closure
- the arteries have normal systolic and diastolic components
- blood pressure is normal

What abnormal results mean

• In the veins:
• Venous occlusion (closing of vein)
• Blood clots
• In the arteries:
• Arterial occlusive disease
• Spastic arterial disease (arterial contractions brought on by cold or emotion)
• Embolic arterial occlusion (obstruction in the artery by a blood clot, a fat globule, or an air bubble)

What the risks are
There are no risks specifically associated with this procedure

Special considerations
Cigarette smoking may alter the results of this test, because nicotine can cause the arteries in the extremities to constrict

Exclude Pulmonary Embolus (caused by DVT)
Investigations of pulmonary embolus:
- Arterial blood gases
- ECG
- CXR
- Ventilation / Perfusion scanning - May confirm or refute diagnosis
- Pulmonary angiography and echocardiography useful if haemodynamic instability
- Spiral CT might replace pulmonary angiography
- Lower limb investigations for DVT as above

Focus on Ventilation/Perfusion Scan (V/Q Scan)

Definition
- a pulmonary ventilation/perfusion scan is a pair of nuclear scan tests
- use inhaled and injected radioactive material (radioisotopes) to measure breathing (ventilation) and circulation (perfusion) in all areas of the lungs

Why the test is performed
- ventilation scan is used to see how well air reaches all parts of the lung
- perfusion scan measures the blood supply through the lungs
- most often performed to detect a pulmonary embolus
- evaluate lung function with advanced pulmonary disease (e.g. COPD), and to detect abnormal circulation (shunts) in the pulmonary blood vessels

How the test is performed
- the V/Q scan is actually two tests, so these tests may be performed separately or together
Perfusion scan:
- a health care provider injects radioactive albumin (mineral technetium) into the patient's vein
- the patient is immediately placed on a movable table that is under the arm of a scanner
- the machine scans the patient's lungs as blood flows through them to detect the location of the radioactive particles (identify areas of the lung that have reduced blood flow)
Ventilation scan:
- performed by scanning the lungs while the patient inhales radioactive gas

In a typical test:
- multiple pictures of the patient’s chest are taken from different angles, using a special camera that detects the radionuclide
- for half of these pictures, the patient is asked to breathe from a tube that has a mixture of air, oxygen, and a slightly radioactive version of a gas called xenon, which can be detected by the camera, and which measures airflow in different parts of the lung
- for the other half of the pictures, the camera tracks the injected radionuclide to determine blood flow in different parts of the lung
- a blood clot is suspected in areas of the lung that have good airflow but poor blood flow

How to prepare for the test
- fasting, special diet, medications not required
- a chest x-ray is usually performed prior to or following the scan

How the test will feel
- the table may feel hard or cold
- the patient may feel a sharp prick while the material is injected into the vein
- the mask used during the ventilation scan may give the patient a claustrophobic feeling
- the patient must lie still during scanning
- the radioisotope injection usually does not cause discomfort

Normal Values
The health care provider should take a ventilation and perfusion scan and then evaluate it with a chest x-ray. All parts of both lungs should take up the radioisotope uniformly.

What abnormal results mean
- results are usually available within a few hours, because the test is done only when the patient is suspected of having a potentially life-threatening condition (pulmonary embolus)
- the doctor interprets the pictures to determine whether the patient’s probability of having a blood clot in your lungs is high, low, or intermediate
- If the probability is high: blood-thinning medicine is ordered
- If it is low: immediate treatment may not be required, but the doctor will want to examine the patient again in a short time
- If it is intermediate, or if the V/Q scan cannot be clearly interpreted: pulmonary angiogram may be ordered to help determine whether the patient has a blood clot. This test is more definitive than a V/Q scan, but because it is more difficult and risky, the V-Q scan usually is done first

Perfusion scan results:
- decreased uptake of radioisotope during a perfusion scan: problem with blood flow, including occlusion of the pulmonary arteries
- a localized decrease in perfusion scan uptake (particularly when the ventilation scan is normal): pulmonary embolus
- larger areas of decreased perfusion scan uptake: condition such as pneumonitis
Ventilation scan results:
- decreased uptake of radioisotope during a ventilation scan: reduced breathing and ventilation ability or airway obstruction
- decreased ventilation uptake (plus x-ray evidence of consolidation): pneumonia
- larger areas of poor uptake: damage from chronic smoking or COPD

What the risks are
- risks are about the same as for x-rays (radiation) and needle pricks
Radiation risk:
- no radiation is emitted from the scanner (it detects radiation and converts it to a visible image)
- small exposure to radiation from the radioisotope. The radioisotopes used during scans are short-lived, with almost all radiation leaving the body in a few days. However, as with any radiation exposure, caution is advised for pregnant or breast-feeding women
Infection risk:
- slight risk for infection/bleeding at the site of the needle insertion (same for any other purpose of needle pricks)
- rare cases: a patient may develop an allergy to the radioisotope, which may include a serious anaphylactic reaction

Sources:
http://www.health.harvard.edu/diagnostic-tests/venous-ultrasound-of-the-legs.htm
http://www.nlm.nih.gov/medlineplus/ency/article/003775.htm
http://www.nlm.nih.gov/medlineplus/ency/article/003828.htm
http://www.health.harvard.edu/diagnostic-tests/ventilation-perfusion-scan.htm
http://www.bmj.com/cgi/content/full/326/7400/1180
http://www.surgical-tutor.org.uk/default-home.htm?system/vascular/venous_thromb.htm~right
http://www.merck.com/mmhe/sec03/ch021/ch021c.html#sec03-ch021-ch021c-122

Further reading on DVT (covers all PCL topics):
http://www.emedicine.com/med/topic2785.htm#section~workup

PCL Week 13: Tasks

Shantz- Definition and pathophysiology

Sri- Risk factors, Epidemiology (Factor V Leiden)

Lawrence- Complications

Vivian- Signs and symptoms of DVT

Ji Keon- Anticoagulants

Christine- Ruptured Bater's Cyst

Madhura- Ix, Ultrasound (Doppler), Ventilation/Perfusion Scan

John- Ix, Thrombophillia Screen

Chris- CAM, psychosocial


Prepared by Chris

RISK FACTORS - DVT

Risk Factors

Most DVT victims are over 60 years of age; however, DVT can strike almost anyone at risk. Genetics plays a part, but so does environment. Factors and conditions that may increase the risk of DVT include:

1) Immobility
Immobility slows down the circulation of blood, and increases the risk if DVT. Those at risk includes patients with reduced mobility who are confined to bed due to illness or hospitalization.

2) Injuries
Blood vessels may be injured in a variety of ways including: a blow to the leg, athletic injuries, surgery, or radiation therapy for cancer. Traumatic injuries may set the stage for DVT because they initiate the blood clotting process and narrow the vein. This slows the passage of blood and encourages pooling.

3) Inherited Clotting Disorders
If blood clots run in your family, you may have an inherited clotting disorder. Among people of European descent, the most common genetic mutations that encourage clotting are the factor 5(V) Leiden and the prothrombin gene mutation. Individuals who inherit one of these mutations from either parent may experience recurrent episodes of DVT, but the risk is highest if both parents were affected.

4) Infections, Inflammatory Diseases
Infections and inflammatory diseases like systemic lupus erythematosus, Crohn's disease, rheumatoid arthritis, and glomerulonephritis may stimulate the blood clotting process and promote DVT.

5) Pregnancy
Pregnant women are 5 times more likely to develop DVT than non-pregnant women. Cases occur most often in the third trimester and immediately following delivery.

6) Oral Contraceptives
Hormonal preparations such as oral contraceptives or replacement estrogens may also increase the risk of clotting, particularly when combined with other risk factors like smoking, hypertension, or obesity (a Body Mass Index of 30 or higher).

7) Cancer
Some cancers release substances that increase the blood's tendency to clot (i.e. prothrombotic). Cancers of the ovaries, pancreas, lymphatic system, liver, stomach, and colon are particularly likely to provoke DVT.

8) Smoking
Tobacco smoke reduces the amount of oxygen carried in the blood and may damage vessel walls, potentially leading to clot formation. It is one of the most modifiable risk factors for cardiovascular disease.

9) Obesity
Once thought to be dangerous only in association with high cholesterol levels, obesity is now recognized on its own as a significant risk factor. Obesity is defined by the National Institutes of Health as having a Body Mass Index greater than 30 (approximately 30 pounds or more overweight). Central obesity, also known as the "apple shape," has been associated with cardiovascular disease - which may increase the risk of DVT.

10) Air Travel with Prolonged Sitting
Prolonged sitting during air travel slows down circulation and increases the blood's propensity to clot. In addition, tightly packed seating and long periods of immobility can contribute to an increased risk of DVT.
Even in young, healthy travelers, long stretches of time spent in cramped seats of an aircraft with very low humidity may set the stage for the formation of a blood clot in the lower leg.

prepared by:
Sri Murniati Rosli

Biochemistry Profile

Hi all, I tried searching the internet for general information about the definition and interpretion of a biochemistry profile in general but there were not many good sites around. Nonetheless, I have made sense of what little I found and tried to come up with something coherent. Hope it makes sense to you.

Generally, a biochemistry profile refers to a report that shows biochemical properties (pH, osmolarity, composition, concentration of chemical substances) of bodily fluids like blood and urine.

It is used in the diagnosis and treatment of certain liver, heart and kidney diseases, acid-base imbalance, lipid metabolism disorders, endocrine disorders, metabolic or nutritional disorders.

Some examples of chemical substances measured in the blood (normal values):
• Bicarbonate (HCO3) (23-33mMol/ L)
• Blood Urea Nitrogen (BUN) (8-20mg/L)
• Calcium (8-10mg/dL)
• Cholesterol (<155mg/dl)
-Some examples of chemical substances measured in urine.
• Protein
• Glucose
• Nitrites
• Ketones
• Haemoglobin
• Bilirubin
• Urobilirubin

Let’s analyze Hazim’s biochemistry profile:

• Na (135-145mMol/dL) 119 - low
• K (3.5-5.0mMol/dL) 3.6 - normal
• Cl (95-105mMol/dL) 98 - normal
• HCO3 (24-30mMol/dL) 22 - slightly low
• Glucose (3.5-5.5mMol/dL) 8.0 - high
• Urea (2.5-6.7mMol/dL) 10.0 - high
• Creatinine (60-120 uMol/L) - normal

Important Notes:

Compare results to chart below.
Come up with a list of differential diagnosis.
Correlate results differential diagnosis with patient’s history. Is it likely to happen?
More tests are usually needed to confirm the diagnosis.
Biochemistry profile cannot tell us the whole picture.

Sources:

Medical Biochemistry at a Glance, Salway

http://www.nlm.nih.gov/medlineplus/ency/article/003579.htm

http://www.cdc.gov/nchs/data/nhanes/frequency/lab18doc.pdf

Contributed by John Lee

Effect on brain injury/surgery on plasma electrolyte level

The two most common electrolyte imbalances following brain injury are hypernatremia and hyponatremia


Brain injury is one of the most common types of traumatic injury. In critical care units, patients with moderate to severe brain injury are often intubated and sedated in an effort to diminish the workload of the brain. Agitation or restlessness is common in these patients and can be associated with fever, posturing, tachycardia, hypertension, and diaphoresis. This exaggerated stress response, known as sympathetic storming, occurs in 15% to 33% of patients with severe traumatic brain injury who are comatose (score on Glasgow coma scale [GCS] = 8). Sympathetic storming can occur within the first 24 hours after injury or up to weeks later. The precise mechanism for the increase in activity of the sympathetic nervous system is unknown, but the increased activity is thought to be a stage of recovery from severe traumatic brain injury. Normally the parasympathetic nervous system dampens the effects of increased activity of the sympathetic nervous system and returns the body to homeostasis. In sympathetic storming, this feedback does not occur and the individual is in an uncontrolled state of stress. Prolonged hypertension, arrhythmias, hyperglycemia, hyperthermia due to elevated metabolic rate, and hypernatremia from severe diaphoresis occur as a result of the sympathetic storm. Signs and symptoms vary from episode to episode and from individual to individual


HYPENATREMIA

Hypernatremia is a relatively common problem that can be produced either by the administration of hypertonic sodium solutions or, in almost all cases, by the loss of free water. However, persistent hypernatremia does not usually occur in these settings, because the ensuing rise in plasma osmolality stimulates both the release of antidiuretic hormone (ADH), thereby minimizing further water loss, and thirst, thereby increasing water intake [1-3]. The decrease in water loss and increase in water intake then lower the plasma sodium concentration back to normal.

This regulatory system is so efficient that the plasma osmolality is maintained within a range of 1 to 2 percent despite wide variations in sodium and water intake. Even patients with diabetes insipidus, who have often marked polyuria due to diminished ADH effect, maintain a near-normal plasma sodium concentration by appropriately increasing water intake.

The net effect is that hypernatremia primarily occurs in those patients who cannot express thirst normally: infants; and adults with impaired mental status. The latter most often occurs in the elderly, who also appear to have diminished osmotic stimulation of thirst.

Hospitalized persons, whether old or young, can become hypernatremic as a result of an inadequate fluid prescription and/or impaired thirst.

Hypernatremia due to water loss is called dehydration. This is different from hypovolemia in which both salt and water are lost.



HYPONATREMIA
Hyponatremia develops as a syndrome of inappropriate secretion of antidiuretic hormone (SIADH) or cerebral salt-wasting syndrome (CSWS). 1-3 SIA[DH is characterized by dilutional hyponatremia, and CSWS is characterized by natriuresis as a result of increased serum levels of natriuretic hormone.4 Diabetes insipidus presents with polyuria, serum hypernatremia and hyperosmolarity, and urine hypo-osmolarity, whereas CSWS is associated with polyuria, serum hyponatremia and hypo-osmolarity, and elevated urinary sodium and hyperosmolarity. Serum hyponatremia, serum hypo-osmolarity, urinary sodium exceeding 25 mmol/l, and euvolemia are typical findings in SIADH.


Symptoms of hyponatremia include:

nausea, abdominal cramping, and/or vomiting
headache
edema (swelling)
muscle weakness and/or tremor
paralysis
disorientation
slowed breathing
seizures
coma


-Hyponatremia (Low Na2+ levels) is common with head injury.
-Caused by inappropriate secretion of ADH, leading to increased water retention
-leads to cerebral oedema, and worsens neurologic outcome
-occurs on 5% to 33% of adults with head injury
-25% prevalence in children with head injury
-Polyurea occurs as well


sources:

Burkhard Simma, MD*§, René Burger, MD*, Markus Falk, MSC, Peter Sacher, MD†,
Timo Torresani, PhD‡, and Sergio Fanconi, MD* The Release of Antidiuretic Hormone Is Appropriate in
Response to Hypovolemia and/or Sodium Administration in
Children with Severe Head Injury: A Trial of Lactated
Ringer’s Solution Versus Hypertonic Saline

ww.anesthesia-analgesia.org/cgi/reprint/92/3/641.pdf

https://www.healthatoz.com/healthatoz/Atoz/common/standard/transform.jsp?requestURI=/healthatoz/Atoz/ency/electrolyte_disorders.jsp

http://findarticles.com/p/articles/mi_qa3912/is_199903/ai_n8836003

http://ccn.aacnjournals.org/cgi/content/full/27/1/30




Prepared by Chris Sim

Importance of Sodium, Hyponatremia, Hypernatremia

Sodium

• most of the sodium is located in the ECF (Extra-cellular Fluid) which is 55% of body's sodium
• 40% is located in the bone, 2%-5% in organs and cells
• normal level of sodiums in the blood are 136 to 145 milliequivalents per liter (mEq/L) of blood
• Sodium is required by all cells in the body to maintain a normal fluid balance
• Sodium also plays a key role in normal nerve and muscle function
• Sodium Input: Food and Drink
• Sodium Output: Sweat and Urine (primarily)
• When sodium intake and loss are not in balance, the total amount of sodium in the body is affected.
• Changes in the total amount of sodium are closely linked to changes in the volume of water in the blood.
• When sodium in the blood decrease, blood volume will decrease in order to maintain the osmolarity of the blood. Thus when blood volume decreases, blood pressure also decreases, heart rate increases, and light-headedness and sometimes shock occur.
• The blood volume increases when there is too much sodium in the body,
• When excess sodium accumulates in the body, extra fluid accumulates in the space surrounding the cells. As a result, the tissues, especially in the feet and ankles, swell (a condition called edema).
• Thus sodium is important in maintaining an effective circulation volume in the body.
  

Hyponatremia

• Sodium in blood is below 135 mEq/L.
• Occurs when sodium is overdiluted in the body
• Sodium can be overdiluted when people drink enormous amounts of water ( happens in patient with psychiatric disorder) or hospitalized patient who receive large amount of fluid intravenously.
• Thus amount of fluid taken in exceeds the kidney's capacity to eliminate the excess fluid.
• Intake of smaller amounts of water—sometimes as little as 1 quart a day—can also lead to hyponatremia in people whose kidneys are not functioning normally, such as people with kidney failure.
• Patient with SIDAH (Syndrome of inappropriate excretion of Anti-Diuretic Hormone) where excessive ADH is produced. Thus large amount water is conserved in the body and overdilute the sodium in the blood
• Hyponatremia also happen in patient with heart failure.
  
• The diagnosis of hyponatremia is made by measuring the sodium level in the blood.
  

Symptoms

• When the sodium level in the blood falls quickly, symptoms tend to develop rapidly and be more severe
• lethargy and confusion (The brain is particularly sensitive to changes in the sodium level in the blood.)
• Severe hyponatremia may cause osmotic shift of water from the plasma into the brain cells (water intoxication). Brain cell expands and ceases to function
• muscle twitching and seizures ( as hyponatremia become more severe)
• coma, and death may follow
  

Hypernatremia

• sodium in blood is above 158 mEq/L.
• The body contains too little water relative to the amount of sodium. The sodium level in the blood becomes abnormally high when water loss exceeds sodium loss, as occurs with dehydration
• In most people, hypernatremia results from dehydration
• Hypernatremia occurs in people who drink too little water and in those who have diarrhea, vomiting, fever, excessive sweating (particularly during hot weather), or abnormal kidney function
• hypernatremia may occur in diabetes insipidus, in which the kidneys excrete too much water
• Hypernatremia is most common among older people, who tend to sense thirst more gradually and less intensely than younger people do
• In addition, the kidneys' ability to concentrate urine declines in advanced age, so older people are less able to conserve water.
• Diuretic can also cause patient to secrete water excessively.
  

Symptoms

• brain dysfunction (mainly) & confusion
• shrinkage of brain cell ( shifting of water from brain cell into ECF)
• seizure & coma
• muscle twiching
• lethargy
• dealth (severe)

Sources: http://www.merck.com/mmhe/sec12/ch155/ch155k.html

Contributed by Lawrence Oh

Treatment & Management of Brain Injury

Yo dawgs, just to let you know, most of my information was taken from the first link provided (see sources below). I have summarized very succintly the information, coz' if I didn't, it would have taken far more space. I don't believe any of you will click on the link, but I have, on my own discretion, taken what I believe is most important to post here. This is a disclaimer so just in case anything comes out in exam, don't come running to me... *insert a very nice smiley face here* Now, on with the show:

Process:

1. First aid
2. ICU
3. Acute Rehabilitation Unit
4. Sub-acute Rehabilitation Unit
5. Day Treatment (Day Rehab or Day Hospital)
6. Outpatient Therapy
7. Home Health Services
8. Community Re-entry
9. Independent Living Programs
10. Brain Injury Support Groups

First aid (Emergency care until help arrives)

1. Call for help (999)
2. ABC, CPR
3. ABC okay, but the person is unconscious: treat as if there is a spinal injury. Stabilize the head and neck by placing your hands on both sides of the person's head, keeping the head in line with the spine and preventing movement.
4. Stop any bleeding by firmly pressing a clean cloth on the wound. If you suspect a skull fracture, DO NOT apply direct pressure to the bleeding site, and DO NOT remove any debris from the wound. Cover the wound with sterile gauze dressing.
5. If the person is vomiting, roll the head, neck, and body as one unit to prevent choking.
   

ICU
Goals: stabilize the patient and prevent further injury

• Adequate oxygen supply to the brain and the rest of the body
• maintain blood flow to the brain
• control blood pressure
• stabilize the airway
• assist in breathing or perform CPR if necessary
• treat associated injuries

Specialized treatment team

• Neurologist: Primary treating physician
• Neurosurgeons: remove blood clots, haematomas (e.g. subdural), intracerebral haemorrhages, perform procedures to relieve increased pressure within the skull
• Intensivists: physicians staffing the ICU
• Respiratory therapists: to monitor respiratory functions
• Specialized nurses & technicians: e.g. radiological technicians
• Trauma specialists: treat associated injuries
  

Equipment in the ICU

• A Ventilator (Also called a Respirator) is a machine that helps a person breathe (as patient may unable to breathe on his/her own) - provides Oxygen
• A tube is placed through the person’s mouth to the trachea: Intubation
• Intravenous lines (IVs): tubes placed in a person’s veins to deliver medications and fluids to the person’s body
• Arterial lines: tubes placed in a person’s arteries to measure blood pressure
• A Foley Catheter is used to collect and monitor a person’s urine output (patient may be unable to control bladder functions
• A rubber tube is inserted into the person’s bladder. This allows urine to move from the bladder, through the tube, and to a container at the end of the tube
• A Nasogastric Tube (NG Tube) is used to deliver medication and nutrients directly to a person’s stomach (patient may be unable to swallow on his/her own)
• A tube is placed through a person’s nose or mouth and ran through the swallowing passage (the esophagus), to the stomach
• An ECG machine monitors a person’s heart.
• A Pulse Oximeter is a small clamp-like device placed on a person’s finger, toe, or earlobe. The Pulse oximeter measures the amount of oxygen in the blood stream.
• An Intracranial Pressure (ICP) Monitor is a device attached to a person’s head with a monitor that indicates the amount of pressure in the brain.
• When the brain is injured it may swell (oedema: subsides within a few days/weeks, but a few minutes or hours of excessive ICP can cause permanent damage).
• When the brain swells, the brain has no place to expand. This can cause an increase in intracranial pressure (the pressure within the skull).
• If the brain swells and has no place to expand, this can cause brain tissues to compress, causing further injury (as blood is prevented from circulating adequately in the brain tissue, causing damage to brain cells)
• ICP can be measured with an intraventricular probe or catheter inserted through the skull into the fluid-filled chambers (ventricles) within the brain. Placement of the ICP catheter is usually guided by CT scan.
• If ICP is elevated, drugs that may decrease ICP (MOA: draw fluid out of the brain and into blood vessels, decrease brain’s metabolic requirements, increase blood flow to injured tissues) include mannitol and barbiturates. NO halothane (cerebrovascular dilator).
• Surgery for elevated ICP:
  
• If severe brain swelling, the elevated pressure can be relieved temporarily by surgically removing a portion of the skull to allow swollen tissues to bulge out, reducing the risk for pressure-induced damage.
  
• A build up of fluid may also cause the ventricles in brain to experience blockage. A ventriculostomy may be needed. A shunt is inserted to drain the fluid build-up (hydrocephalus), causing the ventricles to shrink and restoring normal function to brain cells.

Acute Rehabilitation Unit
When persons are medically stable and have reached a point in recovery where they are able to participate in therapy, they may be transferred to an inpatient Acute Rehabilitation setting.

Goals: assist persons with brain injuries to achieve their highest level of independent life skills used in activities of daily living; detect complications early; prevent additional injury

Acute Rehab Team

A Psychiatrist: the leader for the rehabilitation treatment team; makes referrals to the various therapies and medical specialists as needed. The physiatrist works with the rehabilitation team, the person with a brain injury, and the family to develop the best possible treatment plan.

Physical Therapists evaluate and treat a person’s ability to move the body; improves physical function by addressing muscle strength, flexibility, endurance, balance, and coordination (walking, getting in and out of bed, on and off a toilet, or in and out of a bathtub)

Occupational Therapists use purposeful activities as a means of preventing, reducing, or overcoming physical and emotional challenges (feeding, swallowing, grooming, bathing, dressing etc)

Speech/Language Pathologists evaluate a person’s ability to express oneself (speech, written, or otherwise expressed) and comprehend what is seen or heard. Swallowing issues may also be addressed.

Rehabilitation Nurses attempt to maintain the person’s medical status, anticipate potential complications, and work on goals to restore a person's functioning.

Case Managers/Social Workers are responsible for assuring appropriate and cost-effective treatment and the facilitation of discharge planning.

Recreational Therapists provide activities to improve and enhance self-esteem, social skills, motor skills, coordination, endurance, cognitive skills, and leisure skills.

Neuropsychologists focus on thinking skills, behavior, and emotional processing.

Aquatic Therapists are occupational therapists, physical therapists, or recreational therapists with specialized training to provide therapy in a heated water pool.

Subacute Rehabilitation

• Less intensive level of rehabilitation services, over a longer period of time
• Skilled nursing facility or nursing home.

Day Treatment provides rehabilitation in a structured group setting during the day and allows the person with a brain injury to return home at night.

Outpatient Therapy

• Following acute rehabilitation or sub-acute rehabilitation, a person with a brain injury may continue to receive outpatient therapies to meet continued goals.
• Additionally, a person with a brain injury that was not severe enough to require inpatient hospitalization may attend outpatient therapies to address functional impairments.

Home Health Services
Some hospitals and rehabilitation companies provide rehabilitation therapies within the home for persons with brain injury.

Community re-entry programs generally focus on developing higher level motor, social, and cognitive skills in order to prepare the person with a brain injury to return to independent living and potentially to work. Persons who participate in the program typically live at home.

Independent Living programs provide housing for persons with brain injury, with the goal of regaining the ability to live as independently as possible.

Brain Injury Support Groups can help individuals with brain injury and their loved ones cope and increase their knowledge about brain injury issues. Support group members can provide valuable emotional support because of their experiences and understanding of the impact of brain injury. Brain injury support groups are also a good place to network and learn from others--what they have done in similar situations.

Medications (refer to handout for specific information)
Medications for persons with brain injury are carefully selected, prescribed, and monitored by the physician on an individual basis (overlapping all stages).

With brain injury, the cell’s ability to produce neurotransmitters is reduced either by interference with production, release or absorption. These chemical changes alter the brain’s ability to process information. Medications prescribed after a brain injury improves the brain’s natural ability to produce and utilize neurotransmitters. The medications act as a cast for the neuron to allow more normal activity during recovery. In situations where the neuron fails to recover its function, medications then are used as splints to allow the most normal neuron function possible.

Analgesics may be used for pain relief and pain management.
Anti-Anxiety Agents may lesson feelings of uncertainty, nervousness, and fear.
Anti-Coagulants may be used to prevent blood clots.
Anti-Convulsants may be used to prevent seizures.
Anti-Depressants may be used to treat symptoms of depression.
Anti-Psychotics may be used to target psychotic symptoms of combativeness, hostility, hallucinations, and sleep disorders.
Muscle Relaxants may be used to reduce muscle spasms or spasticity.
Sedative-Hypnotic Agents may be used to induce sleep or depress the central nervous system in areas of mental and physical response, awareness, sleep, and pain.
Stimulants may be used to increase levels of alertness and attention.

Sources:
http://www.biausa.org/Pages/what_is_the_rehab_process.html
http://www.biausa.org/word.files.to.pdf/good.pdfs/good.text.only/RoadToRehab6.txt
http://www.nlm.nih.gov/medlineplus/ency/article/000028.htm#visualContent
http://www.birf.info/home/library/med-procede/med-pro-compev.html
http://www.neurologychannel.com/tbi/treatment.shtml
http://www.neuroitu.co.uk/page10.html - for pictures of haematomas and haemorrhage

tonicity

Tonicity: is the ability of a solution to affect the fluid volume and pressure in a cell.

Hypotonic: has a lower concentration of nonpermeating solutes than the intracellular fluid. Cells in a hypotonic solution absorb water, swell and may lyse.

Isotonic: total concentration of nonpermeating solutes is the same as in intracellular cellular fluid.

Hypertonic: has a higher concentration of nonpermeating solutes than intracellular fluid. It causes cells to lose water and shrivel( crenate).

fluid deficiency
1. hypovolemia: total body water is reduced, isotonic
2. dehydration: total body water is reduced, hypertonic

Fluid excess
1. volume excess:total body water is elevated, isotonic
2. hypotonic hydration:total body water is elevated, hypotonic


















Fluid deficiency: output exceeds intake over a long enough period of time.

Hypovolemia: occurs when PROPORTIONATE amounts of water and sodium are lost without replacement. Total body water declines but osmolarity remain normal.
Occurs: haemorrhage, severe burns, chronic vomiting or diarrhea.

Dehydration: occurs when body eliminates significantly more water than sodium so ECF osmolarity rises.
Occurs: lack of drinking water, diabetes mellitus, ADH hyposecretion( diabetes insipidus), profuse sweating, overuse of diuretics


Fluid excess: less common than fluid deficiency because kidneys are highly effective at compensating for excessive intake by excreting more urine. Renal failure can cause this condition.

Volume excess: both sodium and water are retained and the ECF remains isotonic. This can result from aldosterone hypersecretion or renal failure.

Hypotonic hydration: more water than sodium is retained or ingested and the ECF becomes hypotonic.
Occurs: If you lose a large amount of water and salt through urine and sweat and you replace it by drinking plain water. Without proportionate intake of electrolytes, water dilutes the ECF, makes it hypotonic, and causes cellular swelling. ADH hypersecretion can cause hypotonic hydration by stimulating excessive water retention as sodium continues to be excreted. This can cause pulmonary and cerebral oedema.

Renal Physiology

Note: All these points are considered important since they are already being condensed. No any particular part will be highlighted for your special attention. Thanks.

CAM

Natural therapy
Includes diet, exercise, naturopathy, herbalism, natural hygiene, homeopathy, massage therapy, relaxation techniques (eg. Yoga, Tai Chi), acupuncture, sauna, aromatherapy, and ayurveda medicine.

Head injuries:
Deficit in memory –siberian ginseng, rosemary leaf, peppermint leaf
Learning and memory – tyrosine, pyridoxine, phosphatidylserine
Anger management, anxiety, frustration or depression – St. Johnswort, passionflower, Siberian ginseng, Calamun Root, Prickly Ash Bark
Muscle contraction – acetylcholine (give choline and Vitamin B5)

Acupuncture – pain impulses are blocked from reaching spinal cord or brain
Massage – restoration of proper joint function and strengthening supporting muscles and soft tissues. Stretches and loosens muscle and connective tissue and improves blood flow. Reduces pain by blocking pain impulses from reaching brain.
Cranio-sacral therapy – gentle soft touch no greater than 5 grams to release constrictions in the craniosacral system which improves function of CNS. Used in traumatic brain injuries, motor-coordination impairment
________________________________________________________________________
Aromatherapy
- use of aromatic plant oils for psychological and physical wellbeing.
- may be used as topical application, massage, inhalation or water immersion.
- different aromas and chemical constituents of the oils can produce different emotional
and physiological reactions.
- used to alleviate symptoms of digestive problems, eczema, headaches, insomnia, stress,
relief of pain, care for the skin, alleviate tension and fatigue, promote relaxation, affects
mood
- little evidence that it effectively prevents or cures illness.

People respond to the sense of smell on an emotional level more strongly than any other sense. For example, a single aroma can trigger a whole string of forgotten memories. The area of the brain associated with smell is the same area as that associated with memory. The olfactory nerves are located within the nasal cavity and respond to particular aromas. They send the information to the part of the brain where memory and emotions lie. This area connects with another part of the brain (hypothalamus and pituitary gland) which governs our hormonal systems. These aromas trigger a variety of chemical actions within the body, including the release of specific chemicals. Enkephalin reduces pain and creates a feeling of well-being. Endorphins also reduce pain and induce sexual feelings. Serotonin helps relax and calm. Because the olfactory nerves are a direct extension of the brain's limbic system, reaction to smell is relayed immediately.

After brain injury, patients need to regain strength. Aromatherapy found to help regain strength, improve joint mobility, decrease physical tension.

In the plant, the essence molecules act as regulators and messengers, protect from parasites and disease, role in fertilization, assist adaptation to environment

Things to keep in mind:
Some oils are toxic eg. camphor, wintergreen
Some are very potent and should not be swallowed or applied undiluted to the skin.
Most should not be consumed
Some oils can be dangerous during pregnancy or to certain people with certain conditions eg. epilepsy and high blood pressure
Some people may be sensitive to aromatic plant oils. May have allergic reaction such as skin rashes. Eg. eucalyptus, ginger etc.

Sources:
http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Aromatherapy?OpenDocument
http://www.aromatherapy.com/aromatherapyoverview.html
http://news.scotsman.com/edinburgh.cfm?id=600962006
http://healing.about.com/od/diseasesandhealthissues/a/tbi_5.htm
http://www.tbirecovery.org/Overview.html

(Posted by: Vivian)