CF - clinical features

This wasn't really my area but I decided to post it up since I mentioned a couple of points during my presentation and just to expand a bit on what Vivian has done since Dr. Laksmi asked me to connect the pathophisiology with the signs and symptoms and complications...

So as mentioned earlier, the concentration of sodium and chloride within the ECF and ICF is disrupted because of the failure of opening of the chloride channel in response to elevated cAMP in epithelial cells (CFTR is a chloride channel). Consequences of this:

• In the sweat glands the chloride ions can not be reabsorbed from the sweat before it is expelled onto the skins surface, this also inhibits the reabsorbing of sodium ions. This results in significant loss of these ions, altering the overall balance within the body and which can cause abnormal heart rhythms.
• In the pancreas the inability to move chloride ions out of the cell and into the ducts also prevents the movement of water in the same fashion as the water normally followed the chloride ions via osmosis. These results in digestive enzymes not being carried out into the intestines through the water, the enzymes instead digest the pancreas triggering inflammation and mucus build up (90% of CF patients have pancreatic damage)
• The mutant CFTR also triggers mucous build-up in the lungs, causing the most noticeable symptoms of Cystic Fibrosis. The mucus can partially block parts of the lungs and most importantly is an excellent growing medium for bacteria, leading to chronic respiratory infections that inevitably result in lung damage.
• nutritional effects - malnutrition due to malabsorption and maldigestion
• delayed puberty and skeletal maturity
• males are always almost infertile owing to failure of development of the vas deferens and epididymis. Females are able to conceive but often develop secondary amenorrhoea as the disease progresses

~shantz~