appendicitis/CF

Question

What is the relation between appendicitis and CF?

Answer

Dear questioner,

This is a very relevant question. We will first tell you a little bit about appendix and appendicitis. The appendix is a small piece of intestine that hangs as a dead end structure on the first part of the large intestine. Its function is not really known. The appendix can become infected when -for instance- a residue of food remains stuck there. We then talk about appendicitis. Belly ache, vomiting and sometimes fever are signs suggestive of appendicitis. The diagnosis is made by examining the patient aided by ultrasound: the appendix appears enlarged and often there is inflammation of the surrounding fat. The treatment is surgical removal of the appendix. The whole process runs an acute course and only takes a couple of days. If the diagnosis of appendicitis is missed, the infection can spread to the entire abdomen and be life threatening.

Is there a higher risk of appendicitis in patients with cystic fibrosis?
Surveys show this is not the case. In the normal population the incidence of appendicitis is about 7%. In patients with CF it is a lot lower (1 to 2 %). The reason is likely a protective role against infection by the thick secretions in the appendix. Still appendicitis does occur in patients with CF and can cause problems. Often doctors will not think about this diagnosis early on, because there are very many other causes of abdominal pain in patients with CF (insufficient intake of pancreatic enzymes, constipation, obstruction of the first part of the large intestine by stools, intussusception whereby a part of the small intestine will crawl into the large intestine, or because of scars related to previous abdominal surgery). Also the relatively frequent use of antibiotics to treat airway infection can dampen any start of abdominal infection or appendicitis so that the complaint becomes chronic. On top of all that the appendix of patients with CF is often already thicker than in healthy patients because tenacious secretions build up in the appendix. Up to 80% of patients with CF will have an appendix above normal size on ultrasound, but this is without accompanying signs of infection. That however makes the diagnosis of appendicitis in CF more difficult.
Because of all these facts, the course of appendicitis in patients with CF is often slower and less acute. The complaints will last several days or weeks and are often not recognized as appendicitis. Therefore there are complications more often. The progressive distension of the appendix will lead to microperforations in the wall. The content of the appendix will drip into the belly and an abscess (collection of pus) is formed. This collection of pus again occurs rather slowly, can become encapsulated so that it can last weeks to months before the problem is recognized. It is important to know that if a patient with CF needs surgery for appendicitis the treatment of the lungs cannot be forgotten. Just as with any surgery involving anesthesia extra attention to physiotherapy and treatment with antibiotics IV or oral around the time of surgery is important. In addition good pain control is necessary so that physio can be performed properly.
To conclude, the most common cause of abdominal pain in patients with CF is insufficient treatment with pancreatic enzymes, but other causes including appendicitis should be considered.

Kind regards,
dr. Mieke Boon and K. De Boeck

24.03.2011