CF-arthropathy

Question

Dear expert team,
how can a CF-arthropathy be diagnosed in children?
My daughter is 9 years old with CF and suffers a lot under joint pain, needs a rehabilitation buggy in case of long distances.
Many thanks

Answer

Hello,
you report, that your 9-year-old daughter suffers form strong joint pain and needs a rehabilitation buggy to cope with long distances. You ask, how a CF-arthropathy can be diagnosed in CF-children. At first it has to be said, that there are different forms of joint pain in CF patients.
1) Hypertrophic pulmonary osteoarthropathy
Hereby it deals with changes of the long bones, of the distal phalanxes of the fingers (clubbing fingers) and symmetrically arising bone pain with swelling of the joints and impairment of the joint function (hand-, foot-, knee-joints).
These problems occur mostly only in case of advanced lung disease (in case of latent or manifest lack of oxygen) and are in most cases reversible after successful lung transplantation. One finds typical changes on the x-ray. There are no typical laboratory findings for this problem.
2) Episodic (acute) arthritis
Hereby it deals in the first row with a typical so-called "CF-arthritis". Hereby it deals in general with an acute illness. The joint problems occur asymmetrically and affect small or large joints. The complaints last mostly only for a limited time about 7-14 days. One assumes, that the reactions of the joints are caused by so-called immuno-reactions, which are based on the chronic bacterial inflammation of the lung.
For making the diagnosis, only few things can be found. On the x-ray, swelling of the soft tissues or effusions can be seen. In the laboratory, negative results for the rheumatic factors occur, in single cases so-called immuno-complexes (ANCA) can be positive.
As therapy, painkillers should be used. Of essential importance is an agressive antibiotic therapy.
3) Drug-associated arthritis
Such a reaction of the joints can be seen in case of extremly high dosage of pancreatic enzymes (picture of gout). In general one does find also then increased serum-parameters of uric acid. Additionally, it can come under therapy with so-called gyrase-blockers (antibiotics=chinolones) to symmetrical joint pains, which disappear in general after stopping the drugs.
In the laboratory, one does not find specific results. In single cases positive rheumatic factors and/or circulating immuno-complexes can be found.
In case of occurence of the respective complaints, the antibiotic therapy has to be stopped immediately. In case of increased uric acid, the dosage of the pancreatic enzymes has to be checked.

The so-called CF-arthropathy (No.2) can therefore not be diagnosed via any typical laboratory findings. It is more the result of a diagnosis of exclusion. I would therefore recommend, as your daughter seems to complain already for a long time about massive pain, that your daughter will be presented to an experienced rheumatologist. In case he does not find any typical findings for rheumatism, you should discuss with your CF physicians in charge an intensified antibiotic therapy.
We wish you and your daughter all the best and hope that the joint problems can be treated successfully.

Yours sincerely,
dr. H.-G. Posselt

18.04.2011