Letters

Extraintestinal disease may be associated with Crohn's disease

EDITORA Grand Round discussed a boy who presented with cervical adenitis due to Mycobacterium paratuberculosis and later developed symptoms typical of Crohn's disease.¹ This sequence of events seemed unlikely to be unique; we therefore reviewed the full general practice medical records of 21 patients with Crohn's disease and 21 controls (matched for age, sex, and first letter of the surname) attending Sawston medical practice, a semirural practice of 12 500 patients.

Of the patients with Crohn's disease, 11 had histories consistent with a metastatic infectious disease. Five presented with cervical lymphadenopathy. In one woman "TB glands of the neck" had been diagnosed clinically at the age of 6 and treated with antituberculous treatment for a year; at 21 she had diarrhoea and weight loss and was found to have proctitis with indeterminate histological findings; at 23 she had a sterile abscess involving cervical glands and investigation for tuberculosis yielded negative results; and at 38 a white cell scan showed ileitis and a barium enema gave results typical of Crohn's disease. Two patients who had enlarged cervical glands removed in childhood developed Crohn's disease in adult life, and two others had unexplained cervical lymphadenopathy preceding the diagnosis of Crohn's disease. Two patients had enlarged axillary and inguinal glands. Three patients had sterile abscesses (one ischiorectal, one in inguinal nodes, and one labial with a discharge that contained acid fast bacilli, which failed to grow on culture). One patient had a granulomatous supralaryngeal lesion, which progressed to a stricture and defied diagnosis despite his Crohn's disease.

In the records of the controls there were two references to unexplained lymphadenopathy, but no sterile abscesses or granulomatous lesions were recorded.

These findings indicate that extraintestinal disease consistent with metastatic infection occurs more commonly in association with Crohn's disease than has been recognised and may precede the onset of gastrointestinal symptoms by many years. The frequency of disease in cervical lymph nodes suggests that the source of the organism was ingestedprobably milkas was previously the case in tuberculosis, with a long latent period and metastatic potential. We conclude that our findings lend support to the hypothesis that in some patients "Crohn's disease" is due to mycobacterial infection.