Conclusion-Treatment of chronic activeCrohn's disease with MMF plus cortisone appears to be eVective and well tolerated and should be considered in patients allergic to azathioprine or in whom azathioprine has failed. (Gut 1999;44:625-628)

Because of the large liver stores (about 5 mg), low turnover rate (0.143%) and small daily requirement (3 micrograms), vitamin B12 deficiency does not occur under normal circumstances. This is not the case in individuals with chronic inflammatory or trophic changes at vitamin B12 absorption sites. Without supplementation, vitamin B12 deficiency can be expected within 5 years of gastrectomy. Characteristic features of type A gastritis are hyposecretion and mucosal atrophy in the fundus and body of the stomach, with absent intrinsic factor. In the small intestine, active and/or passive absorption is impaired by extensive ileal resection, exocrine pancreatic insufficiency and chronic inflammatory disorders such as Crohn's disease. Definitive plasma concentrations cannot be quoted for vitamin B12 deficiency. Dietary habits, subjective symptoms, hematological laboratory results, function tests and gastrointestinal endoscopic and histological findings must all be taken into account in the diagnosis. Modern diagnostic parameters, such as methylmalonic acid and homocysteine serum assays, are useful for achieving early diagnosis and hence optimal treatment. With their assured availability, parenteral vitamin B12 preparations remain the treatment of choice. Results from vitamin B12 bioavailability studies in healthy subjects suggest that > 300 micrograms probably suffices as an oral maintenance dose after parenteral loading. Further well-documented cases are needed in order to establish whether these doses are adequate in malabsorption syndromes and gastrointestinal diseases. Various case reports indicate the value of prophylactic and therapeutic oral vitamin B12 administration, especially in disorders of homocysteine metabolism, a substance postulated as a further important risk factor for atherosclerosis.

Treatment with AZA/prednisolone appears to be more effective and safe compared to MMF/prednisolone in patients with chronic active UC. MMF might be an alternative treatment for patients with contraindications to AZA. To further evaluate the effects of MMF in active UC, a placebo-controlled double-blinded study appears warranted.

No abstract

Nephrogenic diabetes insipidus (NDI) is a serious side effect of various drugs. Elevated renal prostaglandin E2 levels have been found in patients with lithium-induced NDI and have been implicated in the pathogenesis. We report the case of a patient who developed NDI following treatment with amphotericin B. Prostaglandin levels were elevated. Indomethacin had an antidiuretic effect and normalized prostaglandin levels.