Intestinal vasculitis and lithium carbonate-associated diarrhoea.

Lithium carbonate is now frequently used in the treatment of both unipolar and bipolar manic depressive states. It is generally thought that the adverse reactions of this drug are associated with plasma levels above the therapeutic range of 0.8-1.2 mmol/ litre, but they may also be associated with long-term usage of the medication within the recommended plasma concentrations. (Persson, 1977). The effect of lithium on the thyroid (Schou et al., 1968a) and on alterations in serum calcium and magnesium concentrations, may occur with totally acceptable plasma concentrations of the drug (Carman et al., 1974). Similarly, reversible electrocardiographic T-wave changes and arrhythmias can occur without a plasma concentration greater than 1[5 mmol/litre (Jaffe, 1977). Nephrogenic diabetes insipidus has also been noted in patients with therapeutic lithium levels, the mechanism involved being thought to be an antagonism of the action of antidiuretic hormone on adenylcyclase. (Editorial, 1977). Diarrhoea is perhaps the most commonly reported side effect of lithium and has been classified into two types. Firstly, a mild variety associated with acceptable serum levels and secondly, a severe form usually associated with levels greater than 2.0 mmol/litre (Schou, Amdisen and Thomsen, 1968b). The following case history is of a patient who experienced severe episodic diarrhoea with acceptable serum levels before presentation as a surgical emergency. Case report