Life-threatening lithium-induced diabetes insipidus after colonic surgery

Colonic surgery is associated with major disturbances to patients’ fluid balance as aresult of pre-operative starvation, intra-operative blood loss, insensible losses, andpost-operative ‘third space’ losses. In the post-operative period, junior surgeons arewell trained to manage oliguria, but have little experience of the management ofpost-operative polyuria. Nephrogenic diabetes insipidus occurs in 12% of patientson lithium therapy and may present in the immediate post-operative period withmassive polyuria, profound dehydration and life threatening hypernatraemia, aspatients are unable to ingest large volumes of fluid orally. We report two cases, onelife threatening, of lithium induced nephrogenic diabetes insipidus (LINDI) whichpresented in the early postoperative period after emergency colonic surgery whilstthe patients were denied oral intake. The first patient attained a peak serum sodiumconcentration of 185mmol/l and required ventilation after a respiratory arrest. Wesuggest any surgical patient who describes a history of bipolar disorder or lithiumtherapy should be questioned directly to ascertain confirmatory features of LINDI,and have post-operative polyuria treated with aggressive fluid replacement