[Unclear lactate acidosis in a patient with heart failure under long-term diuretic therapy]

A severely ill 84-year old patient, known to suffer from a chronic congestive heart failure, was admitted to the emergency room because of increasing dyspnea. His blood pressure was stable (125/80), his heart rate normal (66/min), the respiratory rate, however, was elevated at 35/min and he exhibited substantial peripheral edema. There were no signs indicating an infectious process.

Blood gas analysis yielded a marked, respiratorically compensated metabolic acidosis with a base excess of -8.6. The chest roentgenography showed a markedly dilated heart without pulmonary-vascular congestion or infiltrates. The serum lactate was substantially increased at 11.4 mmol/l (0.6-2.44).

A cardiovascular beriberi syndrome was suspected and 100 mg of thiamine administered i.v. Within hours the clinical picture improved significantly. Two hours after administration of thiamine serum lactate concentration was 5.7 mmol/l, about 12 hours later the patient suffered no longer from dyspnea and the lactate was at a normal level.

Thiamine deficiency as a cause for an elevated serum lactate or lactate acidosis with or without cardiovascular failure may not be overlooked. Without adequate treatment it may end lethally, although it can be treated easily, effectively and without side effects. The potential frequency of thiamine deficiency among the normal population even in our society may be under-estimated due to the particular properties of this vitamin.