Acute adrenal insufficiency is an uncommon complication of lung cancer and adrenal metastasis resection. Diagnosis is difficult to establish but an early recognition and treatment may be life-saving. A 55-year-old man underwent right upper lobectomy and adrenalectomy for lung carcinoma with right adrenal metastasis. Anaesthesia was obtained with propofol, alfentanil, atracurium and isoflurane. Blood pressure remained stable throughout surgical procedure and blood loss was about 3,000 ml. Several hours after the end of the procedure which was uneventful the circulator status worsened. The blood pressure was initially controlled with 500 ml of gelatin. External blood loss was about 200 ml. Clinical examination, chest X-ray and ECG were normal. Postoperative laboratory data showed a serum sodium at 134 mmol-1.l-1 and a serum potassium 5.1 mmol.l-1; haemoglobin concentration was 93 g.l-1. Arterial blood gas analysis, with a 5.1.min-1 nasal O2 flow showed a PaO2 at 108 mmHg, a PaCO2 at 30 mmHg and a pH at 7.44. Twelve hours later, a transient cardiac arrest occurred which responded to fluid load, dopamine and dobutamine. Six hours later, the patient went in ventricular fibrillation responding to an external electric countershock. No change in clinical status was noticed, except hyperthermia at 39.5% degrees C. Serum potassium concentration before cardiac arrest was 4.7 mmol-l-1. Main considered diagnoses were septic shock and acute adrenal insufficiency. Antibiotics (imipenem, amikacin and vancomycin) and hormonal treatment (hydrocortisone 200 mg.day-1), after blood samples had been obtained for bacteriological and hormonal examinations. The patient's condition improved dramatically within 48 hours. Shock was under control, dopamine and dobutamine were rapidly discontinued.(ABSTRACT TRUNCATED AT 250 WORDS)