Infectious mononucleosis complicated by haemolytic anaemia due to the Donath Landsteiner antibody and by severe neutropenia.

A young man developed infectious mononucleosis complicated by profound anaemia due to haemolysis. The Donath Landsteiner antibody was found in his serum. He was treated successfully by blood transfusion but subsequently developed severe neutropenia. Both complications have been reported previously but not in the same individual. No underlying immune deficiency could be identified.

Acute intermittent porphyria in two patients on anticonvulsant therapy and with normal erythrocyte porphobilinogen deaminase activity.

1. Acute intermittent porphyria (AIP) is sometimes termed a 'pharmacogenetic' disease. patients with genetic deficiency of the enzyme porphobilinogen deaminase are liable to develop acute attacks of porphyria if exposed to a variety of drugs. 2. Two patients are reported who had no evidence of deficiency of erythrocyte porphobilinogen deaminase yet developed typical attacks of AIP while on anticonvulsant therapy. 3. Normal activity of erythrocyte porphobilinogen deaminase does not completely exclude porphyria. 4. Acute porphyria should be suspected if clinical deterioration occurs during therapy with anticonvulsants, or other porphyrinogenic drugs, even in the absence of an underlying genetic defect in haem synthesis in peripheral blood cells.

Still's disease and the virus-associated haemophagocytic syndrome.

A 15-year-old male developed features of Still's disease. He was treated, with incomplete response, with aspirin and corticosteroids. Some 10 months after the onset he contracted chickenpox and became gravely ill. A diagnosis of histiocytic medullary reticulosis was made because erythrophagocytic histiocytes were detected in marrow aspirate films. Necropsy studies showed systemic infiltration by benign-appearing histiocytes and led to the final diagnosis of the virus-associated haemophagocytic syndrome due to varicella-zoster infection in an immunocompromised patient.

Prolonged remission in florid Cushing's syndrome following metyrapone treatment.

Two patients presenting with diabetes mellitus and hypokalaemia resulting from markedly increased ACTH and cortisol secretion are described. Neither patient showed any evidence of a tumour and both responded dramatically to treatment with metyrapone in that all abnormal clinical features disappeared, ACTH concentrations returned to normal and both patients showed prolonged remission after metyrapone treatment was stopped. One patient relapsed after a severe viral illness and the administration of dexamethasone and cortisone. It is suggested that these cases may represent an unusual form of Cushing's syndrome in which ACTH secretion is stimulated by increasing concentrations of cortisol. When these are reduced by metyrapone administration ACTH secretion falls in parallel and prolonged remission of disease may result.