Somatostatinoma syndrome: does a clinical entity exist?

We report here 2 patients with somatostatin-secreting tumours and hypersomatostatinaemia. One subject, a 36 year old woman with diabetes, flushing, labile blood pressure and diarrhea, had elevated basal plasma levels of somatostatin-like immunoreactivity (SLIR) and calcitonin. Plasma SLIR increased further following tolbutamide administration. Plasma levels of prostaglandin E2 (PGE2) and pancreatic polypeptide (PP), normal in the basal state, showed exaggerated responses to pentagastrin and secretin, respectively. Immunocytochemistry of the tumour tissue revealed cells containing somatostatin-, calcitonin-, PGE2- and PP-like immunoreactivity. The other patient, a 52 year old male, had an SLIR-secreting tumour of the proximal duodenum and elevated basal and post-tolbutamide SLIR levels but no signs or symptoms suggestive of increased SLIR production. Tumour tissue revealed cells containing somatostatin- and calcitonin-like immunoreactivity. We conclude that patients with somatostatinomas do not always exhibit a predictable syndrome. Patients with these tumours may exhibit a range of clinical, biochemical and immunocytochemical features typical of endocrine tumours of mixed-cell origin, such that the dominant signs and symptoms associated with these neoplasms cannot readily be ascribed to overproduction of any single hormone.     

Progressive multifocal leukoencephalopathy in the absence of immunosuppression

A 69-year-old woman presented with a cortical hand syndrome progressing over several weeks. MRI brain showed characteristic appearances of progressive multifocal leukoencephalopathy (PML), confirmed by detection of the JC virus in CSF, despite the absence of any evidence of immunosuppression. Treatment with mirtazapine, mefloquine and cidofovir did not affect the progression of the disease, which was fatal within 7 months of presentation. This report adds to the small case literature that suggests that PML can occur in immunocompetent people, albeit extremely rarely.     

Glucose and lactate kinetics in children with severe malaria

Children with severe malaria often present with lactic acidosis and hypoglycemia. Although both complications independently predict mortality, mechanisms underlying their development are poorly understood. To study these metabolic derangements we sequentially allocated 21 children with falciparum malaria and capillary lactate concentrations of 5 mmol/L or more to receive either quinine or artesunate as antimalarial therapy, and dichloroacetate or saline placebo for lactic acidosis. We then administered a primed infusion (90 min) of L-[3-13C1]sodium lactate and D-[6,6-D2]glucose to determine the kinetics of these substrates. The mean (SD) glucose disposal rate in all patients was 56 (16) micromol/kg x min, and the geometric mean (range) lactate disposal rate was 100 (66-177) micromol/kg x min. Glucose and lactate disposal rates were positively correlated (r = 0.62; P = 0.005). Artesunate was associated with faster parasite clearance, lower insulin/glucose ratios, and higher glucose disposal rates than quinine. Lactate disposal was positively correlated with plasma lactate concentrations (r = 0.66; P = 0.002) and time to recovery from coma (r = 0.82; P < 0.001; n = 15). Basal lactate disposal rates increased with dichloroacetate treatment. Elevated glucose turnover in severe malaria mainly results from enhanced anaerobic glycolysis. Quinine differs from artesunate in its effects on glucose kinetics. Increased lactate production is the most important determinant of lactic acidosis.     

Obstetrical magnetic resonance imaging: fetal anatomy

Nine patients who were 34-36 weeks pregnant underwent magnetic resonance (MR) imaging. Sagittal images using spin echo technique (TR 2.0 sec, TE 28 msec) were optimal for delineating fetal anatomy. The fetal cardiovascular, pulmonary, and central nervous systems were depicted in all cases. The heart and major vessels were readily seen due to the natural contrast of flowing blood. The intensity of the fluid-filled lungs greatly increased with a longer TR or TE, delimiting thorax from liver. The brain was relatively featureless due to the lack of gray-white matter differentiation. The umbilical cord within the amniotic fluid and its insertion into the placenta and fetus was identified in all cases. MR is a new modality for fetal imaging that offers tissue-characterization information that complements the superior anatomic detail of ultrasound scanning.