A 7-DAY-OLD boy presented with a 1-day history of poor breast-feeding. He was alert, with cold extremities, reduced skin turgor (Figure 1), dry mucous membranes, and a sunken anterior fontanelle. His weight was 2.66 kg, representing a loss of 25% from birth. The plasma sodium level was 174 mmol/L; urea nitrogen, 40 mmol/L (112 mg/dL); creatinine 111 µmol/L (1.25 mg/dL); leukocyte count, 12.3 ×109/L; and fibrinogen, 0.98 g/L (reference range, 1.5-4.5 g/L).
A blood culture was performed prior to administration of intravenous broad spectrum antibiotics. He was treated with intravenous fluids containing 40-mmol/L sodium, at 275 mL/kg per day. Ten hours after admission, his plasma sodium level had fallen to 156 mmol/L and 4 hours later the neonate had 2 brief generalized seizures. Rectal diazepam, intravenous mannitol, and phenytoin were given. He became apneic and required tracheal intubation, mechanical ventilation, and was transferred to the pediatric intensive care unit.
Renal diagnostic ultrasound showed no abnormalities. A cranial sonogram showed effacement of the subarachnoid spaces indicating moderate cerebral edema. An unenhanced computed tomogram (CT) of the brain also demonstrated cerebral edema, and high density and enlargement of the superior sagittal sinus with sparing of the anterior portion (Figure 2). A diagnosis of acute sagittal sinus thrombosis was made. A subsequent color Doppler sonogram also demonstrated absence of flow in the superior sagittal sinus, except in the anterior portion. The sagittal sinus with color flow signal in adjacent cortical arteries is shown (Figure 3).
Intravenous fluids with 140-mmol/L sodium were given during a 72-hour period to correct dehydration. He was treated with ventilatory support and intravenous antibiotics for 2 days. One day after admission, the urinary sodium level was 50 mmol/L and urinary osmolality was 723 mmol/kg. His mother expressed very small volumes of breast milk, with a sodium content of 16 mmol/L. The plasma sodium approached more normal levels during the next 4 days, as progressively more hypotonic fluids and enteral feedings were given.
Hilliard TN, Marsh MJ, Malcolm P, Murdoch IA, Wood BP. Radiological Case of the Month. Arch Pediatr Adolesc Med. 1998;152(11):1147-1148. doi:10.1001/archpedi.152.11.1147