A baby with bulging anterior fontanelle

Abstract

A 7-month-old Saudi girl was admitted in March, 1999, for evaluation of a bulging anterior fontanelle, noticed by her mother 1 week earlier. There was no history of fever or vomiting. She was born at term by normal vaginal delivery following a normal pregnancy. Birth weight was not known. She had been exclusively breast fed since birth. On examination her weight was 5·75 kg, length 59 cm, and head circumference 41·5 cm (all just below 3rd percentile). The anterior fontanelle was wide open, measuring 6 6 cm, and persistently bulging even at rest, although not tense or pulsating. There was mild frontal and parietal bossing, but there was no swelling of wrists or ankles, no bowing of legs, no rachitic rosary, and no Harrison sulcus. She had mild generalised hypotonia but the rest of the examination was normal. On investigation her haemoglobin was 105 g/L, white cell count 13·2 10/L with normal differential, serum calcium 2·39 mmol/L (normal 2·2–2·7 mmol/L), phosphate 0·74 mmol/L (0·87–1·45 mmol/L), and alkaline phosphatase 3970 U/L (98–279 U/L). Urea, creatinine, and other electrolytes were normal. Chest radiograph showed normal heart and lungs but anterior ends of the ribs and upper end of humerus showed evidence of early rickets in the form of mild widening, cupping and fraying (figure). Similar changes were found on the lower ends of radius and ulna on wrist radiograph. Skull radiograph showed thin cortex with slight beaten silver appearance. Computed tomogram scan of brain showed mild dilatation of the anterior horn of lateral ventricles which was within normal limits. Nutritional rickets was diagnosed and she was discharged on vitamin D3, 3000 IU daily for 4 weeks, and her mother was advised to start a weaning diet. 4 months after discharge her weight was 6·6 kg, length 66 cm, and head circumference 43·5 cm which were still below the 3rd percentile but progressing on the same line. Her anterior fontanelle measured 4 4 cm with no bulging. Systemic CASE REPORT