The pattern of intracranial lesions detected by cranial sonography in infants at the Kenyatta national hospital, Nairobi

Abstract

A one year prospective study was carried out at the, Kenyatta National Hospital (KNH) to establish the pattern of intracranial lesions detectable by cranial sonography in 100 infants. Patients were recruited from the paediatric wards and clinics with varied neurological signs and symptoms. A real time, B mode scanner with 3MHZ and SMHZ sector scanning transducers was used to obtain coronal and sagital images of the infants brains. The number of female infants practically equalled their male counterparts. 77% of the infants presented for scanning at or below 6 months of age. Thus 23% of the patients were aged between 7 months and 12 months. The three commonest symptoms were convulsions, fever and enlargement of the head. The combined accounted for 88% of the presenting symptoms. A few patients had two or more presenting symptoms. Enlargement of the head especially when confirmed by measurement of the head circumference was found to be an important symptom and sign. Its presence is a strong indicator that a structural abnormality of the brain detectable by ultrasound is present. Meningitis was the commonest clinical indication for requesting ultrasound evaluation and was diagnosed in 35 infants. Out of these, 30 infants (86%) had normal sonographic findings. 3 had previously unsuspected hydrocephalus and 2 had abscesses. This confirms the limited role of cranial ultrasound in acute meningitis. Hydrocephalus was suspected clinically in 31 patients and confirmed by ultrasound in.27 of these patients, demonstrating good correlation between clinical suspicion and sonographic results. 10 unsuspected cases sent for other reasons were found to have hydrocephalus. Curiously, however, 22 female infants had hydrocephalus while only 15 male patients had sonographically demonstrated hydrocephalus. Also notable was the fact that all the abscesses and neoplasm were diagnosed in only male infants. Intracranial hemorrhage was suspected in 11 patients but only confirmed in 4 cases (36%). The other 2 infants diagnosed by sonography to have hemorrhage in fact were sent with a different indication. Other findings at sonography included, abscesses, intracranial neoplasms, hydranencephaly and encephaloceles.