Changes in echogenicity of spinal subarachnoid space associated with intracranial hemorrhage: new observations.

PURPOSE: The role of subarachnoid blood and secondary, sterile inflammation in the pathogenesis of posthemorrhagic hydrocephalus (PHH) is not well understood. The aims of this study were to study the frequency and rate of spread of blood into the spinal subarachnoid space (SSS) and to evaluate the relationship of this finding and PHH. MATERIALS AND METHODS: Nine premature babies with major intracerebral hemorrhage (ICH, grade 3 or higher), and ten premature infants with minor ICH (grade 1) or no evidence of ICH (control group) were identified and underwent serial cranial and spinal sonography at the time of initial diagnosis, 12-24 h after the ICH and weekly thereafter for at least 9 weeks. Sagittal and axial scans of the thoracolumbar spine were obtained and evaluated for the presence of echogenic debris in the dorsal SSS. Six additional patients who had cranial and spinal sonography died within the 1st week of life and underwent post-mortem examinations. RESULTS: The SSS was echo-free (normal) in all cases at the time of initial sonographic diagnosis of ICH. Within 24 h, all babies with major ICH had developed increased echogenicity of the cervical and thoracic SSS. Echogenicity of the SSS decreased gradually over several weeks. Although transient ventricular dilatation was present in every patient, only one patient had rapidly progressive PHH requiring shunt placement. Transient cysts of the cervicothoracic subarachnoid space were identified in two patients 6-7 weeks after ICH. The subarachnoid space remained echo-free in all control infants At autopsy, all four infants with echogenic spinal debris had blood or blood products in the spinal subarachnoid space, whereas two infants with echo-free spinal images did not. CONCLUSIONS: Spread of blood from the ventricular system into the spinal subarachnoid space after ICH is common and can be seen within 24 h of initial ICH. Subarachnoid blood is associated with post-hemorrhagic ventricular dilatation and transient spinal subarachnoid cyst formation.

Echodense spinal subarachnoid space in neonates with progressive ventricular dilatation: a marker of noncommunicating hydrocephalus.

OBJECTIVE: Our purpose was to evaluate the frequency and clinical significance of echogenic debris in the spinal subarachnoid space of neonates at risk for progressive ventricular dilatation. SUBJECTS AND METHODS: Spinal sonography was performed on 15 neonates with severe intracranial hemorrhage (n = 10) or bacterial meningitis (n = 5). Spinal sonography also was performed on 16 control neonates. Images were analyzed for the presence and location of echogeric debris within the thoracolumbar subarachnoid space. Lumbar punctures were performed on all 31 neonates, and CSF was analyzed for cell count and protein content. Ten of 15 neonates required ventricular drainage procedures. RESULTS: Progressive ventricular dilatation occurred in 11 of 15 neonates with intracranial hemorrhage or meningitis. Echogenic debris was present in the thoracolumbar subarachnoid space on spinal sonography in every neonate with progressive ventricular dilatation compared with none of the 16 control neonates (p < .0001 by chi-square analysis). In addition, the 11 neonates with echogenic subarachnoid space had significantly higher protein and RBC contents in the lumbar CSF (p < .04). CONCLUSION: Echogenic subarachnoid space revealed by sonography is associated with progressive ventricular dilatation after severe intracranial hemorrhage or bacterial meningitis and is caused by high protein and RBC contents in the subarachnoid space. This finding may be helpful in identifying neonates who will not benefit from serial lumbar punctures for treatment of hydrocephalus.