How is hydrocephalus diagnosed in Haemophilus influenzae type b (Hib) meningitis?

Updated: Jul 09, 2018
  • Author: Prateek Lohia, MD, MHA; Chief Editor: Niranjan N Singh, MBBS, MD, DM, FAHS, FAANEM  more...
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Answer

Hydrocephalus, either communicating or obstructive, may occur in Hib meningitis. Such a process should be suspected if the patient has progressive or prolonged altered consciousness despite appropriate antibiotic treatment. Communicating hydrocephalus probably develops because the inflammatory exudate across the vertices impairs the resorptive function of arachnoid granulations. Noncommunicating hydrocephalus usually develops because of exudative blockage of the foramina of Magendie and Luschka.

In distinction to the changes of edema, communicating hydrocephalus enlarges the entire ventricular system, including the fourth ventricle and, in some instances, the extra-axial spaces. Transependymal movement of CSF may result in periventricular lucency of the frontal ventricular horns.

In obstructive hydrocephalus, these periventricular lucencies are even more pronounced and the ventricular enlargement is limited to the lateral and third ventricles without enlargement of the fourth ventricle or extra-axial spaces. Obviously, the periventricular changes are even more evident on MRI than on CT scanning and consist of bright signal on T2 weighting.


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