Cerebrospinal fluid (CSF) shunt related intracranial hypotension: Ultrasound dynamic test of the optic nerve sheath diameter (ONSD), a new technique for diagnostic support

Introduction: CSF overdrainage is a known complication of hydrocephalus diversion procedures while its physiopathology, diagnosis and therapeutic concepts are still topic of discussion. In this setting, intracranial hypotension is well documented. ONSD ultrasound is an emerging procedure validated for intracranial hypertension. Recently, its diagnostic utility has been proposed for patients with spontaneous intracranial hypotension syndrome. Method and Material: We present three cases of CSF shunt associated headache where intracranial hypotension is suspected. Ultrasound dynamic test of the optic nerve sheath diameter, a novel, non invasive, technique is presented as a complementary method for diagnosis and patient follow-up. In all cases CSF shunt valves were replaced, thus achieving complete resolution of symptoms and dynamic ultrasound test normalization. Conclusion: While its a limited case series, we believe that the ultrasound dynamic test of the ONSD can be a useful technique for diagnosis and patient follow-up for CSF shunt related headache in which overdrainage is suspected. This case series seems to be the first report that evaluates the utility of the dynamic ultrasound test of the ONSD for non­invasive evaluation of CSF shunt related headache, leaving an interesting field of research in this complex clinical setting.