[Ultrasonographic measurement of the optical nerve sheath for the diagnosis of intracranial hypertension in the emergency room : a case report].

Early diagnosis and treatment of intracranial hypertension (ICHT) are major components of the management of neurological emergencies. The optic nerve sheath diameter is closely dependent on intracranial pressure and can be measured by bedside ultrasound (US). We report the story of a 70-year-old COPD patient initially admitted to the emergency room for a sepsis of pulmonary origin. An unusual confusion prompted us to perform an US of the optic nerve sheath. This exam clearly suggested the presence of an ICHT. Hence, the diagnostic approach was proceeded and a herpetic encephalitis was demonstrated and successfully treated. In this clinical report, the optic nerve sheath US guided the diagnostic approach and, eventually, therapeutic decision. Several papers have shown the close relationship between increased optic nerve sheath diameter and intracranial hypertension, but we still need further studies to validate a threshold value of this diameter. The clinical relevance of the US optic nerve diameter measure appears interesting. However, further studies on larger samples of patients are needed to confirm this and to establish a validated threshold value.