Treatment of normal pressure hydrocephalus resolves dorsal midbrain syndrome

Abstract

Dear Editors, We present a unique case of a patient presenting with the signs and symptoms of normal pressure hydrocephalus (NPH) and dorsal midbrain syndrome (DMS), and in whom treatment of former led to the improvement of both. DMS has often been described in the presence of increased intracranial pressure and hydrocephalus; however, according to our knowledge, this is the first report that describes a relationship between NPH and DMS. A patient in his seventies was admitted to the hospital under the medicine service for pneumonia, sepsis, and falls. The CT scan of the head showed dilated ventricles out of proportion to sulcal size, concerning for NPH (Fig. 1). Neurology was consulted for confusion, falls, and abnormal CT scan of the head. The patient had been started on memantine by a primary care physician for almost a year. A formal inpatient mental status test was not performed as the patient’s confusion may have been exaggerated by sepsis, and the records from PCP were unavailable. He had slowly developed gait dysfunction over the past months and felt as if his feet were stuck to the floor. The patient had also developed incontinence recently. On examination, the patient had cognitive slowing and difficulty with short-term recall, although recent and remote memory appeared to be intact. During physical examination, the patient also had upgaze paresis and was unable to perform accommodation. He walked stooped forward, legs shoulder width apart, took small steps with occasional festination, and at times, initiation of movement was slowed. MRI of the head was completed to rule out other compressive lesions which could lead to both obstructive hydrocephalus and DMS. MRI did not reveal obstructive hydrocephalus. Interestingly, there was compression of the midbrain by the dilated third ventricle (Fig. 2). The diagnosis of NPH and DMS was deduced based on history, physical examination, and the imaging. The patient had a lumbar puncture (LP) performed revealing only a mild increase in opening pressure, 23 mmHg. Patient showed improvement in gait speed following 40 mL CSF drain. Later, patient received a trial of lumbar drain which showed improvement in dynamic gait index from 2 to 9 in a single day, and the decision for ventriculoperitoneal shunt (VPS) placement was made. Subsequent evaluations following the VPS placement showed patient did not have vertical gaze palsy. It is reasonable to presume that the patient’s vertical gaze palsy and thus his DMS improved, if not resolved, with shunting. DMS is also known as Parinaud syndrome, Sylvian aqueduct syndrome, pretectal syndrome, and Koerber-Salus-