Neuro-ophthalmic features of primary diffuse leptomeningeal gliomatosis

This study published in the December issue of the Journal of Neuro-Ophthalmology reports two cases of primary diffuse leptomeningeal gliomatosis (PDLG) that presented with prominent visual symptoms, along with a review of 22 published cases. The authors describe the results of their in-depth study of the neuro-ophthalmologic signs and symptoms of this rare but fatal disease. They note that involvement of the visual system may be part of the initial presentation of PDLG.

The disease is characterized by diffuse infiltration of the meninges by neoplastic glial cells without evidence of tumor within the brain parenchyma or spinal cord. Clinical presentation encompasses a variety of neurological symptoms, including headache, cranial nerve involvement, vomiting, meningismus and decreased mental status. Cerebrospinal fluid analysis often is nonspecific, and meningeal biopsy usually is necessary to establish a diagnosis. Raised intracranial pressure is the most constant sign as a result of communicating hydrocephalus. The most striking features include rapid onset, short prodromal phase and an aggressive course.

The most frequent neuro-ophthalmic signs reported are papilledema and cranial sixth nerve palsy (a result of communicating hydrocephalus). Other abnormalities include third and fourth nerve palsies, nystagmus and vision loss (which usually occurs late in the course but can be present early). While visual symptoms are often vague at initial clinical presentation, double vision is the most common visual complaint, primarily due to sixth nerve palsy.

The authors say that diagnosis of PDLG is often challenging because the clinical picture is similar to chronic infectious meningitis or polyradiculopathy. Tuberculous meningitis is often suspected as the initial diagnosis, and patients may be started on antituberculosis therapy.

There is no cure for PDLG. However, a variety of chemotherapeutic agents have been used. The combination of temozolomide with radiotherapy has been suggested to improve the prognosis of PDLG. Nevertheless, patients treated with the most aggressive regimens have survived for less than two years.