Study Highlights Benefits of Brain Biopsy In Patients With Atypical Dementia

Thomas S. May MA

BOSTON—The potential benefits of brain biopsy likely outweigh its risks in patients with atypical dementia who received an unclear diagnosis after being thoroughly evaluated by less-invasive means, researchers said at the 2007 annual meeting of the American Academy of Neurology.

Brain biopsy has a 25% to 33% chance of revealing a diagnosis in cases of an unexplained encephalopathic illness, according to Joseph D. Burns, MD, a clinical instructor of neurology at Tufts-New England Medical Center and chief neurology resident, Tufts University School of Medicine, Boston. “Although these might not sound like very good odds, when one considers how sick these patients are and how many prior tests were not helpful for them, these numbers are actually quite good,” he said. “And the benefits [of brain biopsy] all come with a relatively low risk to the patient.”

To determine the value of brain biopsies in patients with atypical dementia and indeterminate brain imaging, Dr. Burns and colleagues reviewed the charts of 42 consecutive patients who underwent nonstereotactic brain biopsy for evaluation of atypical dementia at the Lahey Clinic in Burlington, Mass. All patients had indeterminate or normal imaging results, and most (79%) had been symptomatic for less than one year.

Upon reviewing the results, the researchers found that 15 biopsies were normal, another 15 were nonspecifically abnormal and 12 led to a specific diagnosis. There were no deaths or major complications, and there were only three minor complications (two cases of excessive bleeding and one case of delirium), with no lasting effects in any of these three patients.

Of the 12 diagnostic biopsies, eight showed changes consistent with Creutzfeld-Jacob disease (CJD), three with Alzheimer’s disease and one with vasculitis.

Treatment was significantly altered in five patients (the patient with vasculitis was started on high-dose steroids and cyclophosphamide; steroids and antibiotics, administered for preoperative diagnoses of vasculitis and bacterial meningitis, respectively, were stopped in two patients who were diagnosed with CJD by biopsy; and two patients with preoperative diagnoses of vasculitis but nondiagnostic biopsies had their high-dose steroid treatment discontinued).

Overall, 11 different patients received meaningful benefit from the biopsy, some of them through improved accuracy of prognosis, the investigators reported.

According to Dr. Burns, these results imply that a brain biopsy should be strongly considered in patients who could not be accurately diagnosed despite having been thoroughly evaluated by less-invasive means.

“A biopsy may be needed in order to find an etiologic diagnosis,” he said, “as this will allow for a more accurate prognosis, avoidance of potentially toxic therapies for erroneous provisional diagnoses, and in the best case scenario, it will allow for the implementation of a specific treatment.”