The trusted source for
healthcare information and
Prediabetes and Bell's Palsy
Abstract & Commentary
By Joseph E. Safdieh, MD, Assistant Professor of Neurology, Weill Medical College, Cornell University. Dr. Safdieh reports no financial interest in this field of study.
Synopsis: When compared with controls, patients with Bell's palsy were found to have a higher incidence of impaired glucose tolerance.
Source: Bosco D, et al. Bell's Palsy: A manifestation of prediabetes? Acta Neurol Scand 2010;June 9 [epub ahead of print].
Bell's palsy is the most common cause of peripheral facial weakness. Other causes include trauma, Lyme disease, Ramsay-Hunt syndrome, neoplasms, sarcoidosis and vasculitis. Bell's palsy has been described in all age groups, with peak incidence noted in the fifth decade of life. It occurs more commonly in diabetic patients and pregnant women. Prediabetes is defined as impaired fasting glucose or impaired glucose tolerance following a two-hour oral glucose tolerance test (OGTT). Recently, studies have demonstrated that impaired glucose tolerance is associated with peripheral neuropathy, and may be a cause in a significant percentage of patients with idiopathic peripheral neuropathy. The authors designed a prospective study to evaluate the incidence of prediabetes in patients with Bell's palsy and a control group.
Patients were included in the study if they presented with Bell's palsy. Exclusion criteria included positive family history of facial palsy, concomitant peripheral neuropathy, alcoholism, premorbid use of steroids, pregnancy, sarcoidosis, Lyme disease, autoimmune diseases, abnormal organ function, and multiple sclerosis. All patients underwent MRI, MRA, electromyography and nerve conduction studies, and chest x-ray. Blood testing was performed for ACE level, HIV, B12 deficiency, and Lyme disease. The authors reported that all of the above tests were normal in every subject. Testing for "prediabetes" included BMI, hemoglobin A1C, and glucose and insulin levels while fasting and two hours after a glucose load. Impaired glucose tolerance was defined as two-hour post-prandial glucose level between 140 and 200 mg/dL. Diabetes was defined as fasting glucose > 126 mg/dL or two-hour glucose level > 200 mg/dL. Of note, this testing was all done before any steroid administration to treat the Bell's palsy.
The study enrolled 148 patients with Bell's palsy (mean age 56.1 years) and 128 controls (mean age 50.5 years). The mean fasting glucose was not significantly different between the two groups. However, a statistically significant difference was detected between the two groups in the results of the two-hour OGTT. In the control group, 24% demonstrated impaired glucose tolerance or diabetes (23 IGT, 8 DM). In the Bell's palsy group, 61% of patients demonstrated impaired glucose tolerance or diabetes (60 IGT, 31 DM). After adjustment for age, the differences between the groups was significant, with P < 0.001. Of note, waist circumference, hemoglobin A1C, mean blood pressures, lipids, and triglyceride levels were not different between the groups. The authors conclude that impaired glucose tolerance is frequently associated with Bell's palsy.
Most physicians in clinical practice are quite familiar with the various neurological manifestations of diabetes. Diabetes is the most common cause of peripheral neuropathy, and recent studies have shown that insulin resistance and impaired glucose tolerance contribute to the development of peripheral neuropathy. It is therefore logical to conclude that Bell's palsy, which is a mononeuropathy, would be associated with prediabetes. This study did demonstrate an alarmingly high rate of impaired glucose tolerance and frank diabetes in patients with Bell's palsy. Of note, the hemoglobin A1C and fasting glucose tests were not different between the groups. Based on the conclusions of this study, it is reasonable to consider a 2-hour OGTT in the evaluation of patients with Bell's palsy, but the results of this study should be replicated before OGTT in patients with Bell's palsy is recommended as part of routine clinical practice.