Recovery Time from Bell’s Palsy Longer for Those with Diabetes

Newswise — Bell's palsy, a temporary paralysis of the seventh cranial nerve, affects approximately 25 of every 100,000 people in the United States. The exact cause for this disorder is unknown, although most associate the onset to a viral attack. An association with diabetes mellitus has been noted.

In Japan, the number of diabetic patients is increasing in proportion to the aging society. Researchers in a Japanese medical facility noted that approximately 20 percent of patients with Bell's palsy also suffered from diabetes mellitus. There are some complications observed in patients with diabetes, including cranial nerve disorders, disease of the blood vessels, and severe viral or bacterial infections. These complications may have influence on the patients' ability to recover facial from nerve paralysis. Moreover, recent investigations have revealed that the herpes simplex virus (HSV) infection or reactivation in geniculate ganglions has been implicated as one of the causes of Bell's palsy.

In a new study, a team of researchers from Japan analyzed prognostic differences in Bell's palsy between diabetic and nondiabetic patients in terms of their facial movement score and recovery rate. The authors of "Prognosis of Bell's Palsy: A Comparison of Diabetic Patients and Nondiabetic Patients," are Shin-Ichi Haginomori, MD, Atsuko Hasegawa MD, Miwa Yagi MD, Ryuzaburo Nonaka MD, Michitoshi Araki MD, and Hiroshi Takenaka MD, all from the Department of Otolaryngology, Osaka Medical College, Takatsuki, Japan. Their findings are being presented at the 109th Annual Meeting and OTO EXPO of the American Academy of Otolaryngology—Head and Neck Surgery Foundation, being held September 25-28, 2005, at the Los Angeles Convention Center, Los Angeles, CA.

Methodology: This study enrolled 47 patients with Bell's palsy (14 diabetic patients and 33 nondiabetic patients) divided into two groups: the diabetic group (DG) and nondiabetic group (NDG). There was no statistical difference in age between groups. All patients began receiving intravenous prednisolone injection and oral valaciclovir administration within seven days after the onset of the palsy for eight days. Some diabetic patients needed subcutaneous insulin injection during the treatment for blood glucose control. The grade of each patient's facial score was assessed using the Yanagihara grading system, which is the standard in Japan. The mean values of the Y-system points and recovery rates were analyzed four times in each group at the beginning of the treatment, and one month, three months, and six months after the onset of facial nerve paralysis. Data obtained from the DG and NDG were statistically compared using Mann-Whitney's U-test and Welch's t-test.

Results: There were no differences seen in the averaged Y-system points in between the DG and NDG at the start of the treatment and one month after onset. However, the points in the DG were lower than those in the NDG at three months and six months after onset. On the other hand, the recovery rate in the DG was lower than that in the NDG at three months after onset. However, there were no differences seen in recovery rates at one month (30 percent in DG vs. 42 percent in NDG) and six months (82 percent in DG and 94 percent in NDG) after onset.

No differences in the Y-system points were observed between the diabetic group and nondiabetic group at the start of treatment. This suggests that being diabetic does not influence the severity of facial palsy at the onset. Recovery from Bell's palsy in patients with diabetes was delayed in comparison with the nondiabetic patients. Diabetes may influence recovery from palsy through its angiopathy and low immunity.

The Y-system points in diabetic patients without complete recovery observed within six months after the onset were much lower than those in nondiabetic patients, which indicates that diabetic patients with Bell's palsy need more aggressive treatments, such as facial nerve decompression, when electrodiagnostic methods predict a poor prognosis.

Conclusion: In diabetic patients, recovery from Bell's palsy was delayed and the facial movement score remained low in comparison with nondiabetic patients. More aggressive treatments are needed in diabetic patients with severe Bell's palsy.