How to Treat Sialorrhea in Parkinson's Disease Patients

What is your first line option for treating sialorrhea in Parkinson's disease patients and why? How big of a role does cost play?

Sialorrhea, defined as the inability to control oral secretions resulting in excessive saliva accumulation in the oropharynx, is a vexing and troubling problem, often causing a range of physical and psychosocial complications, including perioral chapping, dehydration, odor, and social embarrassment and isolation.^1,2 In patients with Parkinson's disease, restricted swallowing and dysfunction, rather than hypersecretion of saliva, are thought to be the reasons behind the disorder.¹

"Many patients respond to levodopa; other options include sublingual atropine or botulinum toxin injections," says Marian Evatt, MD. Each patient must be considered individually, with age, cognitive status and out of pocket costs all weighing in the decision, she says. "Anticholinergic use may be limited by presence of symptomatic orthostatic hypotension, urinary retention or cognitive impairment. As with all medications we use in PD, I recommend using the minimum dose required for benefit with acceptable side effects."

Having to weigh out of pocket expenses is always a difficult issue for patients, and the physician may have to approach the potentially sensitive subject. This can force neurologists to find a way to balance the cost factor with attempts to give each patient the best care possible. "I try to take a matter of fact approach. At the end of the day, life is always a tradeoff—people have to figure out what works for them," Dr. Evatt says.

Drooling is a motor disorder, "so the first option would be to refer for specific questioning and assessment to an experienced speech-language pathologist to evaluate severity, frequency and situation-based occurrence of complaints and to check for therapeutic options," says Hanneke Kalf, a speech language therapist.

There have been only a few well-designed studies conducted to determine the optimal treatment for sialorrhoea in PD, but a combination of approaches appears to be necessary to obtain successful results.¹

How prevalent is sialorrhea in Parkinson's?
AA systematic PubMed and CINAHL search by Kalf, et al.,³ including studies published until January 2009, found eight studies presenting prevalence rates of drooling based on responses of PD patients to questionnaires. They found the statistical heterogeneity was highly significant (P < 0.0001), with prevalence rates ranging anywhere from 32 to 74 percent.

The pooled prevalence estimate with random effect analysis was 56 percent (95% CI 44-67) for PD patients and 14 percent (95% CI 3-25) for healthy controls; the pooled relative risk with random effect analysis was 5.5 (95% CI 2.1-14.4). All of the studies reported data of community dwelling idiopathic PD patients, with a mean age around 65 years and mild PD in 50-60 percent of the cases. Heterogeneity was triggered mostly by differences in definition or frequency of drooling. The highest prevalence rates included nocturnal drooling, while others observed only diurnal drooling.

"Analysis of the data of two studies," the authors write, "showed that drooling is reported frequently by 22-26 percent of the patients. Prevalence rates were lower in milder PD patients. The summarized findings demonstrate that drooling can be present in half of all PD patients." In about a quarter of PD patients, drooling appears to be a frequently occurring problem.

WHAT IS THE ROLE OF BOTULINUM TOXIN?
AResearchers recently reported that botulinum toxin type-B is safe and efficacious for treating PD-related drooling, "ensuring a long-lasting waning of this disabling symptom."⁴ To determine the safety, efficacy and effectiveness of BTX-B injections into the parotid glands to reduce drooling in PD patients, study authors conducted a double-blind, randomized, placebo-controlled study of 36 advanced phase PD subjects who reported disabling drooling.

They received either 4000U BTX-B or placebo anatomically guided injections. The outcome measures were selected to allow researchers to assess both the subjective feeling of improvement (i.e., the Drooling Severity and Frequency Scale, DSFS, visuo-analogic ratings of familial distress, VAS-FD, and social distress, VAS-SD) and objective saliva reduction (researchers checked saliva production over five minutes by weighing dental rolls). The Global Impression Score was also used, ranking improvement from 0 to 3.

One month after injections, BTX-B patients "showed a meaningful improvement in almost all subjective outcomes. Two-way analysis of variance gave a significant time x treatment effect, F-value being 52.5 (p < 0.0001) for DS-FS, 23.2 (p < 0.0001) for VAS-FD, 29 (p < 0.0001) for VAS-SD, and 28.9 (p < 0.0001) for UPDRSADL drooling item score." All subjects who received BTX-B reported sialorrhea reduction of any kind (moderate for 44.4 percent cases, and dramatic for 33.3 percent subjects), at variance with 61.1 percent controls who denied any benefit from treatment. (Chi-square = 22.9; p < 0.0001). "When present, benefits lasted on average 19.2 +/- 6.3 weeks in the BTX-B group compared to 6.7 +/- 1.4 weeks in controls (T-value: 26.4; p < 0.0001)," the study found.

1. Merello M. Sialorrhoea and drooling in patients with Parkinson's disease: epidemiology and management. Drugs Aging. 2008;25(12):1007-19.
2. Hockstein, N. et al. Sialorrhea: A Management Challenge. American Family Physician, June 1 2004.
3. Kalf JG, et al. Prevalence and definition of drooling in Parkinson's disease: a systematic review. J Neurol. 2009 Mar 14.
4. Lagalla G et al. Long-lasting benefits of botulinum toxin type B in Parkinson's disease-related drooling. J Neurol. 2009 Apr;256(4):563-7.