Researchers are increasingly recognizing restless genital syndrome (RGS) as a variant of restless leg syndrome (RLS), and a new case study supports that theory.

RGS is a rare disorder that can be a source of distress and disability. In the past, it has been labeled with several different names, including "vulvar dysesthesia" and "persistent genital arousal disorder."

In a report published online October 6 in JAMA Neurology, researchers discussed a woman with Parkinson's disease (PD) and disabling genital discomfort who had a dramatic response to the dopamine agonist pramipexole (0.25 mg at night).

"Our paper describes a patient who previously might have been considered to have something totally different," study coauthor Anthony Lang, MD, director, Division of Neurology, University of Toronto, and director, Movement Disorder Center, University Health Network, Toronto Western Hospital, Ontario, Canada, told Medscape Medical News.

"Similar symptoms had been recognized in Parkinson's disease in the past, but not necessarily linked to this pathogenesis, so these patients may not have been tried on treatment that could have had the striking benefit experienced by our patient."

In describing the patient, researchers hope to raise awareness about this disabling but treatable condition and avoid misdiagnoses and inappropriate investigations.

Pelvic Discomfort

The patient was a 65-year-old woman who had been diagnosed with PD at age 60. She had experienced discomfort in her pelvis and genital region for the previous 3 years and had been to see many different subspecialists.

She described a sensation of "congestion," itching, and "growing" of pelvic organs, symptoms that were triggered by sitting or lying down. There was no restlessness in her legs.

The patient had been taking levodopa/carbidopa for about 3 years.

Repeated gynecologic evaluations were normal, and hormonal replacement with estrogen had been ineffective.

A careful review of her history revealed a temporal relationship between her symptoms and getting ready for bed. Although the symptoms weren't exclusive to the evening, Dr Lang noted, "they did have a certain circadian pattern."

It was recognition of this circadian pattern and its relationship with the more classic RLS "that sort of twigged our thinking," he said.

Looking into the literature, Dr Lang and his colleagues found that others had recognized the relationship between these genital symptoms and RLS. "So we tried treating the symptoms with a dopamine agonist and the patient responded beautifully."

Most dopamine agonists can be effective in treating RGS, said Dr Lang. Patients respond initially to levodopa; however, because it's a relatively short-acting drug, symptoms may rebound and come back through the night or early morning, he said.

Gabapentin, codeine, and opiates may also be effective in treating the symptoms, he added.

The patient in this case study didn't have typical RLS, but in the literature, most patients with RGS also have RLS, said Dr Lang.

Masked Symptoms

RLS occurs more often in patients with PD than in the general public, although because they receive dopamine replacement therapy, their symptoms may not be noticed. Dr Lang pointed out that several years ago, his research group described RLS in patients with PD who had undergone deep-brain stimulation and as a result, their dose of dopamine agonist was reduced.

"There is a literature suggesting that restless leg syndrome is more common in Parkinson's disease, and it may be more common than we appreciate because we are masking the symptoms in many patients."

The authors concluded that RGS should be considered a phenotype of RLS, as should restless bladder and restless abdomen. They emphasized that a detailed clinical history is essential for this diagnosis and that treatment with dopamine agonists can provide some benefit.

Lead author Camilla C. Aquino received a scholarship from CAPES Foundation, Brazil. Dr Lang has received grants from Brain Canada, Canadian Institutes of Health Research, Edmond J. Safra Foundation, Michael J. Fox Foundation, National Parkinson Foundation, Parkinson Society Canada, Tourette Syndrome Association, and W. Garfield Weston Foundation. He has served as an advisor for Abbvie, Allon Therapeutics, Avanir Pharmaceuticals, Biogen Idec, Boehringer-Ingelheim, Ceregene, Medtronic, Merck, Novartis, NeuroPhage Pharmaceuticals, Teva, and UCB. He also has received publishing royalties from Saunders, Wiley-Blackwell, Johns Hopkins Press, and Cambridge University Press and has served as an expert witness in cases related to the welding industry. No other disclosures were reported.

JAMA Neurol. Published online October 6, 2014. Abstract