Restless Leg Syndrome

Below is a collumn about restless leg syndrome that I wrote for the newsletter of the Mississippi Psychiatric Association newsletter:
It’s summer and time for vacation! Although the time spent at the vacation destination is usually pleasant, long car and airplane trips can be tedious. For those with restless leg syndrome, these trips can be pure misery.
Restless leg syndrome (RLS) is characterized by an urge to move the legs, usually accompanied by disagreeable/uncomfortable leg sensations. These sensations, often described as "creeping" or "crawling," are typically perceived in the calves, but can also involve other parts of the lower extremities, and in more severe cases, can involve the upper extremities. RLS is worse in the evening/night and in sedentary situations such as long car rides. The symptoms often interfere with sleep. Vigorous movement improves RLS symptoms. Response to a dopaminergic drug is considered to be supportive of the diagnosis.
Approximately 10% of the population has at least mild, intermittent symptoms of RLS; about 3% of the population has moderate to severe symptoms.
RLS can be idiopathic, familial (often inherited in an autosomal dominant pattern), or secondary. Common secondary causes of RLS include iron deficiency, pregnancy, uremia, and neuropathy. RLS has also been reported to occur in association with folate, B12, and magnesium deficiencies. Many psychiatric medications, including dopamine antagonists, serotonergic antidepressants, and lithium, can unmask or worsen RLS. Wellbutrin, however, does not worsen RLS. Wellbutrin, due to its dopaminergic properties, has been speculated to improve RLS, but data is lacking.
RLS is diagnosed based on history; polysomnography is not necessary or indicated for diagnosis, though in most cases periodic leg movements occur during sleep. The differential diagnosis includes nocturnal leg cramps, neuropathy, akathisia, and vascular disease. The most important lab test to check in someone with restless leg syndrome is a ferritin level. Iron supplementation should be administered to keep the ferritin level above 50.
RLS is commonly treated with dopaminergic agents. Requip (ropinirole) is the first and only FDA-approved medication for the treatment of moderate-to-severe primary RLS. Mirapex (pramipexole) is also commonly used. Ergot-derived medications, such as pergolide, should be avoided due to the risk of cardiac valvuopathy. Sinemet can be used for short-term treatment or to confirm the diagnosis, but has a higher risk of augmentation than the other dopaminergic medications. Augmentation is the shifting of symptoms to several hours earlier than was typical before pharmacologic intervention. Other medications used to treat RLS include benzodiazepines, opioids, and gabapentin.
RLS is a common, unpleasant condition that can be unmasked or worsened by many psychiatric medications. Its prevalence in the psychiatric population is probably higher than in the general population. In cases in which the diagnosis is uncertain or in which the psychiatrist feels uncomfortable treating RLS, referral to a sleep specialist or a neurologist is indicated.