Restless Legs Syndrome (RLS)
Restless legs syndrome (RLS) is felt by some to be a misnomer: it is not always restricted to the legs, and it is often described as an uncomfortable feeling that provokes an irresistible urge to move the legs, rather than pure restlessness or fidgetiness seen in other conditions.
The terms that patients use to describe the symptoms of RLS include throbbing, pulling, creeping, itching, tingling, with an uncontrollable, overwhelming desire to move the limbs. RLS usually occurs in the evening or around bedtime but as the condition progresses it may also occur during the day, such as when seated on an airplane or at the theater. Sometimes these symptoms are associated with involuntary movements of the legs during sleep, known as period limb movements of sleep (PLMS).
By and large, in RLS, the exam is normal, meaning that the diagnosis is based on the clinical history. Because iron deprivation can cause restless legs, it is imperative that iron levels be checked, and iron supplementation be given if iron levels are low or on the low side of normal. Sometimes a sleep study is indicated because other sleep conditions can mimic RLS or worsen it, or cause PLMS. One of the most common sleep conditions which can worsen RLS is obstructive sleep apnea (irregular breathing during sleep because of transient blocking of the airway), which is remedied easily with a device called CPAP. Other diagnostic considerations are medications or alcohol, which can both make RLS worse. RLS can also be seen in pregnancy or with other hormonal changes.
Many patients with intermittent or mild RLS do not require specific treatment, but if the symptoms are disruptive or cause insomnia, treatment should be considered. As above, iron supplementation for low-normal or low iron levels is the primary treatment. If symptoms persist despite iron supplementation, GABA-ergic treatment is the first line. GABA is one of the brain’s inhibitory neurotransmitters, meaning it relaxes the brain activity. Activating GABA helps reduce RLS symptoms by deactivating hypersensitive nerve cells. Examples of GABA-type medications for RLS include gabapentin, pregabalin, and Horizant (gabapentin enacarbil, the long-acting version of gabapentin). These medications can be sedating but that usually helps people sleep and typically washes out before morning. Patients should exercise caution if gabapentin is taken during waking hours as it can cause sleepiness interfering with driving.
The next line medication class is dopaminergic, meaning acting on the dopamine system. Ropinirole (Requip), pramipexole (Mirapex), and Sinemet can be useful for moderate-severe RLS, but the immediate release versions of these medications can cause a syndrome called augmentation, where the symptoms begin occurring earlier in the day and spreading to other parts of the body. Many patients end up taking more and more of the immediate release medications, when in reality what they need is a controlled acting version or a GABA-type medication.