Periodic limb movement of sleep (PLMS) is the most common related condition of restless leg syndrome (RLS). PLMS does not lead to restless leg syndrome; however, most people who already have RLS will develop PLMS. PLMS causes involuntary leg twitching or jerky movements that can last all night occurring at intervals of 15 to 40 seconds, significantly disrupting sleep.
Some related conditions of RLS trigger symptoms and are suspected of causing the disorder, although clinical evidence is still uncertain. Among these are pregnancy, particularly during the last trimester, peripheral neuropathy. an Iron deficiency, kidney failure and diabetes.
Other related conditions of restless leg syndrome include those that produce similar symptoms. RLS usually affects people with Parkinson’s disease; however, a diagnosis of RLS is not an indicator of other neurological disorders. Conditions such as arthritis, muscle cramps, stress and the effects of aging also produce symptoms similar to RLS but are not associated with the disorder. Insomnia and sleep deprivation appear to trigger symptoms but it is not clear if they are directly related conditions of RLS.