However, the associated symptoms of headaches, memory loss, and lack of concentration may be more frequent in head trauma than in idiopathic hypersomnia. "The possibility of secondary narcolepsy following head injury in previously asymptomatic individuals has also been reported." Secondary hypersomnias
Secondary hypersomnias are extremely numerous. Hypersomnia can be secondary to disorders such as clinical depression, multiple sclerosis, encephalitis, epilepsy, or obesity. Hypersomnia can also be a symptom of other sleep disorders, like sleep apnea. It may occur as an adverse effect of taking certain medications, of withdrawal from some medications, or of substance use. A genetic predisposition may also be a factor. In some cases it results from a physical problem, such as a tumor, head trauma, or dysfunction of the autonomic or central nervous system.Sleep apnea is the second most frequent cause of secondary hypersomnia, affecting up to 4% of middle-aged adults, mostly men. Upper airway resistance syndrome (UARS) is a clinical variant of sleep apnea that can also cause hypersomnia. Just as other sleep disorders (like narcolepsy) can coexist with sleep apnea, the same is true for UARS. There are many cases of UARS in which excessive daytime sleepiness persists after CPAP treatment, indicating an additional cause, or causes, of the hypersomnia and requiring further evaluation.Sleep movement disorders, such as restless legs syndrome (RLS) and periodic limb movement disorder (PLMD or PLMS) can also cause secondary hypersomnia. Although RLS does commonly cause excessive daytime sleepiness, PLMS does not. There is no evidence that PLMS plays "a role in the etiology of daytime sleepiness.
This pain resolved when the subjects were able to resume their normal sleep patterns.Chronic kidney disease is commonly associated with sleep symptoms and excessive daytime sleepiness. 80% of those on dialysis have sleep disturbances. Sleep apnea can occur 10 times as often in uremic patients than in the general population and can affect up to 30-80% of patients on dialysis, though nighttime dialysis can improve this. About 50% of dialysis patients have hypersomnia, as severe kidney disease can cause uremic encephalopathy, increased sleep-inducing cytokines, and impaired sleep efficiency. About 70% of dialysis patients are affected by insomnia, and RLS and PLMD affect 30%, though these may improve after dialysis or kidney transplant.Most forms of cancer and their therapies can cause fatigue and disturbed sleep, affecting 25-99% of patients and often lasting for years after treatment completion. "Insomnia is common and a predictor of fatigue in cancer patients, and polysomnography demonstrates reduced sleep efficiency, prolonged initial sleep latency, and increased wake time during the night." Paraneoplastic syndromes can also cause insomnia, hypersomnia, and parasomnias.Autoimmune diseases, especially lupus and rheumatoid arthritis, are often associated with hypersomnia. Morvans syndrome is an example of a rarer autoimmune illness that can also lead to hypersomnia. Celiac disease is another autoimmune disease associated with poor sleep quality (which may lead to hypersomnia), "not only at diagnosis but also during treatment with a gluten-free diet." There are also some case reports of central hypersomnia in celiac disease.