Upper airway resistance syndrome is a sleep disorder characterized by the narrowing of the airway that can cause disruptions to sleep. The symptoms include unrefreshing sleep, fatigue, sleepiness, chronic insomnia, and difficulty concentrating. UARS can be diagnosed by polysomnograms capable of detecting Respiratory Effort-related Arousals. It can be treated with lifestyle changes, orthodontics, surgery, or CPAP therapy. UARS is considered a variant of sleep apnea, although some scientists and doctors believe it to be a distinct disorder. History
Upper airway resistance syndrome was first recognized at Stanford University in the late 1980s and the article that described it by name along with its relationship to OSA was published in 1992 by Dr. Christian Guilleminault et al. Signs and symptoms
Symptoms of UARS are similar to those of obstructive sleep apnea, but not inherently overlapping. Fatigue, insomnia, daytime sleepiness, unrefreshing sleep, anxiety, and frequent awakenings during sleep are the most common symptoms. Oxygen desaturation is minimal or absent in UARS, with most having a minimum oxygen saturation >92%.Many patients experience chronic insomnia that creates both a difficulty falling asleep and staying asleep. As a result, patients typically experience frequent sleep disruptions. Most patients with UARS snore, but not all.Some patients experience hypotension, which may cause lightheadedness, and patients with UARS are also more likely to experience headaches and irritable bowel syndrome.Predisposing factors include a high and narrow hard palate, an abnormally small intermolar distance, an abnormal overjet greater than or equal to 3 millimeters, and a thin soft palatal mucosa with a short uvula.
Potassium-aggravated myotonia is a rare genetic disorder that affects skeletal muscle. Beginning in childhood or adolescence, people with this condition experience bouts of sustained muscle tensing (myotonia) that prevent muscles from relaxing normally. Myotonia causes muscle stiffness, often painful, that worsens after exercise and may be aggravated by eating potassium-rich foods such as bananas and potatoes. Stiffness occurs in skeletal muscles throughout the body. Potassium-aggravated myotonia ranges in severity from mild episodes of muscle stiffness to severe, disabling disease with frequent attacks. Potassium-aggravated myotonia may, in some cases, also cause paradoxical myotonia, in which myotonia becomes more severe at the time of movement instead of after movement has ceased. Unlike some other forms of myotonia, potassium-aggravated myotonia is not associated with episodes of muscle weakness.Mutations in the SCN4A gene cause potassium-aggravated myotonia. The SCN4A gene provides instructions for making a protein that is critical for the normal function of skeletal muscle cells. For the body to move normally, skeletal muscles contract and relax in a coordinated way. Muscle contractions are triggered by the flow of positively charged ions, including sodium, into skeletal muscle cells. The SCN4A protein forms channels that control the flow of sodium ions into these cells. Mutations in the SCN4A gene alter the usual structure and function of sodium channels. The altered channels cannot properly regulate ion flow, increasing the movement of sodium ions into skeletal muscle cells.