The brain is relatively poorly supplied by oxygen as a result of mild hypoventilation during the sleeping hours, and cerebral edema may worsen during the night due to the lying position. The headache is worse on coughing, sneezing, or bending and progressively worsens over time. There may also be personality or behavioral changes.In addition to the above, if mass effect is present with resulting displacement of brain tissue, additional signs may include pupillary dilatation, abducens palsies, and Cushings triad. Cushings triad involves an increased systolic blood pressure, a widened pulse pressure, bradycardia, and an abnormal respiratory pattern. In children, a low heart rate is especially suggestive of high ICP.Irregular respirations occur when injury to parts of the brain interfere with the respiratory drive. Biots respiration, in which breathing is rapid for a period and then absent for a period, occurs because of injury to the cerebral hemispheres or diencephalon. Hyperventilation can occur when the brain stem or tegmentum is damaged.As a rule, patients with normal blood pressure retain normal alertness with ICP of 25–40 mmHg (unless tissue shifts at the same time). Only when ICP exceeds 40–50 mmHg does CPP and cerebral perfusion decrease to a level that results in loss of consciousness. Any further elevations will lead to brain infarction and brain death.In infants and small children, the effects of ICP differ because their cranial sutures have not closed. In infants, the fontanels, or soft spots on the head where the skull bones have not yet fused, bulge when ICP gets too high.
Tasimelteon, sold under the brand name Hetlioz, is a medication approved by the U.S. Food and Drug Administration (FDA) in January 2014, for the treatment of non-24-hour sleep–wake disorder (also called non-24, N24 and N24HSWD). In June 2014, the European Medicines Agency (EMA) accepted an EU filing application for tasimelteon and in July 2015, the drug was approved in the European Union for the treatment of non-24-hour sleep-wake rhythm disorder in totally blind adults, but not in the rarer case of non-24 in sighted people. The most common side effects include headache, somnolence, nausea (feeling sick) and dizziness. Medical uses
In the United States, tasimelteon capsules are indicated for the treatment of non-24-hour sleep–wake disorder (Non-24) in adults and for the treatment of nighttime sleep disturbances in Smith-Magenis Syndrome (SMS) in people sixteen years of age and older. Tasimelteon oral suspension is indicated for the treatment of nighttime sleep disturbances in SMS in children from 3 to 15 years of age.In the European Union, tasimelteon capsules are indicated for the treatment of non-24-hour sleep–wake disorder (Non-24) in totally blind adults.The capsule and liquid suspension forms of tasimelteon are not interchangeable.Tasimelteon is a selective agonist for the melatonin receptors MT1 and MT2, similar to other members of the melatonin receptor agonist class of which ramelteon (2005), melatonin (2007), and agomelatine (2009) were the first approved. As a treatment for N24HSWD, as with melatonin or other melatonin derivatives, the patient may experience improved sleep timing while taking the drug.