Irregular sleep–wake rhythm (ISWD) is a rare form of circadian rhythm sleep disorder. It is characterized by numerous naps throughout the 24-hour period, no main nighttime sleep episode, and irregularity from day to day. Affected individuals have no pattern of when they are awake or asleep, may have poor quality sleep, and often may be very sleepy while they are awake. The total time asleep per 24 hours is normal for the persons age. The disorder is serious—an invisible disability. It can create social, familial, and work problems, making it hard for a person to maintain relationships and responsibilities, and may make a person home-bound and isolated. Causes
ISWD has various causes, including neurological disorders such as dementia (particularly Alzheimers Disease), brain damage, or intellectual disabilities. It is thought that those affected have a weak circadian clock. The risk for the disorder increases with age, but only due to increased prevalence of co-morbid medical disorders. Diagnosis
A sleep diary should be kept to aid in diagnosis and for chronicling the sleep schedule during treatment.
Multiple tumors (no viscera involvement)
Multiple tumors (no viscera involvement) typically occur as dozens to hundreds of mostly small tumors located in various areas such as the skin, muscles, and frontal eye socket, These tumors do not involve visceral organs, often take a benign course, and may regress spontaneously. Multiple tumors (with viscera involvement)
Multiple tumors (with viscera involvement) typically occur as dozens to hundreds of tumors located in the same sites as multiple tumors (no viscera involvement) but also occur in one or more visceral organs such as those in the gastrointestinal tract and upper respiratory tract and/or the heart, liver, cerebellum, rectum, parietal cortex of brain, and lung. This form of IMF, particularly in cases with tumors involving the gastrointestinal tract, heart, and/or lung, has a far higher morbidity and mortality than the other forms with death occurring in infants during the first weeks to 4 months of life in 30–70% of cases Death is typically due to a tumors compression of vital organs or tissues (e.g. blood vessels). However, there are uncommon cases of multiple tumors (with viscera involvement) that were not associated with serious symptoms, were observed without treatment, and over time showed spontaneous regressions of all or almost all of their tumors. Pathology
Microscopic histopathologic analyses of IMF tumor tissues commonly show repeated patterns of a central zone consisting of spindle-shaped cells lining capillaries and round-to-oval cells arranged around prominent "antler-shaped" vascular spaces all of which are surrounded by a peripheral zone of clustered smooth muscle-like cells.