Poliosis (also called poliosis circumscripta), is the decrease or absence of melanin (or colour) in head hair, eyebrows, eyelashes or any other hairy area. It is popularly known as white forelock when it affects hair directly above the forehead. This condition can cause single or, less commonly, multiple white patches on the hair. Some mistake these white patches for simple birth marks. In poliosis there is decreased or absent melanin in the hair bulbs of affected hair follicles; the melanocytes of the skin are usually not affected. Associated medical conditions
Poliosis occurs in several genetic syndromes such as piebaldism, Waardenburg syndrome, neurofibromatosis type I, and tuberous sclerosis. It can also occur in conditions such as vitiligo, Vogt–Koyanagi–Harada disease, alopecia areata, sarcoidosis, and in association with neoplasms and some medications. Popular culture
It is sometimes called a Mallen streak, after a fictional family with hereditary poliosis. The Mallen family featured in a sequence of novels by Catherine Cookson, of which The Mallen Streak was the first. She later adapted them into a TV series called The Mallens.Sports presenter Dickie Davies, runner Sam Brown, punk singer Dave Vanian, and fashion expert Stacy London are also known for their Mallen streaks.During his tenure as the host of Talk Soup, host John Henson repeatedly referred to his own poliosis as a "skunk spot".In DC Comics one of Batmans Robins, Jason Todd, is sometimes portrayed with a white forelock.In Marvel Comics, the X-Men member Rogue has a prominent Mallen streak which is a consistent visual trademark of the character.
Mechanism/Pathophysiology
Megaduodenum can be passed down through families, it occurs when a patient inherits one copy of a muted megaduodenum gene from one parent. When the gene gets interrupted in the cells, it causes tumors. Acute pancreatitis, adhesions, aneurysm all clinically lead to Megaduodenum. Diagnosis
Diagnostic tests and procedures can vary for different types of intestinal disorders. These can include colonoscopy, upper GI endoscopy, capsule endoscopy, endoscopic ultrasound. Since patients with megaduodenum often have atypical symptoms such as hematemesis, steatorrhea, and acute pancreatitis. Therefore, physical and histological examination helps demonstrate the grade of distention and the nutritional status of the patient. Many of the physical examinations include: blood pressure, bowel sounds, blood tests, and thyroid function. In addition, a histological examination such as upper endoscopy, an X-ray of the abdomen, and biopsies can also be performed to diagnose megaduodenum efficiently. Prevention/Treatment
The treatment mainly depends on the underlying conditions and the degree of distention of the duodenum. It can be symptomatic and based on diet and control of bacterial overgrowth. To relieve the obstructive symptoms, latero-lateral duodenojejunostomy, gastrojejunostomy, duodenal-jejunal bypass (DJB), enteral and parenteral nutrition may be helpful. Therefore, early diagnosis and treatment may improve patients outcome and reduce morbidity. Prognosis
As long as Megaduodenum is treated promptly, the chances of making full recovery is possible. Posturing maneuvers during meals may be helpful in some patients, also to relive any compression of the duodenum the patient may lie down in right decubitus position. If the conservative treatments fail, surgery may be performed.