The excess chloride within sweat ducts prevents sodium resorption by epithelial sodium channels and the combination of sodium and chloride creates the salt, which is lost in high amounts in the sweat of individuals with CF. This lost salt forms the basis for the sweat test.Most of the damage in CF is due to blockage of the narrow passages of affected organs with thickened secretions. These blockages lead to remodeling and infection in the lung, damage by accumulated digestive enzymes in the pancreas, blockage of the intestines by thick feces, etc. Several theories have been posited on how the defects in the protein and cellular function cause the clinical effects. The most current theory suggests that defective ion transport leads to dehydration in the airway epithelia, thickening mucus. In airway epithelial cells, the cilia exist in between the cells apical surface and mucus in a layer known as airway surface liquid (ASL). The flow of ions from the cell and into this layer is determined by ion channels such as CFTR. CFTR not only allows chloride ions to be drawn from the cell and into the ASL, but it also regulates another channel called ENac, which allows sodium ions to leave the ASL and enter the respiratory epithelium. CFTR normally inhibits this channel, but if the CFTR is defective, then sodium flows freely from the ASL and into the cell.As water follows sodium, the depth of ASL will be depleted and the cilia will be left in the mucous layer.
Trichotillomania (TTM), also known as hair-pulling disorder or compulsive hair pulling, is a mental disorder characterized by a long-term urge that results in the pulling out of ones own hair. A brief positive feeling may occur as hair is removed. Efforts to stop pulling hair typically fail. Hair removal may occur anywhere; however, the head and around the eyes are most common. The hair pulling is to such a degree that it results in distress and hair loss can be seen.The disorder may run in families. It occurs more commonly in those with obsessive compulsive disorder. Episodes of pulling may be triggered by anxiety. People usually acknowledge that they pull their hair, and broken hairs may be seen on examination. Other conditions that may present similarly include body dysmorphic disorder; however, in that condition people remove hair to try to improve what they see as a problem in how they look.Treatment is typically with cognitive behavioral therapy. The medication clomipramine may also be helpful, as will keeping fingernails clipped. Trichotillomania is estimated to affect one to four percent of people. Trichotillomania most commonly begins in childhood or adolescence. Women are affected about 10 times more often than men. The name was created by François Henri Hallopeau in 1889, from the Greek θριξ/τριχ; thrix (meaning hair), along with τίλλειν; tíllein (meaning to pull), and μανία; mania (meaning madness). Signs and symptoms
Trichotillomania is usually confined to one or two sites, but can involve multiple sites.