4. Healing & Repair Flashcards
Ehlers danlos syndrome
an inherited connective tissue disorder with different presentations that have been classified into several primary types.
caused by a defect in the structure, production, or processing of collagen or proteins that interact with collagen, such as mutations in the COL5A or COL3A genes. (This is the collagen of granulation tissue, and is produced quickly by young fibroblasts before the tougher type I collagen is synthesized, Commonly associated with keloid formation, Reticular fiber, Also found in artery walls, skin, intestines and the uterus.–COL3A1.)
The collagen in connective tissue helps tissues resist deformation. Collagen is an important contributor to the physical strength of skin, joints, muscles, ligaments, blood vessels and visceral organs; abnormal collagen renders these structures more elastic. In some cases, the severity of the mutation can be life-threatening.
Osteogenesis imperfecta
A congenital bone disorder characterized by brittle bones that are prone to fracture.
defective connective tissue, or without the ability to make it, usually because of a deficiency of type I collagen.
Eight types of OI can be distinguished. Most cases are caused by mutations in the COL1A1 and COL1A2 genes.
Alport syndrome
hereditary nephritis
a genetic disorder characterized by glomerulonephritis, end-stage kidney disease, and hearing loss.
can also affect the eyes, causing eye abnormalities including cataracts, lenticonus, kerataconus, as well as retinal flecks in the macula and mid-periphery.
Visibly bloody urine and protein in the urine are common features of this condition.
Liver cirrhosis
A result of advanced liver disease.
It is characterized by replacement of liver tissue by fibrosis (scar tissue) and regenerative nodules (lumps that occur due to attempted repair of damaged tissue).These changes lead to loss of liver function.
most commonly caused by alcoholism, hepatitis B and hepatitis C, and fatty liver disease, but has many other possible causes. Some cases are idiopathic (of unknown cause).
Ascites (fluid retention in the abdominal cavity) is the most common complication of cirrhosis. It is associated with a poor quality of life, increased risk of infection, and a poor long-term outcome. Other potentially life-threatening complications are hepatic encephalopathy (confusion and coma) and bleeding from dilated esophageal veins. Cirrhosis is irreversible, and treatment usually focuses on preventing progression and complications. In advanced stages of cirrhosis the only option is a liver transplant.
Coal worker’s pneumoconiosis
caused by long exposure to coal dust.
It is a common in coal miners and others who work with coal. It is similar to both silicosis from inhaling silica dust, and to the long-term effects of tobacco smoking.
Inhaled coal dust progressively builds up in the lungs and is unable to be removed by the body; this leads to inflammation, fibrosis, and in worse cases, necrosis.
Coal workers’ pneumoconiosis, severe state, develops after the initial, milder form of the disease known as anthracosis (anthrac — coal, carbon). This is often asymptomatic and is found to at least some extent in all urban dwellers due to air pollution. Prolonged exposure to large amounts of coal dust can result in more serious forms of the disease, simple coal workers’ pneumoconiosis and complicated coal workers’ pneumoconiosis.
Keloid scar
formation of a type of scar which, depending on its maturity, is composed mainly of either type III (early) or type I (late) collagen.
It is a result of an overgrowth of granulation tissue (collagen type 3) at the site of a healed skin injury which is then slowly replaced by collagen type 1.
Keloids are firm, rubbery lesions or shiny, fibrous nodules, and can vary from pink to the colour of the patient’s flesh or red to dark brown in colour.
seen 15 times more frequently in highly pigmented ethnic groups than in Caucasians.
Keloids should not be confused with hypertrophic scars, which are raised scars that do not grow beyond the boundaries of the original wound.
Oesophageal strictures
Narrowing/tightening of oesophagus, causing dysphagia
It can be caused by or associated with gastroesophageal reflux disease, esophagitis, a dysfunctional lower esophageal sphincter, disordered motility, lye ingestion, or a hiatal hernia. Strictures can form after esophageal surgery and other treatments such as laser therapy or photodynamic therapy.
While the area heals, a scar forms, causing the tissue to pull and tighten, leading to difficulty in swallowing.
Contractures
permanent shortening of a muscle or joint.
It is usually in response to prolonged hypertonic spasticity in a concentrated muscle area, such as is seen in the tightest muscles of people with conditions like spastic cerebral palsy.
Contractures are essentially muscles or tendons that have remained too tight for too long, thus becoming shorter. Once they occur, it is often argued that they cannot be stretched or exercised away (they must be released with orthopedic surgery). Most of the physical therapy, occupational therapy, and other exercise regimens targeted towards people with spasticity focuses on trying to prevent contractures from happening in the first place.
Contractures can also be due to ischemia, as in Volkmann’s contracture.
Excessive matrix metalloproteinase and myofibroblast accumulation in the wound margins can result in contracture.
Marfan’s syndrome
a genetic disorder of connective tissue.
The most serious manifestations involve defects of the heart valves and aorta, which may lead to early death if not properly managed. The syndrome also may affect the lungs, eyes, dural sac surrounding the spinal cord, the skeleton, and the hard palate.
People with Marfan syndrome tend to be unusually tall, with long limbs and long, thin fingers and toes.
The syndrome is caused by the misfolding of fibrillin-1, a glycoprotein which forms elastic fibers in connective tissue and contributes to cell signaling activity by binding to and sequestering transforming growth factor beta (TGF-β).The mutated fibrillin binds poorly to TGF-β, which results in an accumulation of excess TGF-β in the lungs, heart valves, and aorta. This in turn causes abnormal structure and function of vascular smooth muscle and reduced integrity of the extracellular matrix, which weaken the tissues and cause the features of Marfan syndrome.
Scurvy
Scurvy is a disease resulting from a deficiency of vitamin C, which is required for the synthesis of collagen in humans. The chemical name for vitamin C, ascorbic acid
Scurvy often presents itself initially as symptoms of malaise and lethargy, followed by formation of spots on the skin, spongy gums, and bleeding from the mucous membranes. As scurvy advances, there can be open, suppurating wounds, loss of teeth, jaundice, fever, neuropathy and finally death from hemorrhage when blood vessels become too weak.
Ascorbic acid is needed for a variety of biosynthetic pathways, by accelerating hydroxylation and amidation reactions. In the synthesis of collagen, ascorbic acid is required as a cofactor for prolyl hydroxylase and lysyl hydroxylase. These two enzymes are responsible for the hydroxylation of the proline and lysine amino acids in collagen. Hydroxyproline and hydroxylysine are important for stabilizing collagen by cross-linking the propeptides in collagen. Defective collagen fibrillogenesis impairs wound healing. Collagen is an important part of bone, so bone formation is affected. Defective connective tissue leads to fragile capillaries, resulting in abnormal bleeding.
