Medi-Info.COM » Diseases

Corneal Ulcer

admin — Sat, 07 Aug 2010 09:23:21 +0000

- A local necrosis of corneal tissue that ultimately leads to scarring and reduced visual acuity.

Causes and Incidence The most common cause is infection following trauma or contact lens overwear. Other causes include herpes simplex infection, chronic blepharitis, conjunctivitis, gonorrhea, trachoma, chemical burns, prolonged exposure to air in the absence of a blink reflex, and severe vitamin A or protein depletion resulting from malnutrition.

Disease Process The cornea usually becomes infected or inflamed through an outside agent or chronic irritant, and a dull, grayish lesion forms and then necroses and suppurates, creating an ulcer. The ulcer may or may not infiltrate deeper layers of tissue. The deeper the penetration, the more severe the signs, symptoms, and complications. As the ulcer heals, it is replaced by fibrous tissue, which causes opaque scarring and reduced vision.

Symptoms Pain, tearing, and photophobia are the most common manifestations. Bloodshot eyes and pus in the anterior chamber behind the cornea may be present in chronic cases.

Potential Complications Perforation of the cornea, with a prolapse of the iris and eventual destruction of the eye, is the major complication.

Diagnostic Tests A fluorescein stain turns green and readily delineates the ulcerated area. A slitlamp examination allows inspection of the eye’s surface and the deeper layers of the cornea to determine the extent of ulceration. Cultures identify the infectious organism.

Treatments

Surgery
Repair of any laceration or removal of foreign object; removal of prolapsed tissue; corneal transplantation for severe scarring or perforation.

Drugs
Topical anesthetics for pain; topical and systemic antibiotics, antifungals, and antivirals to treat infection; topical steroids to treat inflammation; mydriatics to dilate pupil with increased intraocular pressure; cycloplegics to restrict eye movement and reduce pain.

General
Warm compresses for lid swelling; irrigation to cleanse eye; bilateral pressure dressings to aid reepithelialization; dark glasses for photophobia.

Medi-Info.COM finds at this phrases

Coronary Artery Disease (See also Angina and Myocardial Infarction)

admin — Sun, 01 Aug 2010 09:21:08 +0000

- A disorder that impedes the bloodflow in the arteries serving the myocardium of the heart.

Causes and Incidence The primary causes of coronary artery disease (CAD) are arteriosclerotic and atherosclerotic processes, which narrow and occlude the vessel lumen and thicken the arterial walls. Risk factors associated with the development of CAD include underlying disease (e.g., hypertension or diabetes); use of tobacco products; familial hyperlipidemia, high-fat diet; sedentary life-style; stress; estrogen use in women under 50 years of age; and obesity.
Vascular disease (CAD and CVA) is the leading cause of death in the United States. The incidence of CAD increases with age, and men seem more susceptible than women, particularly premenopausal women. The death rate among white men 55 to 64 years of age is about 1 in 100. CAD is much more prevalent in Western societies than in other areas of the world.

Disease Process The exact pathologic mechanisms that induce atherosclerosis are not well understood. Current hypotheses are (1) the lipid hypothesis, in which an elevation of plasma low-density lipoprotein penetrates the arterial wall and causes a lipid buildup in the smooth muscle cells, and (2) the endothelial injury hypothesis, which suggests that a mechanical or chemical injury to the endothelial barrier sets up a tissue response, with platelet adhesion and aggregation. In either case, atherosclerosis is marked by changes in and thickening of the intimal lining of the arterial vessel. Lipids, smooth muscle cells, and connective tissue form a plaquelike substance on the lining. This process is slow and may occur over a lifetime. Arteriosclerosis causes hypertrophy and subintimal fibrosis, resulting in intimal thickening and loss of elasticity of the vessel wall, which widens the pulse pressure and increases the systolic pressure. This loss of elasticity is reinforced by atherosclerotic processes. Arterial lumens become increasingly narrow and may become obstructed, causing ischemia of the myocardium. The plaque may harden, calcify, and undergo fissure or rupture, simulating a thrombosis or embolus rapidly occluding a lumen.

Symptoms CAD is asymptomatic until myocardial ischemia occurs. The two major manifestations of ischemia are chest pain (angina) and myocardial infarction. See Angina and Myocardial Infarction for diagnosis and treatment options.

Medi-Info.COM finds at this phrases

Crohn’s Disease (Regional Enteritis)

admin — Thu, 29 Jul 2010 09:19:21 +0000

- A nonspecific chronic inflammatory disease of the gastrointestinal system most commonly affecting the distal ileum and the colon.

Causes and Incidence The etiology is unknown, and research examining the causal role of immune factors, infectious agents, and dietary factors has proved fruitless. There are an estimated 30 to 50 cases per 100,000 population, and the incidence is rising in underdeveloped countries, among blacks and Hispanics, and in Western and Northern European and Anglo-Saxon populations. The disease is equally distributed across gender lines, is most common among Jews, and occurs primarily between 15 and 30 years of age.

Disease Process Crohn’s disease begins with lymphedema in the GI submucosa and microscopic focal ulcerations of the mucosa. The inflammation spreads slowly and progressively, involving all layers of the intestinal wall, which thicken with extensive fibrosis and granulomas as patchy ulcerations form on the mucosa. This process creates a characteristic cobblestone appearance of the mucosa. As the disease progresses, the mesentery becomes edematous and thickens, and mesenteric fat extends onto the serosal surface of the bowel, causing serositis with adhesion of bowel loops to one another. Mesenteric lymph nodes enlarge, and abscess and deep sinus tracts and fissures are formed. Eventually the lumen of the intestine severely narrows or becomes obstructed. This process very often affects one segment of the intestine, skips over normal tissue, then repeats the obstructive process in another segment (iskip lesionsi).

Symptoms Symptoms may be abrupt or insidious in onset and are characterized by exacerbations and remissions. The most common presenting features are chronic diarrhea with urgency and incontinence; abdominal pain and cramping, often in the lower right quadrant; fever; anorexia; and weight loss. However, some individuals have acute abdominal pain resembling that caused by appendicitis.

Potential Complications Complications of Crohn’s disease can be either intestinal or systemic. An anal fistula or perianal abscess caused by chronic diarrhea is the most common complication. Other fistulas may form to the bladder, vagina, or skin. Malabsorption, obstruction, perforation, and cancer of the colon are other intestinal complications. Systemic complications include arthritis, episcleritis, stomatitis, erythema nodosum, pyoderma gangrenosum, ankylosing spondylitis, sacroiliitis, uveitis, and sclerosing cholangitis.

Diagnostic Tests

Barium series
Linear ulcerations, skip lesions, thickening of wall, narrowing of lumen

Colonoscopy
Cobblestone mucosa

Biopsy
To aid in differentiation of disease

Laboratory studies
Nonspecific; may include decreased hemoglobin and hematocrit, serum albumin, and folic acid; elevated erythrocyte sedimentation rate

Treatments

Surgery
Bowel resection with failure to respond to conservative therapy; colectomy with ileostomy when disease is limited to colon; strictureplasty to open obstructions.

Drugs
Sulfasalazine, corticosteroids, and metronidazole to treat inflammation and ulceration; anticholinergics for diarrhea;

fat-soluble vitamins, folic acid, iron, calcium magnesium, and zinc for replacement; immunosuppressive agents for retractive disease.

General
Adequate rest; nutrition: NPO in acute phase to rest bowel, followed by total parenteral nutrition or restricted diet low in fiber; emotional support for anxiety and depression; referral to source of information and support group.

Medi-Info.COM finds at this phrases

Cystic Fibrosis

admin — Thu, 20 May 2010 17:01:21 +0000

- An inherited disease of the exocrine glands that results in multisystem involvement primarily by affecting the respiratory and gastrointestinal systems. It typically is characterized by chronic obstructive pulmonary disease, abnormally high loss of electrolytes through the sweat glands, and pancreatic enzyme insufficiency, leading to digestive impairments and malabsorption syndrome.

Causes and Incidence Cystic fibrosis (CF) is caused by a defective gene that is inherited from both parents as an autosomal recessive trait. The gene is responsible for encoding a membrane-associated protein called cystic fibrosis transmembrane conductance regulator (CFTR). The exact function of CFTR is unknown, but research shows that it is closely tied to chloride transport. Current research focuses on the causes of seemingly unrelated multisystem effects.
CF is the most common lethal genetic disease among white children and young adults in the United States, with an incidence of 1 in approximately every 2,400 live births. Blacks also are affected, but the rate is about 1 in 17,000 births. CF is rare in Asians and Native Americans.

Disease Process In CF, the exocrine glands are affected in one of three ways: (1) they produce and become obstructed by thickened, sticky mucus; (2) they produce excess normal secretions; or (3) they secrete excess sodium and chloride. The lungs are normal at birth, but bronchioles and bronchi soon become clogged with thick mucous plugs, leading to associated opportunistic infections and overinflation of the lungs. Bronchial walls thicken and airways remain filled with purulent secretions, leading to fibrosis and atelectasis. Chronic hypoxemia leads to hypertrophy of the pulmonary arteries, which leads to pulmonary hypertension and right ventricular hypertrophy. The pancreatic ducts also become clogged with mucous plugs, which interfere with pancreatic enzyme activity. Digestive enzymes fail to reach the small intestine, and as a result, digestion and absorption of nutrients are markedly impaired, leading to excess fat and protein in the stools. The biliary tracts in the liver become plugged with mucus and fibrose over time. Salivary glands and bile ducts may also become clogged. Sweat glands secrete abnormal levels of sodium and chloride, leading to excessive loss of these electrolytes.

Symptoms Signs and symptoms vary widely, involve several systems, and change as the disease progresses. Some children show manifestations at birth, whereas others do not develop symptoms for years. Manifestations range from mild to life threatening. The earliest sign is a meconium ileus, seen at birth in about 10% of infants with CF. All children display sweat gland abnormalities, 85% to 90% have pancreatic and gastrointestinal (GI) tract involvement, and 50% show respiratory involvement.

Sweat glands/skin
Salty tasting skin; salt crystals on nose, forehead and hairline; dehydration, alkalosis in heat or with fever

Pancreas/GI tract
Meconium ileus, with cramps, nausea, vomiting, abdominal distention; frequent, bulky, oily, and foul-smelling stools; normal or voracious appetite; weight loss, failure to thrive; pot belly, wasted buttocks, thin extremities; sallow skin; anemia, easy bruising; rectal prolapse

Respiratory tract
Wheezing, dry cough, rhinitis, gagging; dyspnea; intercostal retractions, use of accessory muscles to breathe; barrel chest, digital clubbing, cyanosis; repeated episodes of upper respiratory infection (URI), bronchial pneumonia

Reproductive system
Delayed onset of puberty; amenorrhea, viscous cervical secretions that block sperm entry in women; sterility in men

Potential Complications Complications are numerous and can include biliary cirrhosis, esophageal varices, portal hypertension, diabetes mellitus, pneumothorax, cor pulmonale, congestive heart failure, peptic ulcer, intestinal obstruction, intussusception, pancreatitis, cholecystitis, and cardiac arrhythmias. CF is a terminal disease. However, the median death rate has climbed, from 7 1/2 years in 1966 to 28 years in 1993. A few individuals have survived to 50 years of age or older.

Diagnostic Tests

Clinical evaluation
Any of the above manifestations, particularly salty skin, failure to thrive, and frequent URIs; family history

Quantitative pilocarpine
Sodium or chloride concentration .60 mEq/L

Iontophoresis sweat test
To obtain definitive diagnosis

Treatments

Surgery
Heart-lung or liver transplantation with advanced disease; treatment of complications (e.g., resection of bowel obstructions, cholecystectomy, portal shunt for esophageal varices).

Drugs
Antibiotics to treat pulmonary infections; amiloride HCl (aerosol) to inhibit sodium and water reabsorption in the lungs; DNase and other drugs to thin mucus; alphaantitrypsin to reduce inflammation; pancreatic enzyme replacements (e.g., pancrelipase); bronchodilators to aid breathing.

General
Diet therapy, with 50% increase in normal caloric and protein intake, high fat intake, multivitamins, water-miscible vitamin E, sodium supplements, enteral supplementation in severe cases Prophylaxis against respiratory infection with pertussis, measles, and flu vaccines Chest physiotherapy to increase movement of mucus from lungs (postural drainage, percussion, vibration, and assisted coughing; oxygen therapy for hypoxia; exercise to stimulate mucus movement) Long-term psychologic counseling for individual and family; genetic counseling for parents; support groups; home care, respite care.

Medi-Info.COM finds at this phrases

Cysts (Dermoid, Epidermal, Sebaceous)

admin — Sun, 16 May 2010 10:59:20 +0000

- A slow-growing, benign cystic tumor found in the subcutaneous tissue below the skin or in the intradermal tissue of the skin.

Causes and Incidence Cyst formation is commonly caused by inflammation, internal rupture of an acne pustule or whitehead, impaired localized circulation, or trauma. Some individuals may be genetically predisposed to cyst formation.

Disease Process Cysts contain a soft, yellow-white, cheesy substance that is often fetid and that forms when a hair follicle becomes obstructed. The contents of the cyst are determined by the type of cyst. Dermoid cysts are located deep in the subcutaneous tissue; have walls of keratinizing epidermis containing sweat glands, hair follicles, and sebaceous glands; and are often present at birth. Epidermal cysts (i.e., acne cysts) are found in the epidermis on the face, scalp, neck, and back; they contain laminated layers of keratin. Sebaceous cysts, or wens, occur primarily on the scalp and contain soft keratin, epidermal debris, and greasy material.

Symptoms Cysts are found on or under the skin, are generally less than 3 cm in diameter, and are round, firm, globular, and movable to the touch. They are nontender unless infected. Cysts, particularly sebaceous type, can grow as large as a grapefruit.

Potential Complications Cysts may become infected.

Diagnostic Tests A characteristic lesion is seen on clinical examination.

Treatments

Surgery
Excision of the cyst and cyst wall; incision and drainage of infected cysts.

Drugs
Antibiotics for infected cysts.

General
Instruction not to touch, squeeze, or pick lesions, since this may lead to infection.

Medi-Info.COM finds at this phrases