Mar 302012
 
A common infection in the United States, salmonellosis is caused by gram-negative bacilli of the genus Salmonella, a member of the Enterobacteriaceae family. It occurs as enterocolitis, bacteremia, localized infection, typhoid, or paratyphoid r.
Nontyphoidal forms usually produce mild to moderate illness with low mortality.
Typhoid, the most severe form of salmonellosis, usually lasts from 1 to 4 weeks. Mortality is about 3% in persons who are treated and 10% in those untreated, usually as a result of intestinal perforation or hemorrhage, cerebral thrombosis, toxemia, pneumonia, or acute circulatory failure.
An attack of typhoid confers lifelong immunity, although the patient may become a carrier. Most typhoid patients are younger than age 30; most carriers are women older than age 50. Incidence of typhoid in the United States is increasing as more travelers return from endemic areas.
Enterocolitis and bacteremia are common (and more virulent) among infants, elderly people, and people already weakened by other infections; paratyphoid fever is rare in the United States.
Salmonellosis is 20 times more common in patients with acquired immunodeficiency syndrome. Features are increased incidence of bacteremia, inability to identify the infection source, and tendency of the infection to recur after therapy is stopped.
Causes
Of an estimated 1,700 serotypes of Salmonella, 10 cause the diseases most common in the United States; all 10 can survive for weeks in water, ice, sewage, or food. Nontyphoidal salmonellosis generally follows the ingestion of contaminated or inadequately processed foods, especially eggs, chicken, turkey, and duck. Proper cooking reduces the risk of contracting salmonellosis.
Owning a pet turtle, lizard, iguana, or snake increases the risk factor because reptiles are carriers of salmonella. Salmonellosis may occur in children younger than age 5 from fecal-oral spread.
Typhoid results most commonly from drinking water contaminated by excretions of a carrier.
Signs and symptoms
Signs and symptoms of salmonellosis vary depending on the patient but usually include fever, Continue reading »
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Mar 202012
 
A common cause of vision loss, a cataract is a gradually developing opacity of the lens or lens capsule of the eye. Cataracts commonly occur bilaterally, with each progressing independently. Exceptions are traumatic cataracts, which are usually unilateral, and congenital cataracts, which may remain stationary.
Cataracts are a part of aging and are most prevalent in patients older than age 70. Surgical intervention improves vision in 95% of affected people.
Causes
Cataracts have various causes, depending on their type:
  • Senile cataracts develop in elderly patients, probably because of degenerative changes in the chemical state of lens proteins.
  • Congenital cataracts occur in neonates as genetic defects or as a result of maternal rubella during the 1st trimester.
  • Traumatic cataracts develop after a foreign body injures the lens with sufficient force to allow aqueous or vitreous humors to enter the lens capsule.
  • Complicated cataracts develop as secondary effects in patients with uveitis, glaucoma, retinitis pigmentosa, or a detached retina or in the course of a systemic disease, such as diabetes, hypoparathyroidism, or atopic dermatitis. These cataracts can also result from exposure to ionizing radiation or infrared rays.
  • Toxic cataracts result from prolonged drug or chemical toxicity from prednisone, ergot Continue reading »
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Mar 172012
 
A major burn is a horrifying injury, necessitating painful treatment and a long period of rehabilitation. It’s often fatal or permanently disfiguring and incapacitating (emotionally and physically). In the United States, about 2.5 million people annually suffer burns. It’s the nation’s third leading cause of accidental death.
Causes
Thermal burns, the most common type, are caused by flame, flash, scald or contact with hot objects. Examples are residential fires, motor vehicle accidents, playing with matches, improperly stored gasoline, space heater or electrical malfunctions, or arson. Other causes include improper handling of firecrackers, scalding accidents, and kitchen accidents (such as a child climbing on top of a stove or grabbing a hot iron). Burns in children are sometimes traced to parental abuse.
Chemical burns result from the contact, ingestion, inhalation, or injection of acids, alkalis, or vesicants that cause tissue injury and necrosis. Electrical burns result from coagulation necrosis caused by intense heat; they usually occur after contact with faulty electrical wiring or high-voltage power lines or when electric cords are chewed (by young children). Friction or abrasion burns happen when the skin is rubbed harshly against a coarse surface. Sunburn, of course, follows excessive exposure to sunlight.
Signs and symptoms
Symptoms will vary depending on the degree of burn. Suspect burn injury when the patient presents with blisters, pain, peeling skin, red skin, edema, white or charred skin, or signs of shock. Suspect an airway burn if you see charred mouth, burned lips, burns on the head, neck, or face; wheezing, change in voice, difficulty breathing and coughing; singed nose hairs or eyebrows; or dark carbon- Continue reading »
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