Cholera C10 64.pdf

LWBK720-Part-II-C_p46-85.qxd 9/23/10 1:26 PM Page 64 Aptara Inc 64 Cholera ▼ C ONTACT PRECAUTIONS cholera may be increased by a deficiency or absence of hydrochloric ac...

LWBK720-Part-II-C_p46-85.qxd 9/23/10 1:26 PM Page 64 Aptara Inc 64 Cholera ▼ C ONTACT PRECAUTIONS cholera may be increased by a deficiency or absence of hydrochloric acid. C10- Cholera COMPLICATIONS Complications associated with cholera in- Cholera, also known as Asiatic or epidemic clude hypoglycemia, severe electrolyte deple- cholera, is an acute enterotoxin-mediated GI tion, hypovolemic shock, metabolic acidosis, infection caused by the gram-negative bacillus renal failure, liver failure, bowel ischemia, Vibrio cholerae. It produces profuse, watery di- and bowel infarction. arrhea that starts suddenly and has a “fishy” odor, vomiting, massive fluid and electrolyte ASSESSMENT FINDINGS loss and, possibly, hypovolemic shock, meta- After an incubation period ranging from bolic acidosis, and death. Infection confers only several hours to 5 days, cholera produces transient immunity. A similar bacterium, Vib- acute, painless, profuse, watery diarrhea and rio parahaemolyticus, causes food poisoning. effortless vomiting (without preceding nau- (See Vibrio parahaemolyticus food poisoning.) sea). As diarrhea worsens, the stools contain white flecks of mucus (rice-water stools). CAUSES ALERT Because of massive fluid and elec- Humans are the only hosts and victims of trolyte losses from diarrhea and vomiting V. cholerae, a motile, aerobic organism. It is (fluid loss in adults may reach 1 L/hour), transmitted through food and water contam- cholera causes intense thirst, weakness, inated with fecal material from carriers or loss of skin turgor, wrinkled skin, sunken people with active infections. Infection also eyes, pinched facial expression, muscle occurs after eating shellfish from recognized cramps (especially in the extremities), environmental reservoirs of cholera. cyanosis, oliguria, tachycardia, tachypnea, Cholera occurs during the warmer thready or absent peripheral pulses, months and is most prevalent among lower falling blood pressure, fever, and inaudi- socioeconomic groups. Susceptibility to ble, hypoactive bowel sounds. Vibrio parahaemolyticus food poisoning Vibrio parahaemolyticus is a common cause spontaneously within 2 days. Occasionally, of gastroenteritis in Japan. Outbreaks also however, it's more severe and may even be occur on cruise ships and in the eastern and fatal in debilitated or elderly persons. southeastern coastal areas of the United Diagnosis requires bacteriologic examina- States, especially during summer. tion of vomitus, blood, stool smears, or fecal V. parahaemolyticus, which thrives in a specimens collected by rectal swab. Diagno- salty environment, is transmitted by ingest- sis must rule out other causes of food poi- ing uncooked or undercooked contaminated soning and other acute GI disorders. shellfish, particularly crab and shrimp. After Treatment is supportive, consisting prima- an incubation period of 2 to 48 hours, V. rily of bed rest and oral fluid replacement. parahaemolyticus causes watery diarrhea, I.V. replacement therapy is seldom neces- moderately severe cramps, nausea, vomiting, sary, but oral tetracycline may be prescribed. headache, weakness, chills, and fever. Food Thorough cooking of seafood prevents this poisoning is usually self-limiting and subsides infection. LWBK720-Part-II-C_p46-85.qxd 9/23/10 1:26 PM Page 65 Aptara Inc Cholera 65 Patients usually remain oriented but apa- skin turgor or to replace fluid loss through thetic, although small children may become diarrhea. An oral glucose-electrolyte solution stuporous or develop seizures. If complica- can be substituted for I.V. infusions. In mild tions don’t occur, the symptoms subside and cholera, oral fluid replacement is adequate. If the patient recovers within a week. However, symptoms persist despite fluid and elec- if treatment is delayed or inadequate, cholera trolyte replacement, treatment includes may lead to metabolic acidosis, uremia and, tetracycline. possibly, coma and death. About 3% who recover continue to carry V. cholerae in the NURSING CONSIDERATIONS gallbladder; however, most are free from the ◗ Monitor output (including stool volume) infection after about 2 weeks. and I.V. infusion accurately. To detect over- hydration, carefully observe neck veins, take DIAGNOSTIC TESTS serial weights, and auscultate the lungs (fluid ◗ Stool or vomitus culture will reveal loss in cholera is massive, and improper re- V. cholerae. placement may cause potentially fatal renal ◗ Blood work will reveal elevated blood urea insufficiency). nitrogen and creatinine levels. Increases in ◗ Perform good hand hygiene before and af- serum lactate, protein, and phosphate levels ter contact with the patient or the patient’s result in a reduced bicarbonate level and an environment and when moving from a con- elevated anion gap. The arterial pH is usually taminated area to a clean area during patient low. Calcium and magnesium levels are usu- care. ally high, and potassium levels are either SAFETY Observe standard precautions normal or low. (wear a gown and gloves when handling ◗ Dark-field microscopic examination of feces-contaminated articles or when a fresh feces will show rapidly moving bacilli danger of contaminating clothing exists); (like shooting stars). observe contact precautions if the patient ◗ Stool cultures will be negative for is incontinent or diapered, or to control Escherichia coli infection, salmonellosis, and outbreaks in a facility. shigellosis. Patient teaching TREATMENT ◗ Instruct the patient and family about Improved sanitation and the administration proper hand hygiene. of cholera vaccine to travelers in endemic ◗ Travel precautions to areas where cholera areas can control this disease. The vaccine has occurred should include the following: confers only 60% to 80% immunity and is ef- - Drink only water that has been boiled or fective for only 3 to 6 months. Thus, vaccina- treated with chlorine or iodine. Other safe tion is impractical in endemic areas. beverages include tea and coffee made Treatment requires rapid I.V. infusion of with boiled water and carbonated bottled large amounts (50 to 100 ml/minute) of iso- beverages with no ice. tonic saline solution, alternating with isotonic - Eat only foods that have been cooked sodium bicarbonate or sodium lactate. thoroughly and are still hot, or fruit that Potassium replacement may be added to the you have peeled yourself. I.V. solution. Antibiotic therapy can shorten - Avoid undercooked or raw fish or shell- the course of infection and reduce the rehy- fish, including ceviche. dration requirement. - Eat only cooked vegetables; avoid salads. When I.V. infusions have corrected hypo- - Avoid street vendors. volemia, fluid infusion decreases to quanti- - Do not bring perishable seafood back to ties sufficient to maintain normal pulse and the United States.