Medical Care
Because most cases of acute gastroenteritis are self-limited, specific treatment is not necessary. Strict personal hygiene should be practiced during the illness. Some studies have quantified that only 10% of cases require antibiotic therapy.
The main objective is adequate rehydration and electrolyte supplementation. This can be achieved with either an oral rehydration solution (ORS) or intravenous solutions (eg, isotonic sodium chloride solution, lactated Ringer solution). Note the following:
-
Oral rehydration is achieved by administering clear liquids and sodium-containing and glucose-containing solutions. A simple ORS may be composed of 1 level teaspoon of salt and 4 heaping teaspoons of sugar added to 1 liter of water.
-
The use of ORS has reduced the mortality rate associated with cholera from higher than 50% to less than 1%.
-
ORS also is indicated in other dehydrating diarrheal diseases.
-
ORS promotes cotransport of glucose, sodium, and water across the gut epithelium, a mechanism unaffected in cholera.
-
The World Health Organization (WHO) recommends a solution containing 3.5 g of sodium chloride, 2.5 g of sodium bicarbonate, 1.5 g of potassium chloride, and 20 g of glucose per liter of water.
Intravenous solutions are indicated in patients who are severely dehydrated or who have intractable vomiting.
Absorbents (eg, Kaopectate, aluminum hydroxide) help patients have more control over the timing of defecation. However, they do not alter the course of the disease or reduce fluid loss. Note the following:
-
An interval of at least 1-2 hours should elapse when using other medications with absorbents.
-
Antisecretory agents, such as bismuth subsalicylate (Pepto-Bismol), may be useful. The dose is 30 mL every 30 minutes, not to exceed 8-10 doses.
-
Antiperistaltics (opiate derivatives) should not be used in patients with fever, systemic toxicity, or bloody diarrhea or in patients whose condition either shows no improvement or deteriorates.
-
Diphenoxylate with atropine (Lomotil) is available in tablets (2.5 mg of diphenoxylate) and liquid (2.5 mg of diphenoxylate/5 mL). The initial dose for adults is 2 tablets 4 times a day (ie, 20 mg/d). The dose is tapered as diarrhea improves.
-
Loperamide (Imodium) is available over the counter as 2-mg capsules and as a liquid (1 mg/5 mL). It increases the intestinal absorption of electrolytes and water and decreases intestinal motility and secretion. The dose in adults is 4 mg initially, followed by 2 mg after each diarrhea stool, not to exceed 16 mg in a 24-hour period.
If symptoms persist beyond 3-4 days, the specific etiology should be determined by performing stool cultures. If symptoms persist and the pathogen is isolated, specific treatment should be initiated.
Empiric treatment should be initiated in patients with suspected traveler's diarrhea or dysenteric or systemic symptoms. Treatment with an agent that covers Shigella and Campylobacter organisms is reasonable in patients with diarrhea (>4 stools/d) for more than 3 days and with fever, abdominal pain, vomiting, headache, or myalgias. A 5-day course of a fluoroquinolone (eg, ciprofloxacin 500 mg PO bid, norfloxacin 400 mg PO bid) is the first-line therapy. TMP/SMX (Bactrim DS 1 tab qd) is an alternative therapy, but resistant organisms are common in the tropics. Infection with either V cholerae or V parahaemolyticus can be treated either with a fluoroquinolone or with doxycycline (100 mg PO bid).
In the absence of dysentery, do not administer antibiotics until a microbiologic diagnosis is confirmed and E coli O157:H7 is ruled out.
Diet
During episodes of acute diarrhea, patients often develop an acquired disaccharidase deficiency due to washout of the brush-border enzymes. For this reason, avoiding milk, dairy products, and other lactose-containing foods is advisable.
Prevention
No vaccine is available that can prevent norovirus infection. An early study conducted in a controlled setting assessed the safety, immunogenicity, and efficacy of an investigational, intranasally delivered norovirus viruslike particle (VLP) vaccine to prevent acute viral gastroenteritis. Results suggest the vaccine protects against illness and infection after exposure to the Norwalk virus and could potentially prevent infection in susceptible, high-risk populations. The vaccine has not been tested in the natural setting, however. [16]
The best way to prevent food poisoning caused by infectious agents is to practice strict personal hygiene, cook all foods adequately, avoid cross-contamination of raw and cooked foods, and keep all foods at appropriate temperatures (ie, < 40°F for refrigerated items and >140°F for hot items).
Avoiding eating wild mushrooms prevents mushroom poisoning.
Prevention of fish poisoning requires avoidance of large tropical fish (ciguatera poisoning) and compliance with seasonal or emergency quarantines of shellfish harvesting areas (shellfish poisoning).
Raw or undercooked milk, poultry, eggs, meat, and seafood are best avoided.
Local health authorities should be notified if an outbreak of food poisoning occurs. This leads to appropriate actions to prevent further spread of food poisoning.
Irradiation of food (ie, the use of ionizing radiation or ionizing energy to treat foods, either packaged or in bulk form) can eliminate food-borne pathogens. Annually, more than half a million tons of food is now irradiated worldwide. Treating raw meat and poultry with irradiation at the slaughter plant could eliminate bacteria, such as E coli O157:H7 and Salmonella and Campylobacter organisms. No evidence of adverse health effects has been found in the well-controlled clinical trials involving irradiated food.
The use of low-temperature gas plasmas in the food industry may potentially reduce the incidence of foodborne disease. [17] The gas plasmas have microbiocidal capabilities and may also aid in degrading undesirable chemical compounds that can be found on food and food-processing equipment (eg, pesticide residues, toxins, allergens). [17]
Prophylaxis for traveler's diarrhea is not recommended routinely because of the risk of adverse effects from the drugs (eg, rash, anaphylaxis, vaginal candidiasis) and the development of resistant gut flora. Possible regimens for prophylaxis include bismuth subsalicylate (Pepto-Bismol, 524 mg PO qid with meals and qhs), doxycycline (100 mg PO qd; resistance documented in many areas of the world), TMP/SMX (160 mg/800 mg 1 double-strength tab qd), or norfloxacin (400 mg PO qd; fluoroquinolones should not be prescribed to children or pregnant women). No significant resistance to the fluoroquinolones has been reported in high-risk areas, and they are the most effective antibiotics in regions where susceptibilities are not known.
Long-Term Monitoring
Because most cases of food poisoning are self-limited, prolonged follow-up care is not required.
Stool cultures should be monitored in individuals working in hospitals, food establishments, and daycare centers and who are infected with E coli O157:H7 or Salmonella or Shigella organisms until they become culture-negative without antibiotics. These people should not return to work until that time.
Tables
Causative Agents |
Source and Clinical Features |
Pathogenesis |
Diagnosis and Treatment |
|
Staphylococci |
Improperly stored foods with high salt or sugar content favors growth of staphylococci. Intense vomiting and watery diarrhea start 1-4 h after ingestion and last as long as 24-48 h |
Enterotoxin acts on receptors in the gut that transmit impulses to the medullary centers |
Symptomatic treatment |
|
B cereus |
Contaminated fried rice (emetic) Meatballs (diarrheal) Emetic: Duration is 9 h, vomiting and cramps Diarrheal: Lasts for 24 h Mainly vomiting after 1-6 h and mainly diarrhea after 8-16 h after ingestion; lasts as long as 1 d |
Emetic enterotoxin (short incubation and duration) - Poorly understood Diarrheal enterotoxin (long incubation and duration) - Increasing intestinal secretion by activation of adenylate cyclase in intestinal epithelium |
Symptomatic treatment |
|
C perfringens |
Inadequately cooked meat, poultry, or legumes Acute onset of abdominal cramps with diarrhea starts 8-24 h after ingestion. Vomiting is rare. It lasts less than 1 d. Enteritis necroticans associated with C perfringens type C in improperly cooked pork (40% mortality) |
Enterotoxin produced in the gut, and food causes hypersecretion in the small intestine |
Culture of clostridia in food and stool Symptomatic treatment |
|
C botulinum |
Canned foods (eg, smoked fish, mushrooms, vegetables, honey) Descending weakness and paralysis start 1-4 d after ingestion, followed by constipation. Mortality is high |
Toxin absorbed from the gut blocks the release of acetylcholine in the neuromuscular junction |
Toxin present in food, serum, and stool. Respiratory support Intravenous trivalent antitoxin from CDC |
|
Listeria monocytogenes |
Raw and pasteurized milk, soft cheeses, raw vegetables, shrimp Systemic disease associated with bacteremia Intestinal symptoms precede systemic disease Can seed meninges, heart valves, and other organs Highest mortality among bacterial food poisonings |
Highly motile, heat-resistant, gram-positive organism |
CSF or blood culture Must treat with antibiotics if bacteremic |
|
Enterotoxic E coli (eg, traveler's diarrhea) |
Contaminated water and food (eg, salad, cheese, meat) Acute-onset watery diarrhea starts 24-48 h after ingestion Concomitant vomiting and abdominal cramps may be present. It lasts for 1-2 d |
Enterotoxin causes hypersecretion in small and large intestine via guanylate cyclase activation |
Supportive treatment No antibiotics |
|
Enterohemorrhagic E coli (eg, E coli O157:H7) |
Improperly cooked hamburger meat and previously spinach Most common isolate pathogen in bloody diarrhea starts 3-4 d after ingestion Usually progresses from watery to bloody diarrhea. It lasts for 3-8 d May be complicated by hemolytic-uremic syndrome or thrombotic thrombocytopenic purpura |
Cytotoxin results in endothelial damage and leads to platelet aggregation and microvascular fibrin thrombi |
Diagnosis with stool culture Supportive treatment No antibiotics |
|
Enteroinvasive E coli |
Contaminated imported cheese Usually watery diarrhea (some may present with dysentery) |
Enterotoxin produces secretion Shigalike toxin facilitates invasion |
Supportive treatment No antibiotics |
|
Enteroaggregative E coli |
Implicated in traveler's diarrhea in developing countries Can cause bloody diarrhea |
Bacteria clump on the cell surfaces |
Ciprofloxacin may shorten duration and eradicate the organism |
|
V cholera |
Contaminated water and food Large amount of nonbloody diarrhea starts 8-24 h after ingestion. It lasts for 3-5 d |
Enterotoxin causes hypersecretion in small intestine Infective dose usually is 107 -109 organisms |
Positive stool culture finding Prompt replacement of fluids and electrolytes (oral rehydration solution) Tetracycline (or fluoroquinolones) shortens the duration of symptoms and excretion of Vibrio |
|
V parahaemolyticus |
Raw and improperly cooked seafood (ie, mollusks and crustaceans) Explosive watery diarrhea starts 8-24 h after ingestion It lasts for 3-5 d |
Enterotoxin causes hypersecretion in small intestine Hemolytic toxin is lethal Infective dose is usually 107 -109 organisms |
Positive stool culture Prompt replacement of fluids and electrolytes Sensitive to tetracycline, but unclear role for antibiotics |
|
V vulnificus |
Wound infection in salt water or consumption of raw oysters Can be lethal in patients with liver disease (50% mortality) |
Polysaccharide capsule Growth correlates with availability of iron (especially transferrin saturation >70%) |
Culture of characteristic bullous lesions or blood Immediate antibiotics if suspected (eg, doxycycline and ceftriaxone) |
|
C jejuni |
Domestic animals, cattle, chickens Fecal-oral transmission in humans Foul-smelling watery diarrhea followed by bloody diarrhea Abdominal pain and fever also may be present; it starts 1-3 d after exposure and recovery is in 5-8 d |
Uncertain about endotoxin production and invasion |
Culture in special media at 42°C Erythromycin for invasive disease (fever) |
|
Shigella |
Potato, egg salad, lettuce, vegetables, milk, ice cream, and water Abrupt onset of bloody diarrhea, cramps, tenesmus, and fever starts 12-30 h after ingestion. Usually self-limited in 3-7 d |
Organisms invade epithelial cells and produce toxins Infective dose is 102 -103 organisms Enterotoxin-mediated diarrhea followed by invasion (dysentery/colitis) |
Polymorphonuclear leukocytes (PMNs), blood, and mucus in stool Positive stool culture Oral rehydration is mainstay Trimethoprim-sulfamethoxazole (TMP-SMX) or ampicillin for severe cases No opiates |
|
Salmonella |
Beef, poultry, eggs, and dairy products Abrupt onset of moderate-to-large amount of diarrhea with low-grade fever; in some cases, bloody diarrhea Abdominal pain and vomiting also present, beginning 6-48 h after exposure and lasts 7-12 d |
Invasion but no toxin production |
Positive stool culture finding Antibiotic for systemic infection |
|
Yersinia |
Pets; transmission in humans by fecal-oral route or contaminated milk or ice cream Acute abdominal pain, diarrhea, and fever (enterocolitis) Incubation period not known Polyarthritis and erythema nodosum in children May mimic appendicitis |
Gastroenteritis and mesenteric adenitis Direct invasion and enterotoxin |
Polymorphonuclear leukocytes and blood in stool Positive stool culture finding No evidence that antibiotics alter the course but may be used in severe infections |
|
Aeromonas |
Untreated well or spring water Diarrhea may be bloody May be chronic up to 42 d in the United States |
Enterotoxin, hemolysin, and cytotoxin |
Positive stool culture Fluoroquinolones or TMP/SMX for chronic diarrhea |
|
Parasitic Food Poisoning |
Source and Clinical Features |
Pathogenesis |
Diagnosis and Treatment |
|
E histolytica |
Contaminated food and water 90% asymptomatic 10% dysentery Minority may develop liver abscesses |
Invasion of the mucosa by the parasites |
Criterion standard is colonoscopy with biopsy Ova and parasites may be seen in the stool but has low sensitivity Luminal amebicides (eg, paromomycin) Tissue amebicides (eg, metronidazole) |
|
G lamblia |
Contaminated ground water Fecal-oral transmission in humans Mild diarrhea with nausea and abdominal cramps starts 2-3 d after ingestion; lasts for 1 wk May become chronic |
Unknown Highest concentration in the distal duodenum and proximal jejunum |
Initial diagnostic test is stool enzyme-linked immunosorbent assay Duodenal aspiration or small bowel biopsy Cyst in the stool Metronidazole |
|
Seafood/Shellfish Poisoning |
Source and Clinical Features |
Pathogenesis |
Diagnosis and Treatment |
|
Paralytic shellfish poisoning |
Temperate coastal areas Source - Bivalve mollusks Onset usually is 30-60 min Initial symptoms include perioral and intraoral paresthesia Other symptoms include paresthesia of the extremities, headache, ataxia, vertigo, cranial nerve palsies, and paralysis of respiratory muscles, resulting in respiratory arrest |
Fish acquires toxin-producing dinoflagellates |
General observation for 4-6 h Maintain patent airway. Administer oxygen, and assist ventilation if necessary For recent ingestion, charcoal 50-60 g may be helpful |
|
Neurotoxic shellfish poisoning |
Coastal Florida Source - Mollusks Illness is milder than in paralytic shellfish poisoning |
Fish acquires toxin-producing dinoflagellates |
Symptomatic |
|
Ciguatera |
Hawaii, Florida, and Caribbean Source - Carnivorous reef fish Vomiting, diarrhea, and cramps start 1-6 h after ingestion and last from days to months Diarrhea may be accompanied by a variety of neurologic symptoms including paresthesia, reversal of hot and cold sensation, vertigo, headache, and autonomic disturbances such as hypotension and bradycardia Chronic symptoms (eg, fatigue, headache) may be aggravated by caffeine or alcohol |
Fish acquires toxin-producing dinoflagellates Toxin increases intestinal secretion by changing intracellular calcium concentration |
Symptomatic Anecdotal reports of successful treatment of neurologic symptoms with mannitol 1 g/kg IV |
|
Tetrodotoxin poisoning |
Japan Source - Puffer fish Onset of symptoms usually is 30-40 min but may be as short as 10 min; it includes lethargy, paresthesia, emesis, ataxia, weakness, and dysphagia; ascending paralysis occurs in severe cases; mortality is high. |
Neurotoxin is concentrated in the skin and viscera of puffer fish. |
Symptomatic |
|
Scombroid |
Source - Tuna, mahi-mahi, kingfish Allergic symptoms such as skin flush, urticaria, bronchospasm, and hypotension usually start within 15-90 min |
Improper preservation of large fish results in bacterial degradation of histidine to histamine |
Antihistamines (diphenhydramine 25-50 mg IV) H2 blockers (cimetidine 300 mg IV) Severe reactions may require subcutaneous epinephrine (0.3-0.5 mL of 1:1000 solution) |
|
Heavy Metal Poisoning |
Source |
Symptoms |
Treatment |
|
Mercury |
Ingestion of inorganic mercuric salts |
Causes metallic taste, salivation, thirst, discoloration and edema of oral mucous membranes, abdominal pain, vomiting, bloody diarrhea, and acute renal failure |
Consult a toxicologist Remove ingested salts by emesis and lavage, and administer activated charcoal and a cathartic Dimercaprol is useful in acute ingestion |
|
Lead |
Toxicity results from chronic repeated exposure It is rare after single ingestion |
Common symptoms include colicky abdominal pain, constipation, headache, and irritability Diagnosis is based on lead level (>10 mcg/dL) |
Other than activated charcoal and cathartic, severe toxicity should be treated with antidotes (edetate calcium disodium [EDTA] and dimercaprol). |
|
Arsenic |
Ingestion of pesticide and industrial chemicals |
Symptoms usually appear within 1 h after ingestion but may be delayed as long as 12 h Abdominal pain, watery diarrhea, vomiting, skeletal muscle cramps, profound dehydration, and shock may occur |
Gastric lavage and activated charcoal Dimercaprol injection 10% solution in oil (3-5 mg/kg IM q4-6h for 2 d) and oral penicillamine (100 mg/kg/d divided qid for 1 wk) |
|
