You receive a call from the mother of a previously healthy 2-year-old boy. Yesterday, he developed a temperature of 104°F (40°C), cramping abdominal pain, emesis, and frequent watery stools. The mother assumed he had the same gastroenteritis like his aunt and many other children in his day care center. However, today he developed bloody stools with mucus and seemed more irritable. While you are asking about his current hydration status, the mother reports that he is having a seizure. You tell her to call the ambulance and then notify the local hospital’s emergency center of his imminent arrival.
What is the most likely diagnosis?
How can you confirm this diagnosis?
What is the best management for this illness?
What is the expected course of this illness?
ANSWERS TO CASE 35: Bacterial Enteritis
Summary: This child was exposed in his day care center and at home to gastrointestinal (GI) illnesses. He has fever, abdominal pain, and watery diarrhea that progressed to bloody diarrhea with mucus. He had a new-onset seizure.
• Most likely diagnosis: Bacterial enteritis with neurologic manifestations.
• Diagnostic tools: Fecal leukocytes, fecal blood, and stool culture.
• Management: Varies with age and suspected organism; hydration and electrolyte correction is a priority. Salmonellainfections are self-limited and generally are not treated except in patients younger than 3 months or in immunocompromised individuals; Shigella infections, although self-limited, are generally treated to shorten the illness and decrease organism excretion. Antimotility agents are not used.
• Course: Left untreated, most GI infections in healthy children will spontaneously resolve. Extraintestinal infections are more likely in immunocompromised individuals.
1. Describe the typical clinical presentation of bacterial enteritis.
2. List potential pathogens for gastroenteritis, considering the patient’s age.
3. Discuss treatment options and explain when treatment is necessary.
4. Discuss potential complications of bacterial enteritis.
Bloody stools can be caused by many diseases, not all of which are infectious. In this child, GI bleeding also could be caused by Meckel diverticulum, intussusception, Henoch-Schönlein purpura, hemolytic-uremic syndrome, Clostridium difficile colitis, and polyps. The description is most consistent, however, with infectious enteritis typical of Shigella or Salmonella.
COLITIS: Inflammation of the colon.
DIARRHEA: Frequent passage of unusually soft or watery stools.
DYSENTERY: An intestinal infection resulting in severe bloody diarrhea with mucus.
ENTERITIS: Inflammation of the small intestine, usually resulting in diarrhea; may be a result of infection, immune response, or other causes.
Salmonella organisms are aerobic gram-negative rods and can survive as facultative anaerobes. They are motile and do not ferment lactose. Infection is more common in warmer months. Salmonellainfections can be separated into nontyphoidal disease (gastroenteritis, meningitis, osteomyelitis, and bacteremia) and typhoid (or enteric) fever, caused primarily by Salmonella typhi. Outbreaks usually occur sporadically but can be food related and occur in clusters. Many animals harbor Salmonella. Exposure to poultry and raw eggs probably is the most common source of human infection; sources may also include iguanas and turtles. Infection requires the ingestion of many organisms; person-to-person spread is uncommon.
Gastroenteritis is the most common nontyphoidal disease presentation of Salmonella. Children usually have sudden onset of nausea, emesis, cramping abdominal pain, and watery or bloody diarrhea. Most develop a low-grade fever; some have neurologic symptoms (confusion, headache, drowsiness, and seizures). Between 1% and 5% of patients with Salmonella infection develop transient bacteremia, with subsequent extraintestinal infections (osteomyelitis, pneumonia, meningitis, and arthritis); these findings are more common in immunocompromised patients and in infants.
Shigella organisms are small gram-negative bacilli. They are non-lactose fermenting facultative anaerobes, and have recently been shown to be motile. Four Shigella species cause human disease: S dysenteriae, S boydii, S flexneri,and S sonnei. Infections most commonly occur in warmer months and in the first 10 years of life (peaking in the second and third years). Infection usually is transmitted person to person but may occur through food and water. Relatively few Shigella organisms are required to cause disease. Typically, children have fever, cramping abdominal pain, watery diarrhea (often progressing to small bloody stools), and anorexia; they appear ill. Untreated, diarrhea typically lasts 1 to 2 weeks and then resolves. Neurologic findings may include headache, confusion, seizure, or hallucinations. Shigella meningitis is infrequent. Uncommon complications include rectal prolapse, cholestatic hepatitis, arthritis, conjunctivitis, and cystitis. Rarely, Shigella causes a rapidly progressive sepsis-like presentation (Ekiri syndrome) that quickly results in death.
Salmonella or Shigella tests include a stool culture, although results frequently are negative even in infected test subjects. Fecal leukocytes usually are positive, but this nonspecific finding only suggests colonic inflammation. An occult blood assay often is positive. In Shigella infection, the peripheral white count usually is normal, but a remarkable left shift often is seen with more bands than polymorphonuclear cells. Salmonella infection usually results in a mild leukocytosis.
Treatment focuses on fluid and electrolyte balance correction. Antibiotic treatmentof Salmonella usually is not necessary; it does not shorten the GI disease course and may increase the risk of hemolytic-uremic syndrome (HUS). Infants younger than 3 months of age and immunocompromised individuals often are treated for GI infection, as they are at increased risk for disseminated disease. Shigella is self-limited as well, but antibiotics shorten the illness course and decrease the duration organisms are shed. Antimotility agents are not indicated for either Salmonella or Shigella.
In addition to the above organisms, enteroinvasive Escherichia coli, Campylobacter sp, and Yersinia enterocolitica can cause dysentery, with fever, abdominal cramps, and bloody diarrhea. Yersinia can cause an “acute abdomen” picture. Enterohemorrhagic (or Shiga toxin-producing) E coli can cause bloody diarrhea but usually no fever. Infection with Vibrio cholera produces vomiting and profuse, watery, nonbloody diarrhea with little or no fever.
Hemolytic-uremic syndrome, the most common cause of acute childhood renal failure, develops in 5% to 8% of children with diarrhea caused by enterohemorrhagic E coli (O157:H7); it is seen less commonly after Shigella, Salmonella, and Yersinia infections. It usually is seen in children younger than 4 years. The underlying process may be microthrombi, microvascular endothelial cell injury causing microangiopathic hemolytic anemia, and consumptive thrombocytopenia. Renal glomerular deposition of an unidentified material leads to capillary wall thickening and subsequent lumen narrowing. The typical presentation occurs 1 to 2 weeks after a diarrheal illness, with acute onset of pallor, irritability, decreased or absent urine output, and even stroke; children may also develop petechiae and edema. Treatment is supportive; some children require dialysis. Most children recover and regain normal renal function; all are followed after infection for hypertension and chronic renal failure.
35.1 A 2-year-old boy developed emesis and intermittent abdominal pain yesterday, with several small partially formed stools. His parents were not overly concerned because he seemed fine between the pain episodes. Today, however, he has persistent bilious emesis and has had several bloody stools. Examination reveals a lethargic child in mild distress; he is tachycardic and febrile. He has a diffusely tender abdomen with a vague tubular mass in the right upper quadrant. Which of the following is the most appropriate next step in managing this condition?
A. Computed tomography of the abdomen
B. Air contrast enema
C. Intravenous antibiotics for Shigella
D. Parental reassurance
E. Stool cultures
35.2 A previously healthy 2-year-old girl had 3 days of bloody diarrhea the previous week that spontaneously resolved. Her mother now thinks she looks pale. On examination, you see that she is afebrile, her heart rate is 150 bpm, and her blood pressure is 150/80 mm Hg. She is pale and irritable, has lower-extremity pitting edemas, and has scattered petechiae. After appropriate laboratory studies, initial management should include which of the following?
A. Careful management of fluid and electrolyte balance
B. Contrast upper GI series with small bowel delay films
C. Intravenous antibiotics and platelet transfusion
D. Intravenous steroids and aggressive fluid resuscitation
E. Intubation and mechanical ventilation
35.3 A family reunion picnic went awry when the majority of attendees developed emesis and watery diarrhea with streaks of blood. Unaffected attendees did not eat the potato salad. A few ill family members are mildly febrile. They come as a group to your clinic, seeking medications. Which of the following is the most appropriate management for their condition?
A. Antimotility medication
B. Hydration and careful follow-up
C. Intramuscular ceftriaxone
D. Oral amoxicillin
E. Oral metronidazole
35.4 You are asked to see a 1-month-old infant to provide a second opinion. During a brief, self-limited, and untreated diarrheal episode the previous week, his primary physician ordered a stool assay for Clostridium difficile toxin; the result is positive. The infant now is completely asymptomatic, active, smiling, and well hydrated. His physician said treatment was not necessary, but the mother wants treatment. Which of the following is the most appropriate response?
A.Clostridium difficile commonly colonizes the intestine of infants; treatment without symptoms is not warranted.
B. The infant should take a 7-day course of oral metronidazole.
C. The infant should take a 10-day course of oral vancomycin.
D. The infant should be admitted to the hospital for intravenous metronidazole
E. A repeat study to look for the C difficile organism is warranted.
35.1 B. This child has an intussusception. He has bloody stools, but he also has bilious emesis, colicky abdominal pain, and a right upper quadrant mass. In experienced hands, an air contrast enema procedure may be diagnostic and therapeutic. Ensure that a surgeon and a prepared operating room are available should the reduction through contrast enema fail or result in intestinal perforation. While a CT scan may diagnose intussusception, an enema is preferred as it can be therapeutic as well as diagnostic.
35.2 A. Hemolytic-uremic syndrome may be seen after bloody diarrhea, presenting with anemia, thrombocytopenia, and nephropathy. The child in question is hypertensive and has edema, so large amounts of fluids may be counterproductive. Steroids typically are not helpful. The thrombocytopenia is consumptive; unless the patient is actively bleeding, platelet transfusion is not helpful. Most of the care for such patients is supportive, concentrating on fluids and electrolytes. Early dialysis may be needed. Hypertensive patients should have appropriate control of their blood pressure.
35.3 B. This family probably has Salmonella food poisoning. Antibiotics are not indicated for this healthy family, and antimotility agents may prolong the illness. Frequent handwashing should be emphasized.
35.4 A. Clostridium difficile colonizes approximately half of normal healthy infants in the first 12 months. In this infant without a history of antibiotic treatment or current symptoms, treatment is unnecessary. C difficilecolitis rarely occurs without a history of recent antibiotic use.
In normal children older than 3 months, isolated intestinal Salmonella infections do not require antibiotic treatment; antibiotics do not shorten the course of illness.
Suspected Shigella intestinal infections usually are treated to shorten the illness course and to decrease organism shedding.
Hemolytic-uremic syndrome, a potential sequela of bacterial enteritis, is the most common cause of acute renal failure in children.
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