A few hours after eating a dinner of stuffed turkey, a previously well 7-year-old boy and his parents develop vomiting, abdominal cramps, and diarrhea.
Which of the following culprits is the most likely causative agent of the patient's symptoms?
Correct Answer D: Staphylococcal food poisoning results from eating food contaminated with toxins produced by certain types of staphylococci, resulting in diarrhea and vomiting.
The staphylococci bacteria grow in food, in which they produce their toxins. Thus, staphylococcal food poisoning does not result from ingesting the bacteria but rather from ingesting the toxins that are already present in the contaminated food.
Typical contaminated foods include custard, cream-filled pastry, milk, processed meats, and fish. The risk of an outbreak is high when food handlers with skin infections contaminate foods that are under cooked or left at room temperature.
Symptoms usually begin abruptly with severe nausea and vomiting starting about 2 to 8 hours after the contaminated food is eaten. Other symptoms may include abdominal cramping, diarrhea, and sometimes headache and fever. Severe fluid and electrolyte loss may cause weakness and very low blood pressure (shock). Symptoms usually last less than 12 hours, and recovery is usually complete.
A 12-month-old child who has had gastroenteritis is asymptomatic after two days of dietary management. A stool culture then is reported positive for gram-negative Salmonella typhimurium bacteria.
Which one of the following treatments is the most appropriate?
Correct Answer B: Salmonella gastroenteritis is diagnosed by isolating the organism from stool or another infected site. In bacteremic and focal forms, blood cultures are positive, but stool cultures are generally negative. In stool specimens stained with methylene blue, WBCs are often seen, indicating inflammatory colitis.
Salmonella gastroenteritis is treated symptomatically with oral or IV fluids. For uncomplicated gastroenteritis caused by non-typhoidal Salmonella species, antimicrobial therapy is not indicated because it does not shorten the duration of illness and may prolong the duration of fecal excretion.
Antimicrobial agents and hospital admission may be recommended in Salmonella gastroenteritis in infants younger than 3 months, infants younger than 12 months with temperatures of more than 39°C and unknown blood culture results, and patients with hemoglobinopathies, human immunodeficiency virus (HIV) infection or other causes of immunosuppression, neoplasms, or chronic GI illnesses. Trimethoprim-sulfamethoxazole (TMP-SMX) for children and ciprofloxacin for adults.
Each of the following statements about rotavirus gastroenteritis in children is correct, except:
Correct Answer C: Rotavirus is a common and contagious virus that causes vomiting and diarrhea. Rotavirus is one of the most common causes of diarrhea in children. Although hardly any children die from rotavirus, worldwide the virus causes over 600,000 deaths a year, mostly in developing countries. Infection is spread mainly by swallowing material contaminated by the virus. Adults can become infected, but serious illness is rare.
Symptoms begin with fever and vomiting, followed by watery bloodless diarrhea, which typically lasts 5 to 7 days. If fluid losses are not replaced, dehydration develops. Dehydration makes the child weak and listless, with a dry mouth and rapid pulse. Rough skin or diarrhea-induced diaper dermatitis may occur.
→ In normal hosts, infections rarely occur in another organ system, although extraintestinal infections have been seen in immunocompromised hosts.
A 12-month-old comes into the office with a 5-day history of diarrhea. Stools are soupy without water loss and no blood has been seen. Vomiting is intermittent. No fever has been noted. There is no history of foreign travel, but the child attends daycare.
The most appropriate approach is:
Correct Answer D: This child most likely has a viral gastroenteritis as there is no blood, no fever, the diarrhea is not severe, and the illness is acute. It is best to manage this patient with dietary changes to rest the gastrointestinal tract and provide hydration. If there is no improvement in 2-3 days, consider further workup.
A. Stool culture and sensitivity are not cost effective until the illness is prolonged > 7-14 days or unless there is a history of bloody stools.
B. Parasitic causes are less likely in patients this young without a history of foreign travel.
C. Oral antidiarrheal medications are not necessary, and the risk of obstruction is greater than the benefits.
E. Antibiotics are not necessary because this illness is viral, and antibiotics may worsen the symptoms.
A 21-year-old primigravida has just given birth. Examining her infant, you note that it has what appears to be an enlarged protuberant clitoris along with partially fused, rugated, and pigmented labia majora. No palpable gonads are noted.
Which of the following enzyme defects is the infant most likely to have?
Correct Answer D: 21-hydroxylase (choice D) deficiency accounts for 95% of the cases of congenital adrenal hyperplasia. It is also the most frequent endocrine cause of neonatal death. With severe forms, salt wasting, shock, and significant virilization occur. The genes for this enzyme are within the HLA complex on the short arm of chromosome 6w.
→ 11 beta hydroxylase (choice A) deficiency is one of the causes of congenital adrenal hyperplasia, but it is much less common than 21 alpha hydroxylase deficiency.
→ 3 beta hydroxysteroid dehydrogenase (choice B) converts pregnenolone to progesterone as well as 17 OH prenenolone to 17 OH progesterone, as well as DHEA to androstenedione.
→ 17 beta hydroxysteroid dehydrogenase (choice C) converts androstenedione to testosterone and estrone to estradiol.
→ 17,20 desmolase (choice E) converts 17 OH pregnenolone to DHEA and 17 OH progesterone to androstenedione.
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