Gastro Flashcards
You suspect that a newborn has Hirschsprung disease.
What is the best diagnostic test?
Suction rectal biopsy
Explanation
Rectal biopsy is the gold standard procedure for diagnosis. The most commonly used tool is the suction rectal biopsy, a simple instrument that can be used on infants in the outpatient clinic. Diagnosis is based on the absence of any ganglion cells detected in a biopsy containing adequate submucosa.
A 2-year-old girl presents to the emergency department with several hours of painless, brisk rectal bleeding. Her hemoglobin is falling, and has needed an infusion of PRBCs. She has no other past medical history.
What is the most likely diagnosis?
Meckel diverticulum
Explanation
Most Meckel diverticula are asymptomatic, and occur in 1% of the population. In children, the most common presentation is small bowel obstruction (e.g. intussusception), or brisk, painless rectal bleeding. Some diverticula contain ectopic gastric mucosa. Diagnosis is with a Meckel scan (if gastric mucosa is present) or laparoscopy. Treatment is surgical resection of the diverticulum.
Hamartomatous polyps Hemihypertrophy Gigantism of the extremities Angiomas Pigmented nevi What syndrome presents with these findings?
Proteus syndrome
Explanation
Proteus syndrome is an extremely rare disorder that results from a mutation in the AKT1 gene, which is responsible for regulating cell growth and division. The defect is not inherited but instead occurs randomly in one cell during fetal development. As the cells continue to divide, some will be affected and some will not (i.e., mosaicism). Remember this one on an exam if they describe a patient with hemihypertrophy and hamartomata.
You receive a phone call from a parent of a 5-year-old saying that her son has had diarrhea most of the day. She brings him into the office for evaluation, and you note that he is mildly dehydrated and does not have any other issues or diseases.
What is the best therapy?
Oral rehydration therapy
Explanation
Oral rehydration is the best treatment for acute diarrhea. Commercial electrolyte formulations for children are available. Do not recommend “clear” liquids like juices, soft drinks, or sports drinks because they are hypertonic and have excess glucose or fructose, which prolongs the diarrheal state. Additionally, during an acute infectious diarrheal illness, the AAP recommends continuing a regular diet so that enterocytes can be quickly regenerated and normal digestion can resume.
What is the most common identifiable cause of chronic gastritis in children?
Helicobacter pylori
Explanation
An acute infection of H. pylori can result in nausea, vomiting, decreased appetite, and epigastric abdominal pain, with a short period of increased acid secretion followed by a marked decrease in acid production. The acute symptoms last only about 1 week. A large majority with chronic H. pylori do not have symptoms. Diagnose with biopsy, rapid urease test, urea breath test, or stool antigen test. Treatment is with a combination of antibiotics (typically a macrolide and amoxicillin) and a proton pump inhibitor.
A 15-year-old girl presents with malaise, weight loss, and anorexia. She has occasional jaundice. She has anti-smooth muscle antibodies (ASMA).
What is the most likely diagnosis?
Autoimmune hepatitis (AIH) Type I Explanation AIH Type I is the classic form. It affects girls more than boys and presents between 10 and 20 years of age. ANA is almost always seen, and the more specific ASMA is seen in up to 80% of cases (positive titers for both are > 1:20 in children, > 1:80 in adults). Family history of other autoimmune diseases may be present as well. The key finding is the presence of ASMA!
Bowel involvement can be anywhere from mouth to anus. The lesions skip and are not continuous. Lesions are transmural. Granulomas may be seen in biopsy. Weight loss is much more common. Perianal lesions are common. Aphthous ulcers are more common. Fistulas can occur. Which inflammatory bowel disease is associated with these findings?
Crohn disease
Explanation
Crohn disease is mainly seen in adolescent children. It commonly presents with abdominal pain and bloody diarrhea. Weight loss and growth failure are much more common with Crohn’s than with ulcerative colitis. The terminal ileum is most commonly involved, with 70% of pediatric patients also having some colonic involvement (generally the cecum and/or ascending colon). Although granulomas are considered diagnostic of Crohn disease, they are only seen ~ 40% of the time.
A 1-month-old presents with:
Acute bilious emesis
Abdominal distention
Irritability
Upper GI series shows “bird’s beak” of the 2nd portion of the duodenum.
What is the most likely diagnosis?
Malrotation of the intestines
Explanation
Malrotation of the intestines occurs in about 1/6,000 births. Nonrotation is the most common malrotation abnormality and presents with the cecum to the left and the small intestine to the right of the superior mesenteric artery. The “bird’s beak” is where the gut is twisted. The upper GI series will also demonstrate jejunum to the right of the midline, and failure of contrast to pass the midline at the ligament of Trietz. If not treated, this can lead to volvulus, small bowel obstruction, and bowel necrosis. Treatment is with the Ladd procedure
A 16-year-old boy presents with:
Painful swallowing
Chest discomfort
History of nodular acne on oral doxycycline
What is the most likely diagnosis?
Pill-induced esophagitis
Explanation
Pill-induced esophagitis is fairly common in adolescents who swallow their pills “dry.” Think of this in a teenager with chest pain who is on doxycycline for acne. The most common location for the pill to be stuck is the midesophagus. Symptoms usually begin soon after ingestion, and patients have retrosternal pain and dysphagia. History is usually diagnostic and symptoms resolve in 1–3 weeks. Generally, no specific therapy is necessary, other than advising the patient to take his pills with water.
Core
What is the most common anatomical esophageal abnormality?
Esophageal atresia with distal tracheoesophageal fistula
Explanation
The infant presents in the delivery room with excessive oral secretions and appears to be choking frequently, especially when trying to feed. Diagnose by trying to place a nasogastric tube into the stomach; the blind pouch of the esophagus prevents its passage. EA with distal TEF occurs in 87% of all esophageal atresias. Treatment is surgical repair.
Children with sickle cell disease are prone to developing what complication associated with their gallbladder?
Cholelithiasis (gallstones)
Explanation
Cholelithiasis is also common in children on chronic TPN and in pregnant adolescent females. The most common complication of gallstones is pancreatitis due to an obstructing stone in the common bile duct.
A 12-year-old boy presents with:
Fatigue and anorexia initially
Indigestion and periumbilical discomfort follow.
Fever to 102.0° F (38.9° C) develops quickly with nausea and vomiting.
Complains of abdominal pain when you accidentally bump the examination table
What is the most likely diagnosis?
Acute appendicitis
Explanation
This is the classic cascade of events for acute appendicitis. The only thing missing is at the end, where the pain becomes localized to the right lower quadrant of the abdomen (localization to the RLQ is less likely to occur in children). The diagnosis can be confirmed with ultrasound (preferred) or abdominal CT. Treatment is pre-operative broad spectrum antibiotics and then emergent surgical removal.
A breastfed 2-month-old only passes soft stool once every 5–10 days.
What workup should you initiate?
None, reassure
Explanation
Some breastfed infants pass stool once every 5–10 days. In the absence of other signs or symptoms, they do not need evaluation or treatment. Some older children pass stool only every 3–4 days; they do not have any other symptoms, and this pattern often continues into adulthood.
Wilson disease is a metabolism disorder of what mineral?
Copper
Explanation
Wilson disease is an autosomal recessive disorder of copper metabolism that results in excessive accumulation of copper in the eyes, liver, kidneys, and brain. Kayser-Fleischer rings in the cornea are a classic presentation.
Skin
Mucous membranes
Breast
Thyroid with hyperkeratotic papillomas of the lips and tongue
What syndrome has multiple hamartomas of these areas?
Cowden syndrome
Explanation
Cowden syndrome is very rare. It is most commonly (85%) caused by a mutation on the PTEN tumor suppressor gene on chromosome locus 10q22–23. Cases of Cowden syndrome, along with Bannayan-Riley-Ruvalcaba syndrome (BRRS), are diagnosed as PTEN harmartoma tumor syndrome (PHTS) when the PTEN mutation is identified. For Cowden syndrome, the hyperkeratotic papillomas of the lips and tongue are characteristic.
Which hepatitis virus is composed of DNA?
Hepatitis B
Explanation
Hepatitis B is the only hepatitis virus composed of DNA. The remainder are RNA viruses.
What is the most reliable noninvasive test for lactase deficiency?
Breath hydrogen test
Explanation
When carbohydrate is malabsorbed, bacteria in the colon produce hydrogen gas. This is then absorbed across the colon mucosa into the bloodstream, transported to the lungs, and expired. In the breath hydrogen test, breath is tested sequentially after the patient is given a test carbohydrate substance. If expired hydrogen rises > 10–20 ppm, then carbohydrate is not being absorbed properly. The best test for lactase deficiency is a direct assay from a mucosal biopsy, but this is invasive and requires upper endoscopy to obtain a sample.
