The patient in Question 40 is carefully evaluated. All electrolytes are normal, a plain abdominal x-ray (KUB) reveals multiple air fluid levels, but the barium small bowel follow-through is negative for an anatomic site of obstruction. The most likely etiology of the patient's distention and vomiting is

Correct Answer: D

Rationale: The correct answer is D) intestinal pseudo-obstruction. Intestinal pseudo-obstruction is characterized by symptoms similar to a mechanical bowel obstruction but without a physical blockage. In this case, the absence of an anatomic site of obstruction on the barium small bowel follow-through suggests a functional issue like pseudo-obstruction. This condition can cause severe distention and vomiting due to impaired bowel motility. Option A) hypothyroidism is incorrect because it typically presents with a different set of symptoms, such as fatigue, weight gain, and cold intolerance, rather than acute GI issues. Option B) congenital microvillus inclusion disease is incorrect as it is a rare genetic disorder resulting in severe diarrhea and malabsorption, not typically presenting with distention and vomiting. Option C) pancreatitis is unlikely in this case as it would typically present with abdominal pain, elevated pancreatic enzymes, and possibly changes on imaging studies like CT scans, which are not mentioned in the scenario. Educationally, understanding the differential diagnosis of pediatric GI disorders is crucial for healthcare providers to provide accurate and timely management. Recognizing the clinical presentation and investigative findings of conditions like intestinal pseudo-obstruction can guide appropriate treatment strategies and improve patient outcomes.

Correct Answer: B

Rationale: In this question regarding pediatric GI disorders, the correct answer is B) hyperkalemia. Hyperkalemia is not typically associated with causing constipation in pediatric patients. Constipation is more commonly linked to other metabolic disorders such as hypercalcemia, hypothyroidism, and diabetes mellitus. Hypercalcemia can lead to constipation due to its effect on smooth muscle function in the gastrointestinal tract. Hypothyroidism is known to slow down the digestive system, leading to constipation. Diabetes mellitus can also cause constipation as a result of nerve damage affecting the proper functioning of the intestines. In an educational context, understanding the relationship between metabolic disorders and GI symptoms is crucial for healthcare professionals caring for pediatric patients. By knowing the specific associations between different disorders and gastrointestinal manifestations, healthcare providers can make accurate assessments and provide appropriate interventions for children with GI issues.

Correct Answer: B

Rationale: Rationale: Periodontitis is a condition characterized by inflammation of the gums and damage to the surrounding structures of the teeth. In this case, option B, hypophosphatasia, is the correct answer as it is not typically associated with periodontitis. Leukocyte adhesion defects (Option A) can result in impaired immune response, making individuals more susceptible to periodontitis due to poor defense against bacteria in the gums. Leukemia (Option C) is a type of cancer that can affect the production of white blood cells, increasing the risk of infections like periodontitis. Vitamin D-resistant rickets (Option D) can lead to bone abnormalities, including changes in the structure of the jawbone, which can contribute to periodontal issues. In an educational context, understanding the associations between various medical conditions and periodontitis is crucial for healthcare professionals, especially in pediatric patients. Identifying these relationships can aid in early diagnosis, appropriate management, and prevention of complications related to periodontal disease in children. This knowledge is essential for pediatric dentists, pediatricians, and other healthcare providers who care for children with complex medical conditions.

Correct Answer: B

Rationale: In the case of acute diarrhea in infancy, the most common cause is overfeeding, making option B the correct answer. Overfeeding can overwhelm the infant's gastrointestinal system, leading to diarrhea as the body tries to rid itself of the excess nutrients. This scenario is common in infants who are fed too much formula or solid foods. Option A, primary disaccharidase deficiency, is less likely to be the cause of acute diarrhea in infancy. This condition involves the inability to break down certain sugars properly and usually presents with chronic diarrhea rather than sudden onset acute diarrhea. Hirschsprung disease, option C, is a congenital condition where nerve cells are missing in the colon, leading to severe constipation rather than acute diarrhea. Option D, adrenogenital syndrome, is a hormonal disorder that typically does not present with acute diarrhea in infancy. Educationally, understanding the common causes of acute diarrhea in infants is crucial for healthcare providers working with pediatric patients. Proper feeding practices and recognizing symptoms can help prevent and manage episodes of diarrhea in infants effectively. This knowledge is essential for pediatric nurses, pediatricians, and other healthcare professionals caring for infants.

Correct Answer: C

Rationale: In the context of pediatric GI disorders, contrast radiographic studies play a crucial role in diagnosing various conditions. In this case, the correct answer is C) GERD (Gastroesophageal Reflux Disease). Contrast studies are less sensitive and specific for GERD because it primarily involves assessing the function of the lower esophageal sphincter and detecting esophageal acid exposure, which are better evaluated through pH monitoring and endoscopy. A) Achalasia is a motility disorder characterized by impaired esophageal peristalsis and failure of the lower esophageal sphincter to relax. This condition is better diagnosed through manometry and endoscopy rather than contrast studies. B) Esophageal strictures are often visualized well on contrast studies, showing narrowing of the esophagus. However, the underlying cause of the stricture, such as inflammation, reflux, or external compression, may require additional tests like endoscopy for a definitive diagnosis. D) Gastric outlet obstruction involves a blockage that prevents the normal passage of stomach contents into the small intestine. While contrast studies can help identify the location and nature of the obstruction, other imaging modalities like ultrasound or CT scans may provide more detailed information. Educationally, understanding the limitations and strengths of diagnostic tools is essential for healthcare providers managing pediatric patients with GI disorders. It highlights the importance of selecting the most appropriate diagnostic tests based on the suspected condition to ensure accurate and timely diagnosis, ultimately leading to better patient outcomes.