Gastroenterology Practice Questions

Q: What is true regarding congenital hypertrophic pyloric stenosis?

Hypochloremic alkalosis. ***Hypochloremic alkalosis*** - The forceful vomiting in pyloric stenosis leads to a significant loss of **hydrochloric acid** from the stomach, resulting in **metabolic alkalosis**. - Additionally, the loss of gastric fluid containing chloride contributes to **hypochloremia**. *More common in girls* - **Congenital hypertrophic pyloric stenosis** is significantly more common in **boys**, with a male-to-female ratio of about 4:1. - This gender predilection is a key epidemiological feature of the condition. *Heller's myotomy is the procedure of choice* - **Ramstedt pyloromyotomy** is the standard surgical procedure for pyloric stenosis, involving the incision of the hypertrophied pyloric muscle. - **Heller's myotomy** is a procedure typically performed for **achalasia**, a disorder of the esophagus, not pyloric stenosis. *Most often manifests at birth* - Symptoms of pyloric stenosis usually manifest between **2 and 8 weeks of age**, not immediately at birth. - The hypertrophy of the pyloric muscle takes time to progress sufficiently to cause significant obstruction.

Q: A 4-year-old girl weighing 12 kg, with diarrhea, skin pinch that goes back very slowly, and who is unable to drink, is most likely to:

Start IV fluids per Plan C. ***Start IV fluids per Plan C*** - The child presents with **severe dehydration** based on WHO criteria: **skin pinch goes back very slowly** (>2 seconds) and **unable to drink**. - These two signs mandate immediate **Plan C management** which involves rapid IV fluid resuscitation using **Ringer's Lactate or Normal Saline**. - WHO Plan C protocol: Give **100 ml/kg** IV fluids divided as 30 ml/kg in first hour (if <12 months) or first 30 minutes (if ≥12 months), then 70 ml/kg over next 2.5-5 hours. - Plan C is specifically designed for **severe dehydration** requiring immediate intravenous rehydration, not Plan B which is for moderate dehydration with oral rehydration. *Discharge home with oral fluids* - Discharging a child with **severe dehydration** is inappropriate and potentially life-threatening. - The child **cannot drink** effectively, making home management with oral fluids impossible and dangerous. - This would lead to worsening dehydration, shock, and potentially fatal complications. *Monitor for worsening dehydration* - While monitoring is important, this child requires **immediate active intervention**, not observation alone. - Delaying IV rehydration in a child with **severe dehydration** (unable to drink, very slow skin pinch) could lead to hypovolemic shock, acute kidney injury, and death. *Attempt oral rehydration with ORS* - This child is **unable to drink**, making ORS ineffective and contraindicated. - Oral rehydration (Plan B) is appropriate only for **moderate dehydration** in children who are conscious, alert, and able to drink. - Attempting ORS in a child unable to drink delays appropriate IV therapy and worsens outcomes.

Q: A 12 kg child with diarrhoea and some dehydration: based on WHO guidelines, how much fluid should be replaced in the first 4 hours?

800-1200 ml. ***800-1200 ml*** - For a child weighing **12 kg** with **some dehydration** due to diarrhea, WHO Plan B recommends **75 mL/kg** over 4 hours. - Therefore, 12 kg × 75 mL/kg = **900 mL**, which falls within this range. - This range allows for slight variations in clinical practice while staying close to the WHO standard guideline. *0-400 ml* - This range is significantly **too low** for a 12 kg child with some dehydration, as it would not adequately address the fluid deficit. - Inadequate fluid replacement can lead to worsening dehydration and its associated complications, such as **persistent signs of dehydration or progression to severe dehydration**. *400-800 ml* - While higher than the lowest option, **400-800 mL** is still generally insufficient for a 12 kg child needing rehydration over 4 hours per WHO Plan B. - This amount would only partially correct the fluid deficit, potentially delaying recovery and necessitating further interventions. *1200-1600 ml* - This range is **excessive** for WHO Plan B rehydration in a 12 kg child over 4 hours, potentially leading to **fluid overload**. - While adequate rehydration is crucial, administering significantly more than 75 mL/kg can increase the risk of complications, especially in children with underlying cardiac or renal conditions.

Q: Most common genetic mutation associated with Hirschsprung's disease is:

RET gene. ***RET gene*** - Mutations in the **RET proto-oncogene** are the most common genetic cause of Hirschsprung's disease, accounting for up to 50% of familial cases and 15-20% of sporadic cases. - The RET gene codes for a **receptor tyrosine kinase** involved in the development of the enteric nervous system. *EDN3 gene* - The **EDN3 gene** (endothelin 3) plays a role in Hirschsprung's disease; however, mutations in this gene are much less common than those in the RET gene. - EDN3 mutations are typically associated with a smaller subset of Hirschsprung's cases. *ATP 7A* - The **ATP7A gene** is associated with **Menkes disease**, a disorder of copper transport, not Hirschsprung's disease. - This gene codes for a copper-transporting ATPase. *EDNRB gene* - The **EDNRB gene** (endothelin receptor type B) is involved in some cases of Hirschsprung's disease, but mutations in this gene are less frequent than RET mutations. - It works in conjunction with EDN3 in neural crest cell development.

Q: What are the clinical implications of the persistence of an omphalomesenteric duct?

Meckel's diverticulum. ***Meckel's diverticulum*** - The **omphalomesenteric duct**, also known as the **vitelline duct**, normally obliterates during fetal development. **Meckel's diverticulum** is the most common congenital abnormality of the small intestine, resulting from the incomplete obliteration of the vitelline duct. - This remnant can contain **heterotopic gastric or pancreatic tissue**, leading to complications like **bleeding**, **obstruction**, or **inflammation (diverticulitis)**. *Gastroschisis* - **Gastroschisis** is a birth defect where the intestines and other abdominal organs protrude *outside* the body through a hole next to the naval, *without* a covering membrane. - This condition is not directly caused by the persistence of the omphalomesenteric duct; it's a defect in the **anterior abdominal wall closure**. *Omphalocele* - **Omphalocele** is a birth defect in which the intestines and other abdominal organs protrude *into* the umbilical cord and are covered by a membrane. - This condition also results from a failure of abdominal wall closure during development and is distinct from abnormalities of the omphalomesenteric duct. *Ectopia vesicae* - **Ectopia vesicae**, or **bladder exstrophy**, is a rare birth defect where the bladder is exposed *outside* the body through a defect in the abdominal wall and bladder closure. - This defect is related to a developmental failure of the infraumbilical abdominal wall and the anterior bladder wall, entirely separate from the omphalomesenteric duct.

Q: Aganglionic segment is encountered in which part of the colon in case of Hirschsprung's disease?

Distal to dilated segment. ***Distal to dilated segment*** - In **Hirschsprung's disease**, the aganglionic (lacking nerve ganglia) segment is always located **distal to the dilated segment**. - The dilated segment occurs because stool accumulates *proximal* to the constricted aganglionic portion, which cannot relax to allow passage. - The aganglionic segment is typically in the **rectosigmoid region** (80% of cases), though it can extend more proximally. *In whole colon* - Total colonic aganglionosis is a very rare form of Hirschsprung's disease (~5% of cases), but it's not the typical presentation where a specific segment is affected. - The classic presentation involves a shorter segment of aganglionosis, usually in the rectosigmoid. *Proximal to dilated segment* - The segment *proximal* to the aganglionic zone is typically the normal, ganglionated segment that becomes enlarged due to fecal backup. - The pathology in Hirschsprung's disease is the *absence* of ganglia in the distal segment, not proximal to the obstruction. *In dilated segment* - The dilated segment is **not aganglionic**; it is the normal, ganglionated colon that has hypertrophied and distended due to the obstruction from the distal aganglionic segment. - The problem is *distal* to this dilated, functional (but obstructed) colon.

Q: A newborn child who has not passed meconium for 48 hours. What is the diagnostic procedure of choice?

Contrast enema. **Contrast enema** - A **contrast enema** is the diagnostic procedure of choice to visualize the colon and rectum, evaluate for a **transition zone**, and identify potential causes of **meconium retention**, such as **Hirschsprung disease** or **meconium plug syndrome**. - It can differentiate between various causes of neonatal intestinal obstruction by showing the caliber of the bowel lumen and the presence of any filling defects. *USG* - **Ultrasound** (USG) is generally not the primary diagnostic tool for evaluating delayed meconium passage as it provides limited information about the detailed anatomy and function of the intestinal lumen necessary for diagnosing conditions like **Hirschsprung disease**. - While it can detect some abdominal abnormalities, it is less effective for defining the specific causes of distal intestinal obstruction in this context. *CT* - **Computed Tomography (CT)** scans expose the neonate to significant **ionizing radiation**, and its use is typically reserved for more complex cases or when other less invasive methods have been inconclusive. - While CT can provide detailed anatomical images, it is not the initial or preferred diagnostic procedure for evaluating delayed meconium passage due to the radiation risk and the effectiveness of **contrast enema**. *MRI* - **Magnetic Resonance Imaging** (MRI) also involves prolonged imaging times and may require sedation in neonates, making it less practical as a first-line diagnostic modality for delayed meconium passage. - Although it provides excellent soft tissue contrast, its role in diagnosing intestinal obstructions in newborns is limited, especially given the rapid and effective diagnostic capabilities of a **contrast enema**.

Q: A 5-year-old girl is brought to the physician after her parents notice red blood in her stool. Physical examination reveals mucocutaneous pigmentation. Small bowel radiography discloses multiple, small- to medium-sized polyps that are diagnosed pathologically as hamartomas. Which of the following is the most likely diagnosis?

Peutz-Jeghers syndrome. ***Peutz-Jeghers polyp*** - Characterized by **mucocutaneous pigmentation** and **hamartomatous polyps**, aligning perfectly with the clinical findings of this patient [1]. - Commonly causes gastrointestinal bleeding, as suggested by the presence of **red blood in stool**. *Congenital teratoma* - Generally involves **solid masses** and is **not typically associated** with gastrointestinal polyps or pigmentation. - Would present differently, often as a mass in the **abdomen** or pelvis rather than causing blood in the stool. *Tubular adenoma* - These are **neoplastic polyps** that do not present with **pigmentation**, which the patient has. - Typically associated with **malignant potential**, unlike hamartomas seen in this scenario. *Hyperplastic polyp* - Recognized as a **benign lesion**, which does not present with mucocutaneous **pigmentation** or gastrointestinal bleeding. - Lacks the characteristic features of **hamartomas**, making it an unlikely diagnosis in this case. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 813-815.

Question 1

What is true regarding congenital hypertrophic pyloric stenosis?

Accepted Answer

Hypochloremic alkalosis

Answer

Heller's myotomy is the procedure of choice

Answer

More common in girls

Answer

Most often manifests at birth

Question 2

A 4-year-old girl weighing 12 kg, with diarrhea, skin pinch that goes back very slowly, and who is unable to drink, is most likely to:

Accepted Answer

Start IV fluids per Plan C

Answer

Discharge home with oral fluids

Answer

Monitor for worsening dehydration

Answer

Attempt oral rehydration with ORS

Question 3

A 12 kg child with diarrhoea and some dehydration: based on WHO guidelines, how much fluid should be replaced in the first 4 hours?

Accepted Answer

800-1200 ml

Answer

0-400 ml

Answer

400-800 ml

Answer

1200-1600 ml

Question 4

The commonest cause of intestinal obstruction and abdominal pain in children between 3 months and 6 years of age is:

Accepted Answer

Intussusception

Answer

Meckel's diverticulum

Answer

Intestinal polyp

Answer

Nonspecific cause

Question 5

Most common genetic mutation associated with Hirschsprung's disease is:

Accepted Answer

RET gene

Answer

ATP 7A

Answer

EDNRB gene

Answer

EDN3 gene

Question 6

What are the clinical implications of the persistence of an omphalomesenteric duct?

Accepted Answer

Meckel's diverticulum

Answer

Gastroschisis

Answer

Omphalocele

Answer

Ectopia vesicae

Question 7

Aganglionic segment is encountered in which part of the colon in case of Hirschsprung's disease?

Accepted Answer

Distal to dilated segment

Answer

In whole colon

Answer

Proximal to dilated segment

Answer

In dilated segment

Question 8

A newborn child who has not passed meconium for 48 hours. What is the diagnostic procedure of choice?

Accepted Answer

Contrast enema

Answer

USG

Answer

CT

Answer

MRI

Question 9

What is the calculated fluid requirement for treating dehydration and maintenance over a 4-hour period in a 14 kg, 14-month-old child with a 4-day history of loose stools, decreased urine output, delayed skin pinch, sunken eyes, and dry mucosa?

Accepted Answer

1050 ml

Answer

700 ml

Answer

1200 ml

Answer

2000 ml

Question 10

A 5-year-old girl is brought to the physician after her parents notice red blood in her stool. Physical examination reveals mucocutaneous pigmentation. Small bowel radiography discloses multiple, small- to medium-sized polyps that are diagnosed pathologically as hamartomas. Which of the following is the most likely diagnosis?

Accepted Answer

Peutz-Jeghers syndrome

Answer

Congenital teratoma

Answer

Hyperplastic polyp

Answer

Tubular adenoma

Gastroenterology — MCQs

Gastroenterology — MCQs

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