Abdominal Wall Defects — MCQs
Anorectal anomalies are commonly associated with which of the following congenital anomalies?
Which of the following procedures is not performed in a case of complete hydatidiform mole (CHM)?
Which one of the following life-threatening congenital anomalies in the newborn presents with polyhydramnios, aspiration pneumonia, excessive salivation and difficulty in passing a nasogastric tube?
Omphalocele is caused by:-
What are the clinical implications of the persistence of an omphalomesenteric duct?
Which of the following is a derivative of ventral mesogastrium ?
Which ultrasound finding is associated with trisomy 21 in a fetus?
Investigation of choice to diagnose hypertrophic pyloric stenosis in infants is
The covering of an omphalocele is derived from which of the following layers?
What is the diagnosis based on the image shown?
Abdominal Wall Defects Indian Medical PG Practice Questions and MCQs
Question 1: Anorectal anomalies are commonly associated with which of the following congenital anomalies?
- A. Cardiac anomalies (Correct Answer)
- B. Duodenal atresia
- C. CNS malformations
- D. Abdominal wall defects
Explanation: ***Cardiac anomalies*** - **Cardiac anomalies** occur in approximately 30-50% of patients with **anorectal malformations**, making them the most commonly associated congenital anomaly. - These can range from simple septal defects to complex **congenital heart diseases**, often requiring surgical intervention. *Duodenal atresia* - **Duodenal atresia** is a common gastrointestinal anomaly but is less frequently associated with **anorectal malformations** compared to cardiac anomalies. - It typically presents with **bilious vomiting** and a "double bubble" sign on X-ray, which is not directly linked to the embryological development of the anorectum. *CNS malformations* - **CNS malformations**, such as **spinal dysraphism** (e.g., tethered cord, myelomeningocele), are certainly associated with **anorectal malformations**, particularly in the context of **VACTERL association**. - While significant, their incidence is generally lower than that of **cardiac anomalies** in this group. *Abdominal wall defects* - **Abdominal wall defects** like **omphalocele** or **gastroschisis** are distinct congenital anomalies with different embryological origins than **anorectal malformations**. - They are not considered a primary or most common associated anomaly with **anorectal malformations**.
Question 2: Which of the following procedures is not performed in a case of complete hydatidiform mole (CHM)?
- A. Blood transfusion
- B. Urine microscopy and culture sensitivity
- C. Caesarean section (Correct Answer)
- D. Abortion
Explanation: ***Caesarean section*** - Caesarean section is **NOT performed** for the management of complete hydatidiform mole (CHM). - The standard treatment for CHM is **suction evacuation (suction curettage)**, which is the procedure of choice for removing molar tissue from the uterus. - Caesarean section is a surgical procedure for **delivering a fetus**, not for evacuating gestational trophoblastic disease. - There is **no indication** for Caesarean section in CHM management, even in cases of large molar volume. *Abortion (Suction evacuation)* - **Suction evacuation/curettage** is the primary and definitive treatment for complete hydatidiform mole. - This procedure involves removing the abnormal trophoblastic tissue from the uterus under ultrasound guidance. - It is sometimes referred to as therapeutic abortion in the medical literature. - **Oxytocin infusion** is typically started after evacuation begins to minimize bleeding. *Blood transfusion* - CHM can present with **significant vaginal bleeding**, potentially leading to severe anemia. - **Blood transfusion** may be necessary to correct anemia and stabilize hemodynamic status. - Pre-operative **hemoglobin assessment** and blood grouping/cross-matching are routine in CHM management. *Urine microscopy and culture sensitivity* - While not a routine part of CHM management, this test **may be performed** if there are clinical signs of urinary tract infection. - Patients with CHM may have urinary symptoms due to uterine enlargement or other complications. - This is **not a standard procedure** for all CHM cases but may be indicated based on clinical presentation.
Question 3: Which one of the following life-threatening congenital anomalies in the newborn presents with polyhydramnios, aspiration pneumonia, excessive salivation and difficulty in passing a nasogastric tube?
- A. Choanal atresia
- B. Gastroschisis
- C. Diaphragmatic hernia
- D. Tracheo-esophageal fistula (Correct Answer)
Explanation: ***Tracheo-esophageal fistula*** - This condition presents with **polyhydramnios** due to the fetus being unable to swallow amniotic fluid, **excessive salivation** from accumulated secretions in the blind-ending esophageal pouch, and difficulty passing a **nasogastric tube** because of the esophageal obstruction. - **Aspiration pneumonia** is a common complication as saliva and gastric contents can be aspirated into the lungs through the fistula. *Choanal atresia* - Characterized by **blocked nasal passages**, leading to **cyclical cyanosis** relieved by crying, but not typically associated with polyhydramnios or excessive salivation in this manner. - While it can cause respiratory distress, it does not involve esophageal obstruction or directly cause aspiration pneumonia from swallowed fluids. *Gastroschisis* - This is an **abdominal wall defect** where intestines protrude outside the body, unrelated to swallowing difficulties, polyhydramnios caused by inability to swallow, or excessive salivation. - It does not involve difficulty in passing a nasogastric tube or directly cause aspiration pneumonia. *Diaphragmatic hernia* - Involves **abdominal contents herniating into the chest cavity**, leading to **pulmonary hypoplasia** and respiratory distress. - It does not explain polyhydramnios due to impaired swallowing, excessive salivation, or the characteristic inability to pass a nasogastric tube.
Question 4: Omphalocele is caused by:-
- A. Duplication of intestinal loops
- B. Failure of gut to return to body cavity after its physiological herniation (Correct Answer)
- C. Abnormal rotation of intestinal loops
- D. Reversed rotation of intestinal loops
Explanation: Failure of gut to return to body cavity after its physiological herniation - **Omphalocele** results from a failure of the midgut to properly return to the abdominal cavity after its normal physiological herniation into the umbilical cord during fetal development (around the 6th to 10th week of gestation). - The abdominal muscles fail to close, and the herniated organs (intestines, liver) are covered by a **peritoneal sac** at the base of the umbilical cord. *Duplication of intestinal loops* - **Intestinal duplications** are congenital malformations typically presenting as cystic or tubular structures that are intimately associated with the gastrointestinal tract. [1] - They do not involve the herniation of abdominal contents outside the body cavity. *Abnormal rotation of intestinal loops* - **Malrotation of the gut** refers to abnormal positioning of the intestines within the abdominal cavity due to incomplete or arrested rotation during development. - This can lead to conditions like volvulus but does not involve the organs being outside the abdominal cavity. *Reversed rotation of intestinal loops* - **Reversed rotation** is a very rare form of malrotation where the third stage of midgut rotation occurs in reverse, leading to the small intestine being positioned anterior to the superior mesenteric artery and the colon posterior. - This condition affects the internal arrangement of organs within the abdomen, not their external herniation.
Question 5: What are the clinical implications of the persistence of an omphalomesenteric duct?
- A. Gastroschisis
- B. Omphalocele
- C. Ectopia vesicae
- D. Meckel's diverticulum (Correct Answer)
Explanation: ***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.
Question 6: Which of the following is a derivative of ventral mesogastrium ?
- A. Lesser omentum (Correct Answer)
- B. Splenorenal ligament
- C. Greater omentum
- D. Gastrosplenic ligament
Explanation: ***Lesser omentum*** - The **lesser omentum** is formed from the **ventral mesogastrium**, which connects the developing stomach to the anterior abdominal wall [1]. - It specifically derives from the part of the ventral mesogastrium that encloses the developing liver and extends to the lesser curvature of the stomach and the duodenum [1]. *Greater omentum* - The **greater omentum** develops from the **dorsal mesogastrium**, which means it is a derivative of the dorsal rather than the ventral mesentery [1]. - It arises from a rapid growth and fusion of the **dorsal mesogastrium**, hanging from the greater curvature of the stomach. *Splenorenal ligament* - The **splenorenal ligament** develops from the **dorsal mesogastrium**, specifically from the portion that connects the spleen to the posterior abdominal wall (near the kidney). - Its formation is a consequence of the rotation of the stomach and the development of the spleen within the dorsal mesentery. *Gastrosplenic ligament* - The **gastrosplenic ligament** is also derived from the **dorsal mesogastrium**, connecting the greater curvature of the stomach to the hilum of the spleen. - As the stomach rotates, the dorsal mesogastrium expands, eventually forming both the gastrosplenic and splenorenal ligaments.
Question 7: Which ultrasound finding is associated with trisomy 21 in a fetus?
- A. Choroid plexus cysts
- B. Echogenic foci in heart
- C. Hyperechogenic bowel
- D. Nuchal edema (Correct Answer)
Explanation: ***Nuchal edema*** - Increased nuchal translucency, or nuchal edema, is a classic and **strong marker for Trisomy 21** during the first-trimester ultrasound screening. - This finding reflects fetal lymphatic dysfunction and is a key indicator for further diagnostic testing. *Choroid plexus cysts* - While sometimes seen in Trisomy 18 (Edwards Syndrome), choroid plexus cysts are generally considered a **soft marker for aneuploidy** and are **rarely isolated findings** in Trisomy 21. - Many fetuses with choroid plexus cysts are chromosomally normal, especially if there are no other associated anomalies. *Echogenic foci in heart* - Intracardiac echogenic foci, often called a "golf ball sign," are a **minor or soft marker for aneuploidy**, including Trisomy 21, but their isolated finding has a **low predictive value**. - They represent mineralization within a papillary muscle and are often benign, especially in the absence of other risk factors or anomalies. *Hyperechogenic bowel* - Hyperechogenic bowel is a **non-specific finding** that can be associated with various conditions, including cystic fibrosis, intrauterine infection, or fetal growth restriction, as well as aneuploidy. - While it can be a soft marker for Trisomy 21, its presence alone is not a strong indicator without other associated anomalies.
Question 8: Investigation of choice to diagnose hypertrophic pyloric stenosis in infants is
- A. Gastroscopy
- B. CT scan abdomen
- C. Ultrasound abdomen (Correct Answer)
- D. Contrast radiology
Explanation: ***Ultrasound abdomen*** - **Abdominal ultrasound** is the diagnostic procedure of choice due to its **non-invasive nature**, **lack of radiation exposure**, and high accuracy in visualizing the pylorus. - It allows for direct measurement of the **pyloric muscle wall thickness** (typically >3-4 mm) and **pyloric channel length** (typically >14-17 mm), which are characteristic findings of hypertrophic pyloric stenosis. *Gastroscopy* - While gastroscopy can visualize the gastric outlet, it is an **invasive procedure** and not the primary diagnostic tool due to the risk associated with endoscopy in infants. - It is often reserved for cases where the diagnosis is unclear or other upper gastrointestinal pathologies are suspected. *CT scan abdomen* - **CT scans** expose infants to **ionizing radiation**, making it an unsuitable primary diagnostic investigation, especially when a highly accurate non-irradiating alternative exists. - Although it can show pyloric thickening, its disadvantages outweigh its benefits for this diagnosis. *Contrast radiology* - **Barium studies** are less sensitive and specific than ultrasound for diagnosing pyloric stenosis, especially for distinguishing muscle thickening from spasm. - This method also involves **radiation exposure** and poses a risk of aspiration, making it a secondary choice.
Question 9: The covering of an omphalocele is derived from which of the following layers?
- A. Amnion (Correct Answer)
- B. Chorion
- C. Mesoderm
- D. Endoderm
- E. Ectoderm
Explanation: ***Amnion*** - An **omphalocele** is a congenital abdominal wall defect where abdominal contents protrude through the umbilical ring, covered by a sac derived from the **amnion** and peritoneum. - The covering of an omphalocele defect is an intact peritoneal sac that is covered externally by **amnion**. *Chorion* - The **chorion** is the outermost membrane surrounding an embryo, providing protection and nourishment, but it does not form the covering of an omphalocele. - It works in conjunction with the decidua to form the **placenta** and has finger-like projections called villi on its outer surface. *Mesoderm* - The **mesoderm** is one of the three primary germ layers in embryonic development, giving rise to connective tissue, muscle, and blood cells. - **Fetal skin**, not the omphalocele covering, develops from the mesoderm and ectoderm. *Endoderm* - The **endoderm** is the innermost of the three primary germ layers, giving rise to the lining of the digestive tract and respiratory system. - The omphalocele covering is derived from the amnion, not the endoderm, which is involved in forming internal organs. *Ectoderm* - The **ectoderm** is the outermost of the three primary germ layers, giving rise to the nervous system, skin epidermis, and sensory organs. - While ectoderm contributes to skin development, the omphalocele sac is specifically covered by amnion, not ectodermal derivatives.
Question 10: What is the diagnosis based on the image shown?
- A. Ileal diverticulum
- B. Urachal cyst
- C. Umbilical fistula (Correct Answer)
- D. Omphalocele
Explanation: ***Umbilical fistula*** - The image shows a **patent vitelline duct (omphalomesenteric duct)**, which creates a direct connection between the umbilicus and the ileum, visible as an umbilical fistula. - This condition presents with **fecal discharge from the umbilicus** or **umbilical prolapse of intestinal mucosa**. *Ileal diverticulum* - An ileal diverticulum, such as a **Meckel's diverticulum**, is a blind pouch protruding from the ileum, usually not communicating with the umbilicus. - It would typically be noted as an **outpouching of the ileal wall**, without an external opening at the umbilicus unless complicated by rupture. *Urachal cyst* - A urachal cyst is a remnant of the **urachus**, which connects the bladder to the umbilicus during fetal development. - It would be located **between the umbilicus and the bladder** and contain urine or serous fluid, not intestinal contents. *Omphalocele* - An omphalocele is a **congenital abdominal wall defect** where abdominal organs protrude into the base of the umbilical cord. - The defect is **covered by a membrane**, and it involves herniation of abdominal contents, not a fistula with the intestine.
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