10 MCQs on Anorectal Malformation for Postgraduate Trainees
These multiple-choice questions with clinical scenarios on anorectal malformations will help assess postgraduate trainees' knowledge of diagnosis, classification, associated anomalies, and management approaches.
Question 1
A newborn presents with absence of anal opening. On examination, there is meconium visible at a small opening in the perineum anterior to where the anus should be. What is the most likely diagnosis?
A) Rectourethral fistula B) Rectal atresia C) Perineal fistula D) Vestibular fistula E) Cloaca
Answer: C
Explanation: The presence of meconium at a small opening in the perineum anterior to the normal anal site is characteristic of a perineal fistula, which is considered a "low" anorectal malformation 1, 2.
Question 2
Which imaging study is most appropriate for evaluating the sphincteric musculature development in a 3-month-old infant with anorectal malformation before definitive repair?
A) Plain radiograph B) Barium enema C) Computed tomography D) Magnetic resonance imaging E) Ultrasound
Answer: D
Explanation: Magnetic resonance imaging is the most efficient diagnostic method for evaluating the size, morphology, and grade of development of the sphincteric musculature in anorectal malformations 3, 1.
Question 3
A 2-day-old female neonate has no visible anal opening. There is meconium coming from the vaginal introitus. What is the most appropriate initial management?
A) Immediate posterior sagittal anorectoplasty B) Anoplasty without colostomy C) Sigmoid colostomy followed by delayed repair D) Observation for 48 hours E) Perineal dilation
Answer: C
Explanation: For vestibular fistulas, the recommended approach is a sigmoid colostomy followed by a delayed repair (posterior sagittal anorectoplasty) at around 2-3 months of age 1, 2.
Question 4
Which of the following associated anomalies should be routinely screened for in all patients with anorectal malformations?
A) Cardiac anomalies only B) Renal anomalies only C) Vertebral anomalies only D) Renal, cardiac, and vertebral anomalies E) Limb anomalies only
Answer: D
Explanation: The American College of Radiology recommends screening for renal, cardiac, and vertebral anomalies in all patients with anorectal malformations, as up to 93% of fully screened ARM patients have associated anomalies 1.
Question 5
A 4-year-old child who underwent repair of a vestibular fistula as an infant now presents with fecal soiling. What is the most appropriate initial management approach?
A) Immediate reoperation B) Structured bowel management program with timed enemas C) Permanent colostomy D) Biofeedback therapy alone E) Antidiarrheal medications
Answer: B
Explanation: The American Academy of Pediatrics recommends implementing a structured bowel management program with timed enemas and dietary modifications as the initial approach to manage fecal incontinence in children with repaired anorectal malformations 1.
Question 6
During evaluation of a newborn with imperforate anus, which investigation should be avoided in the initial assessment?
A) Abdominal ultrasound B) Spinal ultrasound C) Probing to search for a fistula D) Echocardiogram E) Plain abdominal radiograph
Answer: C
Explanation: The American Academy of Pediatrics recommends against probing to search for fistulas to avoid iatrogenic complications in patients with anorectal malformations 1, 4.
Question 7
A 5-year-old boy who underwent repair of a perineal fistula as an infant now presents with severe constipation despite medical management. Which surgical intervention might be considered?
A) Redo anoplasty B) Partial sphincterotomy C) Permanent colostomy D) Malone procedure (continent appendicostomy) E) Sacral nerve stimulation
Answer: B
Explanation: In patients with anterior perineal anus and intractable constipation, a partial sphincterotomy has been shown to relieve painful evacuations in 96% of cases 2, 1.
Question 8
What percentage of patients with repaired perineal fistula can be expected to achieve voluntary bowel movements?
A) 25% B) 50% C) 75% D) 90% E) 100%
Answer: C
Explanation: The American Academy of Pediatrics reports that approximately 75% of patients with perineal fistula achieve voluntary bowel movements after appropriate repair 1.
Question 9
A pregnant woman's fetal ultrasound at 20 weeks shows findings suspicious for anorectal malformation. What is the most appropriate next step?
A) Immediate delivery B) Termination of pregnancy C) Detailed fetal ultrasound and fetal MRI D) Amniocentesis only E) No further evaluation needed until birth
Answer: C
Explanation: The American College of Obstetricians and Gynecologists recommends detailed fetal ultrasound and fetal MRI to better characterize the type of ARM and associated anomalies when anorectal malformation is suspected prenatally 1.
Question 10
An 8-year-old girl with repaired cloaca has persistent fecal incontinence despite a bowel management program. Which of the following interventions would most improve her quality of life?
A) Permanent colostomy B) Continent appendicostomy (Malone procedure) C) Sacral nerve stimulation D) Biofeedback therapy alone E) Antidiarrheal medications
Answer: B
Explanation: The American Academy of Pediatrics recommends considering continent appendicostomy (Malone procedure) to improve quality of life in patients with persistent fecal incontinence despite a bowel management program 1.