Sunday, January 13, 2008

14 - Pediatric Surgery Mcqs

1. Regarding inguinal hernias in children

(a) Boys are affected more often than girls
(b) Are less common in preterm infants
(c) In infants (less than one years old) approximately 50% present with incarceration
(d) 50% of hernias are bilateral
(e) Approximately 20% of patients will develop a contralateral hernia

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a , c , e are true . Inguninal hernias are the commonest surgical condition of childhood. Approximately 2% of male infants will develop an inguinal hernia and 99% will be indirect. The male : female ratio is 9:1. Inguinal hernias are more common on the right and 10% are bilateral. Prematurity is a significant risk factor. The risk of incareration is increased in infants and therefore a hernia presenting before one year of age requires urgent surgical assessment. Approximately 20% will develop a contralateral hernia. The role of contralateral groin exploration at the time of a unilateral herniotomy is controversial.

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2. Regarding undescended testes

(a) 75% of undescended testes descend in the first year of life
(b) Is associated with a reduced risk of testicular malignancy
(c) Is associated with an increased risk of infertility
(d) Surgery should be considered in the neonatal period
(e) Laparoscopy is indicated for impalpable testes

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a , c , e are true . Undescended testes afftect 3% of full-term boys. However, the majority of these lie in the inguinal canal and approximately 75% of undescended testes descend into the scrotum during the first year of life. Undescended testes are associated with an increased risk of testicular malignancy which develops in 5% of intra-abdominal testes. Overall, 80% of males with bilateral descended testes are fertile but only 30% of men with bilateral undescended testes have normal fertility. Surgery should be performed during the second year of life. Boys with a palpable testis should undergo a routine orchidopexy. Impalpable testes should be assessed with laparoscopy.

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3. Regarding testicular torsion

(a) The highest incidence is in the neonatal and peripubertal periods
(b) May present with abdominal pain and vomiting and few testicular symptoms
(c) Radiological investigation with doppler ultrasound or isotope scanning is invariably indicated
(d) Testicular viability is reduced if surgery is delayed more than 6 hours
(e) Contralateral orchidopexy should also be performed if a torsion is confirmed

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only c is wrong . The commonest causes of the 'acute scrotum' in childhood are testicular torsion, torsion of an appendix testis and idiopathic scrotal oedema. Testicular torsion can occur at any age but is most common in the neonatal and peripubertal periods. It usually presents with severe testicular pain but this may be absent and the testis should be examined in all boys with abdominal symptoms. If a torsion is clinically suspected then radiological investigations have littel to offer. None are diagnostic and may delay surgery. Testicular viability is reduced with increasing time from the onset of symtoms. Following reduction of a torsion 3-point fixation with an non-absorbable suture should be performed. The contralateral testis should also be fixed.

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4. Regarding exomphalos and gastroschisis

(a) A gastroschisis has a sac
(b) Gastroschisis is associated with major congenital abnormalities
(c) The postoperative mortality of surgery for gastroschisis approaches 50%
(d) Both conditions may be diagnosed prenatally with ultrasound
(e) Both conditions require delivery by caesarian section

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only d is right . Exomphalos and gastroschisis are two different congenital anomalies with different clinical appearances. They are usually diagnosed prenatally by ultrasound but do not inevitably require delivery by caesarian section. An exomphalos (ompalocele) has a sac, which may rupture, with umbilicus arising from the apex of the sac. The sac contains intestinal loops, liver and spleen. It is associated with major congenital anomalies and the prognosis depends on these associated lesions. A gastroschisi never has a sac and the umilical cord arises from the normal site on the abdominal wall. It is rarely associated with other congenital anomalies and the prognosis is better than for exomphalos.

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5. Congenital diaphragmatic hernia

(a) Usually occur through the foramen of Bochdalek
(b) Are more common on the right than the left
(c) Are rarely associated with other congenital anomalies
(d) Present with respiratory distress in the neonatal period
(e) Neonates usually require sedation, ventilation and intestinal decompression prior to surgery

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a , d , e are true . Congenital diaphragmatic hernia occurs in approximately 1 in 4,000 live births. 90% occur in the posterior portion of the diaphragm through the foramen of Bochdalek and 90% occur on the left. The commonest clinical presentation is with respiratory distress in the neonatal period and due pulmonary hypoplasia and compression. The abdomen often has a scaphoid appearance. About 40% of patients have assocaited congenital anomalies. The diagnosis can be confirmed radiologically with bowel loops seen in the chest. Neonates usually require sedation, ventilation and intestinal decompression prior to surgery between 36 and 72 hours after birth.

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6. Regarding oesophageal atresia and tracheo-oesophageal fistula (TOF)

(a) Most cases of oesophageal atresia are associated with a proximal TOF to the lower oesophagus
(b) Often present prenatally with oligohydramnios
(c) Postnatally present with difficulty swallowing and aspiration
(d) The diagnosis may be confirmed by the inability to pass a nasogastric catheter
(e) Radiological evidence of gas in the stomach confirms the presence of distal TOF

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c , d , e are true . Oesophageal atresia is often associated with tracheo-oesophageal fistula (TOF). Approximately 90% of patients have a distal TOF between the upper oesophagus and trachea. Polyhydramnios may be present prenatally. Postnatally the diagnosis my be confirmed by the inability to pass a nasogastric tube more than 10 cm. If doubt continues the diagnosis can be confirmed by passing a small volume of water-soluble contrast down the tube. Radiological evidence of gas in the stomach confirms a distal TOF. Primary repair of the atresia is possible in a significant proportion of neonates

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7. Regarding meconium ileus

(a) Is a rare cause of neonatal intestinal obstruction
(b) Less than 5% of cases are associated with cystic fibrosis
(c) Obstruction usually occurs in the distal ileum
(d) Presents with neonatal bile-stained vomiting and abdominal distension
(e) A plain x-ray may show an intra-luminal 'ground glass' appearance

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c , d , e are true . Meconium ileus is a common cause of neonatal intraluminal intestinal obstruction. Over 80% of cases are associated with cystic fibrosis. In these patients, pancreatic secretions are abnormally viscid and the meconium becomes inspisated in the distal ileum. Beyond the level of the obstrction the bowel is collapsed and the colon is empty. Bile-stained vomiting in a neonate is always abnormal and is a feature of meconium ileus. A plain abdominal x-ray will show dilated ileal loops and intraluminal 'ground glass' appearance. Surgical treatment can be by enterotomy and lavage

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8. Regarding infantile hypertrophic pyloric stenosis

(a) Usually presents between 6 and 12 months of age
(b) The female : male ratio is 4:1
(c) Has a strong familial predisposition
(d) Pathologically shows hypertrophy of the longitudinal muscle layer of the pylorus
(e) Presents with bile-stained projectile vomiting

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only c is right . Infantile hypertrophic pyloric stenosis present most commonly at approximately 6 weeks of age. It is more common in boys with a male : female ratio of 4:1. There is a strong familial predisposition with 5% of affected infants having a mother who also developed the problem. Pathologically, the pyloric 'tumour' arises from hypertrophy the circular muscle layer. Patients present with projectile vomiting that is not bile-stained. Following resusciation and correction of any electrolyte abnormality, surgical treatment is by pyloromyotomy.

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9. Regarding intussusception

(a) It is the commonest cause of intestinal obstruction between 6 and 18 months
(b) Usually occurs in the jejunum
(c) The lead point may be a Peyer's patch or Meckel's diverticulum
(d) Usually presents with few clinical signs
(e) Has a characteristic 'doughnut' appearance on ultrasound

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a , c , e are true . Intussusception is the commonest cause of intestinal obstruction in the 6 to 18 month age group. It often occurs in the distal ileum with an ileo-colic intussusception being the most common type. Lead points include an inflamed Peyer's patch or a Meckel's diverticulum. The infants usually present with severe intermittent colic, bile-stained vomiting, rectal bleeding and 30% have a 'sausage-shaped' abdominal mass. The diagnosis can often be confirmed by a 'doughnut' appearance on ultrasound.

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10. Regarding Hirschsprung's disease

(a) Often presents with neonatal large bowel obstruction
(b) Results from absence of ganglion cells in both the Meissner's and Auberbach's plexus
(c) A contrast-study will show dilatation of the aganglionic segment
(d) The diagnosis can be confirmed by histological evdience of reduced acetylcholinesterase in the aganglionic segment
(e) Early treatment may involve rectal irrigation or an emergency colostomy

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a , b , e are true . Hirschsprung's disease is a common cause of neonatal large bowel obstruction. It results from failure of migration of ganglion cells to the affected segment of bowel. This always involves the distal colon but the proximal extent of the involvement is variable and in rare cases may involve the whole of the large bowel. Histologically, the affected segment has absent ganglion cells in the Meissner's and Auerbach's plexus but immunohistochemical evidence of increased ACE activity. 80% of cases present in the neonatal period. Contrast studies show the affected segment to be tonically contracted. Rectal irrigation or an emergency colostomy may be required before a definative 'pull-through' procedure.

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