Surgery Flashcards
Define Hirschsprung’s disease
Congenital disease in which ganglionic cells fail to develop in the large intestine
- commonly presents as delayed or failed passage of meconium
Epidemiology of Hirschsprung’s disease
1 in 1,500-1,700
90% present in neonatal period
High incidence in males
Genetic component - those that encode proteins for the RET signalling pathway and endothelin type B receptor pathway
Types of Hirschsprung’s disease
Short segment - 85%
Long segment - 10%
Total colonic aganglionosis disease
Pathophysiology of Hirschsprung’s disease
Ganglionic cells of myenteric and submucosal plexuses aren’t present proximally from anus
- due to arrest of neuroblast
Tonic state -> failure in peristalsis and bowel movements
- accumulation of faeces in rectosigmoid region
- functional obstruction
-> bowel dilation, abdo distention, bacterial proliferation, Hirschsprung’s enterocolitis
Risk factors for Hirschsprung’s disease
Males
Chromosomal abnormalities
FHx
Clinical features of Hirschsprung’s disease
Failure to pass meconium - within 48 hrs of birth
Abdo distention
Bilious vomiting
Differential diagnosis of Hirschsprung’s disease
Meconium plug syndrome
- symptoms resolve after passage of plug
Meconium ileus
- distal small bowel impacted by meconium
- differentiated by radiograph or barium enema
Intestinal atresia
- complete obstruction due to congenital malformation
Intestinal malrotation
- midgut volvulus -> bilious vomiting and abdo distention
Anorectal malformation
- differentiated by physical examination
Constipation
- diagnosis of exclusion
Ix for Hirschsprung’s disease
Plain abdo x-ray Contrast enema - short transition zone between proximal end of colon and narrow distal end of colon Rectal suction biopsy - gold standard - submucosa tested for ganglionic cells - stained for acetylcholinesterase
Indications for rectal suction biopsy
Delayed passage of meconium - more than 48 hrs in term babies
Constipation since first few weeks of life
Chronic abdo distension and vomiting
FHx of Hirschsprung’s disease
Faltering growth in addition to any previous features
Management of Hirschsprung’s disease
Initial - IV abx - NG tube insertion - bowel decompression Definitive - surgery - resect aganglionic section of bowel and connect unaffected bowel to the dentate line
Complications of Hirschsprung’s disease
Hirschsprung associated enterocolitis
- stasis of faeces leads to bacterial overgrowth
- C. diff, S. aureus
- present with fever, vomiting, diarrhoea, abdo tenderness and sepsis
- fluid resuscitation, bowel decompression and broad spectrum IV abx
Define intussusception
Movement or telescoping of one part of the bowel into another
- proximal bowel segment to as the intussusceptum
- distal segment is called the intussuscipiens
Epidemiology of intussusception
Peak incidence between 5-7 months
- rare after 2 years
Boys twice as likely to be affected
Pathophysiology of intussusception
Telescoping of one bowel segment into another
- can lead to intestinal obstruction
- 90% of cases are of the ileo-colic type - distal ileum passess into the caecum through the ileo-caeceal valve
Risk factors for intussusception
Most cases are idiopathic 25% have underlying pathology - should be suspected in older child or high recurrence rate - meckel diverticulum - polyps - lymphoma and other tumors - post op
Clinical features of intussusception
Sudden onset inconsolable crying episodes - pallor - knees drawn up to chest - return to normal self inbetween episodes Vomiting and abdo pain Distension Palpable sausage-shaped abdo mass Signs of peritonism
DDx for intussusception
Colic - excessive crying and drawing up of legs in otherwise well infant Testicular torsion Appendicitis - tends to be older children - pain may localise to right iliac fossa Gastroenteritis Volvulus
Investigations for intussusception
AXR - may confirm diagnosis but not recommended due to low sensitivity
- distended small bowel loops
- curvilinear outline of intussusception
- absence of bowel gas in distal colon
Abdo USS - high sensitivity
- doughnut/target sign on transverse plane
- pseudokidney sign on longitudinal plane
Contrast enema
- contraindicated if evidence of peritonitis or perforation
Mx of intussusception
Supportive - fluid resuscitation - NG tube Non-operative reduction - air or contrast enema - contraindicated in perforation, peritonitis or uncorrected shock Surgical reduction - if enema contraindicated or unsuccessful
Complications of intussusception
Obstruction
Perforation
Bowel necrosis
Dehydration and shock
Epidemiology of pyloric stenosis
1 in 500-1000 live births
4 males for every female
Pathophysiology of pyloric stenosis
Characterised by progressive hypertrophy of pyloric muscle
- causing gastric outlet obstruction
- aetiology unknown
Risk factors for pyloric stenosis
Male
Fhx
Clinical features of pyloric stenosis
Presents around 4-6 weeks of age Non-bilious vomiting after every feed - projectile Weight loss and dehydration Visible peristalsis Palpable olive-sized pyloric mass
DDx of pyloric stenosis
Gastroenteritis GORD Over-feeding Sepsis UTI Food allergy
Investigations for pyloric stenosis
Test feed with NG tube in situ and stomach aspirated
USS
- hypertrophy of pyloric muscle
Blood gases show
- hypokalaemia, hypochloremic metabolic alkalosis
Mx of pyloric stenosis
Peri-operatively
- correct underlying metabolic abnormalities
- 10-20ml/kg fluid boluses for acute hypovolaemia
- stop oral feeding
- NG tube passed and aspirated at 4 hourly intervals
Surgery
- Ramstedt’s pyloromyotomy
Complications of pyloric stenosis
Pre-operative - hypovolaemia - apnoea - secondary to hypoventilation associated with metabolic acidosis Post-op - wound dehiscence - infection - bleeding - perforation - incomplete myotomy
