Paeds - Gastroenterology (Surgical) Flashcards
Pyloric Stenosis
Pathophysiology
Clinical Features
Investigations
Management
1.) Pathophysiology - progressive hypertrophy of the pyloric muscle, causing gastric outlet obstruction
- risk factors: male gender, FH of pyloric stenosis
2.) Clinical Features - presents around 4-6wks of age
- forceful (projectile) non-bilious vomiting after every feed, however, the babies continue feeding hungrily
- other sx: dehydration, weight loss, haematemesis
- examination: visible peristalsis, palpable olive-sized pyloric mass, best felt during a feed
- differentials: gastroenteritis, GORD, over-feeding, sepsis, UTI, food allergy, malrotation (bilous vomiting)
3.) Investigations
- test feed w/an NG tube in situ with stomach aspirated to observe peristalsis or palpate a pyloric mass
- US-abdo: pyloric muscle hypertrophy
- capillary blood gas: hypokalaemic hypochloraemic metabolic alkalosis (loss of HCl from vomiting)
4.) Management
- correct metabolic abnormalities: dehydration etc..
- NBM + NG tube passed and aspirated 4hrly
- surgery after fluid/electrolyte abnormalities corrected
- Ramstedt’s pyloromyotomy: babies can feed after 6hrs, PONV is common and not a sign of failure
- complications: hypovolemia, apnoea, infection, bleeding, perforation, wound dehiscence, failure
Bowel Obstruction
Differential Diagnoses/Causes
Clinical Features
Investigations
Management
1.) Differential Diagnoses/Causes
- meconium ileus: often associated with cystic fibrosis
- Hirschsprung’s disease, intussusception
- malrotation of the intestines with a volvulus
- strangulated hernia, imperforate anus
- atresia: oesophageal and duodenal atresia
2.) Clinical Features
- abdominal pain and distention
- persistent vomiting: may contain bright green bile
- absolute constipation: failure to pass stools or wind
- abnormal bowel sounds: can be high pitched and “tinkling” early in the obstruction and absent later
3.) Investigations
- AXR is often the initial investigation when suspecting:
- dilated loops of bowel proximal to the obstruction
- collapsed loops of bowel distal to the obstruction
- the absence of air in the rectum.
4.) Management
- emergency referral to a paediatric surgical unit
- NBM, IV fluids + draining NG tube (drip and suck) whilst awaiting definitive management
Hirschsprung’s Disease (HD)
Pathophysiology
Clinical Features
Differential Diagnosis
1.) Pathophysiology - parasympathetic ganglion cells of the myenteric plexus fail to develop in the LI
- aganglionic segment remains in a tonic state leading to failure in peristalsis and bowel movements
- accumulation of faeces in the rectosigmoid region causes functional obstruction
- risk factors: male gender (4:1), FH (20% of cases) chromosomal abnormalities (esp Down’s), MEN2, neurofibromatosis, Waardenburg syndrome
2.) Clinical Features - 90% present in neonatal period, but may not present until childhood or adolescence
- often presents as delayed passage of meconium
- classical triad is present in around 25% of patients:
- delayed meconium, abdo distension, bilious vomiting
- other sx: constipation since birth, failure to thrive
- examination: palpate faeces in the LLQ, abdomen is sometimes tympanic due to the intestinal distension
- rectal exam shows empty rectal fault but the exam itself may cause stool ejection
3.) Differential Diagnosis - delayed meconium
- meconium plug syndrome: sx resolve after passage of plug, differentiate w/ enema (barium/water-soluble)
- meconium ileus: affects distal small bowel, use abdo-X-ray or enema (barium/water-soluble) to differentiate
- intestinal atresia: complete obstruction
- malrotation: can cause a midgut volvulus
- anorectal malformation: stenosis, imperforate anus
- constipation: diagnosis of exclusion
Management of Hirschsprung’s Disease (HD)
Investigations
Rectal Suction Biopsy
Management
Hirschsprung Associated Enterocolitis (HAEC)
1.) Investigations
- initial investigation is a plain AXR
- rectal suction biopsy (gold standard) for diagnosis
- contrast enema: short transition zone between the proximal and narrow distal end of the colon
- consider a contrast enema to exclude differentials ^^ and to find the extent of aganglionosis, contra-indicated if there’s perforation (laparotomy instead)
2.) Rectal Suction Biopsy - tests ganglionic cells in the submucosa to confirm aganglionosis
- bedside procedure w/o risk associated with a GA
- antibiotic coverage is given around the procedure
- biopsy is stained with AChE to aid interpretation
- risks: perforation, bleeding, inadequate sample
3.) Management
- initial: IV Abx, NG insertion, bowel decompression
- definitive: anorectal pull-through procedures usually performed in the first few months of the neonate’s life
- complications of surgery: constipation, enterocolitis, perianal abscess, faecal soiling and adhesions
4.) Hirschsprung Associated Enterocolitis (HAEC)
- stasis of faeces leads to bacterial overgrowth (esp C.diff, S.aureus, anaerobes) within the colon
- main cause of mortality in patients with HD as it can lead to toxic megacolon and bowel perforation, sepsis
- sx: fever, N+V, diarrhoea, abdo tenderness,
- Tx: IV Abx, fluid resus, bowel decompression
Intussusception
Pathophysiology
Clinical Features
Differential Diagnosis
1.) Pathophysiology - the telescoping of one bowel segment into another can lead to intestinal obstruction
- 90% are ileocolic/ileocaecal (can occur anywhere)
- more common in boys, occurs from 5mths to 2yrs
- most cases are idiopathic but in approx 25% of cases an underlying pathological cause can be identified:
- Meckel diverticulum (main), concurrent viral illness, cystic fibrosis, polyps, Henoch-Schönlein purpura, lymphoma and other tumours, post-op
2.) Clinical Features
- severe, colicky abdominal pain w/ inconsolable crying (may get in knee-chest position to alleviate pain)
- vomiting, pale, lethargic and unwell child
- child returns back to normal in-between episodes
- redcurrant jelly stool: may contain mucus and blood
- palpable ‘sausage-shaped’ abdo mass in the RUQ
- signs of bowel obstruction +/- dehydration/shock
3.) Differential Diagnosis
- colic: excessive crying and drawing up of legs in otherwise well infant
- testicular torsion (male infant w/ excessive crying)
- volvulus, appendicitis, gastroenteritis
Management of Intussusception
Investigations
Management
Complications
1.) Investigations - radiological diagnosis
- 1°abdo US (gold): doughnut/target sign on transverse plane, pseudokidney sign on a longitudinal plane
- 2°contrast enema: can be used in diagnosis or as a therapeutic (enema may reverse bowel invagination), contraindicated in signs of perforation/peritonitis
- AXR: low sensitivity for intussusception but important to quickly exclude bowel obstruction, distended small bowel loops, outline of intussusception, absence of bowel gas distal to the intussusception, Rigler’s sign (perforation)
2.) Management
- fluid resus in any signs of shock or dehydration
- NG insertion may help decompress the bowel
- approx 5% may undergo spontaneous reduction
- non-operative reduction: air/contrast enema w/ USS (contraindicated in shock, perforation/peritonitis)
- surgical reduction: manually reduce intussusception if the enema is contraindicated or unsuccessful, may also need to resect any areas of the necrotic bowel wall
3) Complications - if left untreated
- bowel obstruction, perforation/peritonitis, death
- dehydration and shock: fluid and bowel contents can collect within the intussusception
Meckel’s Diverticulum
Pathophysiology
Clinical Features
Investigation
Management
1.) Pathophysiology - congenital diverticulum of the SI, it is a remnant of the omphalomesenteric duct and contains ectopic ileal, gastric or pancreatic mucosa
- rule of 2s: occurs in 2% of the population, at the age of 2 (1-2yrs), is 2 feet from the ileocaecal valve, and is 2 inches long
2.) Clinical Features - usually asymptomatic
- painless rectal bleeding in a toddler aged 1-2 years
- may also have abdominal pain mimicking appendicitis
- can cause massive bleeding requiring transfusion
- can present as intestinal obstruction secondary to an omphalomesenteric band (most commonly), volvulus and intussusception
3.) Investigation
- technetium scan: if the child is haemodynamically stable with less severe or intermittent bleeding
- mesenteric arteriography may also be used in more severe cases e.g. transfusion is required
4.) Management
- removal if narrow neck or symptomatic
- options are between wedge excision or formal small bowel resection and anastomosis
Appendicitis
Pathophysiology
Clinical Features
Differentials
Management
1.) Pathophysiology - inflammation of the appendix due to infection trapped in the appendix by obstruction at the point where the appendix meets the bowel
- obstruction: faecolith, impacted stool, lymphoid hyperplasia, appendiceal/caecal tumour (rare)
- peak incidence is in patients aged 10 to 20 years
- complications: perforation/peritonitis, appendix mass or abscess
2.) Clinical Features - diagnosis can be made clinically
- poorly localised umbilical pain –> severe RIF
- mild fever, N+V, loss of appetite (hamburger sign)
- tenderness at McBurney’s point (1/3 ASIS -> umbilicus)
- Rosving’s sign: palpation of LIF –> pain in RIF
- inflammation: pain on right knee flexion, Psoas sign
- rebound tenderness and percussion tenderness both suggest peritonitis caused by a ruptured appendix
- appendicitis in children may present atypically
3.) Differentials
- mesenteric adenitis, Meckel’s diverticulum
- boys: testicular torsion, epididymitis
- gynae: ectopic (< 40s need a pelvic US), ovarian cyst,
- caecal cancer: over the 40s need CT scan
4.) Management
- bloods (raised WCC), urinalysis, pregnancy test
- imaging: USS (women <40), CT (>40s)
- analgesia, antibiotics
- surgery: laparoscopic appendectomy
Biliary Atresia
Pathophysiology
Clinical Features
Investigations
Management
1.) Pathophysiology - a congenital condition where a section of the bile duct is progressively fibrosed and destroyed leading to narrowed or absent bile duct
- this prevents the excretion of conjugated bilirubin as there is cholestasis, so bile cannot be transported from the liver to the bowel so it is not excreted
2.) Clinical Features - presents in first few wks of life w/:
- prolonged jaundice (>14d in term, >21d in premature)
- dark urine and pale stools
- hepatomegaly w/ splenomegaly, abnormal growth
- cardiac murmurs if associated cardiac abnormalities
3.) Investigations
- serum bilirubin: conjugated+unconjugated bilirubin
- a high proportion of conjugated bilirubin suggests the liver is processing the bilirubin but can’t excrete it as it cannot flow through the biliary duct into the bowel
- cholangiography (definitive): abnormal biliary tree
- hepatic scintigraphy (technetium-99) radioisotope scan: poor excretion of the radioisotope into the bowel
- abdominal US: echogenic fibrosis
4.) Management - surgery
- Kasai hepatoportoenterostomy: attach a section of the SI to the opening of the liver (‘replace bile duct’)
- this can clear jaundice and prolong survival but patients often still require a full liver transplant
- ursodeoxycholic acid may be given as an adjuvant
Intestinal Malrotation (with Volvulus)
Pathophysiology
Clinical Features
Differentials for Bilious Vomiting
Investigations
Management
1.) Pathophysiology - usually caused by incomplete rotation during embryogenesis (10th week of gestation)
- Ladd’s bands usually attach the caecum to the retroperitoneum but in malrotation, the bands can end up passing over the second part of the duodenum instead, compressing it
- associated with exomphalos (omphalocoele), congenital diaphragmatic hernia, intrinsic duodenal atresia
2.) Clinical Features - often presents 3-7 days after birth
- sudden onset bilious vomiting (volvulus present)
- inconsolable crying, tachycardia, tachypnoea
- may have abdominal distension or the abdominal exam could be normal because the obstruction is higher up the digestive tract
- volvulus with compromised circulation may result in peritoneal signs and haemodynamic instability
3.) Differentials for Bilious Vomiting
- Hirschsprung’s disease, meconium ileus, necrotising enterocolitis duodenal atresia, jejunal/ileal atresia
4.) Investigations
- upper GI contrast study: duodenal-jejunal flexure is more medially placed
- USS: abnormal orientation of SMA and SMV
5.) Management
- laparotomy
- Ladd’s procedure (↑volvulus risk): division of Ladd bands and widening of the base of the mesentery
