Modalities of Enteral Nutritional Support

Figure: Routes of nutritional support - Bailey & Love's Short Practice of Surgery, 28th Edition

1. Oral Nutritional Supplements (ONS)

• Bailey & Love's Short Practice of Surgery, 28th Edition

2. Nasogastric Tube (NGT) Feeding

• Conventional Ryle's tube - larger bore, used for short-term decompression and feeding
• Fine-bore nasogastric feeding tube (e.g. No. 7 French gauge, mercury-weighted tip) - more comfortable for prolonged therapy

• Tube position must be confirmed by X-ray before commencing feeding
• Best delivered via an infusion pump (minimises blockage, ensures smoother delivery vs. bolus feeding)
• Start at half or quarter strength to minimize cramps and diarrhoea
• If the patient is severely hypoalbuminaemic, gastric emptying and absorption may be impaired - parenteral albumin replacement (100-200 mL of 25% albumin) may be needed first
• Gastric residuals ≥200 mL over 4-6 hours or abdominal distension require cessation and rate adjustment

• Pye's Surgical Handicraft, 22nd Edition; Schwartz's Principles of Surgery, 11th Edition

3. Nasojejunal (NJ) Tube Feeding

• Used when gastroparesis is present (e.g. closed-head injury, critical illness) - feeding distal to the pylorus bypasses the problem of delayed gastric emptying
• In acute pancreatitis, the nasojejunal and nasogastric routes are considered equivalent with no significant difference in adverse effects
• Reduces risk of aspiration compared to gastric feeding in some patients
• Schwartz's Principles of Surgery, 11th Edition; Mulholland & Greenfield's Surgery, 7th Edition

4. Percutaneous Endoscopic Gastrostomy (PEG)

• Indications: Patients requiring long-term (>4 weeks) enteral feeding - stroke, motor neuron disease, head and neck cancer, oesophageal obstruction, permanent neurological impairment
• Avoids the discomfort of prolonged nasogastric intubation
• Can be converted to a PEG-J (PEG with jejunal extension) tube to deliver feed beyond the pylorus when gastric emptying is compromised
• Pye's Surgical Handicraft, 22nd Edition; Bailey & Love's, 28th Edition

5. Surgical Gastrostomy

6. Needle Catheter Jejunostomy (NCJ)

• A contrast study on the operating table confirms catheter tip position
• Indications: Proximal GI obstruction, high-output fistula, fragile anastomosis, major upper GI surgery
• Particularly useful for post-operative early enteral feeding following oesophagogastric or pancreatic resections
• Pye's Surgical Handicraft, 22nd Edition

7. Surgical / Endoscopic Feeding Jejunostomy

• Used for long-term feeding when gastric access is not possible (e.g. post-total gastrectomy)
• Avoids aspiration risk entirely

Continuous vs. Intermittent (Bolus) Feeding

• Schwartz's Principles of Surgery, 11th Edition

Enteral Formulae

Practical Points

• Enteral feeding does not require the presence of bowel sounds or passage of flatus as a prerequisite
• Early EN (within 24-48 hours) is recommended in critically ill patients; early "full nutrition" is harmful - target >80% of estimated energy goals by day 3-4
• Low-output enterocutaneous fistulas (<500 mL/day) are not a contraindication to enteral feeding
• A trained dietician should plan and manage the feeding regime
• Monitor weight daily; electrolytes and albumin twice weekly
• Schwartz's Principles of Surgery, 11th Edition; Bailey & Love's Short Practice of Surgery, 28th Edition

Malrotation of the Gut

Definition and Embryology

• The duodenojejunal (DJ) junction and ileocecal junction lying abnormally close together
• A narrow mesenteric base (instead of the broad diagonal attachment from the DJ junction in the left upper quadrant to the ileocecal valve in the right lower quadrant)
• Abnormal peritoneal bands (Ladd's bands) from the cecum across the duodenum to the right peritoneum

• Sabiston Textbook of Surgery, 21st Edition; Current Surgical Therapy, 14th Edition

Types / Spectrum of Rotational Anomalies

Clinical Features

• 70% present in the first year of life; of those, ~70% in the first month
• ~90% present before 12 months; up to 1% present in adults

• Bilious emesis - the cardinal symptom; must always be treated as an emergency until proven otherwise
• Initially: feeding intolerance, irritability, colicky abdominal pain
• Guaiac-positive stool (early mucosal ischaemia)
• Late: progressive abdominal distension, haematemesis, hypotension
• Severe: metabolic acidosis, coagulopathy, shock, transmural midgut necrosis

A somnolent/lethargic newborn with acute onset bilious emesis is an ominous sign mandating immediate investigation.

• Bilious emesis with gastric/proximal duodenal distension
• Without the acute haemodynamic compromise of volvulus

• Mulholland & Greenfield's Surgery, 7th Edition; Sabiston Textbook of Surgery

Associated Anomalies

• Diaphragmatic hernia
• Gastroschisis / omphalocele
• Duodenal atresia
• Biliary atresia, congenital heart disease
• Intestinal atresia and stenosis

Diagnosis

• Gastric and proximal duodenal distension
• Paucity or absence of distal small bowel gas (classic sign)
• Cannot exclude malrotation - a "normal bowel gas pattern" never rules it out

1. Duodenum crosses to the left of the midline (using spine as landmark)
2. C-loop shape - 4th part of duodenum rises to the level of the pylorus
3. Retroperitoneal course toward the spine (on lateral views)

• Malrotation with volvulus: corkscrew or coiled appearance in the distal duodenum
• Extrinsic duodenal compression by Ladd's bands may be visible

Radiographic findings in malrotation - Mulholland & Greenfield's Surgery, 7th Edition

Note: CT scan may identify malrotation incidentally in older children and adults, but has no role as the initial imaging study in symptomatic infants with bilious emesis.

Treatment - Ladd's Procedure

1. Detorse the volvulus - deliver the midgut and rotate counterclockwise ("turning back the hands of time") - usually 180°-360°
2. Lyse Ladd's bands - divide peritoneal bands from the cecum across the duodenum to the right lower quadrant peritoneum
3. Straighten the duodenum - modified Kocher maneuver with complete mobilisation, dividing all anterior, lateral, and posterior duodenal attachments
4. Broaden the mesenteric base - divide peritoneal bands tethering the cecum, small bowel mesentery, mesocolon, and duodenum around the SMA base to widen the pedicle and prevent re-volvulus
5. Place bowel in position of non-rotation - small bowel on the right, colon on the left
6. Appendicectomy - because the appendix will lie in an atypical position after the procedure, potentially causing diagnostic confusion in future

• Current Surgical Therapy, 14th Edition; Mulholland & Greenfield's Surgery, 7th Edition; Sabiston Textbook of Surgery

Outcome

• Overall survival for operated malrotation is good in the absence of midgut necrosis
• Midgut volvulus with complete infarction carries very high mortality
• Short bowel syndrome is the main long-term morbidity following extensive resection
• In adults, mortality from midgut volvulus complicating malrotation may be as high as 3% even with treatment

Small Bowel Malrotation

Part 1: Embryological Principles [4 marks]

Normal Midgut Development

• Small intestine from the duodenum (distal to the bile duct opening) through to the mid-transverse colon
• Cecum, appendix, ascending colon, and right two-thirds of transverse colon
• All supplied by the superior mesenteric artery (SMA)

Stage 1 - Physiological Herniation and Initial 90° Rotation (Weeks 5-10)

• Prearterial (cranial) limb - gives rise to distal duodenum, jejunum, and proximal ileum
• Postarterial (caudal) limb - gives rise to distal ileum, cecum, appendix, and right colon

Stage 2 - Reduction and Further 180° Rotation (Weeks 10-12)

• The prearterial (cranial) segment passes posterior to the SMA; the distal duodenum ends up fixed to the left of the aorta at the ligament of Treitz
• The postarterial (caudal) segment (cecum) passes anteriorly then to the right of the SMA
• The jejuno-ileal loops undergo dramatic elongation forming ~6 primary intestinal loops, filling the right side of the abdomen

Normal midgut rotation - Mulholland & Greenfield's Surgery, 7th Edition

Stage 3 - Fixation (After Week 12)

• Cecum descends to the right iliac fossa
• Duodenojejunal (DJ) junction is fixed at the ligament of Treitz - to the left of the aorta, anterior to the left renal vein, at the level of L1/L2
• The mesentery acquires a broad oblique base running from the DJ junction (left upper quadrant) diagonally to the ileocecal valve (right lower quadrant)
• This wide mesenteric attachment is what prevents volvulus

Pathogenesis of Malrotation

• The Developing Human: Clinically Oriented Embryology; Mulholland & Greenfield's Surgery, 7th Edition; Sabiston Textbook of Surgery, 21st Edition

Part 2: Clinical Presentation [3 marks]

• 70% present in the first year of life, of which 70% in the first month
• Up to 1% present in adults

A. Midgut Volvulus (Surgical Emergency)

• Bilious (green) vomiting - the cardinal sign; must be treated as an emergency until malrotation is excluded
• Colicky abdominal pain, feeding intolerance, irritability
• Guaiac-positive stool (early mucosal ischaemia)
• Relatively soft, non-distended abdomen early on

• Progressive abdominal distension
• Haematemesis, bloody stools (PR bleeding)
• Shock, hypotension
• Metabolic acidosis, coagulopathy
• Peritonitis, sepsis
• If untreated: transmural necrosis of the entire midgut supplied by the SMA

An acutely ill, lethargic/somnolent neonate with bilious emesis is an ominous presentation mandating immediate surgical evaluation.

B. Duodenal Obstruction by Ladd's Bands

• Bilious vomiting with gastric distension
• Less haemodynamically compromised than volvulus
• May present as partial or intermittent obstruction

C. Chronic / Intermittent Presentation

• Recurrent episodes of colicky abdominal pain ("recurrent abdominal pain")
• Intermittent vomiting, failure to thrive, malabsorption
• In adults: chronic abdominal pain, episodic obstruction (can mimic IBS or functional disorders for years)

D. Asymptomatic / Incidental

• Discovered on contrast studies or CT performed for other indications
• Estimated in ~1% of population
• Current Surgical Therapy, 14th Edition; Mulholland & Greenfield's Surgery, 7th Edition

Part 3: Management [3 marks]

Initial Resuscitation

• IV access, fluid resuscitation, correction of electrolyte imbalances
• Nasogastric decompression
• In volvulus with shock: aggressive resuscitation must occur simultaneously with preparation for theatre - not sequentially

Investigations

1. Plain AXR: Paucity of distal small bowel gas; gastric and proximal duodenal distension. A normal gas pattern NEVER excludes malrotation.
2. Upper GI contrast series (UGI) - investigation of choice: Three features must be present to exclude malrotation:
   • Duodenum crosses to the left of the midline (using spine as landmark)
   • C-loop shape - 4th part of duodenum rises to level of pylorus
   • Retroperitoneal course (confirmed on lateral view)
   • Malrotation + volvulus shows corkscrew/coiled appearance in distal duodenum
3. Ultrasound: Inverted SMA/SMV relationship (SMV to the left or anterior to SMA) suggests malrotation
4. Contrast enema: Cecal malposition (in left abdomen or near midline)

If the infant is critically ill with bilious emesis, emergent laparotomy may be indicated without waiting for imaging.

Surgical Management - Ladd's Procedure

1. Detorsion of volvulus - deliver the midgut out of the abdomen; rotate counterclockwise ("turning back the hands of time") - usually 180°-360° until fully unwound
2. Assess bowel viability - frankly necrotic bowel is resected; borderline bowel can be reassessed after 15-20 minutes of warm packs ("second look" laparotomy at 24-48 hours for extensive ischaemia)
3. Divide Ladd's bands - lyse peritoneal bands crossing from the cecum over the duodenum to the right posterior abdominal wall
4. Straighten the duodenum - extended Kocher maneuver; divide all anterior, lateral, and posterior duodenal attachments
5. Broaden the mesenteric base - divide peritoneal bands around the SMA pedicle widely to place the DJ junction and ileocecal valve far apart, preventing re-volvulus
6. Final position - bowel placed in position of non-rotation: small bowel on the right, colon on the left
7. Appendicectomy - incidental appendicectomy is performed as the appendix will be in an atypical position post-procedure (could cause diagnostic confusion in future appendicitis)

Special Situations

• Complete midgut infarction: Requires total enterectomy; carries very high mortality; survivors require permanent TPN or intestinal transplantation
• Asymptomatic incidental malrotation: Elective Ladd's procedure is generally recommended given the unpredictable and potentially catastrophic risk of volvulus at any age
• Adults with malrotation: Same principles apply; mortality from volvulus in adults may approach 3% even with treatment

Postoperative

• Gradual reintroduction of feeds
• Long-term monitoring for adhesive obstruction (rare)
• Excellent outcomes when operated before bowel necrosis occurs; survival >90% in uncomplicated cases
• Sabiston Textbook of Surgery, 21st Edition; Current Surgical Therapy, 14th Edition; Mulholland & Greenfield's Surgery, 7th Edition

Infantile Hypertrophic Pyloric Stenosis (IHPS)

Definition and Epidemiology

• Incidence: ~1 in 300-500 live births (UK: 1:300; USA: 3 in 1000); varies by ethnicity - highest in white northern Europeans, lowest in Asians
• Sex: Males outnumber females 4:1 to 5:1; first-born males particularly affected
• Genetics: Autosomal dominant forms reported; 5 genetic loci identified including NOS1 (12q24), IHPS2/5 (chromosome 16); MBNL1 and NKX2-5 identified on GWAS
• Risk factors: Family history (maternal relatives carry higher risk), macrolide antibiotic exposure in early infancy (including via breast milk), Turner syndrome, trisomy 18, oesophageal atresia

• Localised deficiency of nitric oxide synthase (NOS1) - an enzyme critical for smooth muscle relaxation
• Abnormal neuronal innervation - reduced neurofilaments, nerve terminals, synaptic vesicle protein
• Misplaced interstitial cells of Cajal (pacemaker cells) confined near submucosa rather than throughout pylorus
• Elevated EGF and heparin-binding EGF-like growth factor in smooth muscle cells

Part 1: Presentation [2 marks]

Age of Onset

Symptoms

• Non-bilious projectile vomiting - the hallmark symptom. Vomiting is so forceful it may exit through both mouth and nostrils; can project 1-2 metres. The obstruction is pre-pyloric (above the ampulla of Vater), hence vomiting is never bilious (green)
• Initially mild regurgitation, progressing in frequency and forcefulness daily - distinguishing it from gastro-oesophageal reflux (GOR), which waxes and wanes from birth
• Vomitus may be "coffee ground" coloured or contain small amounts of frank blood (from gastric mucosal irritation) but is never bile-stained
• Hunger after vomiting - infant remains hungry and demands re-feeding immediately after vomiting; this distinguishes it from infective/septic causes of vomiting (e.g. meningitis, UTI) where the infant is unwell and not hungry
• Over time: loss of interest in feeding, weight loss, failure to thrive

Signs

• Visible gastric peristalsis - waves seen passing from left to right across the upper abdomen (left hypochondrium to right), best observed during a test feed
• Palpable pyloric "olive" - a firm, smooth, ovoid mass ~2 cm long palpable in the right upper quadrant/epigastrium, best felt in a relaxed/feeding infant, or after the stomach has been emptied by NGT aspiration, or with the infant prone. Palpable in 70-90% of cases (though now less commonly found as infants are diagnosed earlier)
• Dehydration - sunken fontanelle, dry mucous membranes, reduced skin turgor, reduced urine output
• Wasting/cachexia - in late presentation
• Jaundice - indirect hyperbilirubinaemia in ~2-5% (related to volume depletion and poor caloric intake)
• Bailey & Love's Short Practice of Surgery, 28th Edition; Sleisenger & Fordtran's Gastrointestinal and Liver Disease

Part 2: Diagnosis [3 marks]

Metabolic/Biochemical Findings

Investigations

• Feed the undressed infant cradled in the mother's arm under good light
• Observe for visible left-to-right gastric peristaltic waves
• Palpate for the pyloric "olive" in the RUQ/epigastrium
• When the "olive" is palpated confidently, no imaging is required

• Has replaced barium studies; sensitivity up to 98%, specificity up to 100%
• Performed with a high-frequency linear transducer after emptying the stomach

• "Donut/target sign" on transverse view - hypoechoic thickened muscle ring surrounding hyperechoic mucosa
• "Cervix sign" - hypertrophied pylorus resembles the uterine cervix on longitudinal view
• "Shoulder sign" - hypertrophic muscle bulges into the gastric antrum
• "Nipple sign" - redundant hyperechoic mucosa protrudes into the stomach
• Exaggerated, non-propulsive peristaltic waves seen in real time

Imaging in IHPS - Grainger & Allison's Diagnostic Radiology

• Distended stomach ("single bubble" appearance)
• Paucity of gas beyond the stomach

• "String sign" - elongated, narrow pyloric canal
• "Double channel/rail track sign" - two parallel streaks of contrast in compressed canal
• "Shoulder/beak sign" - indentation of the antrum by the hypertrophied pyloric muscle
• "Mushroom/umbrella sign" - bulging of pyloric mass into gastric antrum
• Sleisenger & Fordtran's Gastrointestinal and Liver Disease; Grainger & Allison's Diagnostic Radiology

Part 3: Management [5 marks]

IHPS is NOT a surgical emergency. It is a medical emergency first - the electrolyte and fluid deficit must be corrected before any anaesthetic or surgery, as severe hypochloraemic alkalosis can precipitate life-threatening anaesthetic complications (apnoea, laryngospasm).

Step 1 - Resuscitation and Correction of Metabolic Derangement

1. Stop oral feeds immediately
2. Nasogastric tube (8-10 Fr) insertion - decompress and empty the stomach
3. IV fluid resuscitation:
   • 0.9% normal saline with 0.15% KCl in 5% dextrose at 6-7.5 mL/kg/h
   • This provides maintenance fluids and corrects the chloride and potassium deficit simultaneously
   • As the chloride deficit is replaced, the kidneys correct the alkalosis and urine becomes alkaline
4. Monitoring: Serial U&E/electrolytes until normalised; urine output >1 mL/kg/h
5. Correction typically takes 24-48 hours
6. Surgery should NOT proceed until: Cl⁻ >95 mmol/L, K⁺ >3.0 mmol/L, pH <7.45, bicarb <30 mmol/L

Step 2 - Ramstedt's Pyloromyotomy (Definitive Treatment)

• Laparoscopic pyloromyotomy - now the preferred approach in most centres (3 ports: umbilical camera, two 3mm working ports); equivalent outcomes, better cosmesis, faster recovery
• Open pyloromyotomy - via supraumbilical curved incision or right upper quadrant transverse (Ramstedt's) incision; remains the approach when laparoscopy is not available or feasible

1. Deliver the pyloric "tumour" into the wound
2. Make a longitudinal serosal incision along the avascular plane of the anterior pylorus, from the gastric antrum proximally to the duodenal fornix distally
3. Split the hypertrophied circular muscle fibres with a pyloric spreader (Ramstedt's dilator), leaving the underlying submucosa and mucosa intact and bulging
4. The incision must extend onto the stomach (gastric side) - a short incision stopping at the pyloric-gastric junction causes early recurrence
5. The duodenal end requires care - the muscle fibres here are thinner and mucosal perforation is most likely at the duodenal fornix
6. Test for mucosal integrity: Air or saline injected via NGT confirms no perforation (bubbles or bile leak)
7. If perforation occurs intraoperatively: close with absorbable suture, rotate the myotomy 90° and repeat

Step 3 - Postoperative Care

• Continue IV fluids until feeds are re-established
• Oral feeding commenced within 24 hours postoperatively - gradual reintroduction of feeds (small volumes initially, progressing to full feeds)
• Early postoperative vomiting is common and expected (due to oedema at the myotomy site and pre-existing GOR); it usually resolves within 24-48 hours
• Persistent vomiting beyond 5-7 days: consider incomplete myotomy or co-existing GOR (more likely than incomplete myotomy)

Complications

Outcomes

• Excellent - mortality essentially nil in well-resourced settings when metabolic correction is completed before surgery
• Full recovery expected; pyloric muscle eventually returns to normal calibre over months
• No long-term sequelae
• Bailey & Love's Short Practice of Surgery, 28th Edition; Sleisenger & Fordtran's Gastrointestinal and Liver Disease; Grainger & Allison's Diagnostic Radiology

Vitello-intestinal Duct (VID) and Its Abnormalities

Embryology and Normal Fate

• At week 5, the following structures pass through the umbilical ring: the connecting stalk (with allantois and umbilical vessels), the yolk stalk (vitelline duct) with its vessels, and intestinal loops during physiological umbilical herniation
• The midgut loop herniates into the proximal umbilical cord at week 5-6 and remains there until week 10, with the VID at the apex communicating with the yolk sac
• As the midgut returns to the abdominal cavity by week 10-12, the VID and yolk sac normally obliterate completely
• By the end of the third month, only the umbilical vessels surrounded by Wharton's jelly remain in the cord

• Langman's Medical Embryology; The Developing Human

Spectrum of VID Remnant Abnormalities

1. Meckel's Diverticulum (Most Common)

• The ileal (bowel) end of the VID persists as a blind-ending outpouching
• A true diverticulum - contains all three layers of the bowel wall (mucosa, muscularis propria, serosa)
• Arises from the antimesenteric border of the ileum

Meckel's diverticulum - Robbins, Cotran & Kumar Pathologic Basis of Disease

• Gastric mucosa - 80-85% of ectopic tissue (secretes acid)
• Pancreatic, duodenal, biliary, or colonic tissue - less common

• Tc-99m (Technetium) pertechnetate scan ("Meckel's scan") - investigation of choice for bleeding; detects ectopic gastric mucosa; sensitivity ~85% in children
• CT scan: blind-ending tubular structure from antimesenteric border of terminal ileum
• CT enterography: improved detection
• Plain X-ray, barium studies, USS: rarely diagnostic

• Symptomatic Meckel's: Always requires surgical excision
• Surgical approach: Diverticulectomy with transverse closure of the defect, or segmental ileal resection with end-to-end anastomosis (preferred if base is wide, indurated, or if ectopic tissue extends to base); can use linear stapler-cutter
• A broad-based diverticulum should not be amputated and invaginated (risk of stricture and leaving ectopic tissue behind)
• Incidental Meckel's in adults: Generally left alone if wide-mouthed and not thickened; prophylactic resection considered in children, or in adults with palpable ectopic tissue, mesodiverticular band, prior bleeding/diverticulitis
• Laparoscopic approach feasible

2. Umbilical Fistula (Patent Vitello-intestinal Duct / Entero-umbilical Fistula)

• Presentation: Discharge of faecal/intestinal contents from the umbilicus in the neonatal period; the ileum may even prolapse through the umbilicus onto the anterior abdominal wall
• Rare but most serious VID remnant
• Management: Surgical excision and closure of the fistula

3. Umbilical Sinus (Umbilical End Patent)

• Presentation: Chronic mucoid or serous discharge from the umbilicus; may become recurrently infected
• Differentiated from urachal sinus (which also opens at umbilicus but is connected to bladder)
• Management: Surgical excision of the sinus tract

4. Vitello-intestinal Cyst (Enteric Cyst / Enterogenous Cyst)

• Presentation: May be asymptomatic (incidental); can cause intestinal obstruction by external compression or volvulus around the cyst; may become infected
• Management: Surgical excision

5. Fibrous Cord (Obliterated VID / Mesodiverticular Band)

• Presentation: The cord acts as a fulcrum around which bowel loops can twist → small bowel volvulus and strangulation; can also cause direct obstruction
• Has been described causing volvulus even in neonatal period
• Management: Division of the fibrous band at laparotomy/laparoscopy; resection of any non-viable bowel

Summary Table

Diagnostic Investigations (Summary)

• Bailey & Love's Short Practice of Surgery, 28th Edition; Robbins, Cotran & Kumar Pathologic Basis of Disease; Sleisenger & Fordtran's Gastrointestinal and Liver Disease; Current Surgical Therapy, 14th Edition; Langman's Medical Embryology

Hirschsprung's Disease (Congenital Aganglionic Megacolon)

Definition and Pathogenesis

• Tonically contracted (functionally obstructed, narrow, normal external calibre)
• Unable to relax the internal anal sphincter

Clinical Features

A. Neonatal Presentation (>90% of cases)

1. Failure to pass meconium within 24-48 hours of birth - the most important early sign; normal neonates pass meconium within 24 hours
2. Abdominal distension - progressive, generalised
3. Bilious vomiting - secondary to the functional distal obstruction

• Tight, empty rectum on digital rectal examination (DRE) - finger meets resistance ("the aganglionic segment grips the finger")
• Explosive passage of meconium or gas on rectal examination (dramatic decompression) - characteristic and temporarily relieves symptoms
• Symptoms recur without definitive treatment
• Regular enemas provide temporary relief

B. Later/Delayed Presentation (in older children and adults)

• Chronic constipation from birth - often lifelong history, intractable to conservative management
• Abdominal distension - persistent, progressive
• Failure to thrive, malnutrition, poor growth
• Ribbon-like, narrow stools (reflecting narrow aganglionic channel)
• In adults: massive megacolon visible on imaging
• Children with longer-segment disease and TCA can paradoxically have milder initial symptoms, causing diagnostic delay

C. Hirschsprung Enterocolitis (Most Serious Complication)

• Bacterial overgrowth in the obstructed, stagnant bowel → mucosal breakdown → bacterial translocation
• Presentation: Explosive, foul-smelling watery or bloody diarrhoea, fever, abdominal distension, lethargy
• Can rapidly progress to: haemorrhagic colitis, peritonitis, septicaemia, shock, death
• Higher frequency in: long-segment disease, diagnosis delayed beyond first week of life

Emergency management of enterocolitis: Rectal washouts (decompression), IV antibiotics, fluid resuscitation; may require urgent colostomy.

• Sabiston Textbook of Surgery, 21st Edition; Grainger & Allison's Diagnostic Radiology

Diagnosis

1. Plain Abdominal Radiograph

• Dilated loops of bowel consistent with low bowel obstruction
• Absence of gas in the rectum
• Massive megacolon in delayed presentations

2. Contrast Enema - Investigation of Choice in Newborns

• Narrow aganglionic rectum with abrupt transition to dilated proximal ganglionated bowel (cone-shaped transition zone)
• Reversed rectosigmoid ratio - normally the rectum should be wider than the sigmoid; in HD this ratio is inverted
• Irregular contractions in the aganglionic segment
• Failure to evacuate contrast at 24 hours strongly suggests HD
• Sensitivity ~70%, specificity ~83%; negative predictive value 98% in infants >1 month

Contrast enema in HD - Grainger & Allison's Diagnostic Radiology

In TCA, the contrast enema may appear normal (colonic shortening and loss of normal flexure contours are subtle signs).

Contraindication: Enterocolitis with severe colitis - contrast enema is contraindicated.

3. Anorectal Manometry

• In toddlers and older children
• Failure of the internal anal sphincter to relax after rectal balloon distension (absent rectoanal inhibitory reflex - RAIR) is diagnostic
• Sensitivity ~75-90%

4. Rectal Biopsy - Gold Standard

• Absent ganglion cells in submucosal and myenteric plexuses
• Hypertrophied nerve trunks (acetylcholinesterase-positive)
• Calretinin immunostaining - an adjunct marker (absent staining in aganglionic segment); now standard

Management

Step 1 - Initial Stabilisation

• Rectal washouts/irrigations - daily with warm normal saline via soft red rubber catheter; decompresses the bowel and prevents enterocolitis
• IV fluid resuscitation and correction of electrolytes
• Nutritional support
• Levelling colostomy - required when:
  • Rectal irrigations are ineffective or not feasible
  • Family circumstances prevent proper irrigation
  • Long-segment or TCA
  • Enterocolitis with deterioration
  • Colostomy is fashioned at the most distal level of ganglionated bowel (confirmed by intraoperative frozen section biopsies)

Step 2 - Definitive Surgery: Pull-Through Procedure

a) Swenson Pull-Through (1949 - the original procedure)

• Full-thickness dissection of the rectum from the surrounding sphincter mechanism
• Dissection from the abdomen extended distally, or starting 5-10 mm proximal to the dentate line extending proximally
• Resection of all aganglionic bowel; coloanal anastomosis performed
• Can be done open, laparoscopic-assisted, or entirely transanal

b) Soave Endorectal Pull-Through (most commonly used)

• Endorectal mucosal dissection within the aganglionic rectum via transanal approach, starting 5 mm proximal to the dentate line
• Leaves the muscular cuff of aganglionic rectum in situ; dissection plane converted to full thickness at the level of the intraabdominal rectum
• Normal ganglionated colon pulled through the muscular cuff after posterior myotomy of the cuff
• Coloanal anastomosis performed at the dentate line
• Can be performed entirely transanally (without abdominal incision) or with laparoscopic assistance

c) Duhamel Retrorectal Pull-Through

• Anterior wall of the aganglionic rectal cuff is left in place
• Normal ganglionated colon is pulled posterior to the cuff (through the retrorectal space)
• Aganglionic cuff anastomosed to the pulled-through ganglionated colon in a side-to-side fashion, creating a common reservoir (neorectum)
• The posterior ganglionated segment drives normal emptying

• One-stage pull-through with rectal irrigations - now the standard for most patients
• Two/three-stage approach (levelling colostomy → pull-through → stoma closure) - reserved for enterocolitis, severely ill neonates, long-segment disease, TCA

Postoperative Care and Complications

• Sabiston Textbook of Surgery, 21st Edition; Grainger & Allison's Diagnostic Radiology; Schwartz's Principles of Surgery, 11th Edition