Midgut Volvulus

Midgut volvulus is twisting of the small bowel and mesentery around the superior mesenteric artery axis, usually caused by intestinal malrotation with a narrow mesenteric root.

Venous obstruction occurs first, followed by:

• Mesenteric oedema
• Reduced arterial perfusion
• Intestinal ischaemia
• Necrosis
• Perforation
• Shock

The entire small intestine and part of the colon can infarct within a short period.

This is one of the most time critical emergencies in paediatric surgery.

The classic presentation is sudden bilious vomiting in a neonate.

Additional findings include:

• Irritability
• Abdominal pain
• Feeding intolerance
• Increasing abdominal distension
• Bloody stool
• Abdominal tenderness
• Lethargy
• Metabolic acidosis
• Shock

Early abdominal examination can be deceptively benign despite evolving mesenteric ischaemia.

Bloody stool, peritonism and shock are late and dangerous findings.

If the child is stable:

Upper gastrointestinal contrast study: can demonstrate the abnormal duodenal course and volvulus.

Ultrasound: a whirlpool configuration of mesenteric vessels strongly supports volvulus.

Do not delay laparotomy for imaging when there is:

• Bilious vomiting with peritonitis
• Shock
• Strong clinical evidence of bowel ischaemia

Immediate resuscitation

Keep nil orally.

Insert an orogastric or nasogastric tube.

Establish IV or intraosseous access.

Correct hypovolaemia with isotonic crystalloid, for example:

0.9% sodium chloride 10 to 20 mL/kg IV, reassessing perfusion after each bolus.

Start broad antibiotics when bowel ischaemia is suspected.

A practical regimen is:

Ceftriaxone 50 mg/kg IV every 24 hours

plus

Metronidazole 10 mg/kg IV every 8 hours

with age and neonatal dosing modification where required.

Septic shock or perforation may justify broader therapy.

Emergency operation

Proceed urgently to laparotomy.

Identify the volvulus.

Detorse the bowel counterclockwise.

The traditional memory aid is to \"turn back the clock\".

After detorsion:

• Release Ladd bands
• Broaden the mesenteric base
• Assess the entire bowel
• Perform the remainder of the Ladd procedure

Bowel viability

Do not immediately resect every dark or cyanotic loop after detorsion.

After restoration of blood flow:

• Warm bowel with saline
• Correct systemic hypotension
• Allow time for reperfusion

Assess:

• Colour
• Mesenteric pulsation
• Peristalsis
• Bleeding from questionable tissue where necessary

Resect bowel that is clearly gangrenous or perforated.

Preserve bowel of uncertain but potentially recoverable viability whenever safe because massive resection can create permanent intestinal failure.

Second look laparotomy

When a large amount of bowel is of uncertain viability, perform temporary abdominal closure and return for a second look approximately 24 to 48 hours later.

This is preferable to sacrificing potentially salvageable intestine during the initial operation.

Massive bowel necrosis

If most of the small bowel is necrotic, document carefully:

• Remaining jejunal length
• Remaining ileal length
• Presence of ileocaecal valve
• Remaining colon

These determine future intestinal function.

Short bowel syndrome can require:

• Long term parenteral nutrition
• Intestinal rehabilitation
• Autologous bowel lengthening
• Intestinal transplantation in selected severe cases

Postoperative deterioration

Persistent acidosis, shock, abdominal distension or rising lactate after surgery should prompt concern for:

• Residual ischaemic bowel
• Recurrent volvulus
• Abdominal compartment syndrome
• Sepsis

Do not assume persistent acidosis is simply postoperative physiology when extensive bowel viability was uncertain.