What are the differences in presentation between malrotation and intussusception in infants and young children?

Distinguishing Malrotation from Intussusception in Clinical Presentation

Malrotation with midgut volvulus classically presents with bilious vomiting in the first days to weeks of life as a surgical emergency, while intussusception typically presents between 3-36 months with intermittent colicky abdominal pain, "currant jelly" stools, and a palpable abdominal mass. 1, 2

Age at Presentation

• Malrotation/Midgut Volvulus: Most commonly presents in neonates and young infants, with 40% occurring in the neonatal period and 73% within the first year of life 3

  • Can present as late as childhood or adulthood, but the highest risk period is the first month of life 1, 2
  • In extremely premature infants (<28 weeks gestation), the prevalence is notably higher at 1.4% compared to 0.2% in term infants 4

• Intussusception: Peak incidence between 3 months and 3 years of age, with most cases occurring between 5-10 months 5

  • Rare in neonates and the immediate postnatal period 6

Cardinal Symptoms

Malrotation with Volvulus:

• Bilious vomiting is the hallmark symptom, typically occurring within the first 2 days of life 1, 7
• Abdominal distension may be present but is variable 1, 4
• Critical caveat: In extremely premature infants, bilious vomiting may be absent; instead, marked abdominal distension without bilious emesis is common, along with non-specific signs like recurrent apnea, bradycardia, and feed intolerance 4
• Blood in stool is uncommon unless bowel ischemia/necrosis has occurred 8

Intussusception:

• Intermittent, colicky abdominal pain with periods of apparent normalcy between episodes
• "Currant jelly" stools (blood and mucus) occur in the classic presentation 5
• Vomiting may occur but is typically non-bilious initially
• Palpable "sausage-shaped" abdominal mass, often in the right upper quadrant
• Lethargy between pain episodes

Clinical Course

• Malrotation/Volvulus: Acute, rapidly progressive deterioration once volvulus occurs, with potential for catastrophic bowel necrosis within hours 8

  • Can present with subacute, intermittent symptoms if volvulus is incomplete or intermittent 7, 4
  • Laboratory abnormalities (metabolic acidosis, elevated lactate) indicate bowel ischemia and portend poor outcomes 8

• Intussusception: Episodic symptoms with pain-free intervals initially, but progressive worsening if untreated

  • May have more insidious onset in cases associated with pathologic lead points 6

Associated Findings

• Waugh Syndrome: The rare association of intussusception WITH malrotation occurs in up to 40% of intussusception cases in some series, though this is likely overestimated 5, 6
  • When intussusception fails non-operative reduction, consider underlying malrotation 5
  • Age range for this combined presentation: typically 4-11 months 5

Diagnostic Imaging Clues

Plain Radiographs:

• Malrotation/Volvulus: May show proximal bowel obstruction pattern, "double bubble" sign (classic or non-classic), paucity of distal gas, or even normal bowel gas pattern in incomplete obstruction 1, 2
• Intussusception: May show soft tissue mass, bowel obstruction, or absence of gas in right lower quadrant

Ultrasound:

• Malrotation/Volvulus: "Whirlpool sign" (clockwise wrapping of SMV around SMA) is highly specific for midgut volvulus 1, 2
  • Reversed SMV/SMA relationship suggests malrotation but has 21% false-positive rate 1
• Intussusception: "Target sign" or "pseudokidney sign" on ultrasound is diagnostic

Upper GI Series:

• Malrotation: Reference standard showing abnormal position of duodenojejunal junction (ligament of Treitz), with 96% sensitivity 1, 3
  • False-negative rate of 3-7% and false-positive rate of 10-15% 1, 7, 3
• Intussusception: Not indicated; contrast enema is diagnostic and potentially therapeutic

Critical Pitfalls to Avoid

• Do not delay surgery for additional imaging in suspected midgut volvulus—this is a true surgical emergency requiring immediate laparotomy 2
• Do not use contrast enema to diagnose malrotation; it has 20% false-negative rate and up to 15% false-positive rate due to mobile cecum 1
• Maintain high suspicion in extremely premature infants with marked abdominal distension even without bilious vomiting 4
• Consider malrotation when intussusception fails non-operative reduction, as the association may be more common than recognized 5
• Normal bowel gas pattern on radiographs does NOT exclude malrotation with incomplete volvulus 1, 7