What are the clinical and laboratory features of malrotation and volvulus in adults?

Clinical and Laboratory Features of Malrotation and Volvulus in Adults

Malrotation and volvulus in adults typically present with abdominal pain, distension, vomiting, and decreased or absent passage of flatus and stool, with the "whirlpool sign" on imaging being the most pathognomonic radiological finding. 1

Clinical Presentation

Cardinal Symptoms

• Abdominal pain:

  • Colicky in nature due to increased motility trying to overcome obstruction
  • Can become intense and unresponsive to analgesics if ischemia develops
  • May present as recurrent episodes in chronic cases 2, 3
  • Some patients have long histories of intermittent abdominal pain 4

• Nausea and vomiting:

  • Earlier and more prominent in small bowel obstruction
  • Vomit may be green/yellow (proximal obstruction) or feculent (distal obstruction) 5

• Abdominal distension:

  • Sudden onset in volvulus
  • Progressive in cases related to malignancy 5
  • High predictive value with positive likelihood ratio of 16.8 5

• Decreased or absent passage of flatus and stool:

  • Highly significant clinical indicator of intestinal obstruction 1
  • Complete cessation of flatus suggests complete obstruction

Physical Examination Findings

• Abdominal distension with tympany to percussion
• Loud or high-pitched bowel sounds
• Visible small bowel peristalsis (in thin patients)
• Asymmetric gaseous abdominal distention with emptiness of the left iliac fossa (pathognomonic for sigmoid volvulus) 5
• Digital rectal examination often reveals an empty rectum 5
• Peritoneal signs (if ischemia or perforation has occurred)

Systemic Signs of Severe Obstruction/Ischemia

• Fever
• Tachycardia
• Hypotension (in advanced cases)
• Altered mental status
• Cool extremities or mottled skin (signs of shock) 5

Laboratory Features

Basic Laboratory Tests

• Complete blood count:

  • Leukocytosis suggests inflammation, ischemia, or perforation
  • Hemoconcentration may indicate dehydration

• Metabolic panel:

  • Electrolyte abnormalities (hypokalemia, hyponatremia)
  • Elevated BUN/creatinine (dehydration)
  • Elevated lactate (suggests bowel ischemia) 5, 1

• Blood gas analysis:

  • Metabolic acidosis (in bowel ischemia)
  • Respiratory alkalosis (in early sepsis)

Specific Tests

• Inflammatory markers:
  • Elevated C-reactive protein
  • Decreased albumin
  • Elevated platelet count
  • Normal fecal calprotectin (helps differentiate from inflammatory bowel disease) 5

Imaging Findings

Plain Radiography

• Dilated bowel loops
• Air-fluid levels
• May show "coffee bean sign" in sigmoid volvulus 5

CT Scan (Gold Standard)

• Whirlpool sign: Twisted mesentery around superior mesenteric artery and vein - pathognomonic for midgut volvulus 2, 6
• Abnormal position of duodenojejunal junction and cecum
• Transition point between dilated and normal-sized bowel
• Reduced bowel wall enhancement (suggests ischemia)
• Pneumatosis intestinalis (gas in bowel wall) in severe cases 4

Ultrasound

• Can demonstrate the "whirlpool sign" in real-time
• Wrapping of superior mesenteric vein and bowel loops around superior mesenteric artery 6
• Less reliable than CT but may be useful in initial assessment

Upper GI Series/Small Bowel Follow-Through

• Twisted, corkscrew appearance of the barium column in the duodenum and proximal jejunum 4
• Abnormal position of duodenojejunal junction
• "Corkscrew sign" caused by dilatation of various duodenal segments at different levels 2

Differential Diagnosis

• Adhesive small bowel obstruction (history of previous surgery)
• Diverticular stenosis (history of diverticulitis)
• Colorectal cancer (history of rectal bleeding, weight loss)
• Opioid-induced bowel dysfunction (history of opioid use)
• Pseudo-obstruction/adynamic ileus (medications affecting peristalsis)
• Inflammatory bowel disease stenosis
• Ischemic stenosis
• Radiation stenosis
• Intussusception

Common Pitfalls in Diagnosis

1. Misdiagnosis: Volvulus, megacolon, and chronic constipation are the most frequent misdiagnoses for intestinal dysmotility 5

2. Intermittent symptoms: Patients may have long-standing symptoms that resolve and recur, leading to delayed diagnosis 3, 4

3. Age-related challenges: Diagnosis can be very difficult in elderly or unconscious patients 5

4. Opioid use: Can mask or mimic symptoms of obstruction and invalidate motility tests 5

5. Failure to obtain imaging during symptomatic episodes: CT scan during an episode of severe pain is most diagnostic 5

By recognizing these clinical and laboratory features promptly, clinicians can expedite diagnosis and management of malrotation and volvulus in adults, potentially preventing life-threatening complications such as bowel ischemia and perforation.