What is the appropriate diagnosis and management for a patient presenting with diarrhea, air in the splenic flexure, and back pain?

Splenic Flexure Syndrome vs. Splenic Infarction/Abscess: Critical Diagnostic Approach

This presentation of diarrhea with air in the splenic flexure and back pain most likely represents splenic flexure syndrome (trapped gas causing referred pain), but you must urgently exclude life-threatening splenic infarction or abscess with immediate CT imaging with IV contrast.

Immediate Diagnostic Workup

Obtain CT scan with intravenous contrast immediately - this is the gold standard with 90-95% sensitivity and specificity for identifying splenic pathology including infarction (appearing as peripheral wedge-shaped low-density areas) or abscess (appearing as contrast-enhancing cystic lesions) 1, 2.

Critical Red Flags Requiring Emergency Imaging:

• Persistent fever - suggests progression to splenic abscess or infectious colitis 1, 2
• Hemodynamic instability (tachycardia, orthostasis, hypotension) - may indicate splenic rupture or severe volume depletion 3, 1
• Severe or progressive abdominal pain - particularly left upper quadrant pain radiating to back suggests splenic pathology 1, 4
• Signs of peritoneal irritation - suggests perforation, rupture, or severe inflammatory process 5

Initial Laboratory Assessment:

• Complete blood count (leukocytosis with neutrophilia suggests infection or infarction) 3, 2
• Blood cultures if febrile (Staphylococcus aureus and Streptococcus viridans account for ~40% each of splenic abscesses) 2, 6
• Electrolytes, renal function, liver function tests 3
• Stool studies: culture, C. difficile, fecal leukocytes, ova and parasites 3

Differential Diagnosis Algorithm

If CT Shows Splenic Infarction:

Most splenic infarcts should be managed conservatively with supportive care, reserving splenectomy only for life-threatening complications 1.

• Monitor hemodynamically with frequent vital signs and serial hematocrit measurements 1
• Implement bed rest for first 48-72 hours 1
• Watch for complications: persistent/recurrent fever, ongoing abdominal pain, bacteremia indicating progression to abscess 1
• Absolute indications for surgery: splenic rupture with hemorrhage, abscess formation, failed conservative management with hemodynamic instability 1, 2

If CT Shows Splenic Abscess:

Start immediate IV broad-spectrum antibiotics targeting S. aureus and Streptococcus viridans, then proceed with image-guided percutaneous drainage for abscesses >4 cm 2, 6.

• For single abscesses >4 cm: Percutaneous catheter drainage under CT/ultrasound guidance (90% success rate for unilocular abscesses) 2
• For multiple or complex abscesses: Proceed directly to splenectomy (percutaneous drainage has 14.3-75% failure rate) 2, 6
• Absolute surgical indications: rupture, drainage failure, multiple complex abscesses, no safe drainage window 2

If CT Shows Colonic Pathology:

Splenic Flexure Volvulus:

• Rare but critical diagnosis - presents with obstipation, progressive abdominal pain, distended abdomen 7
• Plain X-ray shows distended cecum/ascending colon without air distal to splenic flexure 7
• Initial treatment: Endoscopic detorsion if no ischemia/perforation signs 7
• Surgical resection required if gangrenous bowel present 7

Infectious Colitis:

Empiric antibiotics should be considered in patients with severe illness, bloody diarrhea, fever, or immunocompromise 3.

• Adults with bloody diarrhea: Consider fluoroquinolone or azithromycin based on local resistance patterns 3
• CRITICAL EXCEPTION: Avoid antibiotics if STEC O157 or Shiga toxin 2-producing STEC suspected (increases HUS risk) 3
• Most common pathogens: Salmonella, Campylobacter, C. difficile, Shigella, STEC 3

Management of Uncomplicated Diarrhea (If Imaging Normal)

Assess Severity and Complications:

Classify as "uncomplicated" vs "complicated" to determine management intensity 3.

Complicated features requiring aggressive management:

• Grade 3-4 diarrhea (≥7 stools/day above baseline) 3
• Moderate-severe cramping, fever, sepsis 3
• Dehydration, orthostatic symptoms 3
• Frank bleeding, neutropenia 3

Rehydration Strategy:

Oral rehydration is superior to IV fluids for patients able to take oral fluids - less painful, safer, less costly 3.

• Use WHO-recommended solutions (Ceralyte, Pedialyte) with Na 90 mM, K 20 mM, Cl 80 mM, HCO3 30 mM, glucose 111 mM 3
• Patient's thirst decreases with rehydration, protecting against overhydration 3

Epidemiological Risk Factors to Assess:

• Recent travel to developing areas 3
• Day-care exposure, unsafe food consumption (raw meats, unpasteurized products) 3
• Recent antibiotics (C. difficile risk) 3
• Immunosuppression (AIDS, medications) 3

Common Pitfalls to Avoid

• Never rely on clinical splenomegaly - present in only 30% of splenic pathology cases 1, 6
• Do not use antibiotics empirically for all bloody diarrhea - STEC infection worsens with certain antibiotics 3
• Do not delay imaging in patients with persistent fever and abdominal pain - splenic abscess mortality is high without intervention 2
• Avoid nuclear medicine scans - obsolete with no diagnostic value 1
• Consider medication history - anticholinergics can cause colonic dysmotility and volvulus 7