MDM Templates

Low Risk Abdominal Pain / NOS (Male)

Patient’s symptoms not typical for emergent causes of abdominal pain such as, but not limited to, appendicitis, abdominal aortic aneurysm, surgical biliary disease, pancreatitis, SBO, mesenteric ischemia, serious intra-abdominal bacterial illness, atypical ACS.

Workup: ***
Imaging: ***

Reassessment: Patient tolerating PO and pain controlled. Abdomen remains benign on serial exam.

Disposition: Discharge home with strict return precautions. Follow up with PCP within 2–3 days. Return immediately for worsening pain, intractable vomiting, fever, bloody stool, or inability to tolerate PO.

---

Low Risk Abdominal Pain / NOS (Female)

Patient’s symptoms not typical for emergent causes of abdominal pain such as, but not limited to, appendicitis, ovarian torsion, ectopic pregnancy, ruptured ovarian cyst, PID/TOA, surgical biliary disease, pancreatitis, SBO, mesenteric ischemia, serious intra-abdominal bacterial illness, atypical ACS.

bHCG: ***
Workup: ***
Imaging: ***

Reassessment: Patient tolerating PO and pain controlled. Abdomen remains benign on serial exam.

Disposition: Discharge home with strict return precautions. Follow up with PCP within 2–3 days. Return immediately for worsening pain, intractable vomiting, fever, vaginal bleeding, or inability to tolerate PO.

---

Surgical / Acute Abdomen

Patient presenting with acute abdomen concerning for ***. Given history, exam, and workup, surgical consultation obtained emergently.

Interventions:

• NPO status
• IV fluid resuscitation: LR bolus *** mL
• IV analgesia: *** PRN
• IV antiemetic: ondansetron 4 mg IV
• Antibiotics if indicated: ***
• NG tube if indicated for decompression
• Type & Screen / Crossmatch if hemorrhagic concern

Disposition: Admit to surgery / ICU. Patient and family counseled regarding need for operative intervention vs further inpatient evaluation.

---

Clinical Education

Red Flags & Don’t-Miss Diagnoses

Immediate life threats (“can’t-miss” list):

• Ruptured AAA — hypotension + back/flank pain + pulsatile mass (classic triad present in <50%)
• Mesenteric ischemia — pain out of proportion to exam, often elderly with AF or vascular disease
• Bowel perforation — rigid abdomen, free air on imaging
• Ectopic pregnancy — any reproductive-age female with abdominal pain; get bHCG before anything else
• Volvulus — sigmoid (elderly, psych/nursing home) vs cecal (younger); obstipation + distension
• Ruptured spleen — recent trauma or EBV/mono; LUQ pain + Kehr sign (left shoulder pain)

High-risk exam findings:

• Involuntary guarding / rigidity (peritoneal signs)
• Rebound tenderness
• Abdominal distension with high-pitched or absent bowel sounds
• Hemodynamic instability with abdominal pain
• Pain out of proportion to exam (mesenteric ischemia until proven otherwise)
• Fever + jaundice + RUQ pain (Charcot triad → cholangitis)
• Add AMS + hypotension = Reynold pentad → septic cholangitis

---

Cross-Sectional Imaging Considerations

CT with IV contrast only (no oral) is sufficient for most acute abdominal pathology — equivalent sensitivity to IV + oral for appendicitis, diverticulitis, SBO, and bowel ischemia, without the 1–2h oral contrast delay.^[1][2]

CT with IV contrast still detects kidney stones. Most clinically significant stones (>3mm) are visible as hyperdense foci or filling defects. If CT A/P with IV contrast shows hydronephrosis or a ureteral stone, you have your diagnosis — no need to repeat non-contrast.^[5]

Non-contrast CT for AAA/dissection: Identifies aneurysm and measures diameter accurately. Detects most dissection flaps. Reasonable first step with contrast allergy or renal impairment. CTA preferred when obtainable for operative planning and detection of active extravasation.^[6]

---

Appendicitis Pearls

Imaging choice:

• Adults: CT abdomen/pelvis with IV contrast (sensitivity 98%, specificity 98%)^[7]
• Pediatric: Ultrasound first (non-compressible tubular structure >6mm, target sign). CT if US equivocal.
• Pregnancy: US first → MRI without gadolinium if US non-diagnostic. CT acceptable if MRI unavailable (ACOG).^[8]

Atypical locations: Retrocecal appendix (~65% of variants) → back/flank pain, minimal anterior tenderness, positive psoas sign. Pelvic appendix → suprapubic pain, diarrhea, urinary frequency, positive obturator sign.

Pregnancy-specific considerations: Appendix migrates cephalad after 1st trimester — McBurney point unreliable by 3rd trimester (may present as RUQ/right flank pain). Perforation rate ~2–3× higher due to delayed diagnosis. Negative appendectomy carries lower fetal risk than perforation with peritonitis.^[7]

CODA Trial — antibiotics vs appendectomy: In uncomplicated appendicitis, antibiotics-only was non-inferior at 90 days — but ~30% required appendectomy by 90 days, and ~40% by 5 years.^[9][10] Presence of appendicolith = significantly higher failure rate (~40–50% eventually needing surgery). Reasonable option WITHOUT appendicolith when patients want to avoid/delay surgery; shared decision-making essential.

---

Biliary Disease Pearls

Choledocholithiasis imaging pearl: US sensitivity for CBD stones is only ~25–50% (it mainly shows the indirect sign of CBD dilation). CT with IV contrast is superior (~70–85% sensitivity).^[11] MRCP is the best non-invasive test (~95%). ERCP reserved for confirmed/high-probability stones requiring extraction.

Cholangitis antibiotics: Piperacillin-tazobactam 3.375g IV q6h or meropenem 1g IV q8h (PCN allergy / ESBL risk). Tokyo Guidelines 2018/2024 grade severity (I–III) and guide timing of biliary drainage.^[12]

Acalculous cholecystitis: ~5–10% of acute cholecystitis. Think ICU patients, TPN-dependent, HIV/immunocompromised, post-op, burn patients. US findings similar but no stones. Higher morbidity/mortality than calculous cholecystitis.

---

Pancreatitis Pearls

Diagnosis (revised Atlanta criteria): Requires 2 of 3: (1) characteristic epigastric pain radiating to back, (2) lipase >3× upper limit of normal, (3) imaging findings consistent with pancreatitis.

Lipase vs amylase: Lipase is more sensitive and specific. Lipase remains elevated longer (up to 14 days vs 3–5 for amylase). Amylase adds no diagnostic value when lipase is available — do not routinely order both.^[13]

Severity prediction: BISAP score is simpler and available at admission vs Ranson criteria (which requires 48h data). BISAP ≥3 = increased mortality risk.^[14]

Key management points:

• Early goal-directed IVF with LR (1.5 mL/kg/hr initially, reassess with UOP and BUN trends)^[13]
• Early oral feeding as tolerated — even in moderate-severe disease (2024 AGA guidelines)^[13]
• Opioids are NOT contraindicated — the morphine/sphincter of Oddi concern is not supported by evidence
• Antibiotics NOT routinely indicated even in necrotizing pancreatitis unless infected necrosis confirmed

---

Small Bowel Obstruction Pearls

Imaging: CT abdomen/pelvis with IV contrast is the study of choice (sensitivity >95%).^[2] Look for transition point, dilated proximal bowel (>3cm), decompressed distal bowel, small bowel feces sign.

Adhesive SBO (most common cause ~60–75%): Any patient with prior abdominal surgery. Closed-loop obstruction is the surgical emergency — look for C-sign or U-sign on CT with mesenteric swirl at two transition points.

Signs of strangulation/ischemia (need emergent surgery):

• CT: lack of bowel wall enhancement, mesenteric haziness, pneumatosis, portal venous gas
• Clinical: fever, tachycardia, peritoneal signs, elevated lactate, worsening despite decompression

Management: NPO, NG tube decompression, IVF, serial abdominal exams. Gastrografin challenge (100 mL PO/NG) is both diagnostic and therapeutic — if contrast reaches colon by 8–24h, resolution likely. Reduces need for surgery and LOS.^[15]

---

Mesenteric Ischemia

Why it matters: Mortality 60–80% if diagnosis delayed beyond bowel necrosis.^[4]

Classic patient: Elderly, AF or vascular disease, pain out of proportion to exam, rapid gut emptying (vomiting/diarrhea early), elevated lactate is a LATE finding.

Types:

Imaging: CTA abdomen/pelvis (sensitivity >95% for arterial occlusion).^[4] Look for SMA cutoff, bowel wall thickening without enhancement, mesenteric fat stranding, pneumatosis, portal venous gas (late/ominous).

Key point: Normal lactate does NOT rule out mesenteric ischemia. Lactate rises late — by the time it is elevated, bowel necrosis may already be present. A normal lactate in the right clinical context should not provide false reassurance.

---

Abdominal Aortic Aneurysm Pearls

Classic triad of rupture: Hypotension + abdominal/back pain + pulsatile abdominal mass. Present in only ~25–50% of ruptured AAA cases.^[6]

Mimics: Renal colic (most common misdiagnosis), back pain/musculoskeletal, diverticulitis, GI bleed.

Bedside ultrasound: Aorta >3 cm = aneurysmal. If symptomatic + AAA on US → do NOT wait for CT → emergent vascular surgery consult. A negative FAST does not rule out retroperitoneal rupture.

Management of ruptured AAA: Permissive hypotension (SBP 70–90), limit crystalloid (massive transfusion protocol), emergent vascular/IR consult for EVAR vs open repair. Do NOT delay for CT if hemodynamically unstable with known or suspected AAA.

---

Special Populations

Pregnancy

Always get bHCG first in any reproductive-age female with abdominal pain — ectopic pregnancy is life-threatening and easily missed.

Anatomic changes by trimester:

• Appendix migrates superiorly and laterally — by 3rd trimester, may present as RUQ pain
• Uterus displaces bowel — physical exam becomes less reliable
• Physiologic leukocytosis (WBC up to 16,000 in pregnancy, up to 30,000 in labor) — less useful for infection
• Physiologic mild tachycardia and decreased BP in 2nd trimester

Imaging in pregnancy:

Pregnancy-specific causes of abdominal pain:

• Ectopic pregnancy — bHCG + transvaginal US. Discriminatory zone: 1,500–2,000 mIU/mL (if no IUP seen above this level, suspect ectopic)
• Placental abruption — vaginal bleeding + rigid/tender uterus + fetal distress (2nd/3rd trimester)
• HELLP syndrome — RUQ/epigastric pain + hemolysis + elevated LFTs + low platelets (usually >20 weeks). Can occur postpartum.
• Ovarian torsion — more common in 1st trimester due to corpus luteum cyst
• Round ligament pain — common benign cause, sharp groin pain with position change (2nd trimester)
• Uterine rupture — prior C-section scar, acute pain + vaginal bleeding + loss of fetal station

---

Elderly / Atypical Presentations

Why the elderly are dangerous: Higher mortality from same surgical diagnoses (appendicitis mortality ~5% in elderly vs <1% in young adults). Blunted febrile response, blunted leukocytosis, diminished peritoneal signs, pain often understated or attributed to “constipation.”^[16]

Have a lower threshold for imaging in elderly patients with abdominal pain. CT abdomen/pelvis with IV contrast is the most useful single study.

Commonly missed diagnoses in the elderly:

• Mesenteric ischemia — AF + abdominal pain = think mesenteric ischemia. Pain out of proportion. Get CTA early.
• AAA — new back/flank/abdominal pain in patient >65 with vascular risk factors. Bedside US to screen.
• Sigmoid volvulus — elderly, institutionalized, psychiatric medications, chronic constipation. “Coffee bean sign” or “bent inner tube” on XR. First-line treatment: endoscopic decompression with rectal tube.
• Atypical appendicitis — may present with only vague periumbilical discomfort, mild anorexia, or no fever. Perforation rate much higher in elderly (~50–70%).
• Atypical ACS — epigastric pain may be the only symptom. Get ECG on every elderly patient with abdominal pain.
• Incarcerated hernia — always examine the groins in every abdominal pain patient, especially elderly.

Medication considerations: Beta-blockers may mask tachycardia. Anticoagulants increase risk of spontaneous retroperitoneal hemorrhage, rectus sheath hematoma, and intramural bowel hematoma. Steroids/immunosuppressants may blunt fever, WBC, and peritoneal findings.

---

References

1. Anderson BA et al. CT Without Oral Contrast for Acute Abdominal Pain: A Systematic Review. Emerg Radiol. 2020;27:573-582. PubMed
2. ACR Appropriateness Criteria: Acute Nonlocalized Abdominal Pain. American College of Radiology. 2022. ACR
3. Smith RC et al. Acute Flank Pain: Comparison of Non-Contrast-Enhanced CT and Intravenous Urography. Radiology. 1995;194(3):789-794. PubMed
4. Bala M et al. Acute Mesenteric Ischemia: Updated Guidelines of the WSES. World J Emerg Surg. 2022;17:54. PubMed
5. Jancke G et al. CT Urography for Evaluation of Ureteral Calculi. Acta Radiol. 2019;60(5):636-643. PubMed
6. Chaikof EL et al. SVS Practice Guidelines for the Care of Patients with AAA. J Vasc Surg. 2018;67(1):2-77. PubMed
7. Bhangu A et al. Acute Appendicitis: Modern Understanding of Pathogenesis, Diagnosis, and Management. Lancet. 2015;386:1278-1287. PubMed
8. ACOG Committee Opinion No. 723: Guidelines for Diagnostic Imaging During Pregnancy and Lactation. Obstet Gynecol. 2017. ACOG
9. CODA Collaborative. A Randomized Trial Comparing Antibiotics with Appendectomy for Appendicitis. N Engl J Med. 2020;383:1907-1919. PubMed
10. CODA Collaborative. Five-Year Follow-Up of Antibiotics vs Appendectomy for Appendicitis. N Engl J Med. 2024;390:1486-1498. PubMed
11. Anderson SW et al. CT of Suspected Choledocholithiasis: Comparison with ERCP. AJR Am J Roentgenol. 2006;187(1):174-180. PubMed
12. Tokyo Guidelines 2018: Diagnostic Criteria and Severity Grading of Acute Cholangitis. J Hepatobiliary Pancreat Sci. 2018;25(1):17-30. PubMed
13. Crockett SD et al. AGA Clinical Practice Update on Management of Acute Pancreatitis. Gastroenterology. 2024;166(4):570-581. PubMed
14. Wu BU et al. The Early Prediction of Mortality in Acute Pancreatitis: A Large Population-Based Study. Gut. 2008;57(12):1698-1703. PubMed
15. Di Saverio S et al. Bologna Guidelines for Diagnosis and Management of Adhesive Small Bowel Obstruction (ASBO). World J Emerg Surg. 2013;8:42. PubMed
16. Spangler R et al. Abdominal Emergencies in the Geriatric Patient. Int J Emerg Med. 2014;7:43. PubMed