Acute Abdominal Pain

Acute Abdominal Pain

If unstable:

Check for tachycardia, hypotension, signs of hypoperfusion, and signs of dehydration.
If not stable, proceed to resuscitation.

If stable:

[1] Recognizing Impending Shock, Resuscitate

[2] Resuscitation:

Evaluate ABCs and resuscitate as needed.
Cardiac monitoring: BP, HR, SpO2, ± urine output monitoring (via Foley catheter).
Lab tests: Electrolytes, BUN/Cr, CBC with platelet count, coagulation tests, blood typing, crossmatch if hemorrhage is suspected, LFT if hepatobiliary cause is suspected, urinalysis (for KUB system).
If GI bleed is present, refer to the GI bleed section.
Consider blood transfusion.
If infection or sepsis is suspected, perform hemoculture and administer empirical antibiotics.

[3] Focused History Taking and Physical Examination:

Take a detailed history, including any accompanying symptoms and physical examination, focusing on past medical history (especially hepatobiliary), surgical history (check for surgical scars), history of nausea/vomiting, alcohol consumption, UTI symptoms, NPO status, and examination of the groin area (rule out inguinal hernia with/without complications).
For females with lower abdominal pain, always consider OB/GYN causes and perform a urine pregnancy test in women of childbearing age.
Always rule out surgical causes.
If a surgical condition is suspected, consult surgery urgently.
Signs of peritonitis include rigidity, involuntary guarding, rebound tenderness (weaker signs than guarding), or if the patient prefers to lie still to avoid pain.
Pain out of proportion (severe pain without signs) suggests an ischemic cause.
Abrupt onset of severe pain or change in pain location (referred pain).
Abdominal pain occurring before fever or vomiting.
Bilious vomiting.
Sudden onset of pallor (acute anemia) may indicate GI bleeding.

[4] Focused Investigation:

Laboratory Tests and Suspected Conditions:

Amylase, Lipase: More specific for Pancreatitis.
Serum β-HCG, Urine pregnancy test: Pregnancy, ectopic/molar pregnancy.
Platelet count, Coagulogram: GI bleed, coagulopathy, chronic liver disease.
Electrolytes: Dehydration, electrolyte imbalance.
Glucose: DKA, pancreatitis.
Hemoglobin/HCT: GI bleeding.
Lactate: Mesenteric ischemia, sepsis.
Liver function tests: Cholangitis, hepatitis, liver abscess, cholelithiasis.
Renal function tests: Dehydration, AKI, CKD.
Urinalysis: UTI, ureteric colic, pyelonephritis.
ECG & Troponin: MI.
Stool Exam: Inflammatory or infectious diarrhea.
Acute Abdomen Series: Bowel obstruction, ileus, bowel perforation (pneumoperitoneum indicates surgical intervention), gallstone (10%), kidney stone (90%).
Ultrasound: Cholecystitis, cholangitis, pancreatitis, liver abscess, intra-abdominal fluid collection, gynecologic conditions.
CT Abdomen: Uncertain diagnosis.

[5] Supportive Treatment:

Anti-acid drug: Omeprazole (20 mg) 1 tablet orally before meals or, if severe, Omeprazole (40 mg) IV stat.
Anti-spasmodic drug: Hyoscine [Buscopan] 10 mg 1 tablet orally three times daily, or Hyoscine 20 mg IV stat.
Anti-emetics: Ondansetron 4 mg IV as needed every 4 hours; max 32 mg/day (Side Effect: headache), Metoclopramide 10 mg IV (Side Effect: extrapyramidal symptoms, EPS).
Analgesics: Morphine for severe pain 3-5 mg IV as needed every 4-6 hours.
Antibiotics: In cases of peritonitis or sepsis due to intra-abdominal infection, an empirical regimen of Ceftriaxone 2 g IV once daily + Metronidazole 500 mg IV every 8 hours.

Common Pitfalls:

Failure to perform a pregnancy test or consider pregnancy-related causes.
Overlooking aortic dissection or MI.
Not recognizing that DKA can often present with abdominal pain.
Omission of PR, PV, examination of the inguinal area when necessary.
Being misled by lab values within the normal range that mask the diagnosis, despite clinical indications (over-reliance on lab values).
Elderly and immunocompromised patient groups with unclear clinical presentations.

Life-Threatening Conditions: