Abdominal Pain in the Emergency Department

Table of Contents

Resuscitation and Critical Diagnosis

Work-up for abdominal pain begins with resuscitation and exclusion of critical diagnoses:
- AAA (Abdominal Aortic Aneurysm)
- Mesenteric Ischemia
- Perforation
- SBO (small bowel obstruction)
- Ectopic pregnancy
Then, through a detailed history and physical, consider all the causes of abdominal pain

Rule out Genitourinary causes (pyelonephritis vs kidney stone) if possible with Urine Analysis
The differential for upper abdominal pain may come down to Gallstone etiology vs Gastritis/PUD that will need further imaging based on suspicion (ultrasound of abdomen)
The differential for lower abdominal pain may come down to GI (appendicitis, diverticulitis) vs pelvic etiology (in females) and will need further imaging based on suspicion (CT A/P vs pelvic ultrasound)

Resuscitate

IV/O2/Monitor, IV Fluids, Labs as needed, pregnancy test

Abdominal Pain - Causes — Acute Abdominal Pain – Causes and Differential Diagnosis

Acute Abdominal Pain - Differential Diagnosis — Acute Abdominal Pain – Causes and Differential Diagnosis

Emergent Gastrointestinal ( GI ) Causes of Upper Abdominal Pain

Billiary Tract Disease
- Biliary Colic
- Cholecystitis
- Choledocholithiasis
- Gallstone pancreatitis
- Ascending cholangitis
Acute Pancreatitis
Gastritis , GERD , Peptic Ulcer Disease

Upper Abdominal Pain - Diagnosis and Treatment Algorithm — Upper Abdominal Pain – Diagnosis and Treatment Algorithm

1. Billiary Tract Disease

The goal is to find the location of the stone and its associated complications. Is it still in the gallbladder (symptomatic cholelithiasis), in the cystic duct (cholecystitis), or in the CBD (choledocholithiasis, gallstone pancreatitis, ascending cholangitis)

Cholelithiasis

Prevalence of 10% in US, usually asymptomatic (symptoms develop in 2%/yr)

Biliary Colic

Symptomatic cholelithiasis caused by obstruction of cystic duct by gallstones
Clinical: Episodic pain in Right Upper Quadrant (RUQ), minutes to hours, resolves spontaneously
- Precipitated by meals/fatty foods
Treatment: Recurrent biliary colic → pain control, elective outpatient cholecystectomy

Cholecystitis

Clinical (vs biliary colic, may be difficult to distinguish)
- Pain longer in duration (>6 hours), localizes to RUQ, ↑ N/V/F (more nausea, vomitus)
- Murphy’s sign:
  - Localized peritonitis over gallbladder, arrest of inspiration on gallbladder palpation with pain
  - Highest LR+ of PE/lab values
  - Diminished in elderly

Course
- 1/3 will worsen→ complications (cholangitis, perforation)
- 1/2 will improve spontaneously (7-10days)

Laboratory: increased WBC, mild increase of LFTs
Radiology
- Right upper quadrant ultrasound (sensitivity 84-97%, specificity up to 100%)
- Findings: Gallstones, pericholecystic fluid, gallbladder wall thickening (>3mm), sonographic Murphy’s
- HIDA scan: non-visualization of contrast in gallbladder (cholecystitis) or intestine (choledocholithiasis)

Treatmentof Cholecystitis
- NPO / IV Fluids / Broad spectrum antibiotics
- Semi-urgent Cholecystectomy, laparoscopic (at 24-48h) with CBD exploration or ERCP if CBD stone of concern

Complications of Cholecystitis: gallbladder perforation, emphysematous cholecystitis, gangrenous cholecystitis, cholangitis, gallstone ileus

Choledocholithiasis

Define: Gallstone lodged in common bile duct
Clinical: similar presentation to cholecystitis except elevated LFTs (Alkaline Phosphatase (ALP), Total Bilirubin)
Radiology: Right upper quadrant ultrasound
- Dilated CBD (>6mm)
- Common bile duct stone
ERCP
- Diagnose and treat common duct stones (with sphincterectomy)
- Rule out other causes of obstruction (tumors…)

Gallstone Pancreatitis

Elevated amylase and lipase
ERCP to decompress biliary tree

Ascending Cholangitis

Common Bile Duct obstruction causing infection proximal to obstruction, potentially causing sepsis (increased mortality)
Charcot’s triad (RUQ pain, fever, jaundice)
Reynold’s pentad (Charcot + hypotension + AMS)
Treatment
- Conservative (NPO, IV Fluids, broad-spectrum Antibiotics, elective ERCP at resolution)
- If failure of conservative therapy (15%), emergent surgery is indicated (Percutaneous vs ERCP)

Read More: Ascending Cholangitis aka Biliary Sepsis

2. Acute Pancreatitis

Etiology of Acute Pancreatitis:

Gallstones (35%), Alcohol (30%)
Idiopathic (10%), ERCP complications (4%), Tumors, Drugs (furosemide, sulfa, thiazides, valproate, tetracyclines…), infection (viral, mycoplasma), blunt trauma (1.5%), scorpion, hypercalcemia, elevated triglycerides ( hypertriglyceridemia )

Symptoms and Signs of Acute Pancreatitis

Epigastric pain radiating to back
Nausea / Vomitus / fever, jaundice
Abdominal tenderness / guarding, Cullen’s (peri-umbilical ecchymosis), Gray Turner’s (flank bruising)

Diagnosis of Acute Pancreatitis:

Lipase
- Levels peak (12-36h), duration (2 weeks)Test of choice, better sensitivity and specificity over amylase, lipase level 3x normal, more specific
- If high suspicion for pancreatitis and lipase negative, do CT scan
- Level of lipase not predictive of severity of pancreatitis
Amylase
- Less specific, duration (1 week)
- Not used: many false positives and false negatives
- Many sources: bowel, uterus, pancreas
- Amylase: level 3x normal, not specific
CT A/P
- Unsure of diagnosis (high index of suspicion and lipase low)
  - Will see acute and chronic changes on CT
- Rule out surgical issues
- Staging system (Balthazar) → help stage and predict which patients will develop severe complication: necrotizing pancreatitis
RUQ Ultrasound to diagnose gallstone pancreatitis

Ranson criteria to predict severity of acute pancreatitis — Ranson’s criteria to predict severity of acute pancreatitis

Ranson’s criteria to predict severity of acute pancreatitis

Treatment of Acute Pancreatitis

Resuscitation
- NPO / bowel rest / IV Fluids / Nasogastric suction
- Fluid resuscitation (up to 10L/day, maintain adequate urinary output)
Antibiotics
- Meta-analysis showed prophylactic antibiotics for necrotizing pancreatitis decreased sepsis and mortality
- Imipenem/meropenem, for sickest patients
Necrotizing Pancreatitis
- Antibiotics (Imipenem), CT A/P, Urgent surgical consultation, ICU
- Fluid collections, CT or U/S guided drainage
- Infected pancreatic collections benefit from early surgery
Gallstone Pancreatitis
- RUQ Ultrasound to diagnose
- MRCP if not sure of obstructive etiology
- Treatment: ERCP (but may cause pancreatitis)

Complications of Acute Pancreatitis

NECROTIZING PANCREATITIS
- Pancreatitis → necrosis/liquefaction of tissue → local/systemic complications
- Greatest life-threatening complication of pancreatitis (mortality up to 50%)
- Predisposes to sepsis, multi-organ failure and death
- Predictive factors:
  - Hemorrhage (Gray-Turner, Cullen’s, delayed 48h),
  - Pancreatic enzymes (low levels more consistent with necrosis),
  - Severity of pancreatitis (Ranson’s criteria)
    - Hemoconcentration: Hct >47% at 48h has high sensitivity and may need CT early in course (Am J Gastroenterol 1998;93:2130-4)
- Treatment
  - Antibiotics (Imipenem), CT A/P, Urgent surgical consultation, ICU
  - CT or U/S guided drainage for fluid collections
  - Infected pancreatic collections benefit from early surgery

SEPSIS
- Responsible for most mortality associated with Acute Pancreatitis
- See Sepsis algorithm

PSEUDOCYST
- Drainage, >6cm after 6 weeks observation, or causing symptoms (abdominal pain, gastric outlet obstruction, biliary obstruction)
Other
- ↓ Ca, ↑ glucose, ↑ TG, GI hemorrhage, ascites, pleural effusion, ARDS, renal failure

Read More: Acute Pancreatitis – Approach, Evaluation and Management

3. Gastritis , GERD , Peptic Ulcer Disease

General

If patient stable, often considered default diagnosis when work-up negative and excluded lifethreats (MI, perforation…)
Empiric therapy given with abdomen re-check

Clinical

Gastroesophageal reflux disease (GERD): Heartburn, atypical angina, water brash, cough
Gastritis: Asymptomatic vs epigastric pain, N/V, anorexia
Peptic Ulcer Disease: Epigastric pain relieved (duodenal) or worsened (gastric) by food; back pain & elevated lipase (post perforation)

Treatment

Lifestyle change (elevation of head when sleeping), stop precipitants (NSAIDS / alcohol)
H. Pylori treatment, antacid / H2 blocker / PPI

Complications

Peptic Ulcer Disease:
- Hemorrhage, Perforation, Intractable pain, Obstruction
- Posterior perforation may present like pancreatitis (back pain, elevated enzymes, vomiting…)

Read More: From Heartburn to Ulcers – Understanding Peptic Ulcer Disease

Emergent Causes of Lower Abdominal Pain

Appendicitis
Diverticulitis
Pyelonephritis
Nephrolithiasis
Torsion / Pelvic inflammatory disease (PID) / TOA
Acute Scrotum

Differential Diagnosis for Abdominal Right Lower Quadrant (RLQ) Pain

Abdominal Right Lower Quadrant Pain — Differential Diagnosis for Abdominal Right Lower Quadrant (RLQ) Pain

Differential Diagnosis for Abdominal Left Lower Quadrant (LLQ) Pain

Abdominal Left Lower Quadrant Pain — Differential Diagnosis for Abdominal Left Lower Quadrant (LLQ) Pain

1. Appendicitis

Symptoms

Abdominal pain
- Periumbilical colicky pain
- Migration to right iliac fossa, constant and sharp
- Localized peritoneal irritation (McBurney’s point)
- Rovsing’s (palpation in LLQ elicits pain in RLQ)
- Psoas (pain on passive extension of thigh or active flexion of hip, seen in retrocecal appendicitis)
- Obturator signs (pain on flexion and internal rotation of hip)
Anorexia, nausea / vomiting, constipation / diarrhea
Fever, tachycardia, High WBC, High CRP

Strongest predictors of appendicitis: (Meta-analysis Brit J Surg 2004;91:28-37)
- Inflammatory response variables (PMN, WBC, CRP)
- Peritoneal irritation (rebound, percussion tenderness, guarding, rigidity)
- Migration of pain (epigastric/periumbilical then RLQ (right lower quadrant))

Patients at extremes of age may have non-specific symptoms, may cause diagnostic difficulty

Read More: When an Appendicitis Doesn’t Follow the Rules

Appendicitis - Pathogenesis and Clinical Findings — Appendicitis – Pathogenesis and Clinical Findings

Work-up for Appendicitis (Ann Intern Med 2004;141:537-46)

Ultrasound
- Aperistaltic and non-compressible structure > 6mm
- Sensitivity 86%; Specificity 81%
CT
- Abnormal appendix, calcified appendicolith + periappendiceal inflammation or diameter > 6mm
- Sensitivity 94%; Specificity 95%

READ MORE: Imaging of Acute Pancreatitis: to Image or Not to Image

Treatment of Appendicitis

Resuscitation
- Large bore IV, IV Fluids

Pain control
- Opiate administration has no significant association with management errors (JAMA 2006;296:1764-1774)

Antibiotics
- Broad spectrum, empiric
- Lower Incidence of postoperative wound infection and intra-abdominal abscess formation (Cochrane Database Syst Rev 2005;(3):CD001439)
- Antibiotics alone for treatment? (Lancet. 2011:377(9777):1573)
  - Spontaneous resolution can also occur
  - 1 year recurrence rate with antibiotics as sole therapy, 15% most within 10 days

Surgery
- Risk of rupture in 0-36h is < 2%
- Each ensuing 12h period after 36h is 5%
- Timing (Arch Surg 2006;141:504-7)
  - No significant difference between early (<12h after presentation) and later (12- 24h) appendectomy

2. Diverticulitis

Clinical Presentation

Presents like appendicitis, but of the LLQ (lower left quadrant)
Hypogastric pain migrates to LLQ (93-100%)
Fever, High WBC
Diarrhea, guaiac + stools

Acute Diverticulitis - Pathogenesis and Clinical Findings — Acute Diverticulitis – Pathogenesis and Clinical Findings

Work-up for Diverticulitis (Am J Roentgenol 2002;178:1313-8)

Empiric treatment
- No imaging studies needed if diagnosis is clear-cut, can begin empiric treatment

CT
- Sensitivity 69-95%, Specificity 75-100%
- Use for uncertain diagnosis, exclude other causes of abdominal pain, rule out diverticular complications, or clinical deterioration
- Findings: bowel wall thickening (96%), fat stranding (95%), detects complications (free air, abscess, phlegmons, cancer)

Ultrasound
- Sensitivity 84%, Specificity 93%
- Rule out AAA, hypoechoic bowel wall thickening, diverticula, abscess, hypoechoic around bowel wall

Complications of Diverticulitis (Emerg Med Clin N Am 2003;21:937-969)

Abscess
- Can lead to fistula formation and sepsis

Free perforation, peritonitis
- Rupture of diverticular abscess leading to acute surgical abdomen
- More common In elderly and immunosuppressed, high mortality (6-25%)

Fistula
- Fistula between colon and surrounding structures: colovesicular, colovaginal, colocutaneous, coloenteric
- Colovesicular fistula most common (dysuria, pyuria, pneumaturia, fecaluria)

Obstruction
- Uncommon, 2% of cases
- May cause Small-Bowel Obstruction when loops of bowel entangled in peridiverticular adhesions

Treatment of Diverticulitis

Outpatient
- Indication: Mild symptoms, tolerating oral fluids, well appearing (Am Fam Physician 2005;72(7):1229)
- Antibiotics, 7-10days (Amoxicillin / Clavulanic acid, TMP/SMX (Trimethoprim / Sulfamethoxazole), ciprofloxacin/metronidazole)
- Liquid diet, may consider no antibiotics in extremely well appearing patients (Br J Surg 2012;99(4):532)
- If no improvement in 2-3 days consider peridiverticular disease (reassessment and admission?)

Inpatient
- Indication: Severe symptoms requiring narcotics, unable to tolerate oral fluids, elderly, comorbid illnesses, ill/septic, no home support or follow-up
- IV antibiotics (gram negative/anaerobes), bowel rest
- Laparotomy in: generalized peritonitis, sepsis, visceral perforation, clinical deterioration

3. Pyelonephritis

See Low Back Pain Algorithm

4. Nephrolithiasis

See Low Back Pain Algorithm

Other Causes of Lower Abdominal Pain

1. IBD (Inflammatory bowel disease)