Acute Abdominal Pain

Acute abdominal pain is defined as severe pain of more than 6 hours duration in a previously healthy person that requires timely diagnosis and aggressive treatment, usually surgical.

Abdominal pain continues to be the number one complaint in U.S emergency departments. The U,S. populations is progressively aging, with the number of elderly (defined as age > 64 years) projected to reach 20% by 2030. Currently the elderly account for 20% of all emergency department visits per year in the United States and more than 4% of patients with acute abdominal pain. Appendicitis, cholecystitis and choledocholithiasis, intestinal obstruction, pancreatitis, mesenteric ischemia, bowel perforation and diverticulitis account for two thirds of hospital admissions for acute abdominal pain and are associated with significant morbidity and mortality.

Differential diagnosis of acute Abdominal pain

Common conditions	Key Diagnostics Test (s)
Acute Appendicitis	CT scan
Acute cholecystitis, choledocholithiasis	Ultrasound
Acute diverticulitis	CT scan
Acute pancreatitis	Serum amylase/lipase, CT scan
Bowel perforation	CT scan
Acute mesenteric ischemia	CT angiogram, MRI
Ischemic colitis	Colonoscopy
Intestinal obstruction	Flat film, imaging study
Anterior abdominal wall pain (in rectus hematoma)	Carnett sign, Fothergill sign
Nonsurgical disorders simulating acute abdomen	See table 1-2
Acute abdominal pain in women Pelvic inflammatory disease Ectopic pregnancy  Adnexal pathology	Pelvic examination, pelvic ultrasound, laparoscopy
Sigmoid volvulus	Barium enema
Biliary duct pancreatic duct rupture	MRCP, ERCP

The cause of acute abdominal pain remains unclear at the time of discharge in up to 30% of patients. A long and varied group of nonsurgical disorders must be considered in this subgroup of patients. the elderly and young women with functional abdominal pain syndrome (FAPS) represent a large portion of this patient population. A prior diagnosis of irritable bowel syndrome is associated with an increased likelihood of negative appendectomy. careful consideration and close follow-up of patients with undiagnosed acute abdominal pain is strongly advised.

Nonsurgical disorders causing acute abdominal pain

METABOLIC/ENDOCRINE

Category	Key diagnostic feature(s)
Diabetic ketoacidosis	High serum glucose
Hyperthyroidism	High T4, Low TSH
Hypercalcemia	High serum calcium
Hypokalemia	Low serum potassium
Hypophosphatemia	Low serum phosphate
Addison disease	Low serum cortisol, elevated ACTH
Porphyria	High porphobilinogen and delta-ALA
Familial Mediterranean fever	Duration 1-3 days; pleuritis and peritonitis

VASCULAR/ CARDIPULMONARY

Category	Key Diagnostic Feature(s)
Myocardial ischemia/infarction	Abnormal ECG, high troponin
Aortic dissection	Widened mediastinum and diagnostic CT angiogram
Median arcuate ligament syndrome	MRA or CTA
Pneumonia/pleurisy	Chest radiograph
Pulmonary embolus	Wells score, high D-dimer, CTPA (V/Q scan)

DRUG and TOXIN

Category	Key Diagnostic Feature(s)
Salycilate	Tinnitus, confusion, mixed respiratory alkalosis and metabolic acidosis
Anticholinergics	Confusion , dilated pupils, tachycardia, ileus, urinary retention
Tricyclic antidepressants (TCAs)	Delirium, anticholinergic symptoms, ECG changes, serum/urine TCA level
Cocaine	Tachycardia, hypertension, systemic end-organ ischemia, positive toxic screen
Heavy metals	Renal, neurologic toxicity, 24-h urine assay

VASCULITIS/CONNECTIVE TISSUE

Category	Key Diagnostic Feature(s)
Systemic lupus erythematosus	>4 of 11 SLE criteria
Systemic vasculitis	Multiorgan disease with positive P-ANCA and ANA, Low complement
Scleroderma	Skin changes, Raynaud phenomenon and visceral disease

HEMATOLOGIC/IMMUNOLOGIC

Category	Key Diagnostic Feature(s)
Sickle cell crisis	History, periarticular pain, effusions
Henoch-SchÖnlein purpura	Skin biopsy: Leukocytoclastic vasculitis with IgA and C3 deposition
Hemolytic uremic syndrome	ARF with schistocytes on smear
Hereditary angioneurotic edema	Low C1 esterase inhibitor level
Systemic mast cell disease	High serum tryptase and urinary histamine; increased tissue mast cells
Thrombotic thrombocytopenic purpura	Fever, confusion, thrombocytopenia, schistocytes

INFECTIOUS

Category	Key Diagnostic Feature(S)
Staphylotoxin	Fever, hypotension, rash (CDC case definition)
Bornholm disease	Fever, rash, spasmodic pain, enterovirus (coxsackie/echo)
Yersinia enterocolitica	Diarrhea, fever, positive stool culture, ileal inflammation
Tuberculous mesenteritis	Fever, fatigue, diarrhea, RLQ mass and ascites, positive biopsy
Dengue fever	Fever, hemolytic anemia, myalgias/arthralgias, low platelets, high FLTs, positive serology
Malaria	Fever, chill, diaphoresis, hemolytic anemia, myalgia, cough, multiorgan disease, RBC smear

MUSCULOSKELETAL

Category	Key Diagnostic Feature(s)
“Slipping rib” (Lower rib margin) syndrome	Production of pain with rib compression only on affected side
Rectus sheath hematoma/neuroma	Carnet and fothergill signs
Chronic  abdominal wall pain syndrome	RUQ (mainly) tenderness and positive Carnett sign

NEUROPSYCHIATRIC

Category	Key Diagnostic Features(s)
Herpes zoster	Unilateral, painful vesicular rash in dermatomal distribution, positive DFA of lesion or PCR of fluid
Abdominal migraine	Adolescents, cyclic occurrence
Temporal lobe seizures	Adolescents, aura, abnorminal EEG
Radiculopathy	Mechanical pain in dermatomal distribution, positive MRI
Functional abdominal pain syndrome	See Camilleri, 2006, cited in text
Irritable bowel syndrome	Manning or rome III criteria

Source :

Greenberger N J. Current Diagnosis & Treatment: Gastroenterology, Hepatology & Endoscopy. The McGraw-Hill; 2009; Pg 1-3