Acute diarrhea and abdominal pain differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sadaf Sharfaei M.D.[2]

Differential Diagnosis of Acute Diarrhea and Abdominal Pain from other diseases

The following table outlines the major differential diagnoses of acute diarrhea and abdominal pain.

Abbreviations: GI: Gastrointestinal, CBC: Complete blood count, WBC: White blood cell, RBC: Red blood cell, Plt: Platelet, Hgb: Hemoglobin, ESR: Erythrocyte sedimentation rate, CRP: C–reactive protein, IgE: Immunoglobulin E, IgA: Immunoglobulin A, ETEC: Escherichia coli enteritis, EPEC: Enteropathogenic Escherichia coli, EIEC: Enteroinvasive Escherichia coli, EHEC: Enterohemorrhagic Escherichia coli, EAEC: Enteroaggregative Escherichia coli, Nl: Normal, ASCA: Anti saccharomyces cerevisiae antibodies, ANCA: Anti–neutrophil cytoplasmic antibody, DNA: Deoxyribonucleic acid, CFTR: Cystic fibrosis transmembrane conductance regulator, SLC10A2: Solute carrier family 10 member 2, SeHCAT: Selenium homocholic acid taurine or tauroselcholic acid, IEL: Intraepithelial lymphocytes, MRCP: Magnetic resonance cholangiopancreatography, ANA: Antinuclear antibodies, AMA: Anti-mitochondrial antibody, LDH: Lactate dehydrogenase, CPK: Creatine phosphokinase, PCR: Polymerase chain reaction, ELISA: Enzyme–linked immunosorbent assay, LT: Heat–labile enterotoxin, ST: Heat–stable enterotoxin, RT-PCR: Reverse–transcriptase polymerase chain reaction, CD4: Cluster of differentiation 4, HIV: Human immunodeficiency virus, RUQ: Right-upper quadrant, VIP: Vasoactive intestinal peptide, GI: Gastrointestinal, FAP: Familial adenomatous polyposis, HNPCC: Hereditary nonpolyposis colorectal cancer, MTP: Microsomal triglyceride transfer protein, Scl‑70: Anti–topoisomerase I, TSH: Thyroid-stimulating hormone, T4: Thyroxine, T3: Triiodothyronine, DTR: Deep tendon reflex, RNA: Ribonucleic acid

Cause		Clinical manifestation									Lab findings									Extra intestinal findings	Cause/Pathogenesis	Gold standard diagnosis
		Symptoms								GI signs
		Duration		Diarrhea			Fever	Abdominal pain	Weight loss
											Stool exam					CBC			Other lab findings
		Acute	Chronic	Watery	Bloody	Fatty					WBC	RBC	Ova/Parasite	Osmotic gap	Other	WBC	Hgb	Plt
Ischemic colitis		+	+	+	+	–	+	+	+	Hyperactive then absent bowel sounds Abdominal tenderness	+	+	–	Nl	–	↑	↓	↑	Elevated CRP Elevated ESR Elevated serum lactate Elevated lactate dehydrogenase (LDH)  Elevated creatine phosphokinase (CPK) Elevated amylase Hypoalbuminemia	IgA vasculitis	Hypercoagulability  Nonocclusive colonic ischemia Embolic and thrombotic arterial occlusion Mesenteric vein thrombosis	Abdominal CT scan
Lactose intolerance		+	+	+	–	–	–	+	–	Abdominal tenderness Abdominal distention	–	–	–	↑	–	Nl	Nl	Nl	Lactose tolerance test Genetic testing	Headache Vertigo Memory impairment Lethargy	Reduction of lactase enzyme activity or inability to produce persistent lactase Congenital lactase deficiency Secondary lactose malabsorption	Small bowel biopsy  Lactose breath hydrogen test
Tropical sprue		+	+	+	–	+	+	+	+	Angular stomatitis Oral mucosal lesion	+	–	–	Nl	Positive stool culture	Nl	↓	Nl	Fat soluble vitamins deficiency Vitamin B12 deficiency Folate deficiency Hypokalemia	Myalgia Neuropathy Edema	Escherichia coli Klebsiella pneumoniae Enterobacter cloacae	Diagnosis of exclusion
Cause		Duration		Diarrhea			Fever	Abdominal pain	Weight loss	GI signs	Stool exam					CBC			Other lab findings	Extra intestinal findings	Cause/Pathogenesis	Gold standard diagnosis
		Acute	Chronic	Watery	Bloody	Fatty					WBC	RBC	Ova/Parasite	Osmotic gap	Other	WBC	Hgb	Plt
Pseudomembranous enterocolitis		+	–	+	±	–	+	+	±	Generalized abdominal tenderness Abdominal distention Rebound abdominal tenderness	+	+	–	Nl	Enzyme–linked immunosorbent assay (ELISA) Polymerase chain reaction (PCR) assay or C. difficile antigen	↑	↓	↓	Elevated serum creatinine Hypoalbuminemia Elevated lactic acid	Dehydration Acute kidney injury Bacteremia Reactive arthritis Necrotizing fasciitis	Clostridium difficile Recent antibiotics use Recent surgery	Stool exam Pseudomembranes on colonoscopy
Campylobacteriosis		+	–	+	+	–	+	+	–	Diffuse abdominal tenderness	+	+	–	Nl	Positive stool culture	↑	Nl	Nl	Nl	Toxic megacolon Sepsis Arthritis Endocarditis  Guillain–Barré syndrome	Campylobacter jejuni	Stool culture
Salmonellosis		+	+	+	+	–	+	+	–	Abdominal distention Diffuse abdominal tenderness Hepatosplenomegaly	+	+	–	Nl	Positive stool culture Positive serologic testing	↑	Nl	↑	Hypokalemia Hypernatremia Hyponatremia Hypercalciuria Hypocitraturia	Post–infectious arthritis Obtundation Bacteremia Pericarditis Pyelonephritis Brain abscess	Salmonella	Stool culture
Shigellosis		+	–	+	+	–	+	+	–	Abdominal distention Hyperactive bowel sounds Diffuse abdominal tenderness	+	+	–	Nl	Positive stool culture	↑/↓	↓	↓	Elevated CRP Elevated ESR Hyponatremia Hypoglycemia Azotemia	Headache Lethargy Seizures Delirium Post–infectious arthritis Myocarditis	Shigella	Stool culture
Cause		Duration		Diarrhea			Fever	Abdominal pain	Weight loss	GI signs	Stool exam					CBC			Other lab findings	Extra intestinal findings	Cause/Pathogenesis	Gold standard diagnosis
		Acute	Chronic	Watery	Bloody	Fatty					WBC	RBC	Ova/Parasite	Osmotic gap	Other	WBC	Hgb	Plt
Escherichia coli enteritis	EPEC	+	+	+	+	–	+	+	+	Diffuse abdominal tenderness	+	+	–	Nl	Positive stool culture	↑	Nl	Nl	–	–	Enteropathogenic E. coli	DNA probe or polymerase chain reaction (PCR) of the EPEC adherence factor Stool culture
	EIEC	+	–	+	+	–	+	+	–	Diffuse abdominal tenderness	+	+	–	Nl	Positive stool culture	↑	Nl	Nl	–	–	Enteroinvasive E. coli	DNA probe Stool culture
	EHEC	+	–	+	+	–	–	+	–	Diffuse abdominal tenderness	+	+	–	Nl	Positive stool culture	↑	↓	↓	Azotemia	Hemolytic uremic syndrome (HUS) Renal failure	Enterohemorrhagic E. coli  Shiga toxins	Stool culture
	EAEC	+	+	+	+	–	–	+	–	Diffuse abdominal tenderness	+	+	–	Nl	Positive stool culture	↑	↓	↓	–	Chronic infection in immunocompromised patients	Enteroaggregative E. coli	Stool culture
Cause		Duration		Diarrhea			Fever	Abdominal pain	Weight loss	GI signs	Stool exam					CBC			Other lab findings	Extra intestinal findings	Cause/Pathogenesis	Gold standard diagnosis
		Acute	Chronic	Watery	Bloody	Fatty					WBC	RBC	Ova/Parasite	Osmotic gap	Other	WBC	Hgb	Plt
Yersinia enterocolitica		+	–	+	+	–	+	+	–	Abdominal distention Hyperactive bowel sounds Diffuse abdominal tenderness	+	+	–	Nl	Positive stool culture	↑	Nl	Nl	–	Bacteremia Reactive arthritis Glomerulonephritis Endocarditis Erythema nodosum Abscess	Yersinia enterocolitica	Stool culture
Vibrio cholera		+	–	+	–	–	–	+	–		+	–	–	Nl	Positive stool culture	↑	Nl	Nl	Azotemia	Severe dehydration Decreased skin turgor Oliguria Renal failure Muscle cramps Seizure Somnolence	Cholera toxin	Stool culture
Aeromonas		+	+	+	+	–	+	+	–	Abdominal distention Hyperactive bowel sounds Diffuse abdominal tenderness	+	+	–	Nl	Positive stool culture	↑	Nl	Nl	–	Wound infection Bacteremia Hemolytic uremic syndrome  Meningitis Ocular infection Pneumonia  Urinary tract infection Osteomyelitis Peritonitis Acute cholecystitis Opportunistic infections in immunocompromised patients	Aeromonas virulence factors including endotoxins, hemolysins, enterotoxins, and adherence factors	Blood culture Wound culture
Cause		Duration		Diarrhea			Fever	Abdominal pain	Weight loss	GI signs	Stool exam					CBC			Other lab findings	Extra intestinal findings	Cause/Pathogenesis	Gold standard diagnosis
		Acute	Chronic	Watery	Bloody	Fatty					WBC	RBC	Ova/Parasite	Osmotic gap	Other	WBC	Hgb	Plt
Plesiomonas		+	–	+	+	–	+	+	–	Hyperactive bowel sounds Diffuse abdominal tenderness	+	+	–	Nl	Positive stool culture	↑	Nl	Nl	–	Opportunistic infections in immunocompromised patients or hepatobiliary disease Bacteremia Cellulitis and skin abscesses Peritonitis Meningoencephalitis Ocular infection Pneumonia Prosthetic joint infection  Septic abortion	Plesiomonas shigelloides	Blood culture
Mycobacterium avium complex		+	+	+	+	–	+	+	–	Abdominal distention Hepatosplenomegaly	+	+	–	Nl	–	↓	↓	Nl	Elevated liver enzymes	Opportunistic infection in immunocompromised patients Pulmonary infection Adenopathy  Night sweats	Mycobacterium avium complex	Blood culture
Food poisoning Staphylococcus aureus Bacillus cereus Clostridium perfringens		+	–	+	±	–	+	+	±	Abdominal distention	+	±	–	Nl	Positive stool culture	↑	Nl	Nl	–	History of travel or ingestion of infected food	Enterotoxins	Stool culture
Cause		Duration		Diarrhea			Fever	Abdominal pain	Weight loss	GI signs	Stool exam					CBC			Other lab findings	Extra intestinal findings	Cause/Pathogenesis	Gold standard diagnosis
		Acute	Chronic	Watery	Bloody	Fatty					WBC	RBC	Ova/Parasite	Osmotic gap	Other	WBC	Hgb	Plt
Norovirus		+	–	+	–	–	+	+	–	Abdominal distention	–	–	–	Nl	Positive stool reverse–transcriptase polymerase chain reaction (RT–PCR)	↓	Nl	Nl	–	Myalgia Headache  Seizure  Encephalopathy	Norovirus	Clinical diagnosis
Echovirus		+	–	+	–	–	+	+	–	Abdominal distention	–	–	–	Nl	–	Nl	Nl	Nl	–	Liver failure Myocarditis	Echovirus	Clinical diagnosis
Adenovirus		+	–	+	–	–	+	+	–	Abdominal distention	–	–	–	Nl	Viral antigen assay	Nl	Nl	Nl	–	Respiratory disease Follicular conjunctivitis Epidemic keratoconjunctivitis Hepatitis  Urethritis  Myocarditis  Meningitis  Bacteremia	Adenovirus	Clinical diagnosis
CMV colitis		+	+	–	+	–	±	+	–	Diffuse abdominal tenderness	+	+	–	Nl	Viral antigen assay	↓	Nl	Nl	Decreased CD4 level Abnormal liver function test	Encephalitis  Guillain–Barré syndrome Pneumonia  Retinitis Pericarditis and myocarditis Atherosclerosis  Venous thrombosis	Cytomegalovirus	Quantitative PCR tests
Cause		Duration		Diarrhea			Fever	Abdominal pain	Weight loss	GI signs	Stool exam					CBC			Other lab findings	Extra intestinal findings	Cause/Pathogenesis	Gold standard diagnosis
		Acute	Chronic	Watery	Bloody	Fatty					WBC	RBC	Ova/Parasite	Osmotic gap	Other	WBC	Hgb	Plt
Entamoeba histolytica		+	+	+	+	–	+	+	–	Abdominal distention Diffuse abdominal tenderness	+	+	+	Nl	–	↑	Nl	Nl	–	Liver abscess Pleuropulmonary infection Cardiac infection Brain abscess Cutaneous infection	Entamoeba histolytica	Antigen testing Serology
Microsporidia		+	+	+	–	–	+	+	–	Abdominal distention Diffuse abdominal tenderness	–	–	+	Nl	Positive stool microscopy	Nl	Nl	Nl	Decreased CD4 count	Malabsorption Keratitis  Seizure Myositis	Microsporidia	Antigen detection assays
Isospora		+	+	+	–	+	+	+	+	Abdominal distention Diffuse abdominal tenderness	+	+	+	Nl	Positive stool microscopy Positive fecal fat	↑	Nl	Nl	Elevated eosinophils  Hypokalemia Increased creatinine	Chronic illness in immunocompromised patients	Isospora	Detecting oocysts in the feces
VIPoma		+	+	+	–	+	–	+	+	Abdominal distention Abdominal RUQ tenderness Nausea Vomiting	–	–	–	↓	–	Nl	Nl	Nl	Elevated VIP level Hypokalemia Hypochlorhydria or achlorhydria Low osmotic gap (<50 mOsm/kg)	Rash Facial flushing Dehydration Lethargy Muscle weakness	Primary secretory tumor	Blood VIP levels Followed by imaging
Cause		Duration		Diarrhea			Fever	Abdominal pain	Weight loss	GI signs	Stool exam					CBC			Other lab findings	Extra intestinal findings	Cause/Pathogenesis	Gold standard diagnosis
		Acute	Chronic	Watery	Bloody	Fatty					WBC	RBC	Ova/Parasite	Osmotic gap	Other	WBC	Hgb	Plt
Medications ACE inhibitors Digoxin Cephalosporins Statins Thiazide diuretics Triptans Lactulose Anti retroviral agents Chemotherapeutic agents Antifungals Magnesium		+	+	+	–	±	±	+	+	Abdominal distention Dehydration	–	–	–	↑/↓	–	↑	Nl	Nl	Elevated plasma level of drug	–	Inflammation Pseudomembranous colitis	Clinical evaluation after discontinuation of the drugs
Factitious diarrhea		+	+	+	–	–	–	+	+	Abdominal distention	–	–	–	↑/↓	–	Nl	Nl	Nl	Hypokalemia  Metabolic alkalosis Hypermagnesemia	Malabsorption Lethargy Generalized weakness Acute renal failure	Medications	Clinical evaluation after discontinuation of the drugs
Cause		Duration		Diarrhea			Fever	Abdominal pain	Weight loss	GI signs	Stool exam					CBC			Other lab findings	Extra intestinal findings	Cause/Pathogenesis	Gold standard diagnosis
		Acute	Chronic	Watery	Bloody	Fatty					WBC	RBC	Ova/Parasite	Osmotic gap	Other	WBC	Hgb	Plt
Organophosphate poisoning		+	+	+	–	–	–	+	–	Salivation Vomiting	–	–	–	Nl	–	Nl	Nl	Nl	Reduced RBC acetylcholinesterase Plasma cholinesterase activity	Autonomic dysfunction Motor deficit Sensory deficit Bronchospasm Urination Miosis Bradycardia Lacrimation Sweating Cardiac arrhythmias Acute renal injury	Neurotoxins bind to acetylcholinesterase (AChE)	Clinical diagnosis
Opium withdrawal		+	+	+	–	–	–	+	–	Hyperactive bowel sounds	–	–	–	Nl	–	Nl	Nl	Nl	Azotemia Hypokalemia Metabolic alkalosis	Dysphoria  Restlessness Sweating Rhinorrhea Lacrimation Myalgia Arthralgia	Opium withdrawal	Clinical diagnosis following opium withdrawal
Radiation enteritis		+	+	+	+	+	–	+	+	Abdominal tenderness	+	+	–	Nl	Positive fecal fat	Nl	↓	Nl	Vitamin B12 deficiency Hypoalbuminemia	Prior history of malignancy and radiation therapy Malabsorption Telangiectasias	Radiation	Segmental bowel inflammation on endoscopy or colonoscopy