Sandbox: malabsorption

Diarrhea

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,

Categories		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
Gastrointestinal		Crohns disease		–	+	+	+	+	±	+	+	Abdominal tenderness Mouth ulcer Tachycardia Hypotension	+	+	–	–	–	↑	↓	↑	Anti saccharomyces cerevisiae antibodies (ASCA) Vitamin B12 deficiency Elevated ESR Elevated CRP	Uveitis Arthritis Erythema nodosum Pyoderma gangrenosum Amyloidosis Venous and arterial thromboembolism Renal stones Bronchiectasis	Abnormal immune response to self antigens	Colonoscopy with biopsy
		Ulcerative colitis		–	+	+	+	+	+	+	+	Normal in mild cases Abdominal tenderness Tachycardia Hypotension Pallor Blood on rectal examination	+	+	–	–	–	↑	↓	↑	Anti–neutrophil cytoplasmic antibody (P–ANCA) Hypoalbuminemia Hypokalemia Hypomagnesemia Elevated ESR Elevated CRP	Skin rash Iritis Uveitis Seronegative arthritis Clubbing of the fingers Erythema nodosum	Abnormal immune response to self antigens	Colonoscopy with biopsy
		Celiac disease		–	+	±	–	±	–	+	+	Abdominal distention Increased bowel sounds Mouth ulcers Hepatosplenomegaly Ascites	–	–	–	–	Fat droplets on sudan stain	–	↓	–	IgA endomysial antibody Anti–tissue transglutaminase antibody Anti–gliadin antibody	Signs of the fat soluble vitamins deficiency Dementia Dermatitis herpetiformis	HLA–DQ2 HLA–DQ8 Innate responses to wheat proteins	IgA endomysial antibody Anti–tissue transglutaminase antibody
		Cystic fibrosis		–	+	–	–	+	±	+	+	Abdominal distention Hepatosplenomegaly Rectal prolapse	–	–	–	–	Fat droplets on sudan stain	–	↓	–	Positive DNA analysis for cystic fibrosis transmembrane conductance regulator (CFTR) Nasal transepithelial potential difference	Signs of the fat soluble vitamins deficiency Recurrent respiratory tract infection Bronchiectasis Diabetes mellitus Scoliosis Infertility	Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein	Positive genetic testing Elevated sweat chloride ≥60 mmol/L
		Chronic pancreatitis		–	+	+	–	+	–	+	+	Abdominal tenderness	–	–	–	–	Fat droplets on sudan stain Positive fecal elastase measurement	–	–	–	Slightly elevated amylase and lipase Abnormal pancreatic function test Secretin stimulation test	Malabsorption Diabetes mellitus Pancreatic pseudocyst	Toxins Repeated acute pancreatitis Genetic Autoimmune	Magnetic resonance cholangiopancreatography (MRCP)
		Bile acid malabsorption		–	+										–	–
		Microscopic colitis		–	+	+	+	–	–	+	+	Abdominal tenderness			–	–		–	↓	–	Elevated autoantibodies include: RF ANA AMA ANCA	Fecal urgency Fecal incontinence Arthralgia Arthritis Uveitis	Mucosal immune responses to luminal factors in a genetically predisposed individual	Colonoscopy with mucosal biopsy with mononuclear infiltrates: Collagenous colitis is characterized by a colonic subepithelial collagen band >10 micrometers in diameter Lymphocytic colitis is characterized by ≥20 intraepithelial lymphocytes (IEL) per 100 surface epithelial cells
		Infective colitis		–											–	–
		Ischemic colitis		–											–	–
		Mesenteric ischemia		–											–	–
		Lactose intolerance		+	+	+	–	–	–	+	–	Abdominal tenderness Hypotension Tachycardia Nausea and vomiting			–	↑		–	–	–	Hydrogen breath test	Bloating Flatulence Symptoms begin mainly after ingestion of lactose	Reduction of lactase enzyme activity or inability to produce persistent lactase Congenital lactase deficiency	Lactase activity assay
		Irritable bowel syndrome		–	+	±	–	±	–	±	–	Abdominal tenderness Flatulence Hard stool in the rectal vault			–	–		–	–	–				Diagnosis of exclusion
Infection	Bacterial	Whipple's disease		–	+	+	–	+	±	+	+	Hepatosplenomegaly Ascites	–	–	–	–	Fecal fat	↓	↓	↓/↑	Hypoalbuminemia	Abnormal extraocular movement Lymphadenopathy Hyperpigmentation Uveitis Endocarditis Encephalitis Dementia Pleural effusion	Tropheryma whipplei HLA–B27	Small intestine biopsy for Tropheryma whipplei testing PCR testing
		Tropical sprue		+	+	+	–	+	+	+	+	Pallor Angular stomatitis Mouth ulcers Edema			–	–		–	↓	–	Low vitamin B12 Low folic acid Hypokalemia		Unknown Bacteria including Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae	Diagnosis of exclusion
		Small bowel bacterial overgrowth		–	+	+	–	+	–	+	+	Muscle atrophy Abdominal distention			–	–		–	↓	–	Hypoalbuminemia Abnormal hydrogen breath test Lactic acidosis Abnormal fecal fat test	Malabsorption Vitamins deficiencies Rosacea	Excess bacteria in the small intestine Alterations in intestinal anatomy or GI motility Lack of gastric acid secretion	Diagnosis of exclusion
		Food poisoning		–											–	–
		Pseudomembranous colitis		+	–	+	+/–	–	+	+	+/–	Abdominal tenderness Presence of pseudomembranes of endoscopy			–	–	Enzyme immunoassay (EIA) for C difficile toxin A and B Polymerase chain reaction (PCR) assay or C difficile antigen (glutamate dehydrogenase [GDH]) EIA	↑	↓	↓	Leukocytosis Elevated serum creatinine Hypoalbuminemia Anasarca Elevated serum lactate		Recent antibiotics use Recent surgery Colon cancer Diverticulitis Appendicitis	Stool exam CT
		Shigella		–											–	–
		Salmonella		–											–	–
		Campylobacter jejuni		–											–	–
		E–coli	ETEC (Traveler's diarrhea)	+	–	+	–	–	+	–	–				–	–					Enterotoxins: Heat–labile enterotoxin (LT)  Heat–stable enterotoxin (ST)		Enterotoxins: Heat–labile enterotoxin (LT) Heat–stable enterotoxin (ST)
			EPEC	–											–	–
			EIEC	–											–	–
			EHEC	–											–	–
			EAEC	–											–	–
		Yersinia enterocolitica		–											–	–
		Vibrio cholera		–											–	–
		Aeromonas		–											–	–
		Plesiomonas		–											–	–
		Mycobacterium avium complex			+		+		+/–	+	–		+/–	+	–	–		↓	–	–	Immune system analysis may show defects
		Other infections aaaa bbbb			+		+		–	+	+/–		+	+	–	–	Stool culture may be positive for responsible organism	↑	–	–
	Virus	Rotavirus		–											–	–
		Echovirus		–											–	–
		Adenovirus		–											–	–
		Norovirus		–											–	–
		CMV colitis			+		+		+/–	+	–		+/–	+	–	–		↓	–	–	CD 4 level decreased as it is maily associated with HIV
		HIV		–											–	–
		Hepatitis	Hepatitis A	–											–	–
			Hepatitis E	–											–	–
	Parasite	Entamoeba histolytica		–											+	–
		Giardia		–											+	–
		Cryptosporidium		–											+	–
		Microsporidia		–											+	–
		Isospora			+		+			+	–		+	+	+	–		↑	–
		Other Parasitic diarrhea aaaa bbbb		+	+		+		–	+	+/–		+	+	+	–		↑	–	–
Tumors		Carcinoid tumor		–											–	↓
		VIPoma		+	+	+	–	+	–	+	+	Tachycardia Abdominal distention Abdominal RUQ tenderness Nausea Vomiting			–	↓		–	–	–	Elevated VIP level Hypokalemia Hypochlorhydria or achlorhydria Low osmotic gap (<50 mOsm/kg)	Rash Facial flushing Dehydration Lethargy Muscle weakness	Primary secretory tumor	Elevated VIP levels Followed by imaging
		Zollinger–Ellison syndrome		–	+	+	–	+	–	+	+	Abdominal tenderness			–	↓		–	↓	–	Positive secretin stimulation test Elevated serum chromogranin A	Heartburn	Gastrin producing tumor mainly in duodenum	Elevated basal or stimulated serum gastrin> 120 pg/mL
		Somatostatinoma		–											–	↓
		Lymphoma		–											–	–
		Colorectal cancer			+		+			+	+		–	+	–	–		–	↑/↓	–	May be associated with FAP gene or HNPCC gene
Medication/Toxicity		Drug induced enteritis		–											–	–
		Laxative abuse		–											–	↑
		Heavy metal ingestion		–											–	–
		Organophosphate poisoning		–											–	–
		Opium withdrawal		–											–	–
Iatrogenic		Short bowel syndrome		+	+	+	–	+	–	–	+	Abdominal distention Abdominal tenderness Peripheral edema Muscle atrophy			–	–		–	↓	↑	Hypoalbuminemia High level of acute phase reactant Abnormal liver function tests Low vitamin A, B12, C,D, E, and K level High fecal fat	Prior intestinal surgery Crohn's disease Malignancy Radiation enteritis	Surgical intestinal resection
		Radiation enteritis		–											–	–
		Dumping syndrome		–											–	–
Others		Abetalipoproteinemia		–	+	+	–	+	–	+	+	Abdominal distension Visual field defect Dysarthria			–	–		–	–	–	Low triglyceride Low total cholesterol levels  Acanthocytes Low vitamin E levels	Visual impairment Ataxia	Autosomal recessive disorder caused by mutations encoding the microsomal triglyceride transfer protein (MTP)	Clinical findings and low triglyceride and cholesterol level
		Hyperthyroidism		–	+	+	–	–	±	+	+	Lump in the neck Proptosis Tremor Increased DTR			–	–		–	–	–	Elevated T4 Elevated T3 Decreased TSH	Lid lag Sweating Hyperpigmentation	Graves' disease Hashimoto's thyroiditis Toxic adenoma	TSH
		Diabetic neuropathy		–											–	–
		Systemic sclerosis		–											–	–