Sandbox: malabsorption

Chronic diarrhea

Abbreviations: GI: Gastrointestinal; WBC: White blood cells; Plt: Platelets, Hgb: Hemoglobin, IgE: Immunoglobulin E, IgA: Immunoglobulin A

Cause	Clinical manifestation									Lab findings					Extra intestinal findings	Cause/Pathogenesis	Gold standard diagnosis
	Symptoms								GI signs
	Duration		Diarrhea			Fever	Abdominal pain	Weight loss
	Acute	Chronic	Watery	Bloody	Fatty					WBC	Hgb	Plt	Stool exam	Other lab findings
Whipple's disease			+	-	+	±	+	+	Hepatosplenomegaly Ascites	↓	↓	↓/↑		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
Celiac disease			±	-	±	-	+	+	Abdominal distention Tetany Mouth ulcers	-	↓	-		IgA endomysial antibody Anti-tissue transglutaminase antibody Anti-gliadin antibody	Signs of the fat-soluble vitamins A, D, E, and K deficiency Dementia Hepatosplenomegaly Ascites Dermatitis herpetiformis Must follow Gluten-free diet	HLA-DQ2 HLA-DQ8 Innate responses to wheat proteins	IgA endomysial antibody IgA tissue transglutaminase antibody
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
Crohns disease			+	+	+	+	+	+	Abdominal tenderness Tachycardia Hypotension	↑	↓	↑		Iron deficiency Vitamin B12 deficiency Elevated ESR Elevated CRP	Blood seen on rectal exam	Abnormal immune response to self antigens	Colonoscopy with biopsy
Ulcerative colitis			+	+	+	+	+	+	Abdominal tenderness Tachycardia Hypotension Skin rash Aphthous ulcers Clubbing of the fingers	↑	↓	↑		Hypoalbuminemia Hypokalemia Hypomagnesemia Iron deficiency Elevated ESR Elevated CRP	Iritis Uveitis Seronegative arthritis Erythema nodosum	Abnormal immune response to self antigens	Colonoscopy with biopsy
Cystic fibrosis			-	-	+	±	+	+	Digital clubbing Abnormal breathing sounds Cyanosis	-	↓	-		Positive DNA analysis for CFTR Evaluated nasal transepithelial potential difference (NPD)	Diabetes Recurrent upper and lower respiratory tract infections Infertility	Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein	Elevated sweat chloride ≥60 mmol/L
VIPoma			+	-	+	-	+	+	Tachycardia Rash Facial flushing Abdominal distention Abdominal RUQ tenderness	-	-	-		Elevated VIP level Hypokalemia Hypochlorhydria or achlorhydria Low osmotic gap (<50 mOsm/kg)	Dehydration Lethargy Muscle weakness Nausea Vomiting	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
Eosinophilic gastroenteritis			+	-	+	-	+	+	Abdominal distention	↑	-	-		Elevated serum IgE levels Eosinophilia Elevated ESR Hypoalbuminemia	Other allergic disorders Associated with an identifiable dietary antigen	Autoimmune allergic response to food antigens	Eosinophilic infiltration of the gastrointestinal tract on biopsy
Primary bile acid malabsorption			+	-	+	-	+	+		-	↓	-		Low vitamins A, D, E, and K		Genetic defects in SLC10A2 (solute carrier family 10 member 2 gene)	Elevated total and specific bile acids in stool Positive SeHCAT
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
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
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
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
Chronic pancreatitis			+	-	+	-	+	+	Abdominal tenderness	-	-	-		Slightly elevated amylase and lipase Abnormal pancreatic function test	Malabsorption Diabetes mellitus	Repeated acute pancreatitis Alcohol abuse Genetic Autoimmune	Secretin stimulation test ERCP
Cirrhosis			+	-	+	+	+	+	Jaundice Hepatosplenomegaly Abdominal distention Shifting dullness Asterixis Skin telangiectasias	↓	↓	↓		Abnormal liver function tests Prolonged PT/PTT	Coagulopathy Portal hypertension Hepatic encephalopathy	Alcoholic liver disease Viral hepatitis Non-alcoholic steatohepatitis	Liver biopsy
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
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
X-linked agammaglobulinemia			+	-	+	+	+	+	Signs of dehydration Signs of infections	↓	↓	-		Hypogammaglobulinemia	Recurrent respiratory tract infections Gastroenteritis Bacterial infections Malabsorption	Inherited Gene defect	Low circulating immunoglobulin levels (IgG, IgA, IgM, IgE) on blood tests
Intestinal lymphangiectasia			-	-	+	-	-	+	Peripheral edema Macular edema	↓	-	-		Hypoproteinemia Hypogammaglobulinemia	Protein-losing enteropathy Malabsorption Anergy Homograft rejection Pachydermoperiostosis	Dilatation of intestinal lymphatics	Intestinal biopsy
Amyloidosis					+
Mastocytosis
Drug induced enteritis
Giardiasis					+
Strongyloidiasis
Tuberculosis
Chronic laxative abuse