Constipation and rectal bleeding

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

Diseases		History and Symptoms								Physical Examination				Laboratory Findings			Other Findings	Diagnostic study of choice
														Electrolyts [Ca, K, Mg]	Biochemical tests
		GI symptoms				Extra GI symptoms				Abnormal gait	Anal protruding mass	DRE	Deep tendon reflex		FBS	TSH
		Dysphagia	Abdominal pain	Anal pain	Rectal bleeding	Weight loss	Polyphagia, Polyuria, Polydipsia	Dry skin	Tremor
Gastrointestinal diseases	Malignancy	-	-	+/-	+	++	-	-	-	-	-	Empty rectum	Normal	Normal	Normal	Normal	Acute change in bowel habits Rectal bleeding Anemia	Rectosigmoidoscopy with biopsy
	Irritable bowel syndrome (IBS)	-	+	+/-	-	-	-	-	-	-	-	Normal	Normal	Normal	Normal	Normal	Frequent change in bowel habit Abdominal pain alleviating with bowel movement	Rolling out other pathophysiologies
	Rectocele	-	-	-	-	-	-	-	-	-	+	Bulging rectum	Normal	Normal	Normal	Normal	Obstruction Absence of defecation and gas passing	Anoscopy
	Anal fissure	-	-	+++	+	-	-	-	-	-	-	Increased sphincter tone	Normal	Normal	Normal	Normal	Rectal bleeding after defecation Painful DRE	DRE
	Anismus	-	-	+	-	-	-	-	-	-	-	Increased sphincter tone	Normal	Normal	Normal	Normal	Absence of defecation and gas passing	DRE
	Diverticulosis	-	+	-	+	-	-	-	-	-	-	Normal	Normal	Normal	Normal	Normal	Chronic constipation Bowel obstruction	Colonoscopy
Neurogenic diseases	Diabetic autonomic neuropathy	-	-	-	-	+	++	+/-	-	+/-	-	Normal	↓	Normal	↑↑	Normal	Distal neuropathy Gastroparesis Nausea and vomiting	FBS and HbA1C
	Anorexia nervosa	-	-	-	-	++	-	+/-	-	-	-	Normal	Normal	↓ Electrolytes	↓	Normal	↓↓↓ BMI Amenorrhea Depressed mood	Clinical characteristics
	Parkinson's disease	+/-	-	-	-	-	-	-	++	+	-	Normal	↑↑	Normal	Normal	Normal	Muscle stiffness Drooling	Brain MRI
	Multiple sclerosis	+	-	-	-	-	-	-	+	+	-	Normal	↓↑	Normal	Normal	Normal	Blurred vision Erectile dysfunction	Brain MRI CSF biochemical profile
	Depression	-	-	-	-	+	-	-	-	-	-	Normal	Normal	Normal	Normal	Normal	Hopelessness Weakness and fatigue Depressed mood	Psychological examination
	Hirschsprung disease	-	+	-	+	+	-	-	-	-	-	Blood tinged glove	Normal	Normal	Normal	Normal	Abdominal distention Growth retardation Vomiting	Barium enema
	Cerebral palsy	+	-	-	-	+	-	-	+	+	-	Normal	↑	Normal	Normal	Normal	Spastic extremities paralysis Paresthesia	Brain MRI Physical examination
	Chagas disease	+	-	-	-	+	-	-	-	-	-	Normal	↓	Normal	Normal	Normal	Cardiomyopathy Megaesophagus or megacolon	Peripheral blood smear
Endocrine diseases	Hypothyroidism	-	-	-	-	-	-	+	-	-	-	Normal	↓↓	Normal	Normal	↑↑	Weakness and fatigue Dysmenorrhea	Thyroid function tests (TFT)
	Cystic fibrosis	-	+	-	-	+	-	-	-	-	-	Normal	Normal	Normal	Normal	Normal	Recurrent pneumonia Absent vas deferens	Sweat Cl test
	Lead poisoning	-	+++	-	-	-	-	-	+	-	-	Normal	Normal	Normal	Normal	Normal	Sideroblastic anemia Dysesthesia Amnesia	Plasma lead level
	Pheochromocytoma	-	-	-	-	-	-	-	+	-	-	Normal	Normal	Normal	Normal	Normal	Hypertension crisis Severe headache Blurred vision	Urine vanillyl mandelic acid (VMA) level
	Panhypopituitarism	-	-	-	-	-	-	-	-	-	-	Normal	↓	Normal	Normal	Normal	Hypothyroidism Amenorrhea Growth retardation	Hormone levels Brain MRI
Electrolyte disturbances	Hypomagnesemia	-	+	-	-	-	-	-	+	-	-	Normal	↓	↓↓ Mg	Normal	Normal	Nystagmus Seizure	Plasma Mg level
	Hypocalcemia/Hypercalcemia	-	+	-	-	-	-	-	-	-	-	Normal	↓	↓Ca/↑Ca	Normal	Normal	Muscle weakness Dysesthesia	Plasma Ca level
	Hypokalemia	-	+	-	-	-	-	-	-	+/-	-	Normal	↓	↓K	Normal	Normal	Metabolic alkalosis Paralysis Seizure	Plasma K level
Systemic diseases	Pregnancy	-	-	-	-	-	-	-	-	-	-	Normal	Normal	Normal	Normal	Normal	Lower extremities edema Dyspnea Nausea and vomiting	Plasma βhCG Ultrasonography
	Systemic sclerosis	+	-	-	-	-	-	+	-	-	-	Normal	Normal	Normal	Normal	Normal	Raynaud phenomenon Fingertip ulcer	Clinical characteristics Anti-centromere and anti-Scl-70 antibodies