FISIOLOGIA DIGESTIVA (BCM II)
Clase 12: Diarrea
Dr. Michel Baró Aliste
© 2004 Current Medicine Group Ltd
Definiciones
Diarrea: aumento de la frecuencia y/o volumen de las deposiciones
Mayor a 200 g/día
Pseudodiarrea
Incontinencia
Aguda (<2 semanas)
Crónica (>4 semanas)
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Tipos de Diarrea
-Osmótica (malabsortivas)
-Secretora (alteración de transporte de electrolitos)
-Alteración de la motilidad
-Inflamatoria (disenterías)
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Water fluxes through the intestine
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Calculation of osmotic gap
Diarrea Secretora vs. Diarrea Osmótica
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Typical features of secretory diarrhea
TABLE 4 - 5. TYPICAL FEATURES OF SECRETORY DIARRHEA
Voluminous, watery stools
Little or no fecal osmotic gap, stool pH near 7.0
Usually persists during fasting
Usually no pus, blood, or excess fat in stools
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Effects of resection of different parts of small intestine (a)
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Effects of resection of different parts of small intestine (b)
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Effects of resection of different parts of small intestine (c)
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Effects of resection of different parts of small intestine (d)
Umbral catártico de las
Sales biliares: 3 a 5 mmol/L
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Effects of resection of different parts of small intestine (e)
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Mechanisms of diarrhea in enteritis
TABLE 4 - 10. MECHANISMS OF DIARRHEA IN ENTERITIS
Decreased surface area (destruction or resection)
Disrupted mucosal barrier (exudation)
Decreased rate of absorption, caused by inflammatory mediators or enteric nervous system
Diminished electrolyte absorption
Increased electrolyte secretion
Osmotic diarrhea due to malabsorption
Carbohydrates
Fatty acids, hydroxy - fatty acids
Bile acid diarrhea
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Bile acid malabsorption can be caused by various mechanisms
(a)
Diarrea secretora por
Malabsorción de ac. biliares:
Mecanismos:
Tránsito aumentado
Resección intestinal
Daño mucosa del íleon
Ac. biliares en colon > 3 mmol/l = diarrea
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Laxatives and detection methods
TABLE 4 - 15. LAXATIVES AND DETECTION METHODS
Laxative
Detection Method
Phenolphthalein Alkalinization of stool produces pink color; spectrophotometry
Bisacodyl
Thin - layer chromatography
Ipecac
Thin - layer chromatography
Senna
Urinary assay for anthraquinone
Magnesium
Osmotic gap in stool water; increased concentration of magnesium in stool water
Phosphate
Increased concentration in stool water
Sulfate
Increased concentration in stool water
Water
Creation of factitious diarrhea by addition of water to stool specimen can be detected by
measurement of low - stool osmolality (<< 290 mosm/kg)
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Laxative abuse suspects
TABLE 4 - 16. PATIENTS SUSPECTED OF LAXATIVE ABUSE
Type
Characteristics
Patients with bulimia
Usually adolescent to young adult women; concerned about weight or
manifesting an eating disorder
Secondary gain
Ma y have disability claim pending; illness may induce concern or caring behavior
in others
Münchausen's syndrome
Typically, a peripatetic patient who "enjoys" being a challenge to doctors; may
undergo extensive testing repeatedly
Polle syndrome
(Münchausen by proxy)
Dependent child poisoned by parent with laxatives to show how effective parent
can be as a caregiver; may have history of sibling who died with chronic diarrhea
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Diarrheal syndromes related to circulating secretagogues
TABLE 4 - 17. DIARRHEAL SYNDROMES RELATED TO CIRCULATING SECRETAGOGUES
Syndrome
Typical Symptoms
Main Mediators
Zollinger - Ellison
Pancreatic tumor, peptic ulcer, steatorrhea,
diarrhea
Gastrin
Verner - Morrison
Watery diarrhea, hypokalemia, achlorhydria,
(pancreatic cholera) flushing
Vasoactive intestinal polypeptide
Medullary thyroid
carcinoma
Calcitonin, prostaglandins
Thyroid mass, diarrhea, hypermotility
Pheochromocytoma Adrenal mass, hypertension, diarrhea
Vasoactive intestinal polypeptide,
norepinephrine, epinephrine
Carcinoid
Diarrhea, flushing, wheezing, right - sided
cardiac valvular disease
Serotonin, kinins
Somatostatinoma
Nonketotic diabetes mellitus, steatorrhea,
diarrhea, gallstones
Somatostatin
Glucagonoma
Skin rash (migratory necrotizing erythema), mild
Glucagon
diabetes
Hyperthyroidism
Diarrhea, steatorrhea, weight loss, tremor
Thyroxine, tri - iodothyronine
Mastocytosis
Flushing, dermatographism, nausea, vomiting,
diarrhea, abdominal pain
Histamine
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Zollinger-Ellison syndrome results from secretion of gastrin
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Vasoactive intestinal polypeptide-secreting tumors (a)
Sindrome de Verner-Morrison
o Cólera pancreático
-diarrea acuosa
-hipokalemia
-hipocloridia
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AMPc
Vasoactive intestinal polypeptide-secreting tumors (b)
VIPoma
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Vasoactive intestinal polypeptide-secreting tumors (c)
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Vasoactive intestinal polypeptide-secreting tumors (d)
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Medullary carcinoma of the thyroid products
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Drugs associated with diarrhea
TABLE 4 - 29. DRUGS ASSOCIATED WITH DIARRHEA
Antibiotics
Hypocholesterolemic drugs
Antineoplastic drugs
Lovastatin
Antiarrhythmics
Gemfibrozil
Quinidine
Clofibrate
Procainamide
Probucol
Antihypertensives
Gastrointestinal drugs
Beta - blockers
Magnesium - containing antacids
Angiotensin - converting enzyme inhibitors
H2 - receptor antagonists
Hydralazine
Prostaglandin analogues (misoprostal)
Antidepressants
Sulfasalazine
Lithium
Olsalazine
Fluoxetine (Prozac)
Prokinetic drugs (cisapride)
Tranquilizers
Miscellaneous agents
Alprazolam (Xanax)
Methysergide
Meprobamate
Theophylline
Anticonvulsants
Diuretics
Ethosuximide
Oral hypoglycemic drugs
Valproic acid
Colchicine
L - Dopa
Thyroid hormone
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Longstanding diabetes mellitus and chronic diarrhea
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Malabsorción - Esteatorrea
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Diseases that impair nutrient absorption
Classification of Diseases that Cause Intestinal Malabsorption
Premucosal
Mucosal
Postmucosal
Pancreatic insufficiency
Celiac sprue
Congenital lymphangiectasia
Hepatobiliary disease
Tropical sprue
Secondary lymphangiectasia
Bacterial overgrowth
Whipple's disease
Rapid intestinal transit
Eosinophilic enteritis
Gastrectomy
Brush border enzyme deficiency
Lymphoma
Short - bowel syndrome
Prolonged malnutrition
Radiation enteritis
Parasitic infection
Mesenteric ischemia
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Stool fat concentrations as a clue to etiology
9,5%
<6 g/día
>20 g/día
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Effect of oral pancreatic enzyme replacement (A)
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Effect of oral pancreatic enzyme replacement (B)
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Intraduodenal bile acid concentrations and fecal fat output
2,5 umol/mL
Bilirrubina pl >4,5 mg%
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Pathophysiology of bacterial overgrowth
-Daño histológico
-Malabsorción de nutrientes
-Producción de toxinas
Reabsorción en yeyuno
Absorción grasa
Inflamación
Atrofia vellositaria
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Multiple jejunal diverticula
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Multiple small bowel diverticula
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Scleroderma
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Billroth I and II subtotal gastrectomy
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Radiograph of a patient with a Billroth II procedure
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Pathophysiology of lactase deficiency
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Intestinal fluid accumulation with a lactose-containing meal
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Effect of unabsorbed carbohydrate on stool water output
3,5 g H2O / mmol de molécula no absorbida (carbohidrato, ácido orgánico, catión)
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Celiac sprue (A) – Enfermedad Celíaca
Gluten: trigo, centeno, avena
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Celiac sprue (B)
Tres meses después de dieta libre de gluten
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Molecular pathophysiology of celiac sprue (A)
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Molecular pathophysiology of celiac sprue (B)
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Molecular pathophysiology of celiac sprue (C)
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Molecular pathophysiology of celiac sprue (D)
HLA-DQ2 or HLA-DQ8
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Molecular pathophysiology of celiac sprue (E)
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Molecular pathophysiology of celiac sprue (F)
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Detecting celiac sprue (A)
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Detecting celiac sprue (B)
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Classic moulage pattern of celiac sprue
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Tropical sprue
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Whipple's disease
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Eosinophilic gastroenteritis
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Massive small-bowel resection
Predicted Nutritional Outcome in Patients who ha ve had Massive Intestinal Resection
Remaining Jejunal length, cm
Colon
Nutritional outcome
0 - 50
-
TPN
+
TPN
-
IVFM/TPN
+
Modified oral diet
-
Regular or modified oral diet
+
Regular diet
-
Modified oral diet
+
Regular diet
- or +
Regular diet
51 - 100
101 - 150
151 - 200
>200
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Jejunal length and sodium-water absorption (A)
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Jejunal length and sodium-water absorption (B)
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Rehydration therapy enhances sodium and water absorption
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Sodium balance after different sodium-containing test solutions
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Oral rehydration therapy and high-volume ostomy output
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Radiation enteritis
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Lymphangiectasia
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Selected symptoms and signs of nutrient deficiencies
Selected Symptoms and Signs of Nutrient Deficiencies
Symptoms or sign
Possible nutrient deficiency
General
Weakness, weight loss, muscle wasting
Protein, calorie
Skin
Pallor
Folate, iron, vitamin B12
Follicular hyperkeratosis
Vitamin A, vitamin C
Perifollicular petechiae
Vitamin C
Dermatitis
Protein, calorie, niacin, riboflavin, zinc,
vitamin A, essential fatty acids
Bruising, purpura
Hair
Eyes
Mouth
Easily plucked, alopecia
Vitamin C, vitamin K
Corkscrew hairs, coiled hair
Protein, zinc, biotin
Night blindness, keratomalacia, photophobia
Vitamin C, vitamin A
Conjunctival inflammation
Vitamin A
Glossitis
Vitamin A, riboflavin
Bleeding or receding gums, mouth ulcers
Riboflavin, niacin, folate, vitamin B12, protein
Decreased taste
Vitamin A, vitamin C, vitamin K, folate
Burning or sore mouth and tongue
Zinc, vitamin A
Angular stomatitis or cheilosis
Vitamin B12, vitamin C, niacin, folate, iron
Neurologic Tetany
Riboflavin, niacin, pyridoxine, iron
Paresthesias
Calcium, magnesium
Loss of reflexes, wrist drop, foot drop, loss of
vibratory and position sense
Thiamine, pyridoxine, vitamin B12, vitamin E
Dementia, disorientation
Niacin, vitamin B12
Ophthalmoplegia
Vitamin E, thiamine
Depression
Biotin, folate, vitamin B12
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D-xylose to evaluate small-intestine absorptive function
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Enfermedad Inflamatoria Intestinal
•Colitis Ulcerosa
•Enfermedad de Crohn
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Endoscopic features of active ulcerative colitis (B)
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Microscopic features of specimen in Fig 4-8 (B)
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Endoscopic features of Crohn's disease (A)
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Specimen from patient with Crohn's colitis (B)
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Inflammatory bowel disease etiology
TABLE 4 - 26. THEORIES OF INFLAMMATORY BOWEL DISEASE ETIOLOGY
Toxic response to luminal contents
Specific microbial pathogen
Abnormal luminal constituents
Increased absorption of luminal macromolecules
Enhanced immunologic response to normal constituents
Autoimmune response
To epithelial cell or mucus glycoproteins
Molecular mimicry (cross - reactivity of intestinal microflora and epithelia)
To immune cells
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Infliximab
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