© 2004 Current Medicine Group Ltd FISIOLOGIA DIGESTIVA (BCM II) Clase 12: Diarrea Dr. Michel Baró Aliste.
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© 2004 Current Medicine Group Ltd
FISIOLOGIA DIGESTIVA (BCM II)FISIOLOGIA DIGESTIVA (BCM II)
Clase 12: Diarrea Clase 12: Diarrea
Dr. Michel Baró AlisteDr. Michel Baró Aliste
© 2004 Current Medicine Group Ltd
DefinicionesDefiniciones
Diarrea: aumento de la frecuencia y/o volumen de las deposicionesDiarrea: aumento de la frecuencia y/o volumen de las deposiciones
Mayor a 200 g/díaMayor a 200 g/día
PseudodiarreaPseudodiarrea
IncontinenciaIncontinencia
Aguda (<2 semanas)Aguda (<2 semanas)
Crónica (>4 semanas)Crónica (>4 semanas)
© 2004 Current Medicine Group Ltd
Tipos de DiarreaTipos de Diarrea
-Osmótica (malabsortivas)-Osmótica (malabsortivas)
-Secretora (alteración de transporte de electrolitos)-Secretora (alteración de transporte de electrolitos)
-Alteración de la motilidad-Alteración de la motilidad
-Inflamatoria (disenterías)-Inflamatoria (disenterías)
© 2004 Current Medicine Group Ltd
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 (d)
Umbral catártico de las Sales biliares: 3 a 5 mmol/L
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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)
Ac. biliares en colon > 3 mmol/l = diarrea
Diarrea secretora porMalabsorción de ac. biliares:Mecanismos:Tránsito aumentadoResección intestinalDaño mucosa del íleon
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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 May 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 (pancreatic cholera)
Watery diarrhea, hypokalemia, achlorhydria, flushing
Vasoactive intestinal polypeptide
Medullary thyroid carcinoma
Thyroid mass, diarrhea, hypermotility Calcitonin, prostaglandins
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 diabetes
Glucagon
Hyperthyroidism Diarrhea, steatorrhea, weight loss, tremor Thyroxine, tri - iodothyronine
Mastocytosis Flushing, dermatographism, nausea, vomiting, diarrhea, abdominal pain
Histamine
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Vasoactive intestinal polypeptide-secreting tumors (a)
Sindrome de Verner-Morrisono Cólera pancreático-diarrea acuosa-hipokalemia-hipocloridia AMPc
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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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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
<6 g/día >20 g/día
9,5%
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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
InflamaciónAtrofia vellositaria
-Daño histológico-Malabsorción de nutrientes-Producción de toxinas
Reabsorción en yeyuno
Absorción grasa
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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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Massive small-bowel resection
Predicted Nutritional Outcome in Patients who have had Massive Intestinal Resection
Remaining Jejunal length, cm Colon Nutritional outcome
0 - 50 - TPN
+ TPN
51 - 100 - IVFM/TPN
+ Modified oral diet
101 - 150 - Regular or modified oral diet
+ Regular diet
151 - 200 - Modified oral diet
+ Regular diet
>200 - or + Regular diet
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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 Easily plucked, alopecia Vitamin C, vitamin K
Corkscrew hairs, coiled hair Protein, zinc, biotin
Eyes Night blindness, keratomalacia, photophobia Vitamin C, vitamin A
Conjunctival inflammation Vitamin A
Mouth 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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Enfermedad Inflamatoria Intestinal
•Colitis Ulcerosa•Enfermedad de Crohn
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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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