Lecture 21 Acute Diarrhea Moshenko DEFINITION OF DIARRHEA: • Relatively common disorder seen in practice • ↑ frequency, fluidity, volume of fecal discharge • ≥ 3 bowel movements/day EPIDEMIOLOGY: rate of occurrence and severity differs in developed & developing countries DEVELOPED COUNTRIES: Epidemi- ology • No exact profile available • Average of 1.4 episodes/year per person Impact • Not usually fatal, but accounts for 6000 deaths/year in the US • Results in considerable morbidity & substantial health care costs Primary cause • Infectious sources (bacteria, viruses, parasites) DEVELOPING COUNTRIES: Epidemi- ology • Major problem • Average 3 episodes/year in children < 3 yrs of age Impact • In 2008: 1.3-1.9 million deaths/year in children < 5 years of age • Death rates continually decreasing due to extensive distribution and use of oral rehydration solutions, increased breastfeeding, improved nutrition, better hygiene and sanitation Primary cause • Infectious sources (differing frequency profiles from developed countries) • Poor nutrition status, poor sanitation & contaminated water/food supplies PATHOPHYSIOLOGY: NORMAL CONDITIONS (ADULTS): • ~ 9L enters GIT daily from diet, saliva, gastric juice, bile, pancreatic juice & small intestine secretions • Fluid reabsorbed prior to reaching colon (500 mL left), then another 350 mL reabsorbed in colon o Stool weighs 100-200 g (of which 60-85% is water) • Net water loss 50-100 mL/d in feces NATURAL DEFENSE MECHANISMS IN GIT: • Gastric acidity: prevents viable pathogens from entering intestine from stomach • Peristaltic activity: propels pathogens and their toxins along GIT • GIT mucus: forms a protective barrier • Mucosal tissue integrity • Intestinal immunity: acquired with repeated exposure to pathogens DIARRHEA: • Diarrhea occurs when absorptive capacity of small intestine is exceeded, and excess fluid enters colon exceeding its absorptive capacity • Diarrhea results from imbalance b/w fluid & electrolyte absorption/secretion in GIT o These processes are regulated by solute movement (ions, AAs, monosacchs) ▪ Na is principal ion absorbed (active transport) ▪ Cl is principal ion secreted (active transport) o Solute movement controlled by: ▪ Active & passive mechanisms/processes • Active transport requires glucose (energy dependent) ▪ Hormonal control o Water moves passively across gut wall following movement of various solutes (Na + , K + , etc) to balance osmotic gradients ▪ Na is principal ion absorbed (active transport) ▪ Cl is principal ion secreted (active transport) • With diarrhea, many ions are lost goal is to replace ions + water losses ETIOLOGIC AGENTS/CAUSES: no specific etiology agent can be determined/identified in 70-75% of cases Dietary sources • Green apples • Excessive caffeine intake • Spicy foods • Sorbitol, mannitol, fructose (sweeteners) Infection • Bacteria o Invasive = direct damage to GI mucosa (Shigella, Salmonella) o Non-invasive = produce entero-toxins which interfere with active ion transport mechanisms (ETEC, V. cholera) • Viruses (norovirus, rotavirus, adenovirus, calicilviruses) • Parasites (Giarda lamblia, Entamoeba histolytica, Cryptosporidia) Drugs • Magnesium containing antacids • Antibiotics (irritation, bacterial overgrowth, C. difficile, pseudomembranous colitis) • Overuse of stimulant laxatives • Anti-arrhythmics (digoxin, quinidine) • Acid-reducing agents (H2RAs, PPIs) • Narcotic/opioid withdrawal • Anti-neoplastics • Antiretrovirals • Beta blockers • Propranolol • NSAIDs • Alcohol • Metoclopramide • Domperidone • Colchicine • Furosemide • Levothyroxine • Metformin • Misoprostol • SSRIs • Theophylline Psych • Stress, anxiety = mild cases Other • Malabsorption (ex// lactose intolerance) • IBD (ulcerative colitis) • Hyperthyroidism, diabetes, cirrhosis • Carcinoma of intestinal tract • Pyloric dumping syndrome following GI Sx CLINICAL PRESENTATION AND HISTORY: • Abrupt onset of frequent loose, watery stools, flatulence, malaise, abdominal pain/cramps • Depending on etiology, vomiting, fever & muscle aches may be present as well • Generally resolves within 72h, but may persist for up to 5-7 days (usually at ↓ frequency) PATIENT ASSESSMENT (SCHOLAR): Who? • Child, elder, debilitated, pregnant, chronic disease states = high-risk o ↑ risk dehydration, acid-base imbalances, morbidity & mortality Sx (frequency & intensity) • Fever? Blood/mucus in stool? Severe abdominal pain/cramping? N/V? Tenesmus? Weight loss? Signs of dehydration (thirst, tachycardia, decreased urination etc)? Characteristic • Consistency (watery, runny, solid, etc)? • Frequency of bowel movements (any changes)? • Volume/quantity produced? History • What has been done so far? • Has this happened in the past? Onset • When did it start? How long/duration? Abrupt/gradual onset? • Any history of travel to high risk countries (recent, past months)? • Flu? Any other people at home/work who are ill? Aggravating factors • What triggers it? • Eaten anything differently (spicy food, milk products, coffee, alcohol)? • New diet? Food poisoning? New medications/supplements/NHPs? • Family history IBD, etc? Remitting • What treatments have been tried?What helps? REFERRAL: Children (<3 years) Older children (>3 years) & adults • Young (< 6 m) or weight < 18 lb (8.2 kg) • Chronic or concurrent conditions • Premature birth • Fever ≥ 38.4 o if < 3m, ≥ 39 o C if 3-36 m • Blood visible in stool • High output diarrhea • Persistent vomiting • S/S of dehydration (listlessness, dry mouth, ↓ tearing, sunken eyes, dry diaper, poor skin turgor, tachycardia, irritability, poor responsiveness, lightheadeddness, dizziness) • Not drinking enough for rehydration • Elderly individual • Chronic or concurrent conditions • Fever ≥ 39 o C • Blood in stool • Presence of severe abdominal pain • High output diarrhea; duration > 48 hrs • Persistent vomiting • Individual not drinking adequate (dry mouth, ↓ tearing, excessive thirst, poor skin turgor, oliguria, orthostatic hypotension (light-headedness, dizziness), irritability, apathy, lethargy • Not drinking enough for rehydration
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Lecture 21 Acute Diarrhea Moshenko
DEFINITION OF DIARRHEA:
• Relatively common disorder seen in practice
• ↑ frequency, fluidity, volume of fecal discharge
• ≥ 3 bowel movements/day
EPIDEMIOLOGY: rate of occurrence and severity differs in
developed & developing countries
DEVELOPED COUNTRIES:
Epidemi-ology
• No exact profile available
• Average of 1.4 episodes/year per person
Impact • Not usually fatal, but accounts for 6000 deaths/year in the US
• Results in considerable morbidity & substantial health care costs
• Average 3 episodes/year in children < 3 yrs of age
Impact • In 2008: 1.3-1.9 million deaths/year in children < 5 years of age
• Death rates continually decreasing due to extensive distribution and use of oral rehydration solutions, increased breastfeeding, improved nutrition, better hygiene and sanitation
Primary cause
• Infectious sources (differing frequency profiles from developed countries)