Diarrhea Flashcards
What is diarrhea?
Passage of abnormally liquid or unformed stools at an increased frequency >=3x/24hrs
Classification of diarrhea?
- Acute: < 2 weeks
- Persistent: 2-4 weeks
- Chronic: > 4 weeks
Types of diarrhea?
- osmotic
- secretory
Osmotic diarrhea?
- Ingestion of poorly absorbable osmotically active solids
- Fluid drawn in lumen thus the watery stools
- restricted with starvation and commonly has a trigger
Secretory diarrhea?
- Increased secretion/decreased absorption
- Abnormality of ion transport across enterocolic mucosa
Bacteria that cause watery diarrhoea?
- E Coli
- nontyphoidal salmonellae
- campylobacter species
- aeromonas species
- clostridioides
Common viruses that cause watery diarrhiea?
norovirus, rotavirus, adenoviruses, astrovirus and others
Common protozoa that causes watery diarrhoea?
giardia, Cyclospora, entamoeba, cryptosporidium
Causes of acute bloody diarrhoea?
Shigella particularly S. flexneri, Campylobacter jejuni, enterohemorrhagic E Coli, Entamoeba histolytica, non typhoidal salmonella species, and Schistosoma mansoni
Acute diarrhea?
- <2 weeks
- caused by infectious agents
Infectious diarrhoea?
caused by fecal-oral transmission or contamination of food or water source with pathogens
Severe diarrhea?
primarily a disease of children, the elderly and the immunosuppressed
Chronic diarrhoea?
is not infectious- Unless the patient is HIV infected
Treatment of diarrhoea?
- For all causes of diarrhea, maintenance of adequate hydration is essential.
- Electrolyte replacement
- Oral rehydration solution and oral intake are preferred in mild cases
- Moderate to severe cases need intravenous hydration
Food poisoning?
Acute gastrointestinal symptoms developing within 24 hours of food ingestion are likely related to food contaminated with bacteria with a preformed toxin
Bacteria that causes food poisoning?
Staphylococcus aureus and Bacillus cereus are the most common organisms to cause symptoms within 8 hours
- Clostridium Perfringes symptoms present within 16 hours.
Bacteria associated with specific food items?
- S. aureus is typically associated with prepared foods (salads that have be sitting out all day)
- B. Cereus is classically associated with “fried rice”.
Management of food poisoning?
- The disease is generally self-limited and symptoms will resolve within 24 hours.
- Management is symptomatic only
- Antibiotics have no role.
Travelers diarrhea?
- Enterotoxigenic E. Coli is the most common cause of this syndrome
- Diarrhoeagenic heat-labile (LT) and heat-stable (ST) enterotoxins
- The diarrhea is caused by the production of two toxins.
- This is generally self-limited with resolution with 5 days.
Treatment of travelers diarrhea?
Treatment with loperamide reduces symptoms and is sufficient for most
Antibiotics (cotrimoxazole, ciprofloxacin) can reduce symptoms by about one day and are generally not needed.
Organisms that cause dysentry?
- Shigella
- Salmonella
- enterohemmorhagic E.coli
- Camphylobacter
- Amoebiasis (E. Histolytica) - reveal trophozoites in the stool
Management of dysentry?
- Ciprofloxacin 500mg bd po 5/7
- Metronidazole 800mg 8 hourly for 5 to 10 days - amoebic dysentry
Note: Avoid loperamide!
Giardiasis?
Giardiasis (Giardia Lamblia) occurs commonly in individuals exposed to contaminated water sources.
Clinical symptoms of giardiasis?
Clinical symptoms can include malabsorption (flatus, greasy stools that float, weight loss)
Treatment of giardiasis?
Treatment is Metronidazole 400tds for 5 days.
Cholera?
caused by vibrio cholorae
Treatment of cholera?
- Hydration is Critical!
- Antimicrobials may decrease the duration of illness
- Doxycycline 300 single dose or Azithromycin 1g single dose
C. Diffcile colitis?
This infection often occurs after taking antibiotics.
The diarrhea is mediated by a Toxin produced by Clostridium difficile
“Psuedomembrane”may line the colon and toxic megacolon can result
Treatment is Metronidazole 400-800tds for 10 days.
Camplylobacter spp?
A flu-like prodrome followed by crampy abdominal pains, fever and diarrhoea which may be bloody
Complications include Guillain-Barre syndrome
Reactive arthritis formerly known as Reiter’s syndrome (cannot pee-urethritis, cannot see-conjuctivitis, cannot climb the tree -arthritis)
Azithromycin 500 mg/day 3/7 or Erythromycin
Salmonella?
Typhoid fever, or enteric fever- potentially fatal multisystemic infection produced primarily by Salmonella enterica serotype typhi and to a lesser extent Salmonella enterica serotypes and paratyphi A, B, and C
Salmonella mechanism of infection?
- S typhi and paratyphi enter the host’s system primarily through the distal ileum
- adhere to the epithelium over clusters of lymphoid tissue in the ileum (Peyer patches)
Clinical features of salmonella infection?
producing systemic symptoms such as headache, fever, arthralgia, relative bradycardia, abdominal pain, distension, constipation, rose spots: present on the trunk in 40% of patients,
Diagnosis of salmonella?
The definitive diagnosis of enteric fever requires the isolation of S. Typhi or S. Paratyphi from blood, bone marrow, other sterile sites, rose spots, stool, or intestinal secretions
Widal serologic test for “febrile agglutinins” has limited sensitivity and specificity in endemics
Treatment of salmonella?
Ciprofloxacin 500mg PO 12 hourly for 14/7. If not tolerating orals give Ceftriaxone 2g IV 24 hourly 14/7
Complications of salmonella?
Osteomyelitis (especially in sickle cell disease where Salmonella is one of the most common pathogens);GI bleed/perforation; Meningitis; Cholecystitis ;Chronic carriage (1%, more likely if adult females)
Incubation periods of salmonella?
1-6 hrs: Staphylococcus aureus, Bacillus cereus*
12-48 hrs: Salmonella, Escherichia coli
48-72 hrs: Shigella, Campylobacter
> 7 days: Giardiasis, Amoebiasis
*vomiting subtype, the diarrhoeal illness has an incubation period of 6-14 hours
Hive associated diarrhea?
Chronic Diarrhea and wasting in an HIV positive individual is an AIDS defining condition.
Exact infectious etiology is difficult to determine (often require multiple stool samples, special staining and at times, endoscopy)
Treatment is often ineffective and symptomatic therapy with loperamide will likely be necessary.
Antibiotic Treatment of HIV associated diarrhea?
Cotrimoxazole 1920mg PO 12 hourly for 14 days (to treat Isospora)
If no improvement on Cotrimoxazole, Metronidazole 2g po 24 hourly for 5 days (to treat Giardia).
if no improvement on Metronidazole, Albendazole 400mg every 12 hourly PO for 14 days (to treat Microsporidia)
Anti-motility agents in HIV associated diarrhea?
Anti-motility agents: Loperamide 4mg initially then 2mg after each loose stool
(maximum 16mg per day)
Alternative: Codeine Phosphate 30mg 8 hourly PO for 5 days
Etiologies of AIDS related diarrhea?
Cryptosporidium parvum - no effective treatment
Strongyloides – treat with Albendazole 400 od for at least 3 days
CMV colitis- Ganciclovir
Mycobacterium Avium complex- Clarithromycin/Ethambutol
Aetiology of chronic diarrhea?
- bacteria
- functional disorders
- post cholecystectomy diarrhea
- medications
- malabsorption syndromes
- inflammatory bowel disease
Bacterial Aetiology for chronic diarrhea?
Chronic bacterial, Mycobacterial and parasitic infections: C difficile, Giardia, Cyclospora, blastocystis hominis especially in immunosuppressed patients
Malabsorption syndromes associated with chronic diarrhea?
Pale, greasy, voluminous, foul-smelling stools. Associated with flatulence, abdominal distention
Lactose intolerance, Chronic pancreatitis and celiac disease
Inflammatory bowel diseases associated with chronic diarrhea?
Ulcerative colitis: gradual onset of symptoms with episodes of rectal bleeding
Crohn Disease: diarrhea, abdominal pain, weight loss, fever, occult GI blood loss. Other extra GI manifestations- skin changes- erythema, joint pains, anemia, eye changes
History in diarrhea?
DURATION, frequency and characteristics of the stool
Alternating bowel habits between constipation and diarrhea- colorectal Ca and bowel obstruction, IBS
Associated symptoms
Risk factors
Medical history
Surgical History- gastric bypass, vagotomy, bariatric surgery
Family history- colorectal Ca or IBD
Drug history
Physical exam in diarrhea?
Alarm signs: age of onset >50yrs, rectal bleeding, nocturnal pain, progressive abdominal pain, unexplained weight loss, lab abnormalities, first degree relative with IBD or colorectal Ca
Include a rectal exam on physical exam
Lab tests?
FBC
TFT- to identify hyperthyroidism
Celiac serologies
Serum electrolytes
Stool occult blood
Fecal calprotectin and lactoferrin- increased in inflammation- distinguishes inflammatory from non inflammatory causes
Stool microbiological testing- C. difficile, parasites
Management of diarrhea?
- treat underlying cause
- empiric therapy
- symptomatic therapy
Treatment of underlying cause?
IBD- prednisolone and misalazine.
Empiric therapy?
Antibiotics for small intestinal bacterial overgrowth
Watch out in prolonged penicillin use. Treat with antibiotics that cover for C. difficile with metronidazole and vancomycin; probiotics.
Lactose restriction in intolerance
Cholestyramine for bile acid diarrhea
Symptomatic therapy?
Symptomatic therapy- loperamide, intraluminal adsorbents (clays, activated charcoal, bile acid binding resins, bismuth), morphine, codeine
