Infectious Diarrhea Flashcards
1
Q
A: greater than or equal to 3 liquid or semisolid stools daily for at least 2-3 days
B: diarrhea lasting less than 14 consecutive days
A
A: diarrhea
B: acute diarrhea
2
Q
diarrhea lasting between 15-29 days
A
persistent diarrhea
3
Q
diarrhea lasting greater than 30 consecutive days
A
chronic diarrhea
4
Q
bloody and/or pururlen diarrhea often with associated fever, tenesmus and abdominal cramping (i.e, dysentery)
A
inflammatory diarrhea
5
Q
non-bloody diarrhea suggesting an enterotoxic bacterial, viral or protozoan process
A
non-inflammatory diarrhea
6
Q
diarrhea that occurs within 10 days of travel to a developing nation
A
traveler’s diarrhea
7
Q
Causes of acute diarrhea
A
- bacterial or viral infections
- medications
- food intolerances
- mesenteric ischemia= specialist consultation recommended
8
Q
causes of chronic diarrhea?
A
- parasitic infections
- inflammatory bowel disease
- celiac disease
- malabsorption
- irritable bowel syndrome
- pancreatic insufficiency
- hyperthyroidism
- endocrine tumor
9
Q
- Pathogen: Thypoidal (s.typhi & S.paratyphi) or non typhoidal strains (numerous)- aerobic gram-negative bacillus
- source: non-typhoidal- chicken products(eggs, undercooked meat) contaminated processed foods (dairy products), or zoonotic with birds or reptile
- additional risk factors: antacid use, pathogen is very pH sensitive
- 6-72 hours from ingestion, lasts 4-7 days
- diarrhea: purulent, bloody for non-typhoidal strains
- can have fever
- tx:PO ciprofloxacin 500mg BID for 7-14 days
Blood cultures particularly helpful for this
A
Salmonella
Purulent, bloody= non typhoidal, Watery= typhoid
10
Q
- serologic groups A,B (s.flexerni), C & D (S. sonnei) gram-negative, enterotoxin producing bacillus
- source: Anal-oral transmission and sewage contaminated water
- daycares & developing countries at higher risk
- onset: 1-6 days, lasts 1-7 days
- diarrhea: Purulent, bloody, cramping
- fever
- Tx: PO ciprofloxacin 500 MG bid 3 days, PO bactrim as alternative (often used in children)
A
Shigellla dysentery
11
Q
- Comma-shaped gram-negative rod, often in pairs forming a seagull shape. Grows best at higher temps
- Uncooked poultry (10x more common in chickens than salmonella due to higher basal temp) also found in raw milk and other livestock can carry it
- Also pH sensitive, so antacid use increases risk
- onset: 2-5 days, lasts: 2-5 days
- diarrhea: purulent, bloody, cramping
- fever
- TX: PO Azithromycin 500mg once daily for 3 days. Cipro as an alternative
A
Campylobacter dysentery
12
Q
- O157:H7 E coli (aka shiga toxin producing E coli or STEC) gram negative bacillus
- cattle are primary reservoir, so undercook & contaminated ground beef is most common; contaminated cider, milk, and lettuce also infrequently seen
- children most at risk for development of HUS
- 12-60 hours, lasts 5 -10 days
- diarrhea: pururlent, bloody, cramping
- fever
- no antibiotics, supportive only antibiotics increase toxin secretions and worsen HUS
A
Enterohemorrhagic (EHEC) e.coli
13
Q
- mainly cuased by enterotoxigenic e.coli or enteroaggregative e.coli
- water or foods contaminated by sewage; more common in developing countries
- swimming in stagnant water in developing country
- 1-5 days, can last up to two weeks
- diarrhea: watery, cramping
- fever sometimes
- TX:PO ciprofloxacin 500 mg BID for 3 days or po levofloxacin 400mg one daily for 3 days.
- PO rifaximin 200mg TID for prophylaxis
A
traveler’s diarrhea
14
Q
- gram negative bacillus that grows in temperatures at low as 4 degrees celcius
- contaminated & refridgerated meats, particularly pork; also cases of contaminated pasteruized milk in the US- very rare overall
- more common in children of developing nations and northern europe; has a propensity for the terminal ileus and can mimic appendicits with RLQ pain
- 4-7 days, lasts 1-3 weeks
- bloody, watery diarrhea
- fever
- PO Ciprofloxacin 500-750 mg BID for 3-7 days, for severe disease IV doxycycline 100mg bid and IV gentamicin once daily
A
Yersina
15
Q
- gram positive spore forming anaerobic rod
- overgrowth after prior antibiotic exposure that disrupts normal GI flora- PO clindamycin carries the highest risk
- antacids, prolonged healthcare exposure, age > 65 immunosuppressed persons, underlying GI disease and peripartum
- 2-10 days after PO antibiotic exposure
- diarrhea is profuse and very watery
- fever usually in moderate to severe disease
- tx: PO vancomycin (IV DOESN’T WORK) or PO fidaxomicin. 200 bid for 10-14 days, FMT or colectomy if toxic megacolon
A
C. diff
16
Q
- single stranded RNA genogroup, GI, GII and GIV- part of calcivirus family
- very contagious and found in high concentrations of the vomit and stool of infected individuals; most common viral GI pathogen in winter months
- outbreaks often associated with cruise ships and shellfish
- 1-3 days, lasts 1-2 days
- diarrhea is watery
- fever: low grade
- tx: supportive tx
A
norovirus
17
Q
- double stranded RNA, part of the reovirus
- fecal-oral transmission given virus is resistant to hand washing and most surface disinfectants
- children are almost exclusively the at risk group (< 3 years) particularly harmful because it can cause lactase deficiency; infection rates are much less severe with vaccine given in 2 or 3 doses starting at 2 months
- 1-3 days, lasts 5-8 days
- diarrhea: watery
- fever: low grade
- tx: vaccine prophylaxis and supportive if contracted
A
rotavirus
18
Q
- enteric flagellated protozoan
- contaminated water- particularly stream water while camping where it gets its name “beaver fever”
- daycares and MSM also at very high risk
- 5-25 days, lasst 4-6 weeks if left untreated
- diarrhea is watery, associated with lots of bloating
- no fever
- tx: PO tinidazole 2 g ONE DOSE or PO metronidazole 500mg BID for 5-7 days is second line alternative
parasitic
A
Giaridia
19
Q
- intesinal coccidian (similar to malaria) that infected the microvilli of the small bowel
- oocytes are shed from the intestinal lining of the infected person and spread fecal-oral route, autoinfection can occur and lead to more severe disease
- AIDS and other severly immunocompromised patients (ie, transplant and cancer patients) at signficant risk
- 2-10 days, lasts up to 30 days
- watery diarrhea
- fever is possible
- PO nitazoxanide 500mg BID for 14 days if immunocompromised for 3 days for immunocompetent
Parasitic
A
Cryptosporidiosis
20
Q
supportive tx of diarrhea?
A
- fluid and electrolyte replacement (ie pedialyte or gatorade)
- easily digestable foods
- avoid dairy due to transient lactose intolerance
- vaseline anal applications
21
Q
treatment for minimal dehydration ( < 3% fluid loss)
A
- dissolve 1 tbsp salt +2 tbsp sugar into 1L water 120-240ml of oral rehydration solution per stool
22
Q
tx of moderate dehydration ( 3%-9% fluid loss)
A
- can be treated outpatient
- 50-100ml per kg replaced over 3-4 hours
23
Q
treatment of severe dehydration (> 10% fluid loss)
A
- requires hospitalization for IV hydration
- infusion normal saline 20ml/kg until improved
24
Q
- what medications are antimotility drugs? when should you avoid them?
A
- Loperamide (imodium)
- PO diphenoxylate (lomotil)
- must avoid in the setting of dysenteric or confirmed bacterial or parasitic diarrhea)
25
Q
opioid receptor agonist of the enteric nervous system
A
loperamide (imodium)
26
Q
acts on the pre-synaptic opioid receptors(mainly mu receptors) of the enteric nervous system
A
Diphenoxylate (lomotil)
27
Q
- inhibits DNA synthesis in obligate anaerobic organisms
- counsel patients on avoidance of EtOH due to disulfiruam reaction
- can cause metallic taste in the mouth
- cases of peripheral neruopathy with prolonged (> 6 months) use
A
PO, IV metronidazole
28
Q
- targets bacterial DNA gyrase to impair DNA replication
- QT prolongation, interactions with di& trivalent cations (calcium and iron) and spontaneous tendon rupture
- don’t take with milk, or multivitamins for 2 before and 2 hours after
A
PO ciprofloxacin
29
Q
- impairs precursors to penicillin binding proteins needed for peptidoglycan cell wall stabilization
- PO suspension works better than pills, but suspension is more $$$
A
PO vancomycin
30
Q
- indicated for treatment-refractory C-diff
- role is to recolonize the infected patient’s GI tract with healthier GI flora using another person’s stool
- different administration techniques: colonoscopy, EGD, freeze dried capsule
A
Fecal microbiota transplant
