Infectious Diarrhea

Question 1

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

Answer 1

A: diarrhea
B: acute diarrhea

Question 2

diarrhea lasting between 15-29 days

Answer 2

persistent diarrhea

Question 3

diarrhea lasting greater than 30 consecutive days

Answer 3

chronic diarrhea

Question 4

bloody and/or pururlen diarrhea often with associated fever, tenesmus and abdominal cramping (i.e, dysentery)

Answer 4

inflammatory diarrhea

Question 5

non-bloody diarrhea suggesting an enterotoxic bacterial, viral or protozoan process

Answer 5

non-inflammatory diarrhea

Question 6

diarrhea that occurs within 10 days of travel to a developing nation

Answer 6

traveler’s diarrhea

Question 7

Causes of acute diarrhea

Answer 7

• bacterial or viral infections
• medications
• food intolerances
• mesenteric ischemia= specialist consultation recommended

Question 8

causes of chronic diarrhea?

Answer 8

• parasitic infections
• inflammatory bowel disease
• celiac disease
• malabsorption
• irritable bowel syndrome
• pancreatic insufficiency
• hyperthyroidism
• endocrine tumor

Question 9

• 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

Answer 9

Salmonella

Purulent, bloody= non typhoidal, Watery= typhoid

Question 10

• 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)

Answer 10

Shigellla dysentery

Question 11

• 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

Answer 11

Campylobacter dysentery

Question 12

• 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

Answer 12

Enterohemorrhagic (EHEC) e.coli

Question 13

• 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

Answer 13

traveler’s diarrhea

Question 14

• 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

Answer 14

Yersina

Question 15

• 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

Answer 15

C. diff

Question 16

• 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

Answer 16

norovirus

Question 17

• 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

Answer 17

rotavirus

Question 18

• 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

Answer 18

Giaridia

Question 19

• 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

Answer 19

Cryptosporidiosis

Question 20

supportive tx of diarrhea?

Answer 20

• fluid and electrolyte replacement (ie pedialyte or gatorade)
• easily digestable foods
• avoid dairy due to transient lactose intolerance
• vaseline anal applications

Question 21

treatment for minimal dehydration ( < 3% fluid loss)

Answer 21

• dissolve 1 tbsp salt +2 tbsp sugar into 1L water 120-240ml of oral rehydration solution per stool

Question 22

tx of moderate dehydration ( 3%-9% fluid loss)

Answer 22

• can be treated outpatient
• 50-100ml per kg replaced over 3-4 hours

Question 23

treatment of severe dehydration (> 10% fluid loss)

Answer 23

• requires hospitalization for IV hydration
• infusion normal saline 20ml/kg until improved

Question 24

• what medications are antimotility drugs? when should you avoid them?

Answer 24

• Loperamide (imodium)
• PO diphenoxylate (lomotil)
• must avoid in the setting of dysenteric or confirmed bacterial or parasitic diarrhea)

Question 25

opioid receptor agonist of the enteric nervous system

Answer 25

loperamide (imodium)

Question 26

acts on the pre-synaptic opioid receptors(mainly mu receptors) of the enteric nervous system

Answer 26

Diphenoxylate (lomotil)

Question 27

• 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

Answer 27

PO, IV metronidazole

Question 28

• 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

Answer 28

PO ciprofloxacin

Question 29

• impairs precursors to penicillin binding proteins needed for peptidoglycan cell wall stabilization
• PO suspension works better than pills, but suspension is more $$$

Answer 29

PO vancomycin

Question 30

• 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

Answer 30

Fecal microbiota transplant