GI Infections Flashcards
(31 cards)
What is DYSENTERY?
Very severe form of diarrhea, always associated with BLOOD and MUCOUS
Tenesmus (pain)
SALMONELLA, SHIGELLA mainly
Diarrhea
FREQUENT, WATERY STOOLS
> 3 loose, watery stools/day
200 g/day in adults
Stool takes the form of a container
Infectious Causes of Diarrhea
VIRUSES –> Most COMMON CAUSE of infectious gastroenteritis
When it is SEVERE/BLOODY DIARRHEA –> BACTERIAL causes are likely responsible
CAMPYLOBACTER 42%
SALMONELLA 32 %
SHIGELLA 19%
E COLI O517 – 0.14% w/o visible blood, 7.8% with
CAMPYLOBACTER
Non-enterobacteriaceae
MOST COMMON BACTERIAL CAUSE OF DIARRHEA IN THE US
CHICKEN, MILK, CONTAMINATED WATER
Diarrhea may range from loose stools to massively watery/grossly bloody
SELF-LIMITED
Clinical Campylobacter
Culture at 42 C with special media
GASTROENTERITIS –> diarrhea (maybe bloody), malaise, fever, abdominal pain
Patients with HYPOGAMMAGLOBULINEMIA has PROLONGED, SEVERE DIARRHEA
GUILLIAN BARRE SYNDROME –> complication 1:1000, diagnosed primarily with C. Jejuni serotype O:19 and C. upsaliensis
Reactive Arthritis –> REITER’S SYNDROME - rare
Septicemia – associated with C. fetus; especially in debilitated and immunocompromised (alcoholics, DM, malignancy)
Salmonella Overview
NON-TYPHOIDAL –> US
TYPHOIDAL/PARATYPHOIDAL –> Typhoid Fever - almost ALWAYS in developing countries
Non-Typhoidal Salmonella
S. typhimerium, S. enteritidis, S. choleraesius
Enterobacteraciae
2nd most common after campylobacter!
Gram negative, curved rod
PET REPTILES, RAW EGGS, UNDERCOOKED MEAT/POULTRY
Clinical Diseases –> GASTROENTERITIS most common –> symptoms occur 6-48 hours –> fever, n/v diarrhea (bloody or not), abd cramps
SEPTICEMIA –> Highest in PEDIATRIC/GERIATRIC patients and AIDS –> Has bad associations with people (old) who have ATHEROSCLEROSIS – must treat
LOCALIZED SUPPURATIVE INFECTIONS in 10% OF PATIENTS SUCH AS OSTEOMYELITIS (esp sickle cell), ENDOCARDITIS, ARTHRITIS, and infection of ATHEROSCLEROTIC PLAQUES leading to DISSECTING AORTIC ANEURYSMS
Unless severe, we don’t treat, because the CARRIER STATE will be prolonged, can become chronic carriers
TYPHOIDAL Salmonella
ENTERIC/TYPHOID/PARATYPHOID FEVER
Strict human pathogens – NO ANIMAL RESERVOIR - Person-to-person transmission
RAPIDLY multiplies if FOOD is left at ROOM TEMP!!!
High Risk –> Very young, very old, AIDS, leukemia, lymphoma, DECREASED GASTRIC ACIDITY (PPIs!!), Sickle Cell Disease
Pathogenesis of Typhoid
Bacteria translocate through the intestinal wall, get engulfed by macrophages and spread to liver, spleen, bone marrow
Diarrhea/constipation
Initially present with HIGH FEVERS and CHILLS!!!!!
Can get NEURO-PSYCH complications (DELIRIUM, PICKING on the bed sheets?)
3-4 weeks –> Complications such as PERFORATION CAN OCCUR –> Multiplies in PEYER’S PATCHES
Gall bladder can get seeded, and intestines reinfected
Diagnosing Typhoid
Fevers, chills, headache, pain, anorexia, constipation
ROSE SPOTS, relative BRADYCARDIA (fevers usually tachy!), HEPATO-SPLENOMEGALY
Blood and bone marrow culture
Treating Typhoid
GIVING ANTIBIOTICS will PROLONG CARRIER STATE - Carried in GALLBLADDER
Not recommended for most patients!!!
Very ill, Older patients get antibiotics
EAT FULLY COOKED POULTRY AND EGGS!
Non-Enterohemorrhagic E. Coli to Know
ENTEROPATHOGENIC and ENTEROAGGREGATIVE E. Coli cause INFANTILE DIARRHEA in DEVELOPING COUNTRIES
Most common cause of TRAVELER’S DIARRHEA = ENTEROTOXIGENIC E. COLI
Enterohemorrhagic E. Coli
O157:H7 common
Disease ranges from mild, uncomplicated diarrhea, to hemorrhagic colitis with SEVERE ABDOMINAL PAIN, BLOODY DIARRHEA, NO FEVER
HUS (anemia, thrombocytopenia, acute renal failure) in 5-10% of patients (very young, very old)
FROM –> UNDERCOOKED GROUND BEEF, UNPASTEURIZED APPLE CIDER
SHIGA-LIKE TOXIN!!!!!!
Does NOT ferment sorbitol (distinguishes it from other E. Coli)
Diagnosing EHEC
As soon as EHEC is suspected, DO NOT GIVE ANTIBIOTICS –> it is TOXIN MEDIATED –> killing the bacteria will only LIBERATE MORE TOXIN!!!!!
Bloody diarrhea but NO FEVER? THINK EHEC
Bloody diarrhea WITH fever? Salmonella, Campylobacter, Shigella!
SHIGELLA
Humans ONLY RESERVOIR
Person-to-person, Fecal-Oral spread
Highest risk –> MSM, Young Children in DAYCARE, nurseries, siblings and parents of these children
People LOOK VERY ILL WITH SHIGELLA –> most common form is an INITIAL, WATERY DIARRHEA progressing within 1-2 days to ABD CRAMPS and TENESMUS
Antibiotic therapy RECOMMENDED (shortens course and reduces shedding)
YERSINIA
Not routinely cultured (COLD)
UNCOOKED PORK, CHITTERLINGS, TOFU, CHILD CARE
Can be APPENDICITIS-LIKE or ENTERIC FEVER-Like
FEVER + Appendicitis Like Syndrome + Diarrhea = YERSINIA!!!!
What bacteria can cause REACTIVE ARTHRITIS?
Salmonella Shigella Campylobacter Yerysinia Chlamydia
VIBRIO CHOLERA
PROFUSE WATERY DIARRHEA – Can be SO diffuse that patients get SEVERE electrolyte imbalences, dehydration and death!
H2O, FISH, SHELLFISH, STREET VENDORS
Vibrio PARAHEMOLYTICUS
Gastroenteritis – generally self-limited with an EXPLOSIVE ONSET WATERY DIARRHEA and nausea, vomiting, abd cramps, headache, low-grade fever –> NEVER as bad as Vibrio CHOLERA
Vibrio VULNIFICUS
WOUND INFECTION
Severe, potentially fatal infections characterized by ERYTHEMA, PAIN, BULLAE, TISSUE NECROSIS, SEPTICEMIA
How do we get Vibrio?
FISHING with TRAUMA/CUTS –> necrotizing fasciitis!
LISTERIA
Listeria monocytogenes
OF ALL INFECTIOUS BACTERIA, THIS HAS THE HIGHEST MORTALITY!!!!!
Gram Positive Rod –> Grows in VERY COLD ENVIRONMENTS
Hot dogs, Fresh Cheeses, Unpasteurized MILK
Preggos (don’t eat deli meats!!!), immunocompromised, Diabetes
SYSTEMIC ILLNESS –> Infancy Meningitis!!!
C. DIFF
Most commonly ANTIBIOTIC ASSOCIATED –> any antibiotic, but FLUOROQUINOLONES, CLINDAMYCIN, PENICILLINS, CEPHALOSPORINS especially
20% of all antibiotic associated diarrheas
Hospital associated
Diarrhea often with FEVER or BLOOD and LEUKOCYTOSIS
Recurrence in 10-25%
ELDERLY have HIGH RISK of COMPLICATIONS –> Pseudomembranous colitis, Toxic Megacolon!!!!!!
Bacteria with PREFORMED TOXINS
S. Aureus
BACILLUS
CLOSTRIDIA
If you get infected by bacteria with a PREFORMED TOXIN, you get sicker MUCH faster
