Clinical Diagnostics Lab Exam
Terms
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- Endocarditis
-
- bacterial colonies embedded in fibrin on heart valves
- SBE prophylaxis prior to dental procedures: amoxicillin 500mg, 4 po 1hr before -
Endocarditis
- Risk Factors -
- immunosuppressed pt.
- invasive or surgical procedure
- intravascular devices
- widespread use of broad spectrum antibiotics that suppress NL flora - Bacteria that commonly cause Endocarditis
-
1. Viridans streptococci
2. enterococcus
3. Strep. bovis (Group D, non-enterococcus)
4. Cardiobacterium
5. Eikenella
6. Coagulase (-) staph. - Endocarditis: In IV drug abusers, the most common isolate is ______.
- Staph aureus
- Blood culture specimen collection
-
- 3 sets of aer/ana bottles
- 1/2 hr prior to expected onset of fever spike
- separate sites
- prior to admin. of antibiotics
- 5-10mls per bottle
- continuous monitoring - CSF Infections
-
1. Meningitis
2. Encephalitis
3. Meningoencephalitis - Meningitis
- - infx. w/in subarachnoid space
- Encephalitis
- - inflammation of brain parenchyma (usually viral etiology)
- Meningoencephalitis
- - inflammation of meninges
- CSF analysis
- - lumbar puncture: tube #2 goes to micro, spun specimen and sediment plated
-
CSF analysis
a) bacterial etiology
b) viral etiology
c) mycobacterial or fungal etiology -
a) PMNs, low glucose, high protein
b) lymphocytes, NL glucose, NL to mod. elevated protein
c) eosinophilia, low glucose, high protein - Additional CSF testing
-
- latex agglutination testing for antigen
- gram stain
- VDRL for Abs - CSF testing: VDRL for Abs against what organisms?
-
- Treponema pallidum (syphilis)
- Cryptococcal antigen - Prozone effect
- - false negative due to a lot of organisms preset
- NL flora of genital tract of females
-
- varies w/age depending on pH and estrogen concentration
- Staph., Cornyebacterium, Lactobacillus, Streptococci, Enterobacteriaceae, anaerobes - NL flora of genital tract of males
- - Staph, Cornyebacterium, Mycobacterium smegmatis in uncircumcised males
- Pathogens of GU tract
-
- vaginal Candiasis
- protozoan, Trichomonas vaginalis
- N.gonorrheae
- C.trachomatis
- M. hominis
- Peptococcus species
- Ureaplasma urealyticum
- Bacteroids
- H.influenzae
- Gardnerella vaginalis
- Strep. species
- viruses: HSV1 & 2
- Haemophilus ducreyi - Vaginal Candiasis is assoc. with:
-
- antibiotic therapy
- DM
- pregnancy
- immunosuppressed pt.
- corticosteroid use - Vaginal Candiasis presents:
-
- cottage cheese discharge, adheres to vaginal mucosa
- vulvar pruritis (may be exacerbated w/onset of menses and somewhat relieved at onset of menstrual flow) - Most common sx. of vaginal candiasis:
- - vulvar pruritis
- Vaginal candiasis: STD?
- - usually NOT sexually transmitted
- Vaginal candiasis: swab
- - swab lateral and posterior fornices while avoiding cervical mucus with a pH of 7
- Vaginal candiasis: lab
-
- wet mount or saline prep
- 10% KOH prep
- if inconclusive consider vaginal culture
-(+) culture does not mean Candida is responsible for vaginal sxs. - Vaginal candiasis: TX
- - oral or topical azole prep (Diflucan 150mg, single dosing, Gyne-Lotrimin, Monistat, Terazole)
- Caution about vaginal preps
- - oil based and may weaken latex condoms/diaphragms
- Most common cause of inc'd malodorous (fishy) discharge
- - Bacterial vaginitis
- Bacterial vaginitis
-
- fishy smelling discharge
- pH >4.5
- vaginal irritation and pain are UNCOMMON - Bacterial vaginitis: pathogen
-
- no single pathogen is responsible
- usually due to overgrowth of anaerobes replacing NL lactobacillus
- Garderella vaginalis, Mycoplasma hominis, Bacteriodes - Bacterial vaginitis: labs
-
- positive whiff test with 10% KOH
- clues cells on wet mount
- culture not useful as Gardnerella vaginalis can be isoloted from 1/2 of NL women - Bacterial vaginitis: Tx
-
- metroniazole (Flagyl) 500mg PO BID x 7 days
- contraindicated in pregnancy
- avoid alcohol during tx and for 24 hours after tx due to disulfiram-like antabuse effect
- alternate tx: metroniazole gel (Metrogel vaginal) 0.75% one applicator (5g) intravaginially BID x 5 days
- Clindimycin - Clues cells
- - epithelial cells with inclusive bacteria
- Disulfiram-like antabuse effect
- - nausea, flushing, metallic taste
- Trichomonas vaginitis
-
- STD
- protozoan Trichomonas vaginalis - Trichomonas vaginitis: sxs
-
- some are asymptomatic
- copious amts. of malodorous FROTHY YELLOW-GREEN DISCHARGE
- VULVAR IRRITATION
- PRURITIS
- dyspareunia
- worsening following menses
- STRAWBERRY CERVIX due to petechiae
- majority of men are asymptomatic - Trichomonas vaginitis: dx
- - observing motile trichomonads and PMNs on wet mount
- Trichomonas vaginitis: Tx
-
- metroniazole (Flagyl) 2gm single dosing or 500mg BID x 7 days
- contraindicated in first trimester of pregnancy but may be considered after w/2gm single dose - PID
- - Polymicrobial: N.gonorrheae, C.trachomatis, M.hominis, Peptococcus species, U.urealyticum, Bacteroids,H.influenzae, Gardnerella vaginalis, Strep species, viruses
- PID: risk factors
-
- age <25
- multiple sex partners
- IUDs
- recent invasive gyn procedure
- smoking
- vaginal douches
- parturition - PID: clinical dx
-
- BL lower abd. pain
- change in discharges
- irreg. bleeding
- dysuria, fever
- adnexal tenderness/swelling
- cervical motion tenderness aka "CHANDELIER SIGN" - PID: Labs
-
- gram stain
- urine pregnancy (ectopic)
- CBC (appendicitis)
- syphilis serology
- HIV testing - PID: gold standard for confirming dx
- - laparoscopy (invasive)
- Most prevalent STD in U.S.
- - gonorrhea
- Neisseria gonorrheae
-
- gram (-) diplococci
- incubation: 2-5 days - Gonorrhea is characterized by:
-
- MUCOPURULENT DISCHARGE
- acute urethritis in men
- cervicitis in women
- Skene’s & Bartholin glands commonly infected - Gonorrhea: sequellae
-
- salpingitis
- scarring of fallopian tubes
- (PID)
- can lead to sterility - Gonorrhea: Dx
-
- gram stain PMNs & intracellular gram (-) diplococci
- presumptive dx in men, not women-have NL Neisseria in vaginal area - Gonorrhea: culture required growth on _____
- - Thayer-Martin Plate
- Gonorrhea: Tx
-
- all sexual partners w/in past 30 days
- no intercourse until cured
- treat newborns w/anbx drops to prevent gonococcal ophthalmia
- Rochephin 125 mg IM single dose or Cipro 500 mg orally - Syphilis: pathogen
-
- Treponema pallidum
("great masquerader") -
Syphilis:
a) hosts
b) higher incidence -
a) humans are the only host
b) southern U.S., blacks, hispanics - Syphilis: modes of transmission
-
- skin
- mucus membranes
- body fluids & secretions
- transplacentally - Stages of Syphilis
-
- primary
- secondary
- latent
- tertiary - Syphilis: primary stage
-
- painless chancre
- appears 2-6 wks after exposure
- at site of exposure, genital area, lip, tongue, buccal mucosa - Syphilis: secondary stage
-
- 2-6 months later
- skin lesions
- palms and soles
- highly contagious as lesion borders are loaded w/ spirochetes
- sore throat,fever,chills, H/A,anorexia,weight loss, generalized alopecia, lymphadenopathy - Syphilis: latent stage
-
- pt. is asymptomatic but diagnostic testing is (+)
- early latent: up to 1 year
- late latent: after 1 year w/o sxs - Syphilis: tertiary stage
-
- chronic inflammatory dz, can affect any organ
- gummas (thought to result from delayed hypersensitivity rxx) - Granuloma Inguinale
-
- aka Donovanosis
- Calyminatobacterium granulomatis (gnr)
- “Donovan Body†in cytoplasm of mononuclear cells. - Granuloma Inguinale: sns/sxs
-
- painless granulomatous ulcer at inoculation site
- lymphadenopathy is uncommon - Granuloma Inguinale: labs
-
- punch bx
- Wright/Giemsa stain - Granuloma Inguinale: Tx
-
- doxycycline 100mg BID
- or Bactrim - Lymphogranuloma Venereum
- - Chlamydia trachomatis
- Chlamydia trachomatis
-
- uncommon in US
- prevalent in tropical areas
- 2 stages - 2 stages of C.trachomatis
-
1. painless papule that ulcerates
2. tender, U/L inguinal adenopathy, BUBO formation - BUBO formation
-
- accumulation of tender lypmh nodes
- may rupture
- fistula may form - C.trachomatis: labs
-
- Ab/complement fixation test: >1:32 indicative of active dz
- culture of BUBO aspirate - C.trachomatis: Tx
-
- doxycycline for 21 days
- treat any sexual partners w/in past 30 days - Chancroid (Haemophilus ducreyi)
-
- painful genital ulcer
- 1-14 days of incubation
- tropics, subtropics - Chancroid (H.ducreyi): labs
-
- gram stain
- culture ulcer edge or inguinal node aspirates - Chancroid (H.ducreyi): Tx
-
- azithromycin
- erythromycin
- ceftriaxone - HSV 1 and HSV 2
-
- ds DNA virus
- direct contact w/mucus membrane
- 2-20 day incubation - HSV: what happens to virus after acute episode?
-
- virus migrates to sensory or autonomic ganglia
- becomes dormant
- may reactivate - HSV: sxs
-
- painful eruption of localized grouped vesicles on an erythematous base
- fever, malaise, H/A - HSV: initial eruption
- - more severe and lasts longer than subsequent recurrences
- Herpes Genitalis
-
- can occur anywhere on genitals
- on labia in females - HSV: definitive test
- - viral culture
- HSV: labs
-
- viral culture
- special transport media
- cross reactivity
- STD testing
- Tzanck smear - HSV: why are serological tests of limited value?
- - >85% adults have Ab to HSV1
- Tzanck smear
-
- scrape base of lesion with blade
- place on slide
- stain with Wright/Giemsa/toluidine blue - HSV: what is seen on Tzanck smear?
-
- multinucleated giant cells
- negative test does not disprove dx.
- specific only to herpes virus
- WILL NOT DISTINGUISH SIMPLEX FROM ZOSTER - HSV: Tx
-
- Acyclovir (Zovirax)
- Valtrex
- Famvir - HSV: cold sores
-
- treated for 3 days
- Abreva OTC: prevents virus from infecting new cells - HSV: suppressive therapy
-
- Zovirax for up to a year reduces frequency and severity of infxs.
- does not reduce viral shedding. - HSV: prevention
-
- HSV2 vaccines under clinical trial
- condom use - Chlamydia trachomatis invades only ____.
- - columnar epithelium
- GI: S.aureus
-
- S.aureus
- PREFORMED ENTEROTOXIN
- rapid onset
- 2-8hrs of N/V/D, H/A, cramps
- - GI: Clostridium botulinum
-
- anaerobic, spore-forming
- gram (+) bacillus
- one of most powerful toxins known -
GI: C.botulinum
a) incubation
b) symptoms -
- incubation: 12-36 hours
- sxs: N/V/D, dizzy, difficulty swallowing, double vision, nerve paralysis -
GI: C.botulinum
a) dx
b) tx -
a) toxin ID in serum or food source
b) antitoxin and airway maintenance - rice water stools
- - cholera
- Vibrio parahaemolyticus
-
- gram (-) bacillus
- contaminated shellfish, sushi, improperly cooked seafood
- incubation: 2-24 hours
- N/V/D, abd. pain
- tx: self-limiting - GI: Preformed Toxin
-
- S. aureus
- C. botulinum - GI: Enterotoxin
-
- Vibrio cholerae
- Vibrio parahaemolyticus
- Bacillus cereus
- Clostridium difficile - GI: spores may not be killed during cooking, rice/grain dishes
- - Bacillus cereus
- GI: B.cereus
-
- watery diarrhea, abd. pain, rectal spasm, nausea
- lasts about 24-48 hours
- tx: supportive - pseudomembranous colitis
- - Clostridum difficile
- causative agent of antibiotic-associated diarrhea
- - Clostridium difficile
- GI: C.difficile
-
- anaerobic, gpb
- spore forming
- part of NL flora - Antibiotics involved in C.difficile infx.
-
- any antibiotic can cause it
- ampicillin, clindamycin, cephalosporins are the most common causes - C.diff: sxs
-
- may be mild or...
- bloody diarrhea, abd. cramping, fever
- Latex agglutination - C.diff: tx
-
- discontinue antibiotics
- treat with Flagyl or vancomycin - Salmonella
-
- >2000 serotypes
- gnb (Enterobacteriaceae) - Most common species of Salmonella in the U.S.
-
- S. enteridis
- incubation 6-48 hours but may be delayed for 7-12 days - Salmonella reservoirs
-
- livestock, turtles, iguanas, snakes
- food sources: raw eggs, undercooked beef or poultry, cutting boards or contaminated utensils, food handler