Infectious Diseases Flashcards
cell-mediated vs humoral infection response
cell-mediated: involves T-cells (lymphocytes)
humoral: involves B cells (secrete antibodies)
When is the cell-mediated response indicated?
pathogen replication within cells (viruses, some bacteria, parasites)
When is the humoral response indicated?
antigens or pathogens circulating in lymph or blood
*protection of extracellular space
What effect does pregnancy have on B cells?
decreased immature B cells
increased mature B cells
What occurs to WBCs in pregnancy?
increased d/t increased neutrophils
1st tri = 5.7-13.6
rubella
risk factors, s/sx, patho, dx, tx, impact
*acute, mild viral disease
RF: day cares, no vax
s/sx: lymphadenopathy –> rash on face that spreads to body; HA, conjunctivitis, nasal congestion, mild pyrexia, arthralgia
patho: airborne; person-to-person
dx: determine immune status (IgG); throat swab
tx: supportive; sx relief
impact: excellent prognosis; CRS –> SAB, fetal death, LBW, PTB; *trifecta = cardiac disease, deafness, cataract
- CRS most likely to occur when infected early in pregnancy (<20wks)
Hep A
risk factors, s/sx, patho, dx, tx, impact
RF: contaminated food, water; poor hygiene; daycare
s/sx: mild, nonspecific; jaundice = rare
patho: fecal-PO route
dx: serological testing (IgM early, IgG convalescent period = immunity for life!)
tx: hep A vax - both safe in pregnancy; primarily supportive
impact: no known maternal-fetal transmission; can BF - IgG Abs across placenta and protect infant PP
Hep B
risk factors, s/sx, patho, dx, tx, impact
RF: injectable drug use, sex, healthcare, hemodialysis
sx: asymptomatic; fatigue, anorexia, malaise; *acute = most common cause of jaundice in pregnancy
patho: highly contagious! highest conc. in blood; 90% experience complete resolution w/ protective Ab levels
dx:
1) Hep B surface antigen (early infection; clears after 3-4mo)
2) antihep B surface antibody (convalescent period after HbsAg has cleared; INDICATES IMMUNITY - acute infection and vax)
3) antihep B core Ab (prev or ongoing natural infection, NOT vax)
4) HBe antigen (active viral replication and high infectivity)
5) antihep B Ab (recovery phase; decreased infectivity)
tx: supportive; if severe: monitor viral load + antivirals (telbivudine, tenofovir) 6-8wks before labor
* vax safe in pregnancy!
impact: HBV cannot cross placenta; transmission occurs at birth, esp maternal HBeAg +; highest risk = 3rd tri infection
Hep C
risk factors, s/sx, patho, dx, tx, impact
RF: IV drug use, blood transfusion, tattoos, sex partners
s/sx: fatigue, joint pain, jaundice, myalgia, generalized pruritis
- chronic HCV develops in most
patho: most common blood-borne infection in US; leading cause of liver disease
dx: ELISA screening test for HCV-specific Abs
tx: expectant mangement (meds = contraindicated)
impact: higher viral load –> higher risk transmission
HIV
risk factors, s/sx, patho, dx, tx, impact
s/sx: mono-like sx
patho: acute phase = 4-6wks after exposure; lasts several weeks. latent phase = years.
dx: HIV 1 & 2 Ab immunoassay in initial and 3rd tri labs; PCR in infant
tx: prevent HIV progression and transmission; combo care at least 3 drugs from at least 2 classes ARVs
impact: higher transmission risk w/ decreased CD4 count, high viral load, chorio, intrapartum blood exposure, breastfeeding
CMV
risk factors, s/sx, patho, dx, tx, impact
member of herpes family; most common cause of congenital infections
RF: daycare, sexual risk factors
s/sx: ASYMPTOMATIC; maybe mono-like
patho: bodily fluid transmission; secondary infection = reactivation
* most severe fetal injuries occur in first 8wks intrautero*
dx: lab testing only if sx, fetal anomaly, or upon request
tx: not approved for pregnant people
impact: sensoineural hearing loss = most common
HSV
risk factors, s/sx, patho, dx, tx, impact
s/sx:
- 1º = asymptomatic, minor, or severe; lesions larger; flu-like sx
- non-1º, first episode: HSV2 HIGHLY protective against HSV1; milder, less pain, shorter viral shedding, rapid resolution
- recurrent: more common in HSV2; prodrome
patho: HSV1 = oropharyngeal, more easily transmitted ; HSV2 = genital; life-long infection; greatest risk w/ primary infection at birth
dx: sx - IgM and IgG (primary vs recurrent) + viral culture + PCR
tx:
- 1º = acyclovir 400mg PO TID x 7-10days
- recurrent = acycolovir 400mg PO TID x5d OR 800mg BID x 5d
- daily suppression = acyclovir 400mg PO TID from 36wks to delivery
impact: C/S if active lesions or prodrome
parovirus
risk factors, s/sx, patho, dx, tx, impact
RF: winter, spring; daycares
s/sx: asymptomatic; mostly mild and nonspecific; slapped cheek in 3rd wk
patho: respiratory transmission, hand-to-mouth, blood
dx: lab testing when pregnant person exposed to or develops sx OR when abnormal U/S findings suggest congenital infection; serology = ELISA test
tx: none
impact: serial U/S for hydrops; VERY LOW RISK TO FETUS
coxsackie virus
risk factors, s/sx, patho, dx, tx, impact
RF: DAMN KIDS
s/sx: febrile illness
patho: hand, foot, mouth disease; fecal-oral route
tx: NONE
impact: inc rate miscarriage, insulin-dependent diabetes in baby
varicella
risk factors, s/sx, patho, dx, tx, impact
s/x:
1º = fever, malaise, HA 1-2d before rash appears; macule –> papule –> vesicle –> pustule –> crusts (takes 4-7d)
VZV reactivation = shingles; excruciating, unilateral pain; rash = erythematous –> maculopapular –> vesicles –> crust; pain may last for months or years
patho: direct contact w/ vesicular fluid or respiratory droplets; infectious 48h before rash until crusted; neonatal from maternal infection in last 3wks - if w/in first 10-12d = transplacental transmission
dx: PCR of skin lesions; +IgG ELISA = hx VZV
tx: VZIG ASAP after exposure; vax nonpregnant people - wait 1mo before conceiving
impact: BF infected infants
syphilis
risk factors, s/sx, patho, dx, tx, impact
RF: A-A; male>female
s/sx:
- 1º: painless ulcer w/ raised, indurated border; resolves 3-6wks
- 2º: maculopapular rash on palms, soles, mucous membranes; resolves 2-6wks MOST CONTAGIOUS
- 3º: gummatous lesion ; aortic aneurysm; seizure
patho: EASILY CROSSES PLACENTA
dx: cannot culture syph! Sero test at initial visit (RPR, VDRL)
tx: 1º and 2º, early latent = benzathine PCN G 2.4 million unit single dose; late latent or unknown duration = 2.4 u once weekly x3wks
impact: early congenital - snuffles, hepatosplenomegaly, rash; late - Hutchinson teeth, mulberry molars, deafness
gonorrhea
risk factors, s/sx, patho, dx, tx, impact
RF: <25yo; co-infection; hx GT; drug use
s/sx: asymptomatic; +/- vaginal d/c, dysuria, frequency, tender Bartholin’s or Skene’s glands
dx: endocervical swab at initial visit; if +, repeat in 3rd tri
tx: 250mg ceftriaxone IM + azithromycin 1g PO; abstain sex until 7 days s/p tx
impact: PTB, IUGR, ectopic, NEONATAL CONJUNCTIVA
chlamydia
risk factors, s/sx, patho, dx, tx, impact
RF: A-A; <25yo; etc
s/sx: asymptomatic; vaginal d/c, postcoital bleeding, dysuria
dx: mucopurulent cervical d/c; tenderness on bimanual; +/- inc WBCs; NATT w/ endocervical swab
tx: azithromycin 1g; retest in 2-3 wks
impact: ectopic; PTB; PROM
toxoplasmosis
risk factors, s/sx, patho, dx, tx, impact
CATS!
RF: undercooked meats, cat poop
s/sx: asymptomatic; mono-like; RARE = vision changes
patho: ingesting oocysts; transplacental transmission!
dx: abnormal fetal U/S –> lab testing; amniocentesis + PCR after 18wks GA for congenital infection
tx: spiramycin MAYBE
impact: infection more likely in 3rd tri BUT sx worse if infected in 1st tri; rash, hepatosplenomegaly ascites, seizure
trich
risk factors, s/sx, patho, dx, tx, impact
s/sx: green, frothy d/c
dx: saline slide
tx: metronidazole 2g
impact: PROM, PTB, LBW
BV
risk factors, s/sx, patho, dx, tx, impact
RF: douching, frequent intercourse, A-A
s/sx: fishy, white d/c
patho: bacteria imbalance - acidic –> basic
dx: 3/4 - 1) grayish-white d/c, 2) pH>4.5, 3) amine odor, 4) wet mount w/ clue cells
tx: metronidazole 500mg 2x/day x7d
impact: late miscarriage, PPROM, PTL/B, chorio, PP endometriosis; inc risk STI
yeast
risk factors, s/sx, patho, dx, tx, impact
RF: inc levels estrogen/progesterone in pregnancy
s/sx: thick, white d/c; pruritus
dx: wet mount w/ hyphae & buds; pH ≤4.5
tx: miconazole 1% cream 5g vaginally x7nights OR terconazole 0.4% 5g
impact: low risk for poor pregnancy outcomes
GBS
risk factors, s/sx, patho, dx, tx, impact
leading cause of neonatal sepsis and meningitis in first week of life
RF: maternal GBS; GA<37wks; prolonged ROM
s/sx: colonization is NOT illness; infection = rare –> sepsis, amnionitis, UTI
patho: can be in utero OR labor
dx: single swab of introitus and rectum
tx: PCN in labor
impact: meningitis w/ early-onset disease BUT more common in late-onset - characterized by sepsis; deafness; developmental disabilities
asymptomatic bacteriuria
risk factors, s/sx, patho, dx, tx, impact
s/sx: DFD
patho: inc urinary stasis; inc GFR –> dec ability to resist bacteria; 70-80% = E. coli
dx: urine C&S at initial (>10^5 = +)
tx: amoxicillin, ampicillin, cephalexin 250-500mg QID for E. coli, Bactrim, Macrobid = all okay - depends on C&S; 3 day course comparable to 7-10d BUT single dose not as effective in pregnant people
* avoid sulfonamides in 1st tri = teratogenic
impact: if untreated –> UTI, pyelo –> septic shock, resp failure, hypotensive hypoxia
