STDs

Question 1

STDs

Answer 1

relatively few clinical syndromes
MOST COMMON SYMPTOMS
1. urethritis
2. cervicitis
3. vaginitis or vaginosis
4. genital ulcers

Question 2

Inflammatory/Exudate Causes of STDs

Answer 2

Urethritis -> N. Gonorrhea, C. trachomatis
Cervicitis -> C. trachomatis
Vaginitis -> T. vaginalis, C. albicans
Vaginosis -> Gardnerella

Question 3

Nonexudative Causes of STDs (Genital Ulcers)

Answer 3

Syphilis -> T. pallidum (not painful)
Herpes -> HSV-2 (painful)
Chancroid -> H. ducreyi
LGV -> C. trachomatis
Genital Warts -> HPV (not painful)

Question 4

Systemic Infections

Answer 4

AIDS -> HIV 1 and 2

PID -> N. gonorrhea, C. trachomatis, anaerobes

Question 5

Cancer from STDs

Answer 5

Cervical carcinoma - HPV

Kaposi sarcoma - HHV-8

Question 6

HPV

Answer 6

dsDNA -> circular -> icosahedral -> nonenveloped -> papoviridae

• transmitted by direct contact (wart like growths)
• has oncogenes (16, 18)
• vaccine available, no treatment (incurable)
• dependent on host cell replication -> if cell it infects is not replicating, virus cannot infect

Question 7

Neisseria Gonorrhea

Answer 7

gram (-) -> diplococci -> glucose oxidizer
Grows on Thayer-Martin media
- specialized pili with antigenic variation, endotoxin, no capsule, IgA protease
- kills ciliated cells
- treat with ceftriaxone, also pair with doxycycline for chlamydia co-infection
- prophylactic erythromycin eye drops for neonates

Question 8

N. Gonorrhea 3 types of infections

Answer 8

1. Local infection -> genital tract or anorectal infection
2. Systemic arthritis -> invasive pathogen, most common cause of systemic arthritis in sexually active individuals
3. Untreated –> PID, ectopic pregnancy, sterility, Fitz-Hugh-Cutris Syndrome

Question 9

Herpes Simplex Virus 2

Answer 9

dsDNA -> linear -> icosahedral -> enveloped -> alpha herpes virus

• transmitted via direct contact, latency in neurons
• encodes for several proteins required to promote replication (DNA polymerase and thymidine kinase)
• treatment only effective during lytic infection
• visualized on Tzanck smear –> multinucleated giant cells

Question 10

Treatment of Herpes

Answer 10

ACYCLOVIR –> a prodrug that is a guanine base with a modified sugar -> requires viral thymidine kinase to activate -> gets incorporated into viral DNA –> chain terminator
- has 100x more affinity for viral than human

Question 11

Gancyclovir

Answer 11

used for beta-herpes infections

- doesn’t use thymidine kinase -> uses different enzyme

Question 12

Trichomonas Vaginalis

Answer 12

small, pear-shaped protozoa –> 4 anterior flagella and 1 undulating membrane = 5 flagella

• white or yellow-green frothy discharge, foul-smelling, fishy odor
• transmitted via direct contact, treat both patient and partner with metronidazole
• vaginal pH will be elevated
• not an opportunistic infection

Question 13

Candida albicans

Answer 13

• opportunistic infection* –> due to disruption of normal bacterial microbiota
• itchiness, white, clumpy discharge (common cause of vaginitis)
• pseudohyphae indicate rapidly growing
• tx with topical/oral azoles –> tx both patient and partner

Question 14

HIV 1 and 2

Answer 14

RNA virus -> icosahedreal -> enveloped -> ss(+) diploid -> retroviridae

• infects CD4+ Tcells with CXCR4 or CCR5
• gp120 -CXCR4/CCR5, gp41 - entry into cell
• gag = virion core
• pol = RT, integrase, protease
• env = glycoproteins

Question 15

Trepnema pallidum —> SYPHILIS

Answer 15

spirochete -> microaerophilic

• painless ulcers that go away –> come back as full body rash
• rapid plasma regain test
• 3 stages of disease
  1. Primary - appearance of hard chancre at site of entry, loaded with spirochetes
  2. Secondary - weeks/months after -> fever, headache, sore throat, lymphadenopathy, red/brown rash on soles and palms
  3. Tertiary - enter highly varied latent period (years) -> can cause cardiovascular effects (aortic rupture) -> uncommon today because penicillin G effective against all stages of syphilis

Question 16

Argyll Robertson Pupil

Answer 16

condition from syphilis that accomodates to near objects but does not react to light

Question 17

Congenital Syphilis

Answer 17

bacterium can pass through placenta (ToRCHeS)

• most common in 2nd or 3rd trimester
• deafness, mulberry molars, saber shins, saddle nose, Hutchinson’s incisors

Question 18

FTA-BS

Answer 18

fluorescent treponemal antibody absorbance test -> test serum reacts with treponemal cells and then reacted with antihuman globulin antibody labeled with fluorescent dyes -> if antibodies present -> show up labeled

Question 19

Gardnerella vaginalis

Answer 19

no itching
white-gray color
moderate discharge that is malodorous

Question 20

Chlamydia trachomatis

Answer 20

• has both elementary body (EB) and reticulate body (RB)
• multiplies by binary fusion
  Serovars D-K = urethritis, PID, neonatal pneumo, conjuctivitis
  A-C = trachoma (chronic conjuctivitis)
  L = lymphogranuloma venereum

Question 21

Pathophysiology of C. trachomatis

Answer 21

D-K = infects columnar epithelium and generates epithelium
- can spread to fallopian tubes = ectopic pregs –> can infect liver (Fitz-Hugh-Curtis syndrome)
- males can spread to joints -> Reiter’s syndrome
A-C = hand-eye contact and conjuctivitis -> blindness
L - rare but leads to painless ulcers and leads to proctitis and rectal stricture
- treat with azithromycin and tetracyclines