Diagnosing STIs with Laboratory Help

Question 1

What assurance enables better care for adolescents in the clinic being treated for an STI?

Answer 1

Confidentiality assurance!

Question 2

When a patient presents with dysuria, what is your initial leading differential?

Answer 2

UTI

Question 3

What is your DDx for dysuria?

Answer 3

• UTI
• Genital Tract Infection - Cervicitis, Vaginitis
• Skin Related Abnormalities/Mucosall Perineal - Herpes, Trauma

Question 4

What are the 5 P’s of a sexual Hx?

Answer 4

1. Partners - Gender, Number
2. Prevention of Pregnancy
3. Protection from STIs
4. Practices - type of sex
5. Past Hx of STIs

Question 5

What are the three big bugs that cause vaginitis?

Answer 5

1. Trichomonas
2. Bacterial Vaginitis
3. Candida Vaginitis

Question 6

What is the typical presentation of a person with trichomoniasis?

Answer 6

Generally females present with Syx with foul-smelling, frothy discharge, vaginal itching/redness, urge to urinate and dysuria

Question 7

What is bacterial vaginosis?

Answer 7

Fewer than normal hydrogen peroxide producing lactobacilli and prevalence of other types of bacteria in the vagina

Question 8

Typical presentation and sequelae of BV?

Answer 8

Odorous discharge and itching; Pregnancy complications/PID

Question 9

What is the Dx? Typical description and presentation?

Answer 9

Candidiasis; Genital itching/ burning, cottage cheese-like discharge

Question 10

A female patient has trichomonas. What are two findings that strongly suggest this Dx?

Answer 10

1. Frothy gray/yellow-green malodorous discharge
2. Cervical petechiae - Strawberry cervix

Question 11

What vaginal infection(s) occur(s) at a vaginal pH of >4.5?

Answer 11

Bacterial vaginosis and Trichomoniasis

Question 12

What tests are available for Trichomonas Dx?

Answer 12

1. Culture
2. Rapid Antigen Test
3. DNA Probe
4. Wet Mount

Question 13

What tests are available for Candida Dx? What is typically used?

Answer 13

1. DNA Probe
2. Wet Mount

Largely a clinical Dx

Question 14

What are Amsel’s Criteria?

Answer 14

3/4 need to be positive to Dx BV:

1. Whiff Test - Fishy/Musty odor when KOH added to smear
2. Clue Cells - bacteria attached to >20% of borders of epithelial cells
3. ** Vaginal pH** > 4.5
4. Homogenous non-inflamm discharge

Question 15

pH paper shows pH > 4.5, a rapid Trich test is unavailable, we don’t have time to use a KOH test, and you’re too dumb to use a microscope. How are we going to determine whether the infection is BV or Trich?

Answer 15

Treat presumptively! (Tx for BV and Trich is Metronidazole)

Question 16

When treating a patient for Trich, what is another important consideration?

Answer 16

Must Tx partner!

Question 17

What is the most important cause of cervicitis?

Answer 17

Chlamydia

Question 18

Important signs of chlamydia infection?

Answer 18

• Heavy/prolonged menses
• Spotting
• Dysmenorrhea
• Dyspareunia
• Vagina Discharge

Question 19

What are the Syx of females and males with Gonorrhea?

Answer 19

Females:

• Yellow/bloody vaginal discharge
• Dysuria
• Dysmenorrhea

Males

• Painful penile discharge
• Burning with urination
• Orchitis

Question 20

What is the gold standard to evaluate for cervicitis?

Answer 20

Nucleic Acid Amplification Test (NAAT)

Question 21

When would you culture a suspected Gonorrhea/Chlamydia infection?

Answer 21

For medicolegal purposes

Question 22

Describe the specimen collection method for NAAT

Answer 22

Both: 10-15 cc of urine > 2 hr after last void

Women: Vaginal swabs

Question 23

Typical pH with a candida infection?

Answer 23

pH < 4.5

Question 24

A KOH whiff test is positive. What is the Dx?

Answer 24

The Dx is either BV or Trich. BV is classically foul/fishy smell but Trich is often positive as well. Furrther testing is needed (Examine cervix, wet mount)

Question 25

What are the typical findings on PE for candidiasis?

Answer 25

• Inflammation and erythema
• Cottage-cheese discharge