Vaginal Discharge and Vulvar Pruritus

Introduction

Understanding vaginal discharge and vulvar pruritus is crucial for success in the Medical Council of Canada Qualifying Examination Part I (MCCQE1). This comprehensive guide focuses on Canadian medical practices and guidelines, providing you with the essential knowledge needed for your MCCQE1 preparation.

Normal Vaginal Discharge

Before diving into pathological conditions, it's important to understand normal vaginal discharge:

• Composition: Mixture of cervical and vaginal secretions, sloughed epithelial cells, and vaginal flora
• Appearance: Clear to white, non-malodorous
• pH: Typically 3.8-4.5 in reproductive-age women
• Volume: Varies throughout menstrual cycle, increasing mid-cycle

Common Causes of Abnormal Vaginal Discharge

Understanding the common causes of abnormal vaginal discharge is essential for MCCQE1 success. Here's a comparison of the most frequent etiologies:

Vulvar Pruritus

Vulvar pruritus, or itching of the vulva, can occur with or without abnormal discharge. Common causes include:

1. Candidiasis
2. Contact dermatitis
3. Lichen sclerosus
4. Lichen simplex chronicus
5. Vulvar cancer (rare but important to consider)

Canadian Guidelines for Management

The Society of Obstetricians and Gynaecologists of Canada (SOGC) provides guidelines for managing vaginal discharge and vulvar conditions. Key points include:

1. Empiric treatment of bacterial vaginosis and candidiasis is appropriate in low-risk patients with typical symptoms.
2. Screening for chlamydia and gonorrhea is recommended for all sexually active individuals under 25 years old.
3. Partner treatment is crucial for management of sexually transmitted infections.
4. Recurrent vulvovaginal candidiasis (4 or more episodes per year) may require long-term suppressive therapy.

Key Points to Remember for MCCQE1

• 🔑 Bacterial vaginosis is the most common cause of abnormal vaginal discharge in Canada.
• 🔑 Trichomoniasis is less common in Canada compared to other countries but is important to recognize.
• 🔑 Consider non-infectious causes of vulvar pruritus, especially in postmenopausal women.
• 🔑 Always screen for concurrent STIs in patients presenting with vaginal symptoms.
• 🔑 Familiarize yourself with Canadian STI treatment guidelines, as they may differ from international guidelines.

MCCQE1 Practice: Clinical Reasoning

Sample Question

A 25-year-old woman presents to her family physician with a 3-day history of malodorous vaginal discharge and vulvar itching. She is sexually active with multiple partners and uses condoms inconsistently. On examination, there is a frothy, yellow-green discharge and the cervix has a strawberry appearance. Which one of the following is the most appropriate next step in management?

• A. Prescribe fluconazole 150 mg orally as a single dose
• B. Perform nucleic acid amplification testing for chlamydia and gonorrhea
• C. Prescribe metronidazole 500 mg orally twice daily for 7 days
• D. Perform a Pap smear
• E. Prescribe clindamycin cream 2% intravaginally for 7 days

Explanation

The correct answer is:

• C. Prescribe metronidazole 500 mg orally twice daily for 7 days

This patient's presentation is classic for trichomoniasis: malodorous discharge, vulvar itching, frothy yellow-green discharge, and strawberry cervix. The most appropriate next step is to treat for trichomoniasis with metronidazole.

A) Fluconazole is used to treat candidiasis, which typically presents with thick, white, cottage cheese-like discharge and doesn't cause a strawberry cervix.

B) While STI testing is important, especially given her risk factors, treating the likely trichomoniasis is the priority.

C) Correct. Metronidazole is the first-line treatment for trichomoniasis in Canada.

D) A Pap smear is not indicated for acute vaginal symptoms and would not diagnose or treat trichomoniasis.

E) Clindamycin cream is used to treat bacterial vaginosis, which typically presents with thin, grey discharge and a fishy odor.

Canadian Guidelines for Trichomoniasis Management

The Canadian Guidelines on Sexually Transmitted Infections recommend:

1. Metronidazole 500 mg orally twice daily for 7 days (preferred) or 2 g orally in a single dose
2. Treatment of all sexual partners from the 60 days prior to diagnosis
3. Abstinence from sexual activity until treatment is complete and partners have been treated
4. Consideration of HIV and syphilis testing due to increased risk of these infections in individuals with trichomoniasis

References

1. Public Health Agency of Canada. (2020). Canadian Guidelines on Sexually Transmitted Infections. Retrieved from https://www.canada.ca/en/public-health/services/infectious-diseases/sexual-health-sexually-transmitted-infections/canadian-guidelines.html (opens in a new tab)

2. Society of Obstetricians and Gynaecologists of Canada. (2015). Vulvovaginitis: Screening and Management of Vulvovaginal Complaints. Journal of Obstetrics and Gynaecology Canada, 37(11), 999-1010.

3. Sobel, J. D. (2015). Recurrent vulvovaginal candidiasis. American Journal of Obstetrics and Gynecology, 213(1), 15-21.

4. Workowski, K. A., & Bolan, G. A. (2015). Sexually transmitted diseases treatment guidelines, 2015. MMWR Recommendations and Reports, 64(RR-03), 1-137.

5. Sherrard, J., Donders, G., White, D., & Jensen, J. S. (2011). European (IUSTI/WHO) guideline on the management of vaginal discharge, 2011. International Journal of STD & AIDS, 22(8), 421-429.