Sexual Dysfunctions and Disorders

Introduction to MCCQE1 Preparation

Sexual dysfunctions are characterized by a clinically significant disturbance in a person’s ability to respond sexually or to experience sexual pleasure. For the MCCQE1, candidates must demonstrate the ability to take a sensitive sexual history, identify organic versus psychogenic causes, and propose management plans aligned with Canadian Guidelines (e.g., CUA, SOGC).

Understanding the sexual response cycle (Desire, Arousal, Orgasm, Resolution) is fundamental to diagnosing these disorders.

Classification (DSM-5-TR)

The DSM-5-TR classifies sexual dysfunctions by gender and phase of the sexual response cycle. Symptoms must persist for approximately 6 months and cause clinically significant distress.

Etiology: The Biopsychosocial Model

For the MCCQE1, you must approach etiology using a biopsychosocial framework.

Clinical Assessment

History Taking

A thorough history is the cornerstone of diagnosis. Differentiate between Lifelong (Primary) vs. Acquired (Secondary) and Generalized vs. Situational.

Key Questions:

• “Are you currently sexually active?”
• “Do you have any concerns about your sexual function?”
• “Do you have morning erections?” (Presence suggests psychogenic etiology over organic).

The PLISSIT Model

This is a standard framework for sexual counseling often referenced in Canadian medical education.

Physical Examination & Investigations

• Physical: Genital exam (Phimosis, Peyronie’s plaques, Atrophy), DRE (Prostate), Cardiovascular assessment, Neurological reflexes (bulbocavernosus reflex).
• Labs:
  • Fasting Glucose / HbA1c (Diabetes)
  • Lipid Profile (Vascular risk)
  • Morning Total Testosterone (if hypogonadism suspected)
  • TSH, Prolactin (if indicated)

Specific Disorders and Management (Canadian Guidelines)

1. Erectile Dysfunction (ED)

Definition: Consistent inability to attain/maintain penile erection sufficient for sexual performance.

Canadian Urological Association (CUA) Guidelines:

1. Risk Stratification: Assess cardiac risk. Sexual activity is equivalent to walking 1 mile on flat ground in 20 mins.
2. First Line:
   • Lifestyle modifications (Weight loss, smoking cessation).
   • PDE5 Inhibitors (Sildenafil, Tadalafil, Vardenafil).
   • Contraindication: Nitrates (Risk of severe hypotension).
3. Second Line: Vacuum erection devices, Intraurethral alprostadil, Intracavernosal injections.
4. Third Line: Penile prosthesis.

2. Premature Ejaculation (PE)

Management:

• Behavioral: “Stop-Start” technique, “Squeeze” technique.
• Pharmacological (Off-label in Canada): SSRIs (Paroxetine, Sertraline) or TCAs (Clomipramine) taken daily or on-demand to utilize the side effect of delayed ejaculation.
• Topical: Anesthetic creams (Lidocaine/Prilocaine).

3. Female Sexual Interest/Arousal Disorder

Management (SOGC Guidelines):

• Psychotherapy: CBT, Mindfulness-based therapy.
• Hormonal: Systemic estrogen (if vasomotor symptoms present), Vaginal estrogen (for Genitourinary Syndrome of Menopause - GSM).
• Pharmacologic: Flibanserin (approved in Canada for premenopausal women, caution with alcohol).

4. Genito-Pelvic Pain/Penetration Disorder

Management:

• Education: Pelvic anatomy, pain cycle.
• Physical Therapy: Pelvic floor physiotherapy (Gold standard for vaginismus/high-tone pelvic floor).
• Desensitization: Vaginal dilators.
• Medical: Lubricants, moisturizers.

Pharmacotherapy Overview

Key Points to Remember for MCCQE1

• Substance Use: Chronic alcohol use is a major cause of ED and liver disease (leading to high estrogen).
• Antidepressants: If a patient develops sexual dysfunction on an SSRI, strategies include: waiting (tolerance), reducing dose, drug holidays (not for fluoxetine), or switching to Bupropion or Mirtazapine.
• Aging: While refractory period increases and erection rigidity may decrease with age, ED is NOT a normal part of aging. It warrants investigation.
• CVD Link: ED is considered an independent marker for cardiovascular disease. A man with ED has the same vascular risk profile as a man with coronary artery disease until proven otherwise.
• Consent: Always ensure questions regarding sexual history are asked in a private setting.

Sample Question

Clinical Scenario

A 58-year-old male presents to his family physician complaining of a 6-month history of difficulty maintaining an erection sufficient for intercourse. He has a history of stable angina, hypertension, and type 2 diabetes. His current medications include Metformin, Ramipril, Atorvastatin, and Nitroglycerin spray PRN. He requests a prescription for “the blue pill” (Sildenafil) that his friend uses. Physical examination reveals decreased sensation in the feet bilaterally but is otherwise unremarkable.

Question

Which one of the following is the most appropriate management regarding his request for phosphodiesterase type 5 (PDE5) inhibitors?

Options

• A. Prescribe Sildenafil 50mg to be taken 1 hour before sexual activity.
• B. Prescribe Tadalafil 10mg daily as it has a longer half-life.
• C. Advise that PDE5 inhibitors are contraindicated due to his use of Nitroglycerin.
• D. Order a serum testosterone level before prescribing Sildenafil.
• E. Switch his Ramipril to a Beta-blocker to improve erectile function.

Explanation

The correct answer is:

• C. Advise that PDE5 inhibitors are contraindicated due to his use of Nitroglycerin.

Detailed Explanation: The absolute contraindication for the use of PDE5 inhibitors (Sildenafil, Tadalafil, Vardenafil) is the concurrent use of organic nitrates (e.g., Nitroglycerin spray, Isosorbide mononitrate). Both drug classes cause vasodilation via the nitric oxide/cGMP pathway. Co-administration can lead to profound, life-threatening hypotension.

• Option A & B: Incorrect. Prescribing any PDE5 inhibitor is unsafe given his PRN nitrate use.
• Option D: While checking testosterone is part of the workup for ED, the immediate safety issue regarding his request takes precedence. Furthermore, he cannot take the medication regardless of the testosterone result.
• Option E: Incorrect. Beta-blockers are actually more likely to cause or worsen ED than ACE inhibitors (like Ramipril). ACE inhibitors generally have a neutral or beneficial effect on erectile function.

Canadian Guidelines

For further reading and MCCQE1 preparation, refer to these specific guidelines:

1. Canadian Urological Association (CUA): 2015 CUA Practice guidelines for erectile dysfunction.
2. Society of Obstetricians and Gynaecologists of Canada (SOGC): Clinical Practice Guidelines on Female Sexual Health.
3. Choosing Wisely Canada: Recommendations regarding testosterone testing (Don’t prescribe testosterone for ED unless biochemical evidence of testosterone deficiency exists).

References

1. American Psychiatric Association. (2022). Diagnostic and Statistical Manual of Mental Disorders (5th ed., text rev.).
2. Bella, A. J., et al. (2015). 2015 CUA Practice guidelines for erectile dysfunction. Canadian Urological Association Journal, 9(1-2), 23–29.
3. Medical Council of Canada. (n.d.). MCCQE Part I Clinical Decision-Making and Multiple-Choice Questions Objectives.
4. Brotto, L. A., et al. (2016). No. 235-SOGC Clinical Practice Guidelines on Female Sexual Health. Journal of Obstetrics and Gynaecology Canada.