What are the diagnostic criteria and treatment options for Polycystic Ovary Syndrome (PCOS)?

Diagnosing Polycystic Ovary Syndrome (PCOS)

Diagnose PCOS when at least two of three Rotterdam criteria are present: oligo-anovulation, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology on ultrasound, after excluding mimicking disorders. 1, 2, 3

Clinical History Assessment

Document these specific elements to establish diagnostic criteria:

• Menstrual pattern: Cycle length >35 days indicates chronic anovulation; cycles 32-35 days require further ovulatory assessment 1, 2
• Hyperandrogenism onset: Gradual development intensifying with weight gain suggests PCOS, whereas rapid onset with severe symptoms raises concern for androgen-secreting tumors 1, 2
• Medication review: Identify exogenous androgen use that could mimic PCOS 1
• Family history: Document cardiovascular disease and diabetes, as PCOS has strong genetic inheritance 1, 4
• Lifestyle factors: Assess diet, exercise, alcohol use, and smoking 1

Physical Examination Findings

Look for these specific signs:

• Hyperandrogenism markers: Acne, hirsutism (gradual onset), androgenic alopecia (vertex/crown/diffuse pattern, or bitemporal with frontal hairline loss in severe cases), clitoromegaly 1, 2
• Insulin resistance indicators: Acanthosis nigricans on neck, axillae, or groin 5
• Body habitus: Calculate BMI and waist-hip ratio to assess central obesity 1, 5
• Exclude Cushing's syndrome: Check for buffalo hump, moon facies, hypertension, and abdominal striae 1

Biochemical Testing

Total testosterone measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the preferred initial test, offering 74% sensitivity and 86% specificity. 1 This method provides superior specificity (92% vs 78%) compared to immunoassays 1.

Androgen Assessment Hierarchy:

1. Calculated free testosterone (cFT): Highest sensitivity at 89% with 83% specificity; calculate using Vermeulen equation from high-quality total testosterone and SHBG measurements 1
2. Free androgen index (FAI): 78% sensitivity and 85% specificity, but avoid when SHBG <30 nmol/L 1
3. Androstenedione: 75% sensitivity and 71% specificity; useful when SHBG is low 1
4. DHEAS: 75% sensitivity and 67% specificity; most reliable for adrenal androgen production, particularly valuable in women <30 years 1

Additional Laboratory Tests:

• 17-hydroxyprogesterone: Screen for non-classic congenital adrenal hyperplasia 1, 2, 6
• TSH and prolactin: Exclude thyroid disease and prolactin disorders 1

Ultrasound Criteria

Use transvaginal ultrasound with ≥8 MHz transducer frequency in adults (≥18 years) to assess polycystic ovarian morphology. 1

Diagnostic Thresholds:

• Follicle number per ovary (FNPO) ≥20 follicles: Gold standard marker with 87.64% sensitivity and 93.74% specificity 7, 1
• Ovarian volume >10 mL: Alternative when accurate follicle counting is impossible 7, 1
• Follicle number per single cross-section (FNPS): Secondary alternative marker 1

Critical Age-Specific Caveat:

Do not use ultrasound as a first-line diagnostic tool in adolescents (<20 years, at least 1 year post-menarche) due to poor specificity and high false-positive rates. 7, 1 In this population, rely on clinical and biochemical hyperandrogenism plus menstrual irregularity persisting 2-3 years beyond menarche 1, 2.

Metabolic Screening

Screen all women with PCOS regardless of BMI, as insulin resistance occurs independent of body weight:

• Glucose assessment: Fasting glucose followed by 2-hour glucose after 75-gram oral glucose load to detect type 2 diabetes and glucose intolerance 1, 5
• Lipid profile: Fasting total cholesterol, LDL, HDL, and triglycerides 5

Differential Diagnosis Exclusions

Rule out these conditions before confirming PCOS:

• Androgen-secreting tumors: Rapid onset, severe hyperandrogenism, often with clitoromegaly 1, 6
• Cushing's syndrome: Buffalo hump, moon facies, hypertension, abdominal striae 1
• Non-classic congenital adrenal hyperplasia: Elevated 17-hydroxyprogesterone 1, 6
• Thyroid disease and hyperprolactinemia: Check TSH and prolactin 1
• Primary hypothalamic amenorrhea and primary ovarian failure 1
• Acromegaly and genetic defects in insulin action 1

Diagnostic Algorithm Summary

1. Establish oligo-anovulation: Menstrual cycles >35 days or irregular cycles 2-3 years post-menarche in adolescents 1, 2
2. Confirm hyperandrogenism: Clinical signs (hirsutism, acne, alopecia) OR biochemical evidence via LC-MS/MS total testosterone or calculated free testosterone 1, 2
3. Document polycystic ovarian morphology (in adults only): FNPO ≥20 follicles or ovarian volume >10 mL on transvaginal ultrasound with ≥8 MHz transducer 7, 1
4. Exclude mimicking disorders: Check 17-hydroxyprogesterone, TSH, prolactin; assess for Cushing's syndrome and tumors clinically 1, 6
5. Perform metabolic screening: Glucose tolerance testing and lipid profile in all patients 1, 5

Common Diagnostic Pitfalls

• Adolescent overdiagnosis: Avoid ultrasound in girls <17 years; normal puberty includes irregular cycles and multicystic ovaries for 2-3 years post-menarche 7, 2
• Testosterone assay limitations: Standard immunoassays lack sensitivity in the female range; insist on LC-MS/MS methodology 1
• Missing acanthosis nigricans: This finding indicates insulin resistance and rarely may signal insulinoma or gastric adenocarcinoma 5
• Overlooking rapid-onset hyperandrogenism: This pattern suggests tumor rather than PCOS and requires urgent evaluation 1, 2
• Skipping metabolic screening in lean patients: Insulin resistance occurs independent of BMI in PCOS 5