How do I diagnose erectile dysfunction in an adult male who presents with difficulty achieving or maintaining an erection?

Diagnosing Erectile Dysfunction

Begin by proactively asking about sexual function using a validated questionnaire such as the Sexual Health Inventory for Men (SHIM) or Erection Hardness Score, then obtain a detailed sexual history documenting onset pattern, severity, presence of morning/nocturnal erections, and measure morning serum total testosterone in every patient. 1, 2

Essential History Components

Sexual History Details

• Document whether onset was sudden (suggests psychogenic cause) or gradual (suggests organic cause) 2, 3
• Ask specifically about the ability to achieve versus maintain erections, as difficulty achieving erections correlates more strongly with organic pathology, while difficulty maintaining erections is more often psychogenic 4
• Determine if morning or nocturnal erections are preserved—their presence strongly suggests a psychogenic component, though this is not definitive 1, 2
• Assess whether erections occur during masturbation or only fail in partnered contexts, as situational dysfunction points toward psychogenic etiology 1, 2
• Quantify severity and degree of bother to the patient 1

Medical and Medication History

• Review all current medications systematically, particularly antihypertensives (beta-blockers, diuretics, ACE inhibitors), antidepressants (tricyclics, SSRIs), antipsychotics, and sedatives, as these commonly cause ED 2, 5
• Screen for cardiovascular risk factors including diabetes, hypertension, dyslipidemia, smoking, obesity, and family history of vascular disease, because ED is an independent predictor of cardiovascular disease with prognostic strength comparable to smoking 1, 2
• Document prior pelvic or genital surgeries, radiation therapy, or trauma 2
• Assess for symptoms of hypogonadism including decreased libido, loss of morning erections, testicular atrophy, and muscle loss 2, 5

Psychosocial Assessment

• Screen for depression, anxiety, relationship conflict, and recent major life stressors, as psychological factors are primary or secondary contributors in many cases 1, 2
• Inquire about performance anxiety and feelings of attractiveness 1
• When possible, involve the sexual partner in the assessment, as this improves diagnostic accuracy and treatment adherence 1

Physical Examination

Vital Signs and Cardiovascular Assessment

• Measure blood pressure, pulse, waist circumference, and body mass index 1, 2
• Perform cardiac auscultation and assess for carotid bruits and diminished femoral/pedal pulses if cardiovascular disease is suspected 2

Genital Examination

• Inspect penile skin for lesions and assess urethral meatus placement 1
• Palpate the stretched penis from pubic bone to coronal sulcus to detect plaques or deformities suggestive of Peyronie's disease, though palpable plaques do not definitively confirm clinically significant disease 1
• Examine testicular size and consistency to assess for hypogonadism 2
• Look for gynecomastia when testosterone deficiency is suspected 2

Note: Digital rectal examination is not required for ED evaluation, though benign prostatic hyperplasia commonly coexists and may warrant separate assessment 1

Mandatory Laboratory Testing

Hormonal Evaluation

• Obtain morning (8–10 AM) serum total testosterone in every man presenting with ED—this is a moderate recommendation with Grade C evidence and must not be delayed 1, 2, 5
• Testosterone deficiency is defined as total testosterone <300 ng/dL with compatible symptoms 1, 2
• If testosterone is low, repeat the measurement to confirm before initiating therapy 5
• Measure prolactin only if the initial testosterone is low, as hyperprolactinemia can suppress testosterone production 5
• If both testosterone and prolactin are abnormal, obtain LH and FSH to distinguish primary from secondary hypogonadism 5

Metabolic and Cardiovascular Screening

• Order fasting glucose or HbA1c to screen for diabetes mellitus 2, 3, 6
• Obtain a fasting lipid panel (total cholesterol, LDL, HDL, triglycerides) to evaluate dyslipidemia and cardiovascular risk 2, 5, 6
• Consider basic electrolytes to detect endocrine or renal abnormalities that may affect sexual function 5

With the exception of glucose/HbA1c, testosterone, and lipids, no other routine laboratory studies are likely to alter ED management 1

When to Perform Specialized Testing

Specialized diagnostic procedures are reserved for select cases and are not part of routine evaluation 1:

• Nocturnal penile tumescence and rigidity testing may be considered when the distinction between organic and psychogenic ED remains unclear after initial evaluation 3
• Penile ultrasound with intracavernosal injection is indicated when vascular surgery is being considered or when the diagnosis remains uncertain 3
• Additional evaluation for Peyronie's disease (such as penile ultrasound) should be undertaken if plaque or deformity is suspected on examination 1

Cardiovascular Risk Counseling

Counsel every patient that ED is a risk marker for underlying cardiovascular disease and other health conditions that warrant evaluation and treatment—this is a clinical principle 1, 2. ED can precede coronary symptoms by 2–5 years and predicts future cardiac events with magnitude comparable to smoking or family history of myocardial infarction 2, 5.

Referral Indications

Refer to a urologist or sexual medicine specialist when 2:

• Young age with lifelong erectile difficulty
• History of pelvic or genital trauma
• Abnormal testicular or penile findings on examination
• Abnormal initial laboratory results requiring specialized interpretation
• Complex diagnostic testing is needed to guide treatment

Refer to a mental health professional when 1:

• Complex psychiatric disorders are present
• Performance anxiety persists despite initial interventions
• Relationship conflicts dominate the clinical picture
• Psychogenic ED is the primary diagnosis

Common Diagnostic Pitfalls

• Do not assume that preserved morning erections definitively confirm psychogenic ED—they suggest but do not prove a psychogenic component 1, 2
• Do not delay testosterone testing when loss of libido accompanies ED—the combination makes testosterone deficiency highly probable 5
• Do not overlook medication-induced ED—systematically review all drugs and consider alternatives with lower sexual side-effect profiles 2
• Do not evaluate ED without assessing cardiovascular risk—men with organic ED should be considered at increased cardiovascular disease risk until proven otherwise 2, 5
• Do not order LH, FSH, or TSH as first-line tests—reserve these for confirmed testosterone deficiency or specific clinical suspicion 5