Erectile dysfunction

Erectile dysfunction (ED) is the persistent or recurrent inability to acquire or maintain an erection of sufficient rigidity or duration for sexual performance. Causative factors are vascular, neurological, endocrinologic, and/or psychological. ED may also be related to certain medications or substance use. ED is the most common form of sexual dysfunction in men and its prevalence increases with age. Diagnosis is primarily clinical; diagnostic testing focuses on identifying the underlying cause, which can involve blood tests and, sometimes, specialized tests. ED is an early indicator and marker of atherosclerotic cardiovascular disease. Symptomatic treatment options include oral phosphodiesterase-5 inhibitors (e.g., sildenafil), local application of vasodilators (e.g., alprostadil), vacuum-assisted erectile devices, and penile prosthesis.

• Erectile dysfunction: a condition characterized by a persistent or recurrent inability to acquire or maintain an erection of sufficient rigidity or duration for sexual performance
• Erectile disorder: a psychiatric diagnosis that is made if erectile dysfunction persists for ≥ 6 months, is not caused by substance use, medications, or another medical or mental condition, and causes clinically severe distress ^[1]

• The most common form of sexual dysfunction in men
• Affects 10–25% of men
• Becomes more common with age

Epidemiological data refers to the US, unless otherwise specified.

The following conditions and risk factors can cause and/or contribute to ED.

Vascular

• Atherosclerotic cardiovascular disease (ASCVD), e.g., Leriche syndrome
• ASCVD risk factors, e.g.:
  • Smoking
  • Hyperlipidemia
  • Diabetes mellitus
  • Arterial hypertension

Neurological

• Stroke
• Brain or spinal cord injury
• Dementia
• Parkinson disease
• Multiple sclerosis
• Pelvic fracture or surgery (e.g., radical prostatectomy)

Endocrinologic

• Hypogonadism
• Hyperprolactinemia
• Thyroid disorders

Urological

• Peyronie disease
• Urethral injury
• Penile fracture

Psychological

• Performance-related anxiety
• Stressors, e.g.:
  • Relationship issues
  • Traumatic experiences
  • Social pressures, e.g., religious taboos
  • Major life changes, e.g., birth of a child, losing a job
• Psychiatric disorders, e.g.:
  • Major depressive disorder
  • PTSD
  • Generalized anxiety disorder

Medication ^[2]

• Dopamine antagonists (e.g., antipsychotics): may cause hypogonadotropic hypogonadism
• Antidepressants (e.g., SSRIs)
• Antihypertensives; (e.g., beta blockers, thiazide diuretics)

Substance use

• Heavy alcohol use
• Recreational drug use

PENIS: The most common causes of erectile dysfunction are Psychological, Endocrinologic, Neurological, Insufficient blood flow, Substance use.

• Persistent or recurrent inability to acquire or maintain an erection of sufficient rigidity or duration for sexual performance
  • Can be generalized or situation-specific (e.g., with a specific partner)
  • Onset can be sudden, which is typical for psychological causes (e.g., performance anxiety with a new partner), or gradual and progressive (e.g., in patients with vascular or other organic causes). ^[3]
• Associated signs (depending on the underlying etiology)
  • Signs of hypogonadism (e.g., small testes, loss of secondary sexual characteristics)
  • Signs of cardiovascular disease (e.g., abnormal peripheral pulses, blood pressure)
  • Signs of a neurological cause (e.g., abnormal cremasteric reflex, anal tone; , and/or lower extremity sensation)
  • Skin lesions, plaques, deformities

Erectile dysfunction is primarily a clinical diagnosis. Diagnostic tests are mainly used to identify causes, risk factors, and associated diseases.

Clinical evaluation ^[4]

• Obtain a thorough patient history and perform a targeted physical examination, including:
  • Onset and severity of symptoms
  • Specifics on occurrence: e.g., erections during the night, masturbation, or with a specific partner
  • Symptoms or history of potential causes of ED
  • Targeted physical examination: vital signs, BMI, and genital examination
• Consider validated questionnaires to assess severity and support management decisions, e.g.:
  • International index of erectile dysfunction (IIEF) ^[5]
  • Sexual health inventory for men (SHIM) ^[6]
• Evaluate all patients for ASCVD, including family history.

Sudden onset, situational variability, and nocturnal erections generally indicate a psychogenic etiology. ^[3]

ED can be an early indicator of ASCVD.

Laboratory studies ^[2][4]

• All patients
  • Morning serum total testosterone to screen for hypogonadism
    • < 300 ng/dL indicates testosterone deficiency; repeat testing is necessary for confirmation. ^[2][4]
    • If confirmed, consider further studies to differentiate between primary and secondary hypogonadism, e.g., prolactin, SHBG, LH, FSH. ^[2]
  • Serum glucose and/or HbA1c to screen for diabetes mellitus
  • Lipid panel to screen for lipid disorders
• Patients with symptoms of hypothyroidism: TSH to screen for thyroid disorders

Additional testing ^[2][3][4]

In consultation with urology, consider the following tests for certain patients to support management decisions.

• Nocturnal penile tumescence measurement
  • Measures the number, rigidity, tumescence, and duration of erections during sleep (typically performed in a sleep laboratory)
  • Used to differentiate psychogenic from organic erectile dysfunction
  • Findings
    • The absence of nocturnal erections may suggest an organic etiology (e.g., neurological or vascular).
    • Normal findings suggests a psychogenic cause that warrants further psychiatric workup.
• Vascular imaging and functional tests, e.g.:
  • Penile duplex ultrasound to assess for vascular issues
  • Cavernosometry and/or angiography to evaluate vascular reconstructive treatment options

General principles ^[4]

• Encourage lifestyle modifications (e.g., increased physical activity, healthy diet) in patients with comorbidities that may worsen ED (see also “Primary prevention of ASCVD”).
• Treat the underlying cause, e.g.:
  • Low serum testosterone (e.g., in hypogonadism): testosterone replacement
  • Psychological factors: psychotherapy, education, exercise, and/or couples counseling
  • Erectile disorder: see “Psychosexual dysfunction.”
• Counsel patients on symptomatic treatment options.
• Consider referral to psychotherapy or counseling for all patients to improve adherence to therapy.

Symptomatic treatment is still necessary to achieve a satisfactory erection, even if the underlying cause is being treated.

Symptomatic treatment of erectile dysfunction ^[4]

Phosphodiesterase-5 inhibitors; or a vacuum-assisted erectile device are often considered first-line choices.

Oral phosphodiesterase-5 inhibitors

• Agents: sildenafil , tadalafil , vardenafil, avanafil
• Arousal is still necessary to achieve an erection.
• Contraindicated in patients taking nitrates due to the high risk of severe hypotension
• May cause orthostatic hypotension in patients taking alpha blockers (e.g., for BPH) and should, therefore, be taken at least 4 hours apart

Vacuum-assisted erectile device

• An external hollow cylinder is placed on the penis and creates a vacuum to increase blood flow into the corpora cavernosa.
• Once the erection is sufficient, a penis ring is placed around the shaft to obstruct outflow.

Local pharmacotherapy

• Intracavernous injection
  • Injection of vasodilators into the corpus cavernosum
  • Options: alprostadil monotherapy or in combination, e.g., with papaverine (off-label)
• Intraurethral alprostadil: direct administration into the urethra using a catheter

Penile prosthesis

• Used as a last resort when other treatments have failed
• Inflatable cylinders are surgically implanted into the corpora cavernosa, and a saline reservoir and pump into the scrotum.