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Erectile dysfunction

The persistent inability to obtain or maintain an erection firm enough for satisfactory sexual performance.

Prevalence difficult to estimate – increases with age – about 10 – 20 % men in their 50s, > 40 % of men over 70

Risk factors:

“anything affecting vascular and endothelial function”

  • Age
  • Diabetes
  • IHD
  • Obesity
  • Hypertension
  • Depression and mental illness
  • Smoking
  • CKD
  • Medications related
  • Drug use
  • Pelvic surgery i.e. prostatectomy

Classification:

Psychogenic

  • Generally sudden onset, situational, with normal nocturnal erections, and associated with relationship problems or personal trauma.
  • Often principally related to performance anxiety and may be self-perpetuating.

    Organic

    • More progressive gradual loss of erectile function with gradual loss of rigidity, often with progressive loss of morning and nocturnal erections.

      Neurogenic

      • Anything affecting central or peripheral nerves may contribute to ED
        • Parkinson’s, CVA, TBI, dementia etc all associated
        • Reflex erection preserved in most men with upper spinal cord injuries, less (25 %) in lower cord lesions
        • Iatrogenic nerve damage (radical prostatectomy, pelvic surgery)
        • Pelvic fracture
        • Diabetes contributes to neuropathy
        • Age related decreases in sensitivity and tactile response

      Endocrine

      • Low testosterone levels principally associated with reduced libido – many men with low T have normal erections – but also many men with ED will have low T and have benefit in replacement
      • ADT will cause ED
      • Hyperprolactinaemia associated with ED, reduced libido, galactorrhoea, gynaecomastia and infertility
        • Increased PRL levels give -ve feedback to LH and FSH, with subsequent reduction in T
      • Hyperthyroidism also associated with ED

      Arteriogenic

      • Impaired penile blood flow due to generalised atherosclerosis
      • Associated with cardiac risk factors, smoking, diabetes, sedentarism, radiation and obesity
      • Focal stenosis of the common penile or cavernosal arteries as an isolated finding is rare and generally in patients with history of trauma
      • Arteriogenic ED may be a presenting symptom of early widespread atherosclerotic disease (penile vessels smaller calibre than larger vessels) and should prompt cardiac risk stratification and assessment

      Anatomic

      • Penile fracture may impair the tunical mechanism of subtunical and emissary vein compression
      • Inelasticity of the tunica in Peyronie’s may contribute to ED
      • Priapism can result in ED due to corporal fibrosis from the disease itself, or acquired from venous shunts

      Drug Induced

      • Almost all anti-hypertensives have ED as a possible side effect
        • Thiazide diuretics definitely
        • Beta blockers probably, alpha blockers likely OK
        • Calcium channel blockers ok for erections but can cause ejaculatory dysfunction
      • Anti-psychotics associated with high rates ED
      • Anti-epileptics
      • Anti-anxiolytics/benzodiazepines
      • ADT
      • 5a-reductase inhibitors
      • Smoking
      • Alcohol – probably beneficial in small doses, then harmful in large doses or prolonged use
      • Illicit drugs – THC, cocaine, heroin all linked to ED

      Majority of cases will be mixed – organic and psychogenic.

      Primary ED – lifelong inability to achieve or maintain adequate erections beginning with first sexual encounter or masturbation – rare – may be psychological trauma – but consider underlying organic causes (micropenis, hypogonadism, structural vascular anomalies).

      ED and diabetes

      • ED at least 3 times more common in diabetics (overall prevalence at least 30 % vs 10 %)
        • Reported prevalence may be up to 70 %
        • 95 % in men over 70 years with diabetes
      • Presents at an earlier age
      • Presentation with ED may be the presenting symptom for diabetes
      • Increasing frequency of ED with longer duration of DM, and with neuropathic and other end organ diabetic damage
      • Men with ED and diabetes have a 14 x greater risk of coronary artery disease and cardiac mortality
      • Numerous ways diabetes can contribute to ED:
        • Disruption of penile arterial circulation
        • Peripheral neuropathy of both cavernosal nerves and sensory somatic nerves
        • Impaired endothelial function, preventing smooth muscle relaxation
        • Reduced nitric oxide levels

      Assessment of man presenting with ED

      History (preferably with partner present)

      Assessment of ED

      • Ensuring ED is primary problem (cf. libido, ejaculatory dysfunction, anorgasmia, pain, other sexual dysfunction)
      • Presence of nocturnal erections
      • Ability to get erections for masturbation
      • Issue with initiation, sustaining or both
      • Duration of problem
      • Possible precipitants or contributing factors (situational, conflict etc)
      • Attempted treatments or previous therapies and investigations
      • History of trauma (physical or psychological)
      • Level of bother

      Medical and surgical history:

      • Relevant co-morbidities, particularly IHD, diabetes, hypertension, smoking, alcoholism, prostate cancer, neurological disease
      • Previous surgery especially urological or pelvic surgery, radiation
      • LUTS and treatment of same
      • Medications including offending agents, new agents
      • Other drug use

      Psychosexual history:

      • Relationship difficulties, financial difficulties, previous traumas
      • Anxiety, performance anxiety
      • Mental health, depression
      • Physical activity levels

      IIEF or SHIM scoring.

      Cardiovascular risk stratification.

      Examination

      • General assessment of habitus and androgenisation
      • Blood pressure
      • BMI
      • Gynaecomastia
      • Peripheral pulses if concerns of peripheral arterial disease
      • Genitals – penile size (stretched length), plaques, hypospadias, testis size
      • DRE

      Investigations

      • Full blood count
      • Renal function
      • HbA1c
      • Fasting lipids and glucose
      • Early morning testosterone +/- prolactin
      • PSA if appropriate
      • TFTs if appropriate

      If significant risk factors for cardiac disease identified – consider exercise stress test or referral to cardiologist.

      Validated questionnaires

      IIEF – 15 questions scoring 1 – 5 over 5 different domains (erectile function, orgasmic function, sexual desire, intercourse satisfaction and overall satisfaction).

      SHIM (IIEF-5) – 5 questions scoring 1 – 5:

      • Confidence in getting and keeping erection
      • How often are erections enough for penetration
      • How often were you able to maintain erection after penetration
      • How difficult was it to maintain erection to completion
      • How often is intercourse satisfactory

      Specialised investigations:

      Not necessary in the majority of men.

      EAU indications:

      • Primary ED
      • Young patients with history of trauma, who may benefit from revascularisation
      • Patients with penile deformities who may benefit from correction (Peyronie’s)
      • Complex psychiatric or psychosocial contributors
      • Complex endocrine disorders
      • Patient or partner request
      • Medico-legal reasons

      Duplex doppler ultrasound:

      • Must achieve satisfactory smooth muscle relaxation and good rigidity erection for accuracy – usually an intra-cavernosal agent given.
      • Peak systolic velocity (PSV) < 30 cm/sec suggests arteriogenic ED
      • End diastolic velocity (EDV) > 3 – 5 cm/sec suggests venous leak. Negative EDV suggests excellent smooth muscle relaxation.
      • Resistive index (RI) > 0.80 indicates normal veno-occlusive mechanisms.

      Nocturnal penile tumescence and rigidity (NPTR), Rigiscan device

      • Monitoring devices measuring number of erections, tumescence, maximal rigidity and duration of nocturnal erections
      • Should be done on 2 separate nights
      • Functional nocturnal erection defined as > 10 minutes with at least 60 % rigidity
      • Patients with psychogenic ED should have normal findings, although situational confounding factors may limit validity

      Dynamic infusion cavernosometry and cavernosography are described tools for diagnosing venous leak ED.

      • Cavernosography used in UK for patients with high EDV in 2 separate dopplers
      • 2 x cannula in each corpora – one for inflow of contrast fluid, one for measuring pressures
      • Flow needed to maintain erection documented
      • Imaging then delineates venous drainage – potential targets for ligation, but more likely probably just confirming failure of veno-occlusive mechanism

      Pudendal artery angiogram or arteriography can be considered if suspicious of arterial stenosis.

      Complex psychosexual specialist assessment probably most helpful referral.

      MRI pituitary if elevated prolactin.