Erectile Dysfunction

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Introduction

Erectile Dysfunction, or ED, is the consistent or recurrent inability to attain/maintain penile erection, sufficient for sexual performance, lasting at least three months.

 

Approximately 20% of men over 40 are affected, while over half of men over 70% have ED. It is the most common sexual problem in men, and can cause significant emotional distress and impact on relationships.

 

 

 

The Case of...

a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.

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Causes and Risk Factors

Causes of ED include:

medications

 

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Pathophysiology

Vascular is the most common cause.

Arterial:

Venous: inadequate smooth muscle relaxation.

Cavernosal arteries bring blood in.

 

Neurogenic

Sympathetic: alpha adrenoreceptors in penis cause constriction.

cholinergic: muscarinic receptors

NANC: release NO and stimulate cGMP: nonadrenergic, noncholinergic

symp: NE released for detumescence

somatosensory : AD and c fibres, doesal nerve, pudendal nerve, thalalmus, sensory

somatomotor:

 

Iatrogenic

Psychogenic

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Signs and Symptoms

  • history
  • physical exam

History

Introduce the topic directly: "Are you having any problems with your erections?"

 

Time course: last satisfactory erection, onset, attempts at sexual activity

Quantity

  • presence of morning erections (suggests anatomy is satisfactory)
  • stiffness (1-10)
  • ability to initiate or maintain an erection

Quality

  • partner or situation-specific?
  • loss of erection before penetration or climax
  • degree of concentration required
  • percentage of satisfactory sexual attempts
  • impact on quality of life and relationship

Sexual history

  • partners
  • orientation
  • practicies

 

Specific causes

  • testosterone deficiency:, decreased libido, hair loss, muscle wasting, testicular atrophy
  • hypothalamic/pituitary dysfunction: headaches, visual changes, galactorrhea, thyroid symptoms

Past medical history

  • diabetes
  • neurological disorders
  • hypertension
  • coronary artery disease
  • peripheral vascular disease
  • dyslipidemia
  • pelvic trauma or surgery
  • spinal injury
  • priapism
  • Peyrone's disease
  • prostatitis
  • prostatectomy

Medications

 

Social history

  • partner
  • stress
  • smoking
  • alcohol
  • drug use (especially cocaine or amphetamines)

Physical Exam

Assess possible testicular atrophy

digital rectal exam for prostate

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Investigations

  • lab investigations
  • diagnostic imaging

Lab Investigations

Evaluate risk factors:

  • fasting glucose, HbA1c
  • lipids
  • TSH
  • CBC
  • urinalysis

 

Evaluate hypothalamic-pituitary-gonadal axis: testosterone (free + total), prolactin, LH

  • take in morning due to diurnal variation
  • add LH/prolactin only if low serum testosternone

 

Diagnostic Imaging

Vascular diagnostics, such as Dopler or angiography, can be carried out, but are almost never indicated.

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Differential Diagnosis

While it has varying causes, it is difficult to confuse ED itself with other conditions.

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Treatments

 

Lifestyle changes

Reducing alcohol and smoking, while increasing exercise, can be of benefit.

Relationship/sexual counseling can help psychogenic ED.

 

 

Medications

PDE5 inhibitors: very expensive (13$ each); try samples and try 6-8 times.

Phosphodiesterase type 5 inhibitors:

sildenafil (Viagra) - take 0.5-4hr before intercourse; can last up to 24h

tadalafil (Cialis) - can last up to 36 hours

vardenafil (Levitra) - take 1 hour prior

Absolute contraindication: nitro spray

Relative contraindications: active CAD, CHF, hypotension, multiple BP medications

 

alpha adrenergic blockers, ie yohimbe

serotonin antagonist and reultake inhibitor, ie trazodone

 

Testosterone supplementation

Transdermal, oral, or IM.

Significantly more likely to respond to PDE5 inhibition when testosterone has been replaced. Risk of erythrocytosis, elevated transaminases, and prostate cancer.

Must monitor LFTs, PSA, and prostate examination.

When closely monotired, testosterone replacement is considered safe in treated prostate cancer with no detectable PSA.

 

Prostaglandin (PGE1) therapy

60-80% of patients achieve erection sufficient for intercourse

Does not require sexual stimulation

Initial injection administered under medical supervision, which allows for proper technique and dose titration.

Main risk includes penile pain, priapism.

Contraindications include visual loss.

 

Vacuum erection device

Non-invasive, though high drop-out rate due to cumbersome; cold, blue penis, and

 

 

Penile prosthesis

Insertion of inflatable device. Risk of infection is low.

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Consequences and Course

 

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Resources and References

 

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Topic Development

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