Erectile dysfunction –a growing problem

Erection Physics

Sequence of events

Stimulus

Either cerebral cortex or tactile

Visual Auditory Imagined tactile

Penile artery relaxation due to

NO release in muscle cells

Passive engorgement of pudendal arteries

Corpus cavernosa ( 2 main tubes in penis) corpus spongiosum These engorge

Blood pressure strains on sheath Closes vein escape of blood

Blood and nerve function

Blood and nerve supply in perineal area:

Affected by injury (spinal cord) pressure plaque ( diabetes and CVD) medication ( also marijuana) smoking drugs (alcohol)

Other causes

Age ( nerve function, diabetes, proper NO function, testosterone deficiency)

Hypertension High estrogens Prostate cancer treatment ( surgery or

hormonal) Transmitter problems

Erectile Dysfunction (ED)

Definition Epidemiology Aetiology Clinical features

History Examination

Investigation Treatment

Definition

The consistent inability to obtain and maintain penile erection sufficient to complete satisfactory sexual performance

definitions

ED. Impotence Infertility

Basic Penis biology

3 types of cells in penile corpora cavernosa: Neuron cells release Nitric Oxide which

causes calcium ions to enter storage areas and decrease calcium levels in tissue

Then smooth muscles relax and endothelial cells flatten and block exodus of blood

Stimuli--hypothalamus autonomic nerves-- NO--penile muscle relaxationendothelial cells flatten on sides of sinusoids, block veins.

Other neurotransmitters, like norepinephrine Increase calcium which contracts muscle cells Testosterone and acetylcholine also influence

erection.

Summary: Messages via autonomic, cholinergic,

norepinephrine and “T” control Nitric Oxide levels- Calcium levels

Autonomic nerve fibersNOenzyme (Guanylyl cyclase) - converts cGTP into cGMP calcium storage sliding filament relaxation and sinusoids fill

treatments

Penile injections ( smooth muscle relaxants) Converts cGTP to cGMP Calcium levels relaxed sinusoids

Viagra and other ED meds. Inhibit cGMP degradation ( maintains erection)

Phosphodiesterase 5 is the chemical which degrades cGMP…ending the erection

Name a famous drug?

A phosphodiesterase type 5 inhibitor, often shortened to PDE5 inhibitor, is a drug used to block the degradative action of phosphodiesterase type 5 on cyclic GMP in the smooth muscle cells lining the blood vessels supplying the corpus cavernosum of the penis. These drugs are used in the treatment of erectile dysfunction, and were the first effective oral treatment available for the condition

Does Viagra need an intact apparatus?

Needs penile blood flow Intact nerves and sensory impulses NO production Sexual stimulation

Epidemiology

Estimated to affect 152m men worldwide Non-diabetic men 0.1-18.4% prevalence In a study of 541 diabetic males

35% in diabetic men 5.7% in 20-24 year olds 52.4% in 55-59 years olds

ED is a growing problem Massachusetts Male Aging Study estimate an

11% world increase by 2015

Aetiology

Vascular Neurological Endocrine Psychological Pharmacological Penile tissue abnormalities Others

Vascular

Arterial insufficiency Endothelial dysfunction (up to 95%) Discrete lesions

Venous leakage Failure of venule constriction

Neurological

Damage to autonomic nervous system Predominant parasympathetic damage

Endocrine

Hypogonadism Most commonly primary testosterone deficiency Secondary hypogonadism

Hypothyroidism Hyperprolactinaemia

Other causes of ED

Penile Balinitis Phymosis Penile finrosis Tumours Trauma

Pharmacoloical

PMH Glycaemic control Vascular/neurological disease Urological PSH and trauma

DH Anti-hypertensives Androgen antagonists Sedatives Drugs that cause hyperprolactinaemia

(phenolthiazides) Alcohol

Psychological assessment

Oral therapies

Phosphodiesterase V inhibitors Sildenafl (Viagra) 4hr Tadalafil (Cialis) 17hrs Vardenafil (Levita) 4 hrs

Side effects flushing, headache and GI disturbance

Contraindications - nitrates

Efficacy of PDE-V inhibitors

Hundreds of studies internauinally Improved erections and increased successful

episodes of sexual intercourse vs placebo (15 RCTs)

PDE V inhibitor prescribing

Following conditions DM PD, MS, polyiomyelitis Pinal cord injuries, spina bifida Radical prostatectomy

Vacuum devices Can improve erection Messy and user dependent Satisfaction varies 35-80%

Intracavernosal injections

Intracavernosal injections with prostaglandins Alprostadil (prostaglandin E1)

One large RCT found increased rate of satisfactory erections when alprostadil injected compared to placebo

Side effects – pain, priapism

Testosterone replacement

Improves erectile function and libido Preparations

Topical (testim gel) Im testosterone Long-acting depots

Penile implant

•Inflatable

•Malleable

Psychosexual counselling

Talking therapies for men and couples

Summary

ED Common Marker for other forms of neurovascular

complications in diabetes Psychologically damaging Treatable Treat associated hormonal deficiencies