Erectile Dysfunction: Causes and Treatment Options

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Erectile DysfunctionCauses and Treatment
Options

• Robert A. Zimmerman, MD, PhD
• Department of Urology

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Male Sexual Dysfunction

• Erectile Dysfunction (impotence)
• Priapism
• Premature Ejaculation
• Retarded Ejaculation
• Retrograde Ejaculation
• Loss of libido or desire to have sexual
  intercourse

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Definition of Erectile Dysfunction

• The inability to attain or maintain an erection
  adequate for vaginal penetration and sexual
  intercourse.
• Synonymous with the less appropriate term,
  impotence.

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Epidemiology

• 20 million Americans are most likely affected
• 1 in 10 men are affected by it.
• 50 of men gt then 40 have some degree of ED
• Uncommon in young men (except psychogenic)
• To some extent ED is a natural expression of
  aging
• Major Predictors/Risk Factors
• ? in age
• Vascular CAD, MI, HTN, PVD, ? LDL, Smoking
• Metabolic DM, RF, thyroid, EtOH, Liver dz,
  hormone
• NeurologicMS, PD, SC injury, Iatrogenic, CVA,
  MSA
• Psychologic Depression
• Other Peyronies disease AIDS

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Anatomy and Physiology ofErectile Function
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Erectile Bodies

• Filled with lacunar spaces (sinusoids) lined by
  vascular endothelium that are separated by walls
  of smooth muscle and collagen.
• Surrounded by a thick fibrous sheath, Tunica
  Albuginea (TA).
• 3 erectile bodies
• Paired corpora cavernosa fused distally for 3/4
  length, separate proximally where they are called
  crura and fused to the ischium. The erectile
  bodies primarily responsible for erection
• Corpus spongiosum lying ventrally in groove
  formed by cavernosa. It surrounds the urethra.
  Proximally forms the bulb and distally forms the
  glans.

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Arterial Blood Supply of Penis

• Derived principally from arteries which originate
  from the Internal Iliac artery.
• Immediate blood supply from the perineal artery,
  a terminal branch of the pudendal artery, which
  divides into the deep cavernosal artery and the
  dorsal artery of the penis.
• The cavernosal artery while traveling in the
  center of the cavernosa gives off helicine
  branches which supply the lacunar spaces
  (sinusoids).

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Venous System of Penis

• Superficial system
• Consists of superficial dorsal vein which drains
  the subcutaneous tissue to internal saphenous
  vein.
• Intermediate System
• It lies beneath Bucks fascia and consists of the
  deep dorsal vein, multiple circumflex veins, and
  multiple emissary veins (subtunical veins) which
  drain blood from the lacunar spaces of the
  erectile bodies. The deep dorsal vein lies in the
  dorsal cavernosal groove and empties into the
  periprostatic plexus at the urethoprostatic
  junction
• Deep System
• consists of crural bulbar veins which drain
  into internal pudendal vein

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Normal Penile Erectile Function

• 3 principle modes of operation
• Flaccid
• Tumescence
• Detumescence
• Penile tumescence is a hemodynamic response to a
  combination of humoral, neurogenic, and local
  signals.
• Vasodilatory signaling coincides with reduced
  vasoconstrictor activity.
• Ultimately leads to arterial dilation, relaxation
  of sinusoids, and venous constriction.

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Hemodynamic Control Mechanisms

• Relaxation of caveronsal SM via ? cellular Ca
  by
• Activation of guanylate cyclase via nitric oxide
  (NO)
• Activation of adenylate cyclase via PGE1 and VIP
• Activation of potassium/channel ATPase via NO
  which inhibits the opening of voltage-dependent
  Ca channels
• Contraction of caveronsal SM via ? cellular Ca
  by
• Guanidine neucleotide binding protein via NE
• IP3 DAG pathways via Norepinepherine (NE)
• Compression of subtunical and emissary venous
  plexus against the tunica albuginea

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Phases of Erection Process

• Flaccid Phase (1)
• Minimal arterial and venous flow and flow to
  lacunar
• Latent (filling) phase (2)
• ?systolic and diastolic flow in internal
  pudendal artery
• Tumescent phase (3)
• Lacunar pressure ?. Diastolic flow stops.
  Arterial flow ?
• Full erection phase (4)
• Pres. ? systolic, Art. flow? ?, Venous channel
  compresse
• Skeletal or rigid erection phase (5)
• Almost no arterial or venous flow to ctx of
  ischio muscle
• Detumescent phase (6)
• Symp. discharge, venous channel reopen, artery
  and sinusoid contract with decrease arterial
  blood flow

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Neuroanatomy

• Sacral parasympathetic system (S2 -S4)
• Pelvic splanchnic in the pelvic plexus
• Efferent and afferent supply to the vessels and
  erectile bodies
• Thoracolumbar or Sympathetic system (T11-L2)
• Superior hypogastric and pelvic plexus
• Efferent and afferent supply to the prostate,
  bladder neck, and vessels erectile bodies.
• Sacral somatic outflow (S2-S4)
• Pudendal nerve (perineal branch and dorsal nerve)
• Efferent afferent to the ischio bulbocavernosus
  muscles
• Neurotransmitters
• Acetycholine, Nitric Oxide (NO), VIP,
  Norepinephrine,

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Neurologic Control of Erections

• Cavernosal SM relaxation contraction under
• Neurogenic controladrenergic/cholinergic NANC
  (NO
• Endothelial control NO, Prostaglandin,
  Endothelin 1
• Coordinated by different neurologic centers
• Supraspinal erection centers
• medial preoptic and paraventricular areas of
  hypothalamus
• periaqueductal gray of midbrain
• nucleus paragigantocelluaris of medulla
• Autonomic/Spinal erection centers
• intermediolateral nuclei at S2-S4 T12 - L2

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3 Types of Erections

• Genital stimulated (contact or reflexogenic)
• Central stimulated (noncontact or psychogenic)
• Central originated (nocturnal)

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Pathophysiology of ED

• Vasculogenic Causes
• Arterial Insufficiency (PVD 2? to risk factors,
  Meds)
• Intracavernosal SM fibrosis (2? to O2 ?)
• Venous leakage (2? to ? elasticity of TA,
  corporal fibrosis, and ? veins)
• Neurogenic Causes
• Central (CVA, PD, MS, Trauma)
• Peripheral (Diabetic Neuropathy, Iatrogenic, Disc
  dz)
• Psychogenic (Performance anxiety, Depression,
  OCD)
• Endocrine Causes (? Testosterone, ?? Prolactin)
• Most common etilogogies are DM and PVD

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History and Physical

• Patient needs to understand the difference
  between ED, libido, and ejaculatory disturbance.

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History

• Age
• Inability to attain or maintain erection
• Duration, progressiveness Completeness of ED
• Nocturnal Erection erection with masturbation
• Painful erection Past treatment for ED
• Medication, Smoking, EtOH, Drugs
• Chronic Dz
• DM HTN, CAD, PVD, RF, Neurologic dz, Trauma,
  Endocrine
• Claudication, Voiding complaints, Bowel function
• Surgeries
• Stress, Fear, Anxiety, Depression, Desire

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Drugs Associated With Erectile Dysfunction
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Physical Exam

• General
• Neck (thyroid, carotid Bruits)
• Chest (Heart, and surgical scars)
• Abdominal (Girth, Masses, Bruits, Surgical Scars)
• Extremity (Pulses, Skin changes)
• Neurologic (Sensation, strength, reflexes)
• GU (plaques, testicle size and tenderness)
• DRE (prostate smoothness, size, tenderness)
• Bulbocavernosus Reflex
• Dermatologic (hair distribution)

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Evaluation

• Laboratory -- All patients
• UA, CBC, testosterone, SHBG, prolactin, HgbA1c,
  Cholesterol, PSA, LFTs, Cr, electrolytes,
• Empirical Therapy with Viagra
• Diagnostic intracorporeal injection
• CDDU with Intracavernosal injection
• Penile Blood Pressure Monitoring
• Dynamic infusion cavernosometry and
  caveronsography
• Nocturnal Penile Tumescence Test (NPT)
• Pudendal Arteriogram

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Nocturnal Tumescence Tests
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Treatment of Erectile Dysfunction
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Conservative Treatment

• Increase exercise
• Quit smoking
• Quit alcohol
• Healthy diet
• Adequate sleep

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Psychosexual Counseling

• Aims of Treatment established by Masters and
  Johnson in 1970
• Understand the problem
• Establish relearning of sexual behavior
• Remove anxiety
• Teach communication skills
• Redefine success
• Teach permission giving

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Medical Therapies

• Attempt should be made to discontinue medications
  that can contribute to ED.

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Vasculogenic Treatment

• Oral
• Sildenafil (Viagra) PDE5 Inhibitor
• Phentolamine (Vasomax) alpha 1-adrenoreceptor
  antag.
• Doxazosin alpha 1- adrenoreceptor antag.
• Yohimbine alpha 2- adrenoreceptor antag.
• Tazodone Serotonin agonist and sympatholytic
  agent
• Intracavernosal Injection
• Papaverine PDE inhibitor
• Phentolamine alpha 1 adrenoreceptor antag.
• Prostaglandin E1 (PGE1)
• Intraurethral/(MUSE)
• PGE1

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Tx for Psychogenic and ? Libido

• Testosterone replacement (patch,Injection,SL,
  oral)
• Yohimbine alpha 2- adrenoreceptor antag
• Trazodone Serotonin agonist and sympatholytic
  agent
• Sildenafil
• Dopamanergic agonists or precursors
• Transbuccal apomorphine
• Deprynl
• L-dopa
• Sinemet
• Bromocriptine
• Antidepressants as treatment for depression

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Vacuum Devices
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Surgical Therapies

• Implantation of penile prostheses
• Semi-rigid single piece (by AMS Mentor)
• One component inflatable (by Dynaflex)
• Two component inflatable (by AMS Mentor)
• Three component inflatable (by AMS Mentor)
• Correction of venous leakage
• Arterial revascularization
• Correction of Peyronies Disease
• Correction of pituitary adenoma/prolactinoma
• Renal transplant

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One Piece Semi-rigid
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Three Piece Inflatable
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Refer to a Urologist for ED

• Patients fail empirical treatment with Viagra

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