Erectile Dysfunction 1: The Case of Mr. Bond's Ineffective Gadget
Mr. Bond gradually develops erectile dysfunction (ED) during the latter part of his government career. You are expected to direct the evaluation, education, and management of this patient.
LEARNING OBJECTIVES for The Case of Mr. Bond's Ineffective Gadget
Identify and name the major anatomic features of the penis required for erection
Describe the physiology of penile erection in a healthy patient
List and briefly describe the major etiologies of erectile dysfunction (ED)
List the important components of the history and physical examination of a patient with ED
List the treatment options for erectile dysfunction and describe the mechanisms by which these treatments work
Describe the indications, contra-indications and side-effects of phosphodiesterase inhibitors, such as sildenafil (Viagra)
Describe how to counsel a patient so that he uses phosphodiesterase inhibitors effectively
Describe when a patient with ED should be referred to a urologist
Mr. Bond's Visit to his Primary Care Physician - 1
Mr. Bond, a 62-year old British government employee, enters the office of his primary care physician after having been slightly grazed by several bullets the week before. After examining and cleaning the wounds, his doctor inquires about other aspects of his health. Mr. Bond states that his recovery from the coronary artery bypass grafting (CABG) surgery last year is now almost complete. He admits, though, that he is been unable to quit smoking one-to-two packs of cigarettes a day, which he greatly enjoys with his martinis that are shaken but not stirred each night. In addition, he mentions that it has become increasingly difficult for him to achieve a firm erection. Mr. Bond's past medical history is notable for uncountable traumatic injuries, sexually-transmitted diseases, and an inguinal hernia repair as a child. His physical exam is normal except for some tenderness of his prostate. What is the most likely etiology of Mr. Bond's erectile dysfunction? (Please select the single best answer.)
a. Neurologic b. Vascular c. Hormonal d. Traumatic e. Infectious f. Iatrogenic g. Psychogenic
Mr. Bond's Visit to his Primary Care Physician - 2
Mr. Bond looks a bit confused when the doctor explains to him that vascular disease may reduce his ability to have an erection. He raises a single eyebrow in his characteristic way and asks the doctor to brief him about the process by which an erection normally occurs. In layman's terms, the doctor states that the initial event in the development of an erection is: (please select the single best answer)
a. physical compression of the venous outflow channels against the tunica b. parasympathetic-mediated constriction of venous outflow channels c. constriction of the bulbocavernosus muscle via somatic innervation d. constriction of the bulbospongiosus muscle via sympathetic innervations e. nitric oxide-mediated relaxation of arterioles
Mr. Bond's Visit to his Primary Care Physician – 3
Mr. Bond loses interest halfway through the doctor's explanation and interrupts him, saying "what can we do now to get my equipment back in working order?" The doctor tells him that standard treatments for erectile dysfunction include: (Please select all answers that apply.)
a. vacuum constriction device b. prostaglandin E1 injections c. intra-urethral prostaglandin E1 administration d. surgical placement of penile prosthesis e. testosterone supplementation f. oral phosphodiesterase inhibitors, like sildenafil (Viagra)
Mr. Bond's Visit to his Primary Care Physician – 4
Mr. Bond has heard that both his colleagues "M" and "Q" have had excellent results from taking sildenafil (Viagra). Phosphodiesterase inhibitors like sildenafil (Viagra) work by: (Please choose the single best answer.)
a. potentiating neural signals to the penis b. enhancing vasodilation of penile arterioles c. stimulating central dopaminergic pathways d. facilitating constriction of corporal venous channels e. downregulating seratonin-signalling in the pelvic plexus
Mr. Bond's Visit to his Primary Care Physician – 5
Mr. Bond cannot wait to give the medication a test drive. As the doctor is writing the prescription, he questions whether Mr. Bond has any contra-indications for sildenafil (Viagra). Mr. Bond is 62-years old and underwent a CABG last year for significant three-vessel coronary artery disease. He is currently angina-free while fighting, chasing cars and gambling with the Queen's money. His past medical history also includes hypertension and hypercholesterolemia, and his current medications are simvastatin, atenolol, baby aspirin and Prozac. His blood pressure is checked in the office and is 130/65. How should his doctor proceed? (Please select the single best answer.)
a. Prescribe sildenafil (Viagra) b. Obtain a cardiology consult prior to prescribing Viagra c. Refer to a urologist d. Discontinue the simvastatin e. Check a blood cholesterol level
Mr. Bond's Referral to a Urologist – 1
Mr. Bond returns to his primary care physician in low spirits because therapy with an oral phosphodiesterase inhibitor was ineffective. Since Mr. Bond's erectile dysfunction is refractory to oral therapy, his doctor recommends that he see a urologist to discuss further treatment options. Mr. Bond agrees. The urologist "Dr. U," repeats a thorough history, highlighting potential risk factors for erectile dysfunction. What are the risk factors for ED? (please select all correct answers)
a. Smoking b. Diabetes mellitus c. Prolonged bicycle riding d. Perineal trauma e. Wearing "tighty whitey" underwear
Mr. Bond's New and Improved Gadget
The urologist "Dr. U" then performs a thorough physical examination of the penis, looking specifically for deformities or fibrosis in the corpora. No abnormalities were noted. "U" then injects Mr. Bond's penis with prostaglandin E1, and no erection was achieved. This injection directly relaxes the penile arterioles, and therefore, no neural input is needed to obtain an erection. Since Mr. Bond did not achieve an erection upon injection, he either suffers from an inflow problem (severe peripheral vascular disease) or an outflow problem (a leak in the veno-occlusive mechanism of the penis). Given his history of vascular disease, Mr. Bond most likely suffers from the former.
"U" then discusses with Mr. Bond that he would be a good candidate for surgical placement of a penile prosthesis. "U" shows him various models, and Mr. Bond eagerly decides to have surgery with the high-tech, top-of-the-line inflatable model. A small pump will be placed in his scrotum so that he can pump fluid into the inflatable tubes located in his corpora and speedily obtain a serviceable erection.
Two weeks later, the surgery is performed with no difficulties. Six weeks post-op, "U" instructs Mr. Bond how to "fire this thing up." The resulting erection meets the demanding standards to which Mr. Bond is accustomed.
LEARNING OBJECTIVES for The Case of Mr. Bond's Ineffective Gadget
Penile erection is achieved via two crucial steps: (1) parasympathetic-mediated relaxation of arterioles to the penis, and (2) mechanical compression of the venous outflow channels.
Common etiologies of ED are vascular, neurologic, iatrogenic, traumatic, and/or psychogenic in origin.
Risk factors for ED include smoking, diabetes, hypertension, hypercholesterolemia, prolonged bicycle riding, vascular disease, trauma to the penis/perineum, pelvic surgery and pelvic radiation.
Treatments for ED include oral phosphodiesterase inhibitors, vacuum constriction devices, prostaglandin E1 injections, intra-urethral administration of prostaglandin E1, and surgical placement of a penile prosthesis.
Phosphodiesterase inhibitors such as sildenafil (Viagra) are potentiators of neural signals, resulting in increased relaxation and dilation of penile arterioles.
Sildenafil (Viagra) has been shown to be effective across a broad range of etiologies of erectile dysfunction.
American Heart Association contra-indications to the use of sildenafil (Viagra) include use of nitrates, active cardiac disease, and/or hypertension which requires complex, multi-drug therapy.
All patients with erectile dysfunction should be given an empiric trial of sildenafil (Viagra), as long as they do not have any contra-indications for the drug.
Patients with ED refractory to therapy with oral phosphodiesterase inhibitors should be referred to a urologist for consideration of other therapies.