Introduction

Erectile Dysfunction (ED) is defined as a persistent or recurrent inability to achieve and maintain a penile erection of sufficient rigidity to permit satisfactory sexual activity and adversely impacts physical and psychosocial domains. [1-4] Erectile function is dependent on coordinated and synchronous action of the nervous system, cardiovascular system, endocrine and reproductive system. [5] Erections are a neurohumoral vascular process involving the peripheral autonomic and central nervous systems acting upon the functional penile vascular system. [5,6] ED is reported to affect more than 300 million men worldwide with prevalence increasing with age. [6] Major risk factors for ED include diabetes, hypertension, smoking, chronic alcohol use, illicit substance abuse, dyslipidaemia, metabolic syndrome, multiple sclerosis, Parkinson’s disease, previous stroke, chronic renal failure, COPD, vascular endothelial dysfunction and obesity. [5,6] Medication is implicated in up to 25% of ED cases and these include statins, digoxin, antihypertensives, H2 receptor antagonists, anticholinergics, and psychiatric medication including antipsychotics and SSRIs [5-7].

Multiple comorbid conditions can contribute directly or indirectly to ED through their effects on the male sexual response cycle. [5] Psychiatric conditions and their treatment, surgery, trauma, radiation, cardiovascular disease, androgen deficiency, Peyronie’s disease and neurological factors can all contribute to ED. [2,3,5-7] Diabetes and metabolic syndrome are associated with an earlier age of onset of and more severe forms of ED. [2,5] The presence of ED itself serves as an important predictor marker of future cardiovascular risk with the risks of cardiovascular disease and death increasing steadily with the severity of ED [5].

Aim

This review paper provides an overview of the clinical assessment and evidence-based management strategies for these ED. A Medline literature search for English language papers based on the keyword “erectile dysfunction” was performed, and a narrative review was completed.

Discussion

Diagnostic Assessment

What Features of the History are Important?: Patient history remains an integral part of evaluating patients presenting with ED. Care needs to be taken to ensure sensitivity to patients’ unique sociocultural backgrounds while maintaining patient confidentiality and engaging in an open dialogue [2]. History taking should be undertaken to understand the dysfunction and its cause, differentiate between organic and psychogenic causes, assess the contribution of underlying medical comorbidities, and assess for modifiable contributory factors (Table 1). [4] A brief assessment of psychological factors should be included in the initial evaluation of patients presenting with ED [3,4].

Table 1: Clinical evaluation for erectile dysfunction.

What Physical Examinations Should be Performed?: General physical examination should be undertaken, including an assessment of the cardiovascular system, vascular competence and neurological integrity. [4] A careful assessment of secondary sex characteristics of genitalia, including penile examination for masses, plaques, angulation, phimosis, urethral opening, testicular size & consistency and prostate. [2,4] Care should be taken to maintain confidentiality, privacy and comfort [2].

What Investigations are Useful in Primary Care?: Initial blood tests include fasting glucose and lipid, and hormone profile. [4] Further investigations such as blood tests (thyroid function, prolactin and extensive hormone panels) and penile colour duplex ultrasonography can be undertaken by specialist to provide additional information [2].

What Management Options Exist?

Initial management involves psychosexual counselling and management of modifiable factors including smoking cessation, better diabetic control, weight loss and use of different medications [4].

Psychological Therapy: Psychosexual counselling is important given psychological factors affects sexual function and causes ED. [4] Psychosexual therapy in combination with pharmacological intervention results in greater improvement in ED compared to oral agents alone. [3,4] A variety of psychological interventions can be used, including individual or couple based therapy. [2] Therapy aims to minimise anxiety around performance, understand the couple’s sexual relationship and improve patient compliance with pharmacological intervention [2].

Oral Drugs: Phosphodiesterase inhibitor (PDE5i) drug forms first line pharmacological intervention and should be commenced by general practitioners (Table 2). PDE5i is contraindicated in patients on nitrates, and should be used cautiously in combination with anti-hypertensives due to the risk of orthostatic hypotension. [4] PDE5i are well tolerated, effective and safe when prescribed appropriately. [2,4] Restoring untreated hypogonadal patients to eugonadism can enhance PDE5i responsiveness [4].

Table 2: Available medical drugs for erectile dysfunction.

ICI Therapy: Intercavernosal Injection (ICI) of vasoactive substance such as alprostadil or papaverine and can be co-administered with PDE5i. [2] Patients should receive technical instruction and education about priapism. ICI therapy is often associated with low treatment compliance and high drop-out rates [2].

Vacuum Pump: Vacuum pumps provide passive engorgement of the penis through negative pressure, and a penile ring can be placed at base of penis to impede venous drainage and maintain penile erection. [4] Vacuum pumps are a relatively safe and effective treatment option, with reported success rates of up to 90%. [2,4] Common side effects include pain, petechiae, bruising, discoloration, painful or obstructed ejaculation [2,4].

Surgery- Penile Prosthesis: Patients may be considered candidates for penile prosthesis if they have failed or have contraindications to less invasive treatment options. [2,4] The inflatable penile prosthesis implant closely replicates a normal penile erectile function compares to the malleable penile prosthesis, and patients should be counselled that this surgery is irreversible and regarding potential surgical risks [2,4].

Regenerative Therapy: The idea of restoring spontaneous erection with regenerative therapy is interesting but lacks actual clinical translation due to absence of long-term data and safety. [8] Regenerative therapies such as low intensity shockwaves, and stem cell or platelet-rich plasma injections are not well regulated and should not be offered as standard of care [8].

Conclusion

ED is often multifactorial in nature and general practitioners should initiate medical therapy following careful evaluation for cardiovascular and metabolic risks. Referrals to a relevant specialist(s) should be undertaken if patients do not respond and/or require further interventions.

References

1. Mitchell KR, Mercer CH, Ploubidis GB, Jones KG, Datta J, et al. (2013) Sexual function in Britain: findings from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). Lancet 382: 1817-1829.
2. Montorsi F, Adaikan G, Becher E, Giuliano F, Khoury S, et al. (2010) Summary of the recommendations on sexual dysfunctions in men. J Sex Med 7: 3572-3588.
3. Brotto L, Atallah S, Johnson-Agbakwu C, Rosenbaum T, Abdo C, et al. (2016) Psychological and Interpersonal Dimensions of Sexual Function and Dysfunction. J Sex Med 13: 538-571.
4. Chung E, Lowy M, Gillman M, Love C, Katz D, et al. (2022) Urological Society of Australia and New Zealand (USANZ) and the Australasian Chapter of Sexual Health Medicine (AChSHM) for the Royal Australasian College of Physicians (RACP) clinical guidelines on the management of erectile dysfunction. Med J Aust 217: 318-324.
5. Chen L, Shi GR, Huang DD, Li Y, Ma CC, et al. (2019) Male sexual dysfunction: A review of literature on its pathological mechanisms, potential risk factors, and herbal drug intervention. Biomed Pharmacother 112: 108585.
6. Hatzimouratidis K (2007) Epidemiology of male sexual dysfunction. Am J Mens Health 1: 103-125.
7. Irfan M, Hussain NHN, Noor NM, Mohamed M, Sidi H, et al. (2020) Epidemiology of Male Sexual Dysfunction in Asian and European Regions: A Systematic Review. Am J Mens Health 14: 1557988320937200.

8. Eric C (2022) A review of regenerative therapies as penile rehabilitation in men following primary prostate cancer treatment: Evidence for erectile restoration and cavernous nerve regeneration. Asian J Urol 9: 287-293.