Contents
Introduction
Erectile dysfunction is the inability to achieve or maintain an erection sufficient for satisfactory sexual performance. It affects up to 50% of men between 40 and 70.
Erection requires an intact parasympathetic reflex at S2 and S3.
Ejaculation requires an intact sympathetic L1 root.
Mnemonic: Erection & ejaculation = Point & Shoot (Para & Sym)
Aetiology
Organic causes
- Spinal cord or cauda equine disease
- Multiple sclerosis
- Endocrine disease
- DM
- Hypogonadism
- Hyperprolactinaemia
- Generalised vascular disease
- Trauma causing nerve or vascular disease
- E.g. after surgery for prostate ca
- Hypertension
- Drugs
- SSRIs
- Antihypertensives
- Antipsychotics
- Anticholingerics
- Androgen deficiency is a very rare cause – typically affecting middle aged men
Psychological causes
- Depression
- Relationship problems
- Sexual orientation uncertainties
- Primary psychogenic erectile dysfucntion
- Accounts for about 20% of cases
- Typically young men at the begging of their sexual experience
Age-related problems (>50) tend to follow a common vicious circle:
Epidemiology
- ED occurs in 52% of men aged 40-70:
- 17% have occasional ED
- 25% have moderate ED
- 10% have complete ED
History
- Sexual history
- Smoking history
- Hx of hypertension
- Hx of diabetes
- Hx of cardiovascular disease
- Hx of prostate disease or cancer
- Medications
- Ilici drug use
- Depression
Investigations
All patients should have a random plasma glucose or urinalysis for glucose to exclude diabetes. Further tests to consider include:
- FBC
- LFTs
- Fasting lipid profile
- Assessing for cardiovascular disease risk factors
- Fasting glucose (or HbA1c)
- U+Es (for renal function)
- Leutenising Hormone in the most useful hormonal test
- Testosterone, prolactin and hormone binding globulin may be considered as second line investigations
- TFTs
Treatment
Some general principles include:
- Smoking cessation
- Ensure underlying disorders are well controlled
- Hypertension
- Diabetes
- Cardiovascular disease
- Treating these is unlikely to reverse the course of erectile dysfunction alone but may prevent it from deteriorating further
Pharmaceutical treatments
Before starting pharmacotherapy – ensure sufficient cardiovascular fitness to engage in sexual activity.
First line
- Phosphodiesterase-5 inhibitors eg. Sildenafil citrate (Viagra), tadalafil, verdenafil
- +/- counselling as appropriate
- Ensure not taking nitrites (contra-indicated – may cause FATAL hypotension go straight to second line agents)
- e.g. Sildenafil 50mg orally – one hour before intercourse
- e.g. Tadalafil 10mg orally – PRN – effects may be present up to 24 hours after dose
- Both are maximum of one dose per 24 hours
- Sildenafil comes in 100mg tablets – it may be cost effective for patients to be prescribed this dose and then use half or even a quarter of a tablet PRN
- These agents do NOT cause erection without sexual arousal
- Possible side effects include: dizziness, headache, facial flushing, nasal congestion, disturbance in colour vision
- Side effects are dose related
Second line
- Intracavernosal injections of alprostadil
- Carry a risk of priapism and patients must be educated about how to manage this – including keeping pseudoephedrine at home in case of emergency use
- Other risks include – haemorrhage and bruising, cavernosal fibrosis and localised pain
- Teach patients to inject themselves
- Start with a low dose and titrate to effect – e.g. 2.5 mcg (Max dose 60 mcg)
- Give the lowest dose that achieves erection within 60 minutes
- Duration is dose dependent
- Vacuum erection device – may also be considered
Third line
- Intracavernosal combination – alprostadil, papaverine, phentolamine
Fourth line
- Surgery – penile implant
- If severe cardiovascular disease of the pudendal arteries exists then management of this may also be appropriate (e.g. with bypass graft – similar to CABG)
Other experimental treatments – such as shockwave therapy – are unproven (and likely ineffective – and expensive!)
Anxiety-induced ED (primary psychogenic erectile dysfunction) is treated using a therapeutic regimen based:
- Sexual history
- A period of abstention for several weeks
- Onset of therapy
References
- Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
- Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
- Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy