Differentials
| System |
What might it be? |
What might I find? |
| Endocrine |
Primary Hypogonadism |
Hypergonadotropic hypogonadism – testicular failure to produce testosterone.
Causes: testicular trauma, chemotherapy, Klinefelter syndrome (XXY), mumps. Sx of ↓testosterone e.g, Erectile dysfunction, ↓fertility, ↓libido, ↓muscle mass, ↓bone density, ↑body fat, depression. Bloods: ↓testosterone, ↑FSH/LH. |
|
Secondary Hypogonadism |
Hypogonadotropic hypogonadism – inadequate pituitary LH/FSH production.
Causes: pituitary tumour, radiotherapy, hyperprolactinaemia, anabolic steroids. Sx of ↓testosterone as above. Bloods: ↓testosterone, ↓FSH/LH. |
|
|
Age-related ↓testosterone |
Levels of testosterone naturally decline with increasing age.
May be referred to as the ‘andropause’. |
|
|
Thyroid disease |
↑/↓thyroidism can affect sexual function; mechanisms not fully understood.
Hyperthyroid: sweaty, palpitations, weight loss, insomnia, diarrhoea, fatigue. Hypothyroid: weight gain, dry skin, fatigue, constipation, menorrhagia, cold. |
|
| Cardiovascular |
Hypertension |
Reduction in blood flow to the penis secondary to a combination of endothelial dysfunction, vascular damage & atherosclerosis. Antihypertensive medications may also contribute (see below). |
|
Hyperlipidaemia |
Similar mechanism to hypertension (see above). | |
|
Diabetes |
Mechanism multifactorial: microvascular and macrovascular damage, neuropathy, psychological distress, hypogonadism and medication. | |
|
Obesity |
Obesity causes reduced testosterone levels due to ↑conversion of androgens to oestrogens by the enzyme aromatase found in adipose tissue. | |
| Neurological |
Central |
Example causes: Parkinson’s disease, cerebrovascular disease, stroke, MS. |
|
Peripheral |
Example causes: Diabetic neuropathy, alcohol excess, CKD, liver disease. | |
| Other |
Psychogenic |
Often causes sudden onset of erectile dysfunction, with low libido and normal spontaneous, morning and self-stimulated erections.
May be secondary to depression, anxiety, stress, major life change or external stressors, inter-personal issues with partner. Antidepressants may contribute. |
|
Urological |
Example causes: Peyronie’s disease, phimosis, prostate hypertrophy, prostate cancer, micropenis. | |
|
Pharmacological |
Culprit medications include: beta-blockers, verapamil, thiazide diuretics, spironolactone, SSRIs, venlafaxine, GnRH agonists, finasteride, corticosteroids, certain older antipsychotics and anti-epileptic drugs.
Recreational substances e.g., alcohol, cocaine, anabolic steroids and opiates. |
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|
Iatrogenic |
Structural damage after medical intervention e.g., Pelvic surgery, radical prost-atectomy, radiotherapy, chemotherapy, urethral surgery, TURP, prostate biopsy. |
Checklist
| Preparation | Wash – Name – Explain | |
| Presenting Complaint | Open question to establish reason for presentation | |
| Allow patient time to talk uninterrupted | ||
| History of Presenting Complaint | Onset | |
| Frequency | ||
| Associated symptoms | ||
| Exacerbating & relieving factors | ||
| Impact | ||
| System-specific | Libido | |
| Spontaneous or self-stimulated erections | ||
| Sexual function | ||
| Lower urinary tract symptoms (LUTS) | ||
| Pain | ||
| Anatomical abnormalities of penis or testes | ||
| Red Flags | Rule in/out serious disease | |
| Relevant Systems Review | Cardiovascular | |
| Endocrine | ||
| Psychological | ||
| ICE | What do you think is going on? | |
| Is there anything that is worrying you? | ||
| What were you hoping we would do today? | ||
| Past Medical History | Past medical history | |
| Past surgical history | ||
| Drug History | Prescribed medication | |
| Over-the-counter medication | ||
| Drug allergies | ||
| Social History | Smoking | |
| Alcohol | ||
| Recreational drugs | ||
| Work | ||
| Driving | ||
| Who is at home? | ||
| Sick contacts | ||
| Forgeign travel | ||
| Family History | Do any family members have any urological problems? | |
| Do any health conditions run in the family? | ||
| Comm. Skills | Establish rapport | |
| Use open and closed questions appropriately | ||
| Structured history taking | ||
| Pick up on cues | ||
| Rule in/out differential diagnoses | ||
| Summarise succinctly |
Explanation
“I have been asked to speak to you today about the difficulty you have noticed getting and maintaining an erection. I will ask you some questions to try to determine what might be causing the problem. Does that sound all right?”
History of Presenting Complaint
Key points in an erectile dysfunction history include:
- Onset – when did it start?
- Frequency – how often is it happening?
- Associated symptoms
- Exacerbating and relieving factors
- Impact – on the patient or their partner.
Sudden onset erectile dysfunction is more often associated with psychogenic causes. Ask about associated stress or traumatic events around the time that the symptoms started.
Insidious onset is more likely to have an organic cause (e.g., cardiovascular or endocrine disease).
Ask about frequency. Intermittent symptoms are more likely to be psychogenic, whereas persistent symptoms are more likely to be organic.
Does anything make the problem better or worse? Underlying hypogonadism can cause symptoms resistant to medication (e.g., PDE-5 inhibitors).
Has there been a negative impact on the patient’s self-confidence, relationships, or mood?
System-specific History
Urological symptoms to enquire about include, but are not limited to:
- Libido (low if psychogenic or endocrine, normal if vascular or neurological)
- Spontaneous or self-stimulated erections
- Sexual function (e.g., ejaculation, orgasm)
- Lower urinary tract symptoms (indicating possible prostatic hypertrophy or cancer)
- Painful erections (e.g., Peyronie’s disease or phimosis)
- Anatomical abnormalities of the penis or testicles
Spontaneous morning erections are commonly maintained if the problem is psychogenic, and lost when the underlying cause is organic.
Lower urinary tract symptoms (LUTS) often co-exist with erectile dysfunction, either as storage (frequency, urgency, nocturia) or voiding (hesitancy, poor flow, terminal dribbling) symptoms.
Deviation of the penis when erect indicates Peyronie’s disease. Micropenis or small testes may be indicative of underlying hypogonadism.
Red Flags
Red flag symptoms in an erectile dysfunction history include:
- Unintentional weight loss
- Severe back pain
- Cauda equina syndrome
Malignancy (e.g., prostate cancer) may present with erectile dysfunction associated with unintentional weight loss or back pain (especially severe, unrelenting pain that wakes the patient from sleep).
History concerning for cauda equina syndrome includes back or sciatic pain associated with sudden-onset sexual dysfunction, with or without bladder or bowel dysfunction and saddle anaesthesia.
Relevant Systems Review
Relevant systems to review when taking a history of erectile dysfunction include the following:
- Cardiovascular
- Endocrine
- Psychological
Cardiovascular disease is a significant risk factor for erectile dysfunction. Ask about cardiovascular risk factors (e.g., obesity, sedentary lifestyle, smoking, poor diet, family history, etc.).
Ask about vascular or ischaemic symptoms (e.g., intermittent claudication or angina).
Underlying endocrine causes may present with symptoms of thyroid disorders (e.g., goitre, temperature intolerance, fatigue, tremor), or hypogonadism (e.g., sub-fertility, low libido, low muscle mass).
Psychogenic erectile dysfunction is very common. Ask about low mood and anxiety, as well as external stressors (e.g., financial, relationship, social, or employment difficulties).
Ideas, Concerns & Expectations (ICE)
Does the patient or their partner have any thoughts as to what might be causing their erectile dysfunction?
Is the patient worried about their symptoms (e.g., the impact on their relationship with their partner going forward)?
What does the patient want out of the consultation (e.g., a blood test, medication)?
Past Medical History
Pre-existing medical conditions that may be associated with erectile dysfunction include:
- Cardiovascular disease (e.g., hypercholesterolaemia or hypertension)
- Diabetes
- Obesity (causes reduced testosterone via aromatase conversion to oestrogen)
- Klinefelter syndrome (chromosomal abnormality XXY)
- Neurological disease (e.g., MS or Parkinson’s disease)
- Iatrogenic causes (e.g., prostatectomy, TURP or radiotherapy)
Drug History
Common pharmacological causes of erectile dysfunction include:
- Antidepressants – for low mood, anxiety or PTSD (e.g., SSRIs and venlafaxine).
- GnRH agonists – often used for hormonal treatment of prostate cancer (e.g., goserelin, leuprorelin).
- 5-alpha-reductase inhibitors – treatments for LUTS (e.g, finasteride).
Social History
Smoking and alcohol are causes of erectile dysfunction and increase the risk of cardiovascular disease. Alcohol can have a negative impact on mood.
Recreational drug use is associated with erectile dysfunction (e.g., cannabis, heroin, cocaine, anabolic steroids, and opiates).
Family History
Several conditions associated with erectile dysfunction have a genetic predisposition:
- Cardiovascular disease
- Diabetes
- Prostate cancer
- Thyroid disorders
Finishing
Thank the patient and wash your hands.
Consider your differential diagnosis and how you might narrow this down further through examination, bedside tests, or further investigation and imaging.
Last updated July 2025
Head to members.zerotofinals.com for practice OSCE stations, including an interactive checklist, specific cases and clinical findings.
