Definition and Symptoms of Male Hypogonadism
Hypogonadism is a clinical condition characterized by low serum testosterone levels in association with specific signs and symptoms that impact multiple organ systems and quality of life. 1, 2
Definition and Classification
Male hypogonadism represents a failure of the testes to produce adequate androgen, resulting in testosterone deficiency combined with clinical manifestations 1, 3. The condition requires both biochemical evidence (low testosterone) and clinical symptoms for diagnosis 2.
The classification system distinguishes several types:
- Primary (hypergonadotropic) hypogonadism: Caused by testicular dysfunction with low testosterone and elevated gonadotropin (LH/FSH) levels 2, 4
- Secondary (hypogonadotropic) hypogonadism: Results from impairment of the hypothalamic-pituitary-gonadal axis with low testosterone and normal or low gonadotropins 2, 4
- Compensated hypogonadism: Normal testosterone levels maintained through elevated LH production 2
- Functional hypogonadism: Low testosterone without organic HPG axis alterations, often secondary to comorbidities 2
Specific Symptoms
The European Association of Urology categorizes symptoms by specificity and type 1:
Sexual Symptoms (Most Specific)
- Reduced libido 1
- Erectile dysfunction 1
- Decreased spontaneous/morning erections 1
- Reduced frequency of sexual intercourse 1
- Reduced frequency of masturbation 1
- Delayed ejaculation 1
Physical Symptoms (Most Specific)
- Decreased vigorous activity 1
- Difficulty walking >1 km 1
- Decreased bending ability 1
- Hot flushes 1
- Decreased energy 1
- Decreased physical strength/function/activity 1
- Reduced muscle mass and bone density 1
- Anemia 1
Psychological Symptoms (Most Specific)
- Low mood/mood deflection 1
- Decreased motivation 1
- Fatigue 1
- Concentration or mnemonic difficulties 1
- Sleep disturbances 1
- Depression 1
Common Etiologies
Primary Hypogonadism Causes
- Congenital disorders: Klinefelter's syndrome, chromosomal abnormalities, Down syndrome 2, 5
- Acquired disorders: Testicular trauma, orchitis, orchiectomy, vanishing testis syndrome, chemotherapy, radiation damage, toxic damage from alcohol or heavy metals 2, 5
Secondary Hypogonadism Causes
- Congenital disorders: Idiopathic hypogonadotropic hypogonadism, Kallmann syndrome 2
- Acquired disorders: Pituitary tumors, traumatic brain injury, metabolic syndrome, HIV infection, chronic organ failure 1, 2
- Drug-induced: Opiates, GnRH agonists/antagonists, glucocorticoids, estrogens, anabolic steroids 1, 2
- Functional causes: Glucocorticoid excess (Cushing syndrome), eating disorders, endurance exercise, acute/critical illness, aging 1
Diagnostic Requirements
Diagnosis requires both clinical symptoms AND biochemical confirmation with low serum testosterone levels measured on at least two separate mornings. 5 The normal testosterone range is 300-1,000 ng/dL 5. Assessment should include evaluation of sexual function, energy levels, mood, and physical changes 1.
Clinical Pitfalls
The most specific symptoms for hypogonadism are the sexual symptoms (reduced libido, erectile dysfunction, decreased morning erections), followed by specific physical symptoms (decreased vigorous activity, difficulty walking >1 km) 1. Less specific symptoms like fatigue, sleep disturbances, and decreased energy can be related to numerous other conditions and should not be used in isolation for diagnosis 1.