What could be causing my sudden onset of decreased libido, reduced ejaculation intensity, and dulled sensation during urination, which started abruptly like a switch being flipped?

Sudden Onset of Decreased Libido, Reduced Ejaculation Intensity, and Dulled Urinary Sensation

You are most likely experiencing nerve damage affecting the pelvic floor and autonomic nervous system, which can occur from trauma, surgery (particularly anal/pelvic procedures), neurological conditions, or acute vascular events—this requires urgent evaluation by a urologist to assess for neurogenic sexual dysfunction and potential underlying neurological or endocrine causes. 1

Immediate Diagnostic Priorities

The abrupt "light switch" nature of your symptoms strongly suggests an acute neurological or vascular event rather than gradual hormonal decline. You need:

• Morning serum total testosterone measurement to rule out acute hypogonadism, as low testosterone directly correlates with reduced libido and ejaculatory dysfunction 1, 2
• Comprehensive neurological examination focusing on perineal sensation, anal sphincter tone, and bulbocavernosus reflex to assess for nerve damage 3, 1
• Detailed history focusing on any recent trauma, surgery (especially anal/pelvic), new medications, or systemic symptoms that preceded the onset 1
• Basic metabolic panel, lipids, and hemoglobin A1c to screen for diabetes or other conditions causing acute neuropathy 1

Understanding Your Symptom Pattern

Your constellation of symptoms—simultaneously decreased libido, reduced ejaculatory force/pleasure, and dulled urinary sensation—points to disruption of the autonomic nervous system controlling pelvic organs:

• Post-surgical pelvic floor changes (if you had anal surgery like fistulotomy) can alter ejaculatory mechanics and reduce both force and pleasure 1
• Autonomic neuropathy affects smooth muscle relaxation in the corpus cavernosum, impairs nitric oxide synthase function, and disrupts sensory pathways for both sexual and urinary function 3
• The sudden onset distinguishes this from gradual age-related decline, making organic causes (nerve damage, vascular event, acute hormonal disruption) more likely than psychological factors 3

Critical Differential Diagnoses to Rule Out

Neurological Causes

• Spinal cord lesion or cauda equina syndrome can present with this triad of symptoms and requires urgent MRI if accompanied by any weakness, saddle anesthesia, or bowel dysfunction 4
• Peripheral neuropathy from diabetes, B12 deficiency, or other metabolic causes 3
• Autonomic neuropathy specifically affecting pelvic organs 3, 4

Endocrine Causes

• Acute hypogonadism from pituitary apoplexy, testicular infarction, or medication effects 3
• Hyperprolactinemia universally causes reduced libido and should be measured if testosterone is low 5

Medication-Induced

Even though you state "no medication," review for:

• Recent SSRIs, antipsychotics, or antihypertensives which commonly cause this symptom pattern 2
• 5-alpha reductase inhibitors (finasteride/dutasteride) which can cause persistent sexual dysfunction even after discontinuation 3

Treatment Algorithm Based on Underlying Cause

If Testosterone is Low (<300 ng/dL)

Testosterone replacement therapy is indicated as it improves libido, erectile function, and ejaculatory function in hypogonadal men 1, 2. However, rule out pituitary pathology first with prolactin and MRI if indicated 3.

If Nerve Damage is Confirmed

• Referral to sexual health specialist or urologist for formal assessment of ejaculatory dysfunction 1
• Sympathomimetic agents (pseudoephedrine 60-120 mg taken 120-150 minutes before sex, or ephedrine 15-60 mg taken 1 hour prior) may improve ejaculatory force and sensation, though this is off-label 1, 2
• Behavioral modifications including changing sexual positions or practices to increase arousal 2

If Comorbid Erectile Dysfunction Exists

Treat the erectile dysfunction first with PDE5 inhibitors (sildenafil, tadalafil, vardenafil), as ED and ejaculatory disorders share common risk factors and ED treatment may resolve ejaculatory complaints 3, 1, 2

If Psychological Factors are Present

• Mental health referral with sexual health expertise is appropriate, as psycho-behavioral strategies may enhance arousal and remove barriers to sexual excitement 1, 2
• Include sexual partner in decision-making when possible to optimize outcomes 3, 2

Critical Pitfalls to Avoid

• Do not assume this is purely psychological without ruling out organic causes—the sudden onset strongly suggests a physical etiology 1
• Do not confuse these symptoms with premature ejaculation or isolated erectile dysfunction—this is a distinct pattern requiring different evaluation 3, 1
• Do not delay evaluation if any "red flag" symptoms exist: progressive weakness, saddle anesthesia, bowel incontinence, or severe pain, which could indicate cauda equina syndrome requiring emergency intervention 4
• Recognize that many men under-report sexual dysfunction due to embarrassment—74% of men with ED fail to discuss it with their physician due to embarrassment 6

Prognosis and Expectations

• Treatment success is measured by patient and partner satisfaction, not arbitrary physiological measures 1, 2
• Many men experience improvement with appropriate treatment, though complete restoration to pre-event function may not always be achievable 1
• The abrupt onset suggests a potentially reversible cause if identified and treated promptly, making urgent evaluation critical 1