Lyrics · 完整歌詞
Benign prostatic obstruction reflects both a structural component, arising from glandular enlargement,
and a dynamic component, determined by smooth-muscle tone.
The static arm runs from testosterone through 5-alpha-reductase to dihydrotestosterone,
which drives glandular growth.
Finasteride and dutasteride block the enzyme, but the gland shrinks slowly,
so benefit takes three to six months
and is significant only above about 40 mL.
These drugs halve the PSA,
so the measured value is doubled when cancer is being followed.
The dynamic arm depends on alpha-1A receptors,
about 70 per cent of prostatic alpha-1 receptors;
tamsulosin and silodosin block them within days at any gland size.
Alpha-1D receptors, in the detrusor and spinal cord,
are not tamsulosin's main target.
Creatinine and renal ultrasound are the least urgent initial tests
unless obstruction is suspected.
PSA is organ-specific, not cancer-specific.
Prostatitis, infection, digital examination, cycling, ejaculation and benign enlargement all raise it.
A raised PSA with pyuria of 50 to 60 leucocytes per high-power field is
inflammation
until proven otherwise:
treat, then repeat the PSA before any biopsy.
A raised PSA with a free-to-total ratio below 15 per cent
and a hypoechoic lesion points to cancer and warrants MRI-guided
or transrectal biopsy.
PSA is insensitive for nodal spread, below 40 per cent,
so staging relies on pelvic CT or MRI
and a bone scan for osteoblastic metastases.
Post-prostatectomy erectile dysfunction follows injury to the parasympathetic cavernous nerves in the posterolateral neurovascular
bundle.
Benign prostatic obstruction reflects both a structural component, arising from glandular enlargement,
and a dynamic component, determined by smooth-muscle tone.
Renal cell carcinoma is usually clear cell,
linked to VHL on chromosome 3p and to smoking.
It is the internist's tumour: erythropoietin causes polycythaemia,
PTHrP hypercalcaemia and renin hypertension.
Stauffer syndrome is hepatic dysfunction without hepatic metastases,
driven by interleukin-6 and reversible after nephrectomy.
VEGF tyrosine kinase inhibitors treat advanced disease;
their commonest adverse effect is hypertension, not hypothyroidism.
Angiomyolipoma declares itself by fat density on CT; it is benign,
associated with tuberous sclerosis, and treated only above 4 cm.
A filling defect in the renal pelvis or ureter suggests urothelial carcinoma,
linked to smoking, phenacetin and aristolochic acid.
Bladder cancer is urothelial, not adenocarcinoma; smoking is the dominant risk,
Schistosoma haematobium drives squamous carcinoma, and painless haematuria is the presentation.
Testicular germ cell tumours divide into seminoma and non-seminoma.
Seminoma is radiosensitive and never raises AFP.
Non-seminomatous tumours raise AFP through yolk sac or embryonal elements
and are treated with orchidectomy and BEP chemotherapy.
Bleomycin scars the lung, and cisplatin injures the kidney and cochlea.
Cryptorchidism raises cancer risk, and orchidopexy does not lower it;
it only makes the testis examinable.
Erection begins with nitric oxide,
which raises cyclic GMP and relaxes cavernosal smooth muscle.
PDE5 degrades cyclic GMP, so sildenafil sustains the erection;
slight inhibition of retinal PDE6 explains transient blue vision.
Nitrates also raise cyclic GMP,
so their combination causes profound hypotension and is an absolute contraindication.
Rifampicin induces CYP3A4 and merely weakens the drug;
it is not a contraindication.
Myocardial infarction within six months,
severe hypotension and aortic stenosis remain serious cautions.
Benign prostatic obstruction reflects both a structural component, arising from glandular enlargement,
and a dynamic component, determined by smooth-muscle tone.