# Prostatitis > Prostatitis for NEET-PG Pathology: NIH categories I-IV, expressed prostatic secretion findings, granulomatous prostatitis after BCG and the prostatitis-PSA relationship. - Canonical URL: https://prepelephant.com/topics/neet-pg/pathology/prostatitis-pathology - Exam / course: NEET-PG · Subject: Pathology - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Prostatitis", PrepElephant, https://prepelephant.com/topics/neet-pg/pathology/prostatitis-pathology ## Direct answer Roughly nine of ten men labelled clinically with "chronic prostatitis" have no cultivable organism in the gland — they occupy category III of the four-part National Institutes of Health classification, chronic pelvic pain syndrome. Category I is acute bacterial prostatitis, a febrile Escherichia coli urinary infection in which neutrophils fill the glands; category II is chronic bacterial prostatitis, smouldering and relapsing with the same organism, driven by prostatic stones and ductal obstruction; category III splits into inflammatory (IIIa, leucocytes in expressed prostatic secretions) and non-inflammatory (IIIb, formerly prostatodynia); category IV is asymptomatic inflammation found incidentally in biopsies done for a raised prostate-specific antigen. Granulomatous prostatitis — post-surgical, tuberculous or bacille Calmette-Guerin-related — is the histological wildcard that mimics carcinoma clinically. ## What you must remember - **NIH framework:** I acute bacterial, II chronic bacterial, IIIa/IIIb chronic pelvic pain syndrome with or without leucocytes, IV asymptomatic — quote the number and the phrase together. - **Microbiology:** Escherichia coli dominates both bacterial categories; other Enterobacteriaceae, enterococci and, in sexually active men, Chlamydia trachomatis account for the rest. - **Localisation tests:** the Meares-Stamey four-glass test, or its simplified two-glass pre- and post-massage comparison, assigns organisms to the prostate rather than the urethra or bladder. - **Expressed prostatic secretion rule:** more than 10 leucocytes per high-power field defines the inflammatory (IIIa) subset, with lipid-laden macrophages accompanying active inflammation. - **Granulomatous prostatitis sources:** prior transurethral resection, tuberculosis, and intravesical BCG instillation for urothelial carcinoma — the last is a favourite Indian exam scenario. - **PSA lesson:** both acute and chronic inflammation raise serum PSA, so infection must be treated and the test repeated before biopsy is committed. - **Therapy logic:** fluoroquinolones for 2-4 weeks (category I) or 4-6 weeks (category II); category III gets alpha-blockers, anti-inflammatory agents and neuromodulatory strategies, not endless antibiotics. ## Reading a biopsy that came out granulomatous A 66-year-old treated with intravesical BCG for high-grade non-muscle-invasive bladder cancer undergoes prostate biopsy for a rising PSA. Instead of Gleason-patterned glands, the cores show non-caseating epithelioid granulomas with scattered giant cells rimmed by lymphocytes — BCG-related granulomatous prostatitis, reported after a substantial fraction of intravesical instillation courses. The pathologist's task is triage: stains for acid-fast bacilli exclude tuberculosis, and the intact residual acini with preserved basal cells (p63 and high-molecular-weight cytokeratin positive) exclude carcinoma. PSA falls over the following months without any oncological intervention. The same logic governs category IV disease found on random biopsies: inflammation is noted, scored for extent, and correlated with the PSA trend, but it neither demands treatment nor licenses a cancer label. ## Where candidates slip Two slips recur. First, acute bacterial prostatitis is made a contraindication to vigorous massage and biopsy — the fear is bacteraemia — so diagnosis rests on urine cultures and the tender, boggy gland, with blood cultures if septic. Second, candidates call category IIIb "psychological": it is a genuine pain syndrome with measurable central sensitisation, and the exam answer is multimodal therapy rather than antibiotics. The granuloma trap closes the set: on digital rectal examination a granulomatous prostate is firm and nodular enough to simulate carcinoma, and only histology separates them — which is precisely why the BCG history must reach the pathologist on the request form. ## Frequently asked questions ### Which NIH category covers chronic pelvic pain syndrome? Category III, subdivided into IIIa (inflammatory, leucocytes in expressed prostatic secretions) and IIIb (non-inflammatory, formerly prostatodynia). ### Which test localises infection to the prostate? The Meares-Stamey four-glass test, comparing first-void urine, midstream urine, expressed prostatic secretions and post-massage urine; the two-glass pre- and post-massage version is the practical shortcut. ### Why does intravesical BCG cause granulomatous prostatitis? Attenuated mycobacteria reach the prostatic ducts and stroma through reflux, inducing epithelioid granulomas that can mimic carcinoma on rectal examination. ### How does prostatitis affect PSA interpretation? Both acute and chronic inflammation elevate PSA, so the value should be repeated after treatment before proceeding to biopsy. ### How long should category II chronic bacterial prostatitis be treated? Fluoroquinolones for 4-6 weeks, chosen for prostatic penetration, with reassessment for obstructing stones or ductal pathology if relapse follows. ### What histology defines acute bacterial prostatitis? Neutrophils streaming through and distending glandular lumina, sometimes with microabscesses, against an oedematous stroma.