Experiments in animals show that most antimicrobial agents diffuse very poorly into the prostatic tissue and prostatic secretions. Experimentally, a notable exception was trimethoprim. Trimethoprim diffuses easily into prostatic secretion because of its favorable pharmacokinetics, which includes the pH of the prostatic fluid and tissue as well as the specific negative logarithm of the ionization constant of the drug. Trime-thoprim-sulphamethoxazole or trimethoprim alone have been the antimicrobial agents with the best documented record of success in treating chronic bacterial prostatitis. Theoretically, erythromycin and minocycline also achieve therapeutic levels in the secretions. However, these drugs are characterized by a high incidence of adverse side effects, and neither is really suitable for long-term use.
The only antibiotic approved for chronic bacterial prostatitis is carbenicillin. Studies have not confirmed that this is the most appropriate drug for this disease. The new quinolones offer theoretical efficacy in that they do diffuse very freely into the prostatic secretion and are effective against most organisms that cause bacterial prostatitis. Preliminary clinical studies have, in fact, shown that chronic bacterial prostatitis can be successfully treated with the new-generation quinolones.
Acute prostatitis. The management of the different prostatitis syndromes is very different. Some men with acute bacterial prostatitis require hospitalization. The patient requires supportive care, including intravenous hydration. Acute urinary retention is not infrequent. Suprapubic urinary drainage by means of a percutaneous cystotomy is much preferable to a urethral catheter in acute prostatic inflammation. If hospitalization is required, parenteral antibiotic therapy should be instituted immediately after urine and blood have been taken for culture and sensitivity.
An aminoglycoside-ampicillin combination is recommended to cover both the Gram-negative bacteria and the enterococci. Clinical experience indicates that these drugs do diffuse into the prostate at adequate levels during the acute inflammatory stage. Perhaps the physiologic barriers to diffusion of most antibiotic agents in the prostatic fluid are disrupted by such acute inflammation.
Response to treatment is usually rapid, and oral antibiotic therapy can be instituted in several days. If the patient is not severely ill, outpatient treatment with oral antibiotics can be initiated at the first presentation. If fever and pain persist, further investigation, such as intravenous pyelography and ultrasonography, should be done to rule out stones, obstruction, and abscess. While the optimal duration for antimicrobial therapy is unknown, one must always be aware that inadequately treated acute bacterial prostatitis could evolve into difficult-to-treat chronic bacterial prostatitis. Therefore, one further month of oral antibiotic therapy with either trimethoprim or a trimethoprim-sulphamethoxazole combination or one of the newer quinolones is recommended.
Chronic bacterial prostatitis. Chronic bacterial prostatitis is much more difficult to treat. Once the bacteriologic diagnosis is obtained, the goal of treatment is, of course, to cure the patient: to completely eradicate the focus of infection in the prostate and to eliminate the cause of persistent bacteria within the gland. There is, however, a high failure rate and a very high relapse rate with antibiotic therapy in this disease, and sometimes suppression is all that can be achieved. As previously discussed, the diffusion of antibiotics in the prostate gland in chronic bacterial prostatitis is perhaps the single most important factor in choosing an antibiotic. Trimethoprim and the newer quinolones appear to be the drugs of choice. Of course, the selection of antibiotics must be modified according to the sensitivity of the bacteria obtained on culture. A minimum of 6 weeks’ treatment is recommended; however, most experts find that it usually takes 3 months of continuous antibiotic therapy to cure the disease. The cure rate, with these medications, ranges from 40% to 70%.’ While full-dose antibiotic therapy is generally well tolerated, about 15% of patients experience adverse side effects.
When the disease cannot be cured, the physician must consider low-dose, suppressive therapy. The drugs used most often are low-dose trimethoprim at 50 mg/d, low-dose trimethoprim-sulphamethoxazole at half a tablet per day, or nitrofurantoin at 50 mg/d. These are remarkably effective in suppressing the symptoms and eradicating the bacteriuria, but once they are discontinued, the disease can recur because of bacteria persisting within the prostate gland.
Recently there has been some interest in intraprostatic antimicrobial injection. This is thought to produce antimicrobial concentrations in the parenchyma and ducts of the prostate that greatly exceed those achievable with systemic administration. Certainly this technique deserves further clinical exploration, but at present it is not a practical consideration.
Surgery is really the treatment of last resort. Complete total prostatectomy, including complete excision of the prostate and seminal vesicles, should constitute a predictable cure for chronic bacterial prostatitis; however, its application is limited by the anticipated and certainly the potential morbidity. Impotence and incontinence are both possible results.
Radical transurethral resection has been suggested as an alternate surgical approach. This is only rarely successful, because the inflammation associated with chronic bacterial prostatitis is largely confined to the periphery rather than to the central portion of the prostate gland. Some investigators, however, report reasonably good results, and long-term antibiotic therapy can be considered. Patients with prostatic calculi that have become secondarily infected by bacteria will rarely be cured by antibiotic therapy alone. Transurethral resection to remove all the stones is a reasonable approach, and it is appropriate to have an intraoperative radiographic assessment of the prostate gland to ensure complete removal of the calculi.
Non-bacterial prostatitis. Non-bacterial prostatitis is difficult to treat because the cause is unknown. It could be a manifestation of a variety of different inflammatory processes, or it could be secondary to infection with such bacteria as coagulase-negative staphylococcus or such organisms as chlamydia or mycoplasma. Our approach in patients with a definite prostatic inflammation but no bacteriologic localization is to use tetracycline or doxycycline for 2 weeks and then assess the results of therapy. Erythromycin and, to a lesser extent, tiimethoprim-sulphamethoxazole are also active against these agents.
If the patient is responding, we will continue for another 4 weeks. Chronic antibacterial therapy should, however, be avoided, especially if it is not working. Treatments that occasionally help include hot sitz baths, avoidance of alcohol and foods that aggravate the problem, a trial of anticholinergic and anti-inflammatory agents, and possibly a trial of anxiolytic medications. Oral zinc treatment, which is advocated by some, has never been proved effective.
Prostatodynia. The patient with prostatodynia does not have inflammation and will not benefit from a trial of antibiotics. An important component of management is to clinically eliminate all extraprostatic causes for the symptoms, such as interstitial cystitis, carcinoma of the bladder, and other conditions that could give pelvic pain. If urodynamic investigation reveals vesical sphincter dyssynergia, pharmacologic management with OC-blockers, such as prazosin, can help. Agents such as diazepam and oxybutynin can also help in selected cases.
Bladder neck incision has been used with variable success. Biofeedback technology has demonstrated some improvement in symptoms. We find that the best treatment is reassurance and counseling by the family physician, the urologist, and if necessary, psychologists or psychiatrists. The physician’s common sense, compassion, and concern for the patient’s very real frustrations are the keys to successful management of prostatodynia. Usually this chronic disorder remains undefined despite repeated investigations and treatment.
Conclusion
Prostatitis has been called a "wastebasket of clinical ignorance." If this situation is to change, family physicians must develop an awareness of the importance of proper classification based on an understanding of the etiology of these syndromes. A rigorous systematic diagnostic plan, especially at first presentation, is essential to understanding and treating the whole spectrum of specific and undefined prostatic disorders. ■