MANAGEMENT OF URINARY INFECTIONS:

by Dr Tan Eng Choon

Consultant Urologist

Mt Elizabeth Medical Centre

Singapore 0922.

& Dr Peter Lim Huat Chye

Senior Consultant & Head

Division of Urology

Toa Payoh Hospital, Singapore 1129.

Urinary tract infections can present as single uncomplicated episodes or they may present with recurring & persistent problems. Occasionally., life threatening situations develop from uncontrolled urosepsis, especially in patients who are diabe tics or in immunocompromised states. Females are more commonly affected than males. About 4% of young adult females are affected with the incidence rising with age to 7% at 50 years.

In the adult male, the incidence is low until late adulthood, when bladder outlet obstruction predisposes to infection & other problems. In infants, the incidence is approximately equal amongst males & females.

Urinary infection presents usually with complaints of frequency, dysuria, urgency, haematuria, fever, chills, rigors & loin pain. Lower Urinary Tract infection is characterised byfrequency, dysuria, urgency & haematuria whereas Upper Urinary Tr act infection often includes fever, chills, loin pain & haematuria. Upper tract infection can be more serious leading to bacteraemia, septicaemia & renal damage. Tuberculosis of the Urinary Tract is somewhat different presenting with severe freque ncy, nocturia & persistence of the infection & requires a high index of suspicion for its diagnosis.

Urinary tract infection is deemed to be established when a mid-stream urinary culture yields 10,000,000 organisms/ml or more with the commoner organisms being E. coli, Klebsiella spp., Proteus mirabilis, Enterobacter, Citrobacter & Pseudomonas. The se organisms originate mainly from endogenous colonic flora. Confirmation of TB requires special culture media & fungal infection is not common in general, except for diabetics & immunologically compromised patients. Pyuria by itself is a poor ind icator of infection. Infection by Proteus spp.typically produces an alkaline urine due to urea-splitting bacteria.

Simple, uncomplicated urinary tract infections may not have an obvious identifiable cause wilst recurrent or persistent infections often have an underlying etiology. The single most important factoris stasis in the urinary tract leading to bacterial pr oliferation & infection. Congenital anomalies very common in children are not uncommonly seen also in adults.They include congenital pelvi-ureteric junction obstruction, megaureter & ureterocele. About 15% of the local Singapore population present s with clinical upper urinary tract due to obstruction. Diabetic patients are prone to develop urinary tract infection & in those with sloughed necrotic papillae, the obstruction which ensues commonly leads to severe urosepsis. All foreign material e. g. catheters, stents , stones etc in the urinary tract are potential sources for bacterial colonisation & should be removed as soon as possible.

In addition to bacterial culture & sensitivity, other tests done should include Ultrasound, Intravenous Urography, Micturitating Cystourethrogram & Radioisotope renography to confirm the underlying pathology. Occasionally, more invasive investi gations such as Antegrade nephrostogram, Endoscopy & Biopsy may be required to confirm diagnosis.

The simple Cystitis common in females in the reproductive age group are usually self-limiting & respond well to simple antibiotics like Nalidixic Acid, Nitrofurantoin or Bactrim. Detailed Work-up is not usually needed in this group.

Childhood infections during the first 2 years of life are serious & need full evaluation. For acute management of infection, stronger antibiotics with broader spectrum of activity are needed e.g. Amoxycillin/Clavulanate(Augmentin), Sultamicillin to sylate(Unasyn), Cefuroxime axetil(Zinnat) and others are often mandatory to curtail the potential life-threatening urosepsis. After the situation is brought under control, the full work-up mentioned earlier (vida supra) should be instituted & followed by surgical correction if needed e.g. correction of vesico-ureteric relux, PUJ obstruction etc. Infection of the older child is usually less ominious & could stop at Ultrasonography of the urinary tract if the later is normal.

In adults, a search for stone disease is vital as this is commonly the predisposing cause - hence a plain KUB & Ultrasound often is sufficient to diagnose this. A failure to respond to parenteral administration of the more potent antibiotics like

Sultamicillin tosylate (Unasyn)

Amoxycillin/Clavulanate (Augmentin)

cefuroxime axetil (Zinnat)

Seventy-five percent of patients with renal parenchymal infection are usually diabetics & immunocompromised patients presenting with renal abscesses, renal carbuncles or perinephric abscess.Aggressive management with intravenous potent antimicrobia ls for antisepsis & resuscitation is required followed by surgical drainage and even nephrectomy may be necessary in as many as two-thirds of patients.

Tuberculosis if diagnosed is treated primarily by anti-TB Drugs. Previous, Streptomycin, PAS & INH were used routinely for extended periods. With the advent of Rifampicin, short courses are today the norm. Reconstructive surgery is reserved for str icture or contracted bladders with nephrectomy occasionally warranted for the "burnt out" autonephrectomy kidney.

Urinary tract infection is a common problem seen in community practice as well as in hospitals. Upper urinary tract infection with fever & loin pain is more serious than lower tract infections & requires appropriate antimicrobial therapy. In re current & persistent infections a full work-up to exclude the underlying cause & treatment of the latter prevents relapse of infection. Tuberculosis can only be detected if the clinician exhibits a high index of suspicion. In life-threatening uros epsis due to severe renal parenchymal infection, timely nephrectomy often makes the difference between life & death.