Renal tuberculosis
Aetiology and
pathology
Tuberculosis of the urinary tract arises from
haematogenous infection from a distant focus which is often impossible to
identify. The lesions are usually confined to one kidney. A group of tuberculous
granulomas in a renal pyramid coalesces and forms an ulcer. Mycobacteria and pus
cells are discharged into the urine. Untreated, the lesions enlarge and a tuberculous
abscess may form in the parenchyma. The necks of the calyces and the renal
pelvis stenosed by fibrosis confine the infection so that there is tuberculous pyonephrosis which is sometimes localised to one pole of the kidney.
Extension of pyonephrosis or tuberculous renal abscess leads to perinephric
abscess and the kidney is progressively replaced by caseous material (putty
kidney) which may be calcified (cement
kidney). At any stage the plain radiograph may show areas of calcification (pseudocalculi).
Less commonly the kidneys may be bilaterally affected as part of the
generalised process of miliary tuberculosis (Fig.
64.34).
Renal
tuberculosis is often associated with tuberculosis of the bladder and typical
tuberculous granulomas may be visible in the bladder wall. In the male,
tuberculous epididymoorchitis may occur without apparent infection of the
bladder.
Clinical
features
Renal tuberculosis usually occurs between 20
and 40 years of age, and is twice as common in men as in women; also, the right
kidney is affected slightly more often than the left.
Urinary
frequency is often the earliest symptom and may be the only one. The patient
complains that, over a period of months, there has been a progressive increase
in both daytime and night time frequency.
‘Sterile’
pyuria. In early cases the urine is pale and slightly opalescent. Routine urine
culture is negative.
Painful
micturition is a feature as soon as tuberculous cystitis sets in. First there
is a suprapubic pain if voiding is delayed; later a burning pain accompanies
micturition. When there is secondary infection a superadded agonising pain
referred to the tip of the penis or to the vulva is often associated with
haematuria and strangury.
Renal pain is often minimal but there may be a dull ache in the loin.
Haematuria
In 5
per cent of cases the first symptom is haematuria occurring from an ulcer on
a renal papilla. The tuberculous lesion may be difficult to detect
radiologically and mycobacteria may not be cultured from the urine until the
onset of more suggestive symptoms some months later.
A tuberculous kidney is oedematous and friable
and is more liable to damage than a normal kidney.
Constitutional symptoms are common. Weight
loss is usual and a slight evening pyrexia is typical. A high temperature
suggests secondary infection or dissemination, i.e. miliary tuberculosis.
On
examination
It is unusual for a tuberculous kidney to be palpable. The prostate,
seminal vesicles, vasa and scrotal contents should be examined for nodules or
thickening.
Investigation
Bacteriological
Bacteriological examination of at least three
full specimens of early morning urine should be sent for microscopy and culture
before specific chemotherapy is started. Staining of the urine sediment with the
Ziehl—Neilsen stain occasionally shows the presence of acid-fast bacilli but
proof that these are pathological mycobacteria must await prolonged culture on
Lowenstein—Jensen medium. Where the clinical picture is convincing it is
permissible to start antituberculous therapy in anticipation of the culture
results which will come some 6 weeks later.
Radiography
A plain abdominal radiograph may show the
calcified lesions described above.
Intravenous
urography
In the very earliest stages of the disease the normally clear cut outline of a renal papilla may be rendered indistinct by the presence of ulceration. Later there may be evidence of calyceal stenosis (Fig. 64.35) and/or hydronephrosis caused by stricture of the renal pelvis or the ureter draining the affected kidney; this may be more easily demonstrable by retrograde ureterography (Fig. 64.36). A tuberculous abscess appears as a space-occupying lesion which causes adjacent calyces to splay out. The bladder may appear shrunken with its wall irregular or thickened. In late stages there may be dilatation of the contralateral ureter from obstruction where the ureter passes through a thickened and oedematous bladder wall.
Cystoscopy
Cystoscopy is not indicated as a routine part
of the investigation of urinary tuberculosis but is often performed because
there has been haematuria or unexplained bladder symptoms. There may be little
to see in the first stages of the disease but later the bladder urothelium is
found to be studded with granulomas which cluster particularly around the
ureteric orifices. The tubercles may coalesce to produce a tuberculous ulcer.
As the bladder wall fibroses the bladder capacity decreases. Contraction of the
fibrosed ureter tugs at the ureteric orifice which is displaced upwards, its
mouth wide open (the so-called ‘golf-hole’ ureteric orifice).
Chest
radiograph
A chest radiograph is indicated to exclude an
active lung lesion.
Treatment
Antituberculous chemotherapy is best managed
by a physician with experience of the most modern drug regimens and their
potential adverse effects. The surgeon must ensure that the state of the urinary
tract is reviewed during the first few weeks of therapy because stricturing
of the renal pelvis and ureter may continue after treatment has started.
Prognosis
in renal tuberculosis is good and there should be no recrudescence of the
disease if the patient completes the course of chemotherapy.
Operative
treatment
Operative treatment should be as conservative
as possible. The aim is to remove large foci of infection, which are difficult
to treat with drugs, and to correct the obstruction caused by fibrosis. The
optimum time for surgery is between 6 and 12 weeks of the start of
antituberculous chemotherapy.
The
surgeon needs a repertoire of procedures to deal with various potential effects
of urinary tuberculosis. An obstructed lower pole calyx may be drained into
the upper ureter. A strictured renal pelvis needs a pyeloplasty. Ureteric
stenosis and shortening may require a Boari operation or a bowel interposition,
depending on the level and extent of the fibrosis. If the kidney has no
function it is best to perform a nephroureterectomy (Fig.
64.37). A bladder
which is so contracted that it can no longer function as a reservoir for urine
may need to be replaced with a neobladder
fashioned from a loop of bowel in a substitution
cystoplasty.