74

3 Pelviureteric Junction (PUJ) Obstruction

– The degree of renal damage generally is

3.4

Etiology of PUJ Obstruction

less than that of intrinsic obstruction

because the pressure damage is only evi-

• There are several causes of PUJ obstruction

dent intermittently.

and these can be divided into two groups, pri-

• This obstructive nephropathy is progressive if

mary and secondary causes.

the PUJ obstruction is not relived and this

• Primary causes include (Figs. 3.4 and 3.5):

manifest in progressive deterioration of the

–

Intrinsic obstruction from stenosis at the

renal function (Figs. 3.2 and 3.3).

PUJ due to scarring of ureteral valves.

• Sometimes, the obstructive nephropathy will

– An abnormal or high insertion of the ureter

progress and becomes irreversible in spite of

into the renal pelvis. This is controversial

relive of the PUJ obstruction.

ad many consider this a secondary phe-

• There is also activation of the renin-

nomenon to obstruction.

angiotensin system and administration of the

– Ureteral hypoplasia may result in abnormal

angiotensin-converting enzyme (ACE) inhibi-

peristalsis through the PUJ.

tors has been shown to maintain renal blood

–

Asymmetry of ureteral wall musculature

flow and prevent the histologic changes of

may inhibit the natural peristaltic emptying

glomerulosclerosis.

of the renal pelvis into the ureter.

• The long-term effects of PUJ obstruction on

• Secondary causes include (Figs. 3.6, 3.7, 3.8,

the kidney are quite variable and depend on

3.9, 3.10, 3.11 and 3.12):

several factors including:

– Crossing lower-pole renal vessel(s).

– The variability in the degree of

–

Fibrous bands

obstruction

–

Kinks

– The timing of the obstruction

– Horseshoe or pelvic kidney

– The ability of the renal pelvis and renal col-

–

Duplex collecting systems

lecting system and renal parenchyma to

– Rotational abnormalities of the kidney

adjust to the changes associated with

– Renal hypermobility can cause intermittent

obstruction.

obstruction that is solely dependent on the

– Early PUJ obstruction causes severe mal-

position of the kidney relative to the ureter.

formation of the kidney (dysplasia),

–

Secondary PUJ obstruction can be caused

whereas late occurring PUJ obstruction

by prior surgical intervention to treat other

may not affect the kidney as severely.

renal disorders (e.g., renal stone)

3.4 Etiology of PUJ Obstruction

75

–

Failed repair of a primary PUJ obstruction.

– Ureteral-wall and periureteral scar forma-

–

Inflammation at the PUJ secondary to an

tion as a result of inflammation or prior sur-

obstructing stone.

gical repair.

76

3 Pelviureteric Junction (PUJ) Obstruction

3.5 Clinical Features

77

•

Prior

to the use of prenatal ultrasonography,

• Renal failure is an unusual presentation,

most patients with PUJ obstruction present with:

and occurs in infants with a single

–

Pain

obstructed kidney or with bilateral

–

Hematuria

severe hydronephrosis.

–

Urinary tract infection

• Older children may present with:

–

Failure to thrive

– The presentation of patients with PUJ is vari-

–

A palpable mass

able depending on the severity of obstruction.

• Currently, with the availability and routine use

– Intermittent back pain, flank pain or

of

prenatal ultrasonography, urologic

abdominal pain

abnormalities including PUJ obstruction are

– The pain may worsen during brisk diuresis

being diagnosed earlier and more frequently.

–

Abdominal pain may be accompanied by

•

50 %

of patients diagnosed with antenatal

nausea and vomiting

hydronephrosis are eventually diagnosed with

– A detailed history may reveal that the pain

PUJ obstruction upon further workup.

correlates with periods of increased fluid

• Fetal and neonatal hydronephrosis:

intake or ingestion of a food with diuretic

–

Most cases of PUJ obstruction are diag-

properties (i.e. Dietl’s crisis).

nosed antenatally during routine antenatal

–

Urinary tract infection

ultrasound.

–

A flank mass representing the hydrone-

–

These cases are confirmed by postnatal

phrotic kidney

ultrasound.

– The enlarged kidney is vulnerable to trau-

– Newborns may present with:

matic injury (Figs. 3.13, 3.14 and 3.15)

• A palpable abdominal mass caused by

–

Hematuria

an enlarged obstructed kidney.

–

Renal calculi

•

Urinary tract infection

–

Hypertension

•

Hematuria

–

An incidental finding on abdominal ultra-

•

Failure to thrive

sound evaluation

78

3 Pelviureteric Junction (PUJ) Obstruction