Page 260 - Medicine and Surgery

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256 Chapter 6: Genitourinary system

Macroscopy hypertrophy or carcinoma are most common. With
There are single or multiple cysts up to 5–6 cm in diam- increasingageinbothsexesretroperitonealorpelvicma-
eter filled with clear watery fluid, which have a smooth lignancy should be suspected. See Table 6.12.
lining.
Pathophysiology
Investigations If urine continues to be produced, obstruction causes a
If there are multiple cysts, a diagnosis of adult polycystic rise in pressure and dilatation of the proximal part of the
kidney disease should be considered. If the cyst looks as urinary tract. The effects of obstruction depend on the
if it may have any solid or mixed echogenicity compo- site, severity and rate of onset of obstruction.
nents, a thickened wall, or appears loculated on ultra- Renal obstruction usually causes loin pain, whereas
sound, then further investigation by CT may be indi- bladder outflow obstruction may cause a sensation of
cated, to differentiate a cyst from a possible malignancy. a full bladder (see page 261).
Cyst aspiration/drainage is indicated for infected cysts as If both kidneys are completely obstructed (either at
diagnosis and treatment. the level of the ureters (uncommon) or because of
bladder outflow obstruction), or if there is only one
Management functioning kidney which becomes obstructed, com-
Nospecifictreatmentrequired,exceptforcomplications. plete anuria may occur. More commonly partial ob-
struction can lead to renal impairment, despite con-
tinued passage of urine. Partial obstruction may also
Renal tract obstruction
sometimescausepolyuria,duetolossofconcentrating
ability of the tubules.
Urinary tract obstruction Acute obstruction is almost always associated with
Definition pain, but chronic progressive obstruction usually
Obstruction of the urinary tract at any level, whether causes dilatation with little or no pain.
partial or complete, can cause symptoms and renal im-
pairment. Clinical features
Renal obstruction should be considered as a diagnosis
Aetiology in all presentations of renal failure, as it is often asymp-
The likely causes depend on the age of the patient and tomatic. Loin pain, which may be dull, sharp, constant
the level of obstruction. In children, abnormal anatomy or intermittent, may occur. High intake of fluids may
such as urethral valves or stenosis is most likely, whereas exacerbate the pain. Loin tenderness may be present, a
stones are more likely in adults. In older men prostatic distendedbladdermaybepalpableandrectalandvaginal

Table 6.12 Causes of urinary tract obstruction
Level Intrinsic Wall Extrinsic
Kidney and ureter Clot Urothelial Tumour Tumour of pelvis
Renal Tumour Stricture (Idiopathic Aortic aneurysm
Cysts hydronephrosis) Idiopathic retroperitoneal fibrosis
Casts, protein etc TB
Radiation Fibrosis
Bladder Tumour Prostate – BPH or carcinoma
Foreign body
Urethra Tumour Urethral valve
Foreign body Stricture
Tumour