The Urinary System
Urinary calculi (urolithiasis, nephrolithiasis) consist of aggregates of crystals and small amount of proteins and glycoproteins Type of stones in the order of how frequent they are:
Different type of stone occur in different parts of the world and dietary factors probably play a part in determining the varying patterns. In developing countries bladder stones are common particularly in children whereas in industrialised developed countries the incidence of childhood bladder stone is low and renal stones in adults more common.
Conditions associated with stone formation:
Urine normally contains glycosaminoglycans, pyrophosphate and citrate which, by forming complexes, may keep otherwise insoluble salts in solution. Artificially made solution with chemical composition of urine but without these anti-precipitating agents is very unstable and prone to crystalisation. It appears that in certain circumstances these protective mechanisms fail, which may result in stone formation.
Today, in prosperous countries most stones occur in healthy young men in whom investigations reveal no clear cause for stone formation. Multiple aetiological factors are probably present in such cases, and an alteration in the relative proportions of crystalloids and glycosaminoglycans in the urine may be of particular importance. On the other hand women tend to suffer more that men from magnesium ammonium phosphate stones because UTIs are more common in women.
Urinary calculi vary greatly in size. There may be particles like sand anywhere in the urinary tract or large round stones in the pelvic or bladder. Staghorn calculi fill the whole renal pelvis and branch into the calyces forming casts of the kidney outflow section; they are usually associated with chronic pyelonephritis. Deposits of calcium may be present throughout the renal parenchyma, giving rise to nephrocalcinosis.
Clinical features: < BACK TO TOP >
vary according to the size, shape and position of the stone(s), and the nature
of the underlying condition.
may be asymptomatic, discovered incidentally during radiological or ultrasound
commonly they cause pain or recurrent urinary infection.
pain is intermittent and dull in the loin or back, increased by movements as
the stone bumps into the mucosa, and there may be some blood in the urine due
to mucosal damage.
in the bladder may cause suprapubic pain and haematuria.
stone moves from the pelvis and becomes impacted in the ureter an attack of
renal colic develops, when the pain is excruciating and radiates round the
flank to the genital region and inner thigh.
pain is caused by vigorous contractions of the ureteric muscle trying to push
down the impacted stone, whose surface is often rough, sometimes with sharp
edges or spikes.
intensity of pain steadily increases to reach a maximum in a few minutes, and
the patient is restless and generally tries to obtain relief by changing
position and by pacing the room.
is pallor, sweating, nausea and often vomiting.
dysuria and haematuria may occur (sometimes fresh red blood is voided).
The intense pain usually subsides within 2 hours, or on treatment only to recur again later in similar fashion, until the stone is passed into the bladder or returned into the pelvis.
Diagnosis: < BACK TO TOP >
diagnosis of renal colic is usually suspected from the history and by finding
abundant red blood cells in the urine.
patient suspected of having stones should have an X-ray of the urinary tract;
most urinary stones can be visualised on X-ray, except cystine and pure uric
may detect all stones, including those not visible on plain X-ray, but very
small stones (sand) may be missed.
there is doubt about the cause of pain an IVU may help (stones are seen as
filling defects), as well as CT.
Chemical analysis of the excreted calculus provides information as to what investigation to pursue; urine collected for 24 hours may be checked for calcium, urate, cystine or oxalate.
Management < BACK TO TOP >
immediate treatment of loin pain or renal colic is bed-rest, application of
warmth to the site of pain, and administration of strong analgesics
[Pethidine, Fortral, Tramal] and antispasmodic drugs [Pro-Banthine, Buscopan,
Mebentyl] usually intramuscularly.
possible the patient should drink 2 L/day of fluid, which increases urine flow
and may help to flush the stone out.
stones, less than 5 mm in diameter, are usually passed naturally in a day or
is a method of applying shock (hydraulic) waves to the body surface precisely
focused on the stone through a water-filled cushion on a special table, when
the fragmentation of relatively small stones (< 2 cm in diameter) can be
achieved. Full name of this procedure is extracorporeal shock wave lithotripsy
(ESWL). This procedure is generally well tolerated and may cause only minor
pain, haematuria or bruising in the lumbar area.
retrograde intrarenal surgery (RIRS) a this fibreoptic endoscope is placed
through the urethra into the bladder and into the ureter and kidney pellvis.
The stone is seen through this optical instrument and can be manipulated,
crushed by ultrasound probe, evaporated by laser probe, grabbed by small
forceps, pushed back into the kidney (for subsequent ESWL). This is done under
general anaesthesia, but there is no hospitalisation or skin incision.
stones can be removed by open surgery or endoscopically via percutaneous
nephrostomy and nephrolithotomy (fragmentation of the stone with an
Antibiotic cover should be given for stone removal to prevent secondary infection.
Prognosis < BACK TO TOP >
Dr Zoran Pletikosa)
speaker Mr NgThian Watt the Principal Trainer from
Napoleon Hill Associates MalaysiaDetails
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