Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2012.)
MODERN MEDICINE
CPD ARTICLE NUMBER FOUR: 1 point
The new stone age
PHILLIP M KATELARIS, MB BS(Hons), FRACS(Urol)
useful, there is a possibility that
calcium stones may be precipitat­
ed in an alkaline urinary pH.
^
Shared care of the acute renal
colic patient requires good commu­
nication between the primary care
practitioner and the urologist.
Initial management, monitoring
and metabolic investigations,
where indicated, should be per­
formed by the general practitioner.
Epidemiology
Stone disease is commonest
betw een the th ird and fifth
decades of life, with initial mani­
festation of clinical stone disease
commonly occurring in the third
decade. Calcium-containing stones
occur in men three times as fre­
quently as in women. Individuals
w ith a sedentary lifestyle are
known to be more susceptible to
calcium stone disease, as are those
in professional and managerial
occupations. The incidence is high­
er in patients with urinary vol­
umes that are persistently low.
As many as one in ten men and
one in 20 women will experience
an episode of renal colic. Stoneforming patients in whom a meta­
bolic cause has been excluded have
a 50% chance of recurrence within
five years.
Dr Katelaris is consultant urologist,
Sydney Adventist and Hornsby Ku-RingGai Hospitals, Sydney, Australia. He wrote
this article specially for M o d e r n M e d ic in e .
M anagem ent of different
types of stones
Appropriate investigation and
medical management of kidney
stone disease is essential.
Uric a c id stones
Patients with gout and patients
with myeloproliferative disorders
th a t are being tre a ted w ith
chemotherapy are particularly at
risk of forming uric acid stones.
Uric acid stones can also occur in
patients with normal levels of uric
acid in their serum and urine.
These stones occur in acidic urine
and can often be dissolved if the
patient drinks two litres of water
each day and maintains a urinary
pH greater than seven. The latter
can be achieved by administering
sodium bicarbonate (4g per day, in
divided doses).
Care should be exercised when
administering high doses of sodi­
um bicarbonate to patients with
congestive cardiac failure. Patients
should use urinary test strips to
ensure they have alkaline urine.
For patients with recurrent uric
acid stone formation who are com­
pliant with the above measures,
allopurinol, in doses of 200 to
400mg per day, should be consid­
ered. However, although urinary
alkalinization for dissolving uric
acid and cystine stones may be
C ystine stones
Cystine stones are rare but prob­
lematic. Cystinuria is an inborn
error of metabolism and there is
frequently a family history in
affected individuals. Cystine stone
onset often occurs at an early age.
Cystinuria can be diagnosed by
stone analysis or by performing a
24-hour cystine urinary excretion
test. As with uric acid stones, a
high output of dilute urine is criti­
cal and patients must be encour­
aged to drink four litres of water
per day — every day — without
fail. Urinary alkalinization is also
helpful. Should these strategies
fail, penicillamine, which is a cys­
tine binding drug, should be con­
sidered; because of its many seri­
ous side-effects, it is best adminis­
tered by a nephrologist.
S tru vite stones
Struvite stones are also known as
infection stones because they are
known to be caused by urea-splitting organisms such as Proteus
m irabilis and Klebsiella spp.
These stones are composed of
magnesium and ammonium phos­
phate. Struvite stones frequently
cause staghom calculi, which are
the most challenging of the uri­
nary stones.
Urological intervention is indi­
cated, though successful dissolu­
tion with hemiacidrin can occa­
sionally occur. Hemiacidrin, a solu­
tion of magnesium hydroxycarbonate, magnesium acid citrate, citric
acid (anhydrous), D-gluconic acid
and calcium carbonate, can be
administered either retrogradely
or antegradely by using ureteric
catheters or percutaneous nephros­
tomy catheters, respectively. Close
monitoring of fluid and electrolyte
FEBRUARY 2000 / MODERN MEDICINE OF SOUTH AFRICA
63
Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2012.)
N ew stone age
I
c o n tin u e d
I
balance is critical.
Prevention of staghom struvite
recurrence is dependent upon total
stone clearance to remove frag­
m ents th a t act as nucleators.
Constant monitoring and appro­
priate treatment of recurrent uri­
nary tract infection is critical.
C alciu m oxa la te stones
Calcium oxalate stones are hard
and insoluble. Despite the fre­
quent claims of herbalists, they
cannot be dissolved in vivo.
Screening for hypercalcaemia and
hyperuricaemia by measuring cal­
cium and uric acid levels in serum
is useful at the time of the initial
presentation.
Parathyroid hormone estima­
tion may confirm a diagnosis of
hyperparathyroidism in a hypercalcaemic patient. Other causes of
hypercalcaemia, such as sarcoido­
sis, need to be borne in mind.
Detailed metabolic evaluation,
such as 24-hour urinary collection
for quantifying calcium, phos­
phate, urate, oxalate and citric
acid secretion, is only indicated in
the most problematic of stone-
A s m any as one in ten men
a n c i o n e i n 2 0 women will
experience an episode o f renal colic.
MODERN MEDICINE PATIENT HANDOUT
D ietary advice for p atients
• Drinking two litres of water every day is the most effective dietary modifi­
cation for the stone-forming patient to make.
• Calcium restriction is no longer thought to be helpful in stone prevention.
» Your consumption of foods that contain oxalate or uric acid should be
minimized. Foods that contain oxalate include:
— chocolate
— rhubarb
— coffee
— tea
— cola drinks
— vitamin C tablets.
Foods that contain uric acid include:
— beer
— red meat
— red wine.
• Avoid processed meats, yeast spreads and other high salt foods Restrict
your salt intake to 2,3mg per day
• Your protein consumption should be reslricled to no more than one gram
of protein per kilogram of body weight per day
• Remember to drink two litres of water each day!
forming patients. Twenty-fourhourly m easurem ents of these
chemicals suffer from very poor
te st and re te st reliability.
Furthermore, normal levels have
not been clearly established.
Renal tubular acidosis, if sus­
pected in a patient with recurrent
stone formation, can be diagnosed
Figure 1. A premedicated patient about to receive extracorporeal shock wave lithotripsy. Modem lithotnptors
don't require that the patient is immersed in a waterbath, hospitalized or anaesthetized.
64
MODERN MEDICINE OF SOUTH AFRICA / FEBRUARY 2000
by the ammonium chloride loading
test. Medullary sponge kidney has
a pathognomonic intravenous
pyelographic appearance indicat­
ing ectasia of the renal papillae.
Calcium restriction is no longer
considered to be appropriate
dietary advice (see the Patient
Handout above). Inadequate calci-
Figure 2. Patients need to be counselled that the first
treatment of lithotripsy is only 80% successful and that
20% of patients require two or more treatments.
Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2012.)
For effective qlycaemic control
Now there's a simpler way.
Trials show less risk of hypoglycaemia1
Helping you manage postprandial hyperglycaemia2
In trials involving type 2 and type 1 patients with similar
HbA1c levels the average number of nocturnal
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less than with human 30/70.
Thanks to improved postprandial control, your patients can worry
less about hyperglycaemia after meals.
Rate o f Nocturnal Hypoglycaemia "
(20:00 to 7:00) per Patient During the 3 Month
Treatment Period
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insulin) mayresult intheneedlor achangeindosage.
H u m a lo g M lx 2 5
n=t100
‘p = <0.025
Ahypogtycaemic episode was defined asany time apatient fait, or anotherpersonobserved, that he.-'sheis experiencinga
wgivsymptom»yt»cnhe/she would associate wrth ftypogfycasmia ora Woodglucosemeasurement lessthan3.0mmol (64m^'dL).
Researchshows that nlghtime hypogtycaeme episodesoocor frequently •43%ol ail episodesintheOCCTstudywerenocturnal.
The S i m p l e P r e m i x
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Action.
Relererx»s'. t) Malone JK. etai Less nocturnal hypoglycaemta dunngtreatment wrtheveningadrmnisjrstionol HumalogMix2S. afcspnymtefmed
insulin mixture. Oabefc MedGntt 1998,15(supp) 2};S34. 2) KornsloVA. ToocmnenJA, EbelmgP. LisproMix25Insulin aspremeal therapyinTyp«
diabeticpetieris DiabetesCam1999; 22(3):459-462. 3) Dataonfile, Eli LillyandCompany. IODN(siiwruttedtoEASO1998). 4) Packageinsert
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Reg. No. 33/21.1«073 Bi Lilly(SA) (Ply) Ltd. Reg. No 57.W37W07
u
M
m
ix 2
a
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5
25% insulin lispro 75% insulin
lispro protamine suspensbn
Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2012.)
W e are all different. Different in age, in size with different cultures, environments and education. W e are
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This all means it’s impossible to control our diabetes in any one given way.
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IS3I Humulin N. Suspension for injection. Isophane Biosynthetic Human Insulin (rDNA origin). 100IU/ml Reg. No. R/21.1/1
Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2012.)
Stone-form ing patients w ith
a metabolic cause excluded have a 50%
chance o f recurrence w ithin five years.
um in the gut increases oxalate
reabsorption from the small intes­
tine, thereby increasing urinary
oxalate concentrations and precip­
itating calcium oxalate crystalliza­
tion in the renal microtubules.
H yperoxaluria also occurs in
patients with inflammatory bowel
disease. Restriction of dietary pro­
tein and salt is recommended.
Previous advice suggesting high
fibre diets to limit calcium reab­
sorption is no longer given because
this may increase oxalic acid reab­
sorption in the gut.
In summary, calcium oxalate
stones account for 95% of stones
seen in clinical practice. The best
dietary advice currently available
to give patients is:
• drink a minimum of two litres of
water each day
• restrict protein intake to lg per
kg of body weight per day
• re stric t salt to less than
lOOmmol per day (do not add salt
to food; salt restriction lowers uri­
nary calcium excretion).
Differential diagnosis
of renal colic
The diagnosis of renal colic is well
known to most practitioners. It
can, however, be mimicked by
spinal, ovarian or appendiceal
pathology.
Particular care should be given
to an elderly patient presenting
with an initial episode of renal
colic. Vascular events are common
in the elderly and frequently
mimic renal colic. Acute renal
artery occlusion from thrombo­
embolic disease may occur in
patients with generalized athero­
sclerosis or patients suffering atri­
al fibrillation. A dissecting abdom­
inal aortic aneurysm, especially
involving the left iliac artery, may
mimic acute renal colic and care­
ful abdominal examination for a
pulsating mass is mandatory.
When an acute vascular event is
suspected, an abdominopelvic CT
scan is the initial investigation of
choice. Performed with and with­
out intravenous contrast, it may be
used to identify a stone in the
ureter, abdominoiliac
aneurysmal disease
or other associated
intra-abdominal pa­
thology. Should the
CT scan demonstrate
a nonfunctioning,
nonobstructed kid­
ney, urgent investi­
gation for a vascular
cause is essential.
Doppler ultrasound
of the renal artery as
an initial investiga­
tion is useful, fol­
lowed by selective
angiography should
surgical intervention
be contemplated.
Imaging the
urinary tra c t
Figure 3 (above). Real view of stone in renal
pelvis. A guide wire and balloon catheter are
visible.
Imaging the urinary tract is useful
for patients with renal colic.
A b d o m in a l X -ray
Plain abdominal radiography is of
limited benefit at the time of ini­
tial presentation. It is more useful
for tracking the progress of a small
opaque stone over time, as it pass­
es through the u reter into the
bladder. Uric acid stones are
nonopaque and will therefore not
be seen on plain abdominal radiog­
raphy. Other small stones overlying bony prom inences or
obscured by bowel gas will also not
be evident on plain radiography.
U rinary tr a c t u ltra so u n d
Ultrasound is useful to demon­
strate nonopaque uric acid stones
in the kidney. It will also demon­
strate hydronephrosis. However, a
normal renal ultrasound does not
exclude a diagnosis of renal colic.
In traven ou s p yelo g ra p h y
Intravenous pyelography will con­
firm a diagnosis and provide infor­
mation relating to stone size and
position. This information will
enable a decision to be made with
respect to the likelihood of the
stone passing. Intravenous pyelog­
raphy will also dem onstrate
abnormalities of the urinary tract
and the degree of hydronephrosis.
H elica l CT scan n in g
The new helical CT scanning tech­
nique is a very practical alterna­
tive to intravenous pyelography as
it is rapid and will demonstrate
nonopaque stones and nonurinary
tra c t pathology. Unlike in tra ­
venous pyelography, delayed films
are not necessary to demonstrate
the level of ureteric obstruction.
M anagem ent of ac u te renal
colic
It is important to make an accurate
diagnosis, especially of an initial
episode of renal colic. Intravenous
pyelography or helical CT scanning
are the modalities of choice.
Most initial presentations of renal
colic are due to small, opaque distal
stones that will pass over a matter
of days to weeks. The attending
practitioner should provide pain
relief, monitor the patient for com­
plications such as sepsis, and track
the passage of the stone with plain
radiography. Anti-prostaglandin
medication provides the best analge­
sia. Nonsteroidal anti-inflammatory
drugs are better than intramuscular
narcotics, and far superior to oral
hyoscine butylbromide which is of
very limited benefit.
FEBRUARY 2000 / MODERN MEDICINE OF SOUTH AFRICA
65
Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2012.)
N ew stone age
I
continued
I
S p ecia l cases o f ren a l colic
Pregnancy
Renal colic is common during
pregnancy. At 16 weeks the gravid
uterus compresses the ureter, par­
ticularly the right ureter at the
pelvic brim. This is a cause of
renal colic and can occasionally be
relieved by changes in the moth­
er’s position. More common, how­
ever, is the presence of a distal
ureteric stone.
R adiation exposure is best
avoided during pregnancy and
therefore ultrasound is the modali­
ty of choice. Renal ultrasonogra­
phy may demonstrate unilateral
hydronephrosis but will seldom
show the stone because it is not an
accurate means of imaging the
ureter. Initial management is con­
servative, with an expectation that
the stone will pass. Should conser­
vative measures fail, referral to an
urologist is necessary for appropri­
ate intervention, which would nor­
mally involve the passage of a J J
silicon stent.
Drug addicts
Drug addicts frequently present
claiming a long history of renal
colic, blood in their urine and aller­
gy to contrast media, thereby defy­
ing accurate diagnosis. The new
helical CT scanning technique is
especially useful in these situa­
tions because diagnoses can be
confirmed or denied w ithout
administering an intravenous con­
trast medium. The intramuscular
analgesic ketorolac trometamol
(30mg, injected intramuscularly) is
an effective agent in the presence
of renal colic. Use of ketorolac
trometamol avoids the need to give
a drug addict narcotic analgesia.
Septic patient
Obstruction, regardless of cause,
in the urinary tract associated
with infection is a potentially fatal
combination. Any patient with
renal colic and fever needs urgent
hospital admission for parenteral
antibiotic therapy and urgent
intervention such as the percuta­
neous placement of a decompres­
sive nephrostomy tube. Failure to
66
Calcium oxalate stones account for 95%
0f those seen in clinical practice. Do not
I advise dietary calcium restriction.
tre a t the obstructed infected
patient aggressively may lead to
overwhelming septicaemia.
The solitary Kidney
A patient with a solitary kidney
and acute ureteric colic due to a
ureteric stone may suffer acute
renal failure if the ureter becomes
obstructed. This patient requires
early referral to a urologist and
early intervention.
Technologies for urinary
stone m anagem ent
‘C utting for the stone’ now
accounts for only 5% of urological
stone interventions. Newer tech­
nologies are explained below.
The Parke-Med
cardiovascular range
the stone (Figure 1).
Lithotripsy is particularly effec­
tive for renal and upper ureteric
stones, though it can also be used
for stones in the pelvic ureter.
Stones greater than 2cm in diame­
ter generally require ancillary pro­
cedures, rather than lithotripsy as
monotherapy.
To avoid unrealistic expecta­
tions, patients need to be carefully
counselled th at 80% of patients
require only one treatment where­
as 20% require two or more treat­
ments (Figure 2). Calcium mono­
hydrate stones are particularly
dense and more likely to require
multiple treatments. Ten per cent
of patients who receive lithotripsy
for an intrarenal stone will experi­
ence renal colic if a large fragment
passes down the ureter.
Percutaneous nephrolithotom y
Percutaneous nephrolithotomy
involves a general anaesthetic in
Caring for the
hearts of Africa
PARKE-
ED
Q U A L I T Y W I T H O U T C O M P R O M IS E
£
www.parke-med.co.za
E x tra co rp o rea l shock w ave
lith o trip sy
A high energy shock wave is gen­
erated and focused on the patient’s
stone with the intention of frag­
menting the stone and allowing
the small fragments to pass spon­
taneously. Modem lithotriptors no
longer require that the patient is
immersed in a waterbath or hospi­
talized. With modem lithotripsy,
the patient has a mild premedica­
tion, lies on an adapted X-ray
table, and has a treatment lasting
45 m inutes during which time
4000 shock waves are delivered to
MODERN MEDICINE OF SOUTH AFRICA / FEBRUARY 2000
Figure 4 Using ureteroscope
transvesically with lithoclast,
video cam era and m onitor.
Endourological procedures are
generally day only procedures
and patients can return to work
within 24 hours.
Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2012.)
W hat seems to be renal colic
in an elderly p a tien t is quite likely
to be an acute vascular event.
which the kidney is accessed percutaneously by means of a needle
puncture. The percutaneous punc­
ture tract is dilated such that a
nephroscope with a video camera
can be introduced into the kidney
(Figure 3). In tra re n a l access
allows passage, through the
nephroscope, of intracorporeal
lithotriptors such as the Swiss
lithoclast. Percutaneous nephro­
lithotomy is particularly applica­
ble for large stones such as
staghom calculi. A combination of
lith o tripsy and percutaneous
extraction is frequently performed
for large, complicated stones in the
upper tract.
Endourological procedures
The development of semirigid mini
ureteroscopes that can be passed
transvesically into the ureter has
greatly facilitated the management
of impacted distal ureteric stones.
In skilled hands, this technique is
successful in the m ajority of
patients and is far superior to blind
stone extraction with a dormia
basket. Intracorporeal lithotriptors
include the ballistic Swiss litho­
clast and laser fibres that facilitate
intraureteric lithotripsy in situ.
These devices are passed through
the operating channel of the mini
ureteroscope (Figure 4).
J J silicon sten ts
J J stents are particularly useful in
a variety of urological applications.
They are soft, perforated silicon
tubes that are placed cystoscopically in order to relieve calculus
obstruction and facilitate a defini­
tive treatment, such as lithotripsy.
They can be removed in the office
using nonanaesthetic flexible cystourethroscopy when the stone has
been adequately fragmented.
P ercu taneous nephrostom y
tubes
Percutaneous X-ray guided place­
ment of intrarenal decompressive
nephrostomy tubes is an essential
part of the management of the
obstructed septic patient.
Conclusion
Shared care is appropriate for
most cases of acute renal colic
when an accurate diagnosis has
been made and the stone is judged
to have a high likelihood of pas­
sage. A detailed metabolic work up
is not appropriate in the initial
stone-forming stage. Calcium and
uric acid levels should be checked
and the patient should be encour­
aged to drink two litres of water
each day, every day. Modem uro­
logical stone centres are now
equipped with a range of invasive
and noninvasive technologies that
facilitate prompt nonoperative
management of the majority of
renal stones. ■
References
1. Marshall VR. The simple inves­
tigation and medical treatment of
renal calculi. Aust Prescriber 1996;
19(4): 94-97.
2. Katelaris PM. Managing kidney
stones. Medical Observer 1993; 23
Jul: 47-49.
CPD questions appear on page 68
P ractice points
• Acute renal colic Is a common presentation. Special consideration should
be given to particular categories of stone patients, such as pregnant
women and drug addicts, and patients with a solitary kidney
• Patients with goul and patients with myeloproliferative disorders that are
being treated with chemotherapy are particularly at nsk of forming uric
acid stones
• Calcium restriction is no longer considered to be appropriate dietary
advice for calcium oxalate stone-forming patients.
• Patients should be referred to a urologist when they:
— are pregnant
— have a solitary kidney
— present wHh a stone that tails to pass
— present with (ever
— present with a stone larger than 5mm In diameter.
• Beware the elderly patient with an aneurysm masquerading as renal colic.
A ccuracy of health inform ation on th e In tern et questionable
Much of the health information on the Internet is inaccu­
rate. inappropriate, misleading, or not reviewed by doc­
tors, report a group of researchers from the University of
Michigan Health System in the August 1, 1999, issue of
Cancer.
After performing typical Internet searches for informa­
tion on an uncommon type of cancer, Ewing's sarcoma,
the sarcoma, the researchers found that nearly half ol the
sites that contained treatment information had not been
peer-reviewed. In addition, about six percent of sites had
wrong information and many others were misleading.
A total of 400 sites were evaluated in the study and
these pages were randomly selected from the more than
27 000 sites retneved when four different spellings ot the
disease's name were entered Into four search engines.
'For the public's sake, we should work to improve the
quality of health Information on the Internet, and to
increase public understanding of how important it is for
medical data to go through the process of scientific verification,’ says lead author J Sybil Biermann, MD. 'In the
meantime, the best advice for the public Is “Consider the
source*' she adds.
FEBRUARY 2000 / MODERN MEDICINE OF SOUTH AFRICA
67
Reproduced by Sabinet Gateway under licence granted by the Publisher (dated 2012.)
QUESTIONS FOR CPD ARTICLE NUMBER FOUR
CPD: 1 point
The new stone age
Instructions
1. Before you fill out the computer answer form, mark
your answers In the box on this page. This provides
you with your own record,
2 The answer form is perforated and bound into this
/oumal Tear it out carefully.
3. Read the instmctions on the answer form and fol­
low them carefully:
4. Your answers for the February issue must reach
M o d e rn M edicine, PO B o x 2271, Clareinch 7740, by
May 31. 2000
5. You must score at least 60% in order to be award­
ed the assigned CPD points.
Answer true or false to parts (a) to (e) of the following
questions.
Part 1. The following statements are true:
a. Stone disease is most common after the fifth decade
of life.
b. Uric acid stones account for 95% of stones seen in
clinical practice.
c. Calcium-containing stones are more common in men
than in women.
d. An active lifestyle is protective against calcium stone
disease.
e. The incidence of stone disease is higher in patients
with urinary volumes that are persistently high.
Part 2. In the investigation and management of
stone disease:
a. Uric acid stones can occur in patients with normal
levels of uric and in their serum and urine.
b. Cystinuria can be diagnosed by stone analysis.
c. Stuvite stones are caused by urinary infection.
d. A 24-hour urine collection should be ordered routinely
for all patients who form calcium oxalate stones.
e. Calcium oxalate stones can be dissolved in vivo.
Part 3. When imaging the urinary tract:
a. Abdominal radiography is a useful method of tracking
the progress of an opaque stone passing through the
ureter into the bladder.
b. Uric acid stones are opaque.
c. Ultrasound is a useful method of demonstrating the
presence of uric acid stones in the kidney.
d. Helical CT scanning will demonstrate the presence of
a nonopaque stone.
e. Helical CT scanning requires delayed films to demon­
strate the level of ureteric obstruction.
Part 4. The following statements are true:
a. Renal colic is common during pregnancy.
b. ‘Cutting for the stone' now accounts for 50% of uro­
logical stone interventions.
c. More than 95% of patients who receive extracorporeal shock wave lithotripsy require more than one episode
of treatment.
d. Percutaneous nephrolithotomy is often indicated for
staghorn calculi.
e. JJ stents are used to relieve calculus obstruction.
C PD Article 4
a
MODERN MEDICINE OF SOUTH AFRICA / FEBRUARY 2000
Part 4
Part 3
a
©
©
a
g
g
©
©
b
©
©
b
©
©
b
©
©
©
©
c
©
©
c
©
©
c
©
©
©
©
d
©
©
d
©
©
d
©
©
©
©
e
©
©
e
©
©
e
©
©
See tear-out sheet for details
68
Part 2
Part 1