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Sudden onset of severe pain in the flank is most often due to the
passage of a stone formed in the kidney, down through the ureter.
The pain is characteristically of very sudden onset, is colicky in
nature (waves of increasing severity are followed by a reduction
in severity, but it seldom goes away completely), and it radiates
to the groin as the stone passes into the lower ureter. The pain
may change in location, from the flank to the groin, but the location
of the pain does not provide a good indication of the position
of the stone, except in those cases where the patient has pain
or discomfort in the penis and a strong desire to void, which
suggest that the stone may have moved into the intramural part
of the ureter. The patient cannot get comfortable, and may roll
around in agony. Indeed, the majority of women we have seen
with radiologically confirmed ureteric stones and who have also
had children, describe the pain of a ureteric stone as being worse
than the pain of labour.
The problem with these classic symptoms of ureteric colic is
that approximately 50% of patients with the symptoms we have
just described do not have a stone con.rmed on subsequent
imaging studies, nor do they physically ever pass a stone (Smith
et al. 1996, Thomson et al. 2001). They have some other cause
for their pain. The list of differential diagnoses is very long. A
sample of those that we have personally seen include leaking
abdominal aortic aneurysms, pneumonia, myocardial infarction,
ovarian pathology (e.g., twisted ovarian cyst), acute appendicitis,
testicular torsion, in.ammatory bowel disease (Crohn’s, ulcerative
colitis), diverticulitis, ectopic pregnancy, burst peptic ulcer,
bowel obstruction, and malaria (presenting as bilateral loin pain
and dark haematuria—black water fever)!
The point, then, in making a diagnosis is to exclude other
causes of flank pain, many of which are serious and may be lifethreatening
(leaking aortic aneurysm, gastrointestinal causes,
medical causes), from those cases where the pain is due to a
ureteric stone, which is very rarely life-threatening.
Age of the patient can help in determining whether a diagnosis
of a ureteric stone is more or less likely. Ureteric colic tends
to be a disease of men (and to a lesser extent women) between
the ages of roughly 20 and 60. It does affect younger and older
patients, but the range of differential diagnoses at the extremes
of age, and in women, is greater. Thus, a 25-year-old man who
presents with sudden onset of severe, colicky flank pain probably
has a ureteric stone, but an 80-year-old woman probably has
something else going on.
Examination and Simple Tests
The pain from a ureteric stone is colicky in nature. It makes the
patient want to move around, in an attempt to .nd a comfortable
position. The patient may be doubled-up with pain. On the
other hand, patients with conditions causing peritonitis, such as
appendicitis or a ruptured ectopic pregnancy, want to lie very
still. Any movement is very painful and in particular they do not
like palpation of their abdomen. Thus, when you approach
patients, just spend a few seconds looking at them. If they are
lying very still, you may be dealing with a non-stone cause of
flank pain.
Pregnancy Test
All premenopausal women with acute flank pain should undergo
a pregnancy test. If this is positive, they are referred to a gynaecologist.
If it is negative, they should undergo imaging to determine
whether or not they have a ureteric stone. It goes without
saying that any premenopausal woman who is going to undergo
imaging using ionising radiation, should have a pregnancy test
done .rst.
Dipstick or Microscopic Haematuria
While many patients with ureteric stones have dipstick or microscopic
haematuria (and more rarely macroscopic haematuria),
10% to 30% of such patients have no blood in their urine
(Kobayashi et al. 2003, Luchs et al. 2002). There is evidence that
if a stone has been present in the ureter for 3 to 4 days, there is
a greater likelihood that haematuria will not be detectable.
The sensitivity of dipstick haematuria for detecting ureteric
stones presenting acutely is in the order of 95% on the .rst day
of pain, 85% on the second day of pain, and 65% on the third
and fourth days (Kobayashi et al. 2003). Dipstick testing is
slightly more sensitive than urine microscopy for detecting
stones (80% versus 70%), and both ways of detecting haematuria
have roughly the same speci.city for diagnosing ureteric
stones (about 60%). The slightly greater sensitivity of dipstick
testing over microscopy reflects the fact that seeing red blood
cells depends on how good the technician is at looking for them,
and that they lyse, and therefore disappear, if the urine specimen
is not examined under the microscope within a few hours.
Thus, if you see a patient with a history suggestive of ureteric
colic, and their pain started 3 to 4 days ago, they may well have
no blood detectable in their urine even though they do have a
stone.
The relatively poor speci.city of dipstick or microscopic
haematuria for detecting ureteric stones re.ects the multiple
other pathologies that can mimic the pain of a ureteric calculus
combined with the fact that blood is detectable in a proportion
of patients without demonstrable urinary tract pathology; in
fact, no abnormality is found in approximately 70% of patients
with microscopic haematuria, despite full investigation with
cystoscopy, renal ultrasound, and intravenous urography (IVU)
(Khadra 2000). Thus, blood in the urine may be a completely
coincidental .nding in a patient who presents with flank pain
due to a non-stone cause.
Temperature
Perhaps the most important aspect of examination in patients
with a ureteric stone confirmed on imaging is to measure their
temperature. If patients have a stone, and they have a fever of,
say, 39°C, they may well have infection proximal to the obstructing
stone. A fever in the presence of an obstructing stone is an
indication for urine and blood culture, intravenous fluids and
antibiotics, and nephrostomy drainage if the fever does not
resolve within a matter of hours of commencement of antibiotics.
Investigation of Suspected Ureteric Colic
The intravenous urogram (IVU) was for many years the mainstay
of diagnostic imaging in patients with flank pain
The last few years have seen a move toward computed tomography
(CT) urography (CTU) CTU has the following
advantages over IVU:
1. It has greater speci.city (95%) and sensitivity (97%) for
diagnosing ureteric stones than has IVU (Smith et al. 1996). CTU
can identify other, non-stone causes of flank pain such as leaking
aortic aneurysms
2. There is no need for contrast administration with CTU.
This avoids the chance of a contrast reaction. The risk of fatal
anaphylaxis following the administration of low-osmolality contrast
media for IVU is on the order of 1 in 100,000 (Caro et al.
1991).
3. CTU is faster, taking just a few minutes to image the
kidneys and ureters. An IVU, particularly where delayed .lms are
required to identify a stone causing high-grade obstruction, may
take hours to identify the precise location of the obstructing
stone
4. In some hospitals, where high volumes of CT scans are
done, the cost of CTU is equivalent to that of IVU (Thomson et
al. 2001).
If you only have access to IVU, remember that it is contraindicated
in patients with a history of previous contrast reactions,
and should be avoided in those with hay fever or a strong history
of allergies or asthma who have not been pretreated with highdose
steroids 24 hour before the IVU. Patients taking metformin
for diabetes should stop this for 48 hours prior to an IVU. Clearly,
being able to perform an alternative test in such patients, such
as CTU, is very useful.
In hospitals where 24-hour access to CTU is not possible,
patients with suspected ureteric colic may be admitted for pain
relief, and undergo a CTU the following morning. It is our policy,
when CT urography is not immediately available (between the
hours of midnight and 8 a.m.), to perform an abdominal ultrasound
in all patients over the age of 50 years who present with
flank pain suggestive of a possible stone. This is done to exclude
serious pathology such as a leaking abdominal aortic aneurysm
and to demonstrate any other gross abnormalities due to non–
stone-associated flank pain.
Plain abdominal x-ray and renal ultrasound are not suffi-
ciently sensitive or speci.c for their routine use for diagnosing
stones.
Magnetic Resonance Urography
This is a very accurate way of determining whether or not a stone
is present in the ureter (Louca et al. 1999; O’Malley 1997).
However, at the present time, cost and resticted availability limit
its usefulness as a routine diagnostic method of imaging in cases
of acute flank pain. This may change as MR scanners become
more widely available.
Acute Management of Ureteric Stones
The management of any acutely presenting ureteric stone starts
with pain relief. Nonsteroidal anti-inflammatory drugs (NSAIDs),
such as diclofenac (Voltarol) given by intramuscular or intravenous
injection, by mouth, or per rectum can, in many cases,
provide rapid and effective pain control (Laerum et al. 1996). In
other cases opiate analgesics such as pethidine or morphine are
required, in addition to NSAIDs.
There is no need to encourage the patient to drink copious
amounts of fluids or to give them large volumes of .uids intravenously,
in the hope that this will ‘.ush’ the stone out. Renal
blood .ow and urine output from the affected kidney will tend
to fall during an episode of acute partial obstruction due to a
stone, and any excess .uid that is excreted will tend to cause a
greater degree of hydronephrosis in the affected kidney, which
will make ureteric peristalsis even less ef.cient than it already is.
Remember, peristalsis, the forward propulsion of a bolus of urine
down the ureter, can occur only if the walls of the ureter above
the bolus of urine can coapt, i.e., close .rmly together. If they
cannot, as occurs in a ureter distended with urine, the bolus of
urine cannot move distally. This is why insertion of a percutaneous
nephrostomy tube can restore ef.cient peristalsis. By
draining the hydronephrosis and hydroureter, it allows the
ureteric wall to coapt and thus encourages a return to normal
peristaltic function.
In many instances, small ureteric stones pass spontaneously
given a period of ‘watchful waiting’ with analgesic supplements
for exacerbations of pain. Accurate determination of stone size
(on plain abdominal x-ray if the stone is so visible or by CTU)
can help predict the chances that the stone will pass out of the
ureter and into the bladder; 95% of stones measuring 5mm or
less pass spontaneously (Segura et al. 1997). However, it never
ceases to amaze us that stones much larger than 5mm do, from
time to time, drop harmlessly out of the ureter, and that others
that are only 4 mm in diameter stubbornly remain in the ureter.
Whether patients opt for watchful waiting or active intervention
will, to a certain extent, depend on other factors, such as
their job. Young, active patients may be very keen to opt for surgical
treatment because they need to get back to work or their
child-care duties, whereas some patients will be happy to sit
things out. Discuss the options with patients so they are able to
make a rational decision.
Indications for Intervention to Relieve Obstruction and/or
Remove the Stone
1. Pain that fails to respond to analgesics, or that initially
does so but then recurs and cannot be controlled with additional
pain relief, is an indication for drainage of the kidney (by JJ stent
insertion or percutaneous nephrostomy) or emergency de.nitive
treatment of the stone.
2. Where there is an associated fever, one should have a low
threshold for draining the kidney, and this is usually done by
percutaneous nephrostomy.
3. Where renal function is impaired because of the stone
(solitary kidney obstructed by a stone, bilateral ureteric stones,
or preexisting renal impairment that gets worse as a consequence
of a ureteric stone), the threshold for intervention is lower.
4. Obstruction unrelieved for >4 weeks can result in longterm
loss of renal function. In a study of 239 patients presenting
with unilateral ureteric stones, after 2 weeks the stones were still
present in 143 patients (Holm-Nielsen et al. 1981). Of these 143
patients, 50% had renal obstruction de.ned by isotope renography;
11 of 31 patients (35%) with obstruction for >4 weeks developed
varying degrees of irreversible renal damage. The problem
with current imaging for stones, which nowadays is essentially
CTU, is the absence of any information on the presence of renal
obstruction (most urologists do not routinely obtain isotope
renograms in patients with ureteric colic). However, what we do
know from the Holm-Nielsen study is that only 50% of patients
with ureteric stones that are still present at 2 weeks, have renographic
evidence of obstruction. It seems reasonable to limit the
period of watchful waiting for spontaneous stone passage to
approximately 4 weeks and to intervene to remove the stone or
drain the kidney (by, for example, JJ stent placement) if it has
not passed at this time.
5. Personal or occupational reasons. As stated above, some
patients will not be able to wait for spontaneous stone passage
and therefore may accept the risks associated with active intervention.
The classic example would be the airline pilot who is
unable to .y until he is stone free.
Emergency Temporising and Definitive Treatment of the Stone
Where the pain of a ureteric stone fails to respond to analgesics
or where renal function is impaired because of the stone, then temporary
relief of the obstruction can be obtained by insertion of a
JJ stent or percutaneous nephrostomy tube. This has the advantage
of not taking much time to perform. However, the disadvantage
is that the stone is still present. While the stone may pass down
and out of the ureter with a stent in situ, in many instances the
stone simply sits where it is and subsequent definitive treatment is
still required. Furthermore, though a JJ stent can relieve the pain
due to the stone, it can cause bothersome irritative bladder symptoms
(pain in the bladder, frequency, and urgency). Having said
this, a JJ stent will usually result in passive dilatation of the ureter
so that subsequent stone treatment in the form of ureteroscopy is
technically easier and therefore more likely to be successful. Similarly,
by allowing passive dilatation of the ureter, fragments of
stone produced by extracorporeal shock-wave lithotripsy (ESWL)
may be more easily able to pass out of the ureter.
General options for de.nitive treatment of a ureteric stone
are ESWL and ureteroscopic stone removal. ESWL is suitable for
stones in the upper and lower ureter. Ureteroscopy can be used
to treat stones at any level in the ureter, although access and
fragmentation of stones in the lower ureter is generally easier
Whether you decide to carry out definitive stone treatment,
and what type of treatment you offer, will depend on local facilities
and expertise. Many hospitals do not have daily access to
ESWL. In others, surgeons with experience of ureteroscopic
stone fragmentation are not always available.
Emergency Treatment of an Obstructed, Infected Kidney
The rationale for performing percutaneous nephrostomy rather than JJ stent insertion for an infected,
obstructed kidney is to reduce the likelihood of septicaemia
occurring as a consequence of showering bacteria into the circulation.
It is thought that this is more likely to occur with JJ
stent insertion than with percutaneous nephrostomy insertion.
Other Non-Stone Causes of Acute Flank Pain
These include pelviureteric junction obstruction (PUJO), which
is called ureteropelvic junction obstruction (UPJO) in North
America, and infective causes such as acute pyelonephritis,
emphysematous pyelonephritis, and xanthogranulomatous
pyelonephritis.
Pelviureteric Junction Obstruction
This is a functional impairment of transport of urine from the
renal pelvis into the ureter. It may be acquired or congenital. The
majority of cases are probably congenital in origin, but do not
always present in childhood. Indeed, many present in young
adults. The precise cause of the aperistaltic segment of ureter
that leads to congenital cases of this condition is not known.
Acquired causes of PUJO include stones (the investigation and
management of which is discussed above), urothelial tumours
(transitional cell carcinoma), and inflammatory and postoperative
strictures.
Not infrequently PUJO may present acutely with flank
pain, which may be severe enough to mimic an ureteric stone.
When imaging (nowadays usually a CT scan) demonstrates
hydronephrosis, with a normal-calibre ureter below the pelviureteric
junction (PUJ) and no stone (or tumour) is seen, the
diagnosis of PUJO becomes likely, and a renogram (e.g., MAG3
scan) should be done to conform the diagnosis. | 
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