Kidney Colic- Renal colic is a very severe pain that can present suddenly and
without warning. It is usually caused by stones in the kidney, renal pelvis or
ureter. The pain is caused by dilatation, stretching and spasm of the ureter. In
contrast, the slow stretching associated with chronic obstruction with some
types of cancer is painless. In most cases no cause is found.
The lifetime risk for stones is said to be about 10% for men with a maleto-female ratio of 3:1.1
A family history of stones doubles the risk but most patients with renal
colic do not have a family history.
The peak age of onset is 20 to 40 and if stones present significantly
outside this age group there is a greater chance of an underlying
The risk of stones is higher in higher socio-economic groups.
Risk factors- Predisposing factors to renal stones are many but can be summed
up as follows:
Excessive calcium in the urine
Excessive oxalate in the urine
Excessive excretion of uric acid, with or without clinical gout
Deficiency of citrate in the urine
Cystinuria (an autosomal recessive aminoaciduria)
Drugs, especially thiazide diuretics
People with urinary stasis due to anatomical abnormalities of the pelvicalyceal system, e.g. medullary sponge kidney, pelvi-ureteric junction
obstruction, ureteric stricture, vesico-ureteric reflux, horseshoe kidney
Presentation- The classical features of renal colic are sudden severe pain:
Pain starts in the loin about the level of the costo-vertebral angle (but
sometimes lower) and moves to the groin, with tenderness of the loin or
renal angle, sometimes with haematuria.
If the stone is high and distends the renal capsule then pain will be in the
flank but as it moves down pain will move anteriorly and down towards
A stone that is moving is often more painful than a stone that is static.
The pain radiates down to the testis, scrotum, labia or anterior thigh.
Whereas the pain of biliary or intestinal colic is intermittent, the pain of
renal colic is more constant but there are often periods of relief or just a
dull ache before it returns. The pain may change as the stone moves.
The patient is often able to point to the place of maximal pain and this
has a good correlation with the current site of the stone.
There is usually associated nausea and often vomiting.
There are often urinary symptoms that may be dysuria, frequency,
oliguria and haematuria.
There may be a previous history of renal colic.
There may have been recent dehydration, including strenuous physical
exercise or starting a drug that increases the risk.
The pain of renal colic can be divided into 3 phases. It usually lasts between 3
and 18 hours, moving down the dermatomes from T10 to S4.
Acute phase: the onset is usually at night or in the early morning, waking
the patient from sleep. If it starts in the day, the onset is often slow and
insidious. The pain is constant although there may be paroxysms of even
more severe pain. It reaches maximum intensity between ½ and 6 hours
but usually between 1 and 2 hours.
Constant phase: usually lasts between 1 and 4 hours but can last as long
as 12 hours. This is the time during which most people reach A&E, the
surgery or a GP out-of-hours centre for treatment.
Abatement phase: usually lasts between 1 and 3 hours. The pain eases
and the patents often falls asleep, perhaps exhausted by the ordeal or
under the influence of strong analgesia.
The patient with colic of any sort writhes around in agony. This is in
contrast to the patient with peritoneal irritation who lies still.
The patient is apyrexial in uncomplicated renal colic (pyrexia suggests
infection and the body temperature is usually very high with
Examination of the abdomen will usually reveal tenderness over the
affected loin. Bowel sounds may be reduced. This is common with any
There may be severe pain in the testis but the testis should not be
Blood pressure may be low.
Full and thorough abdominal examination is essential to check for other
possible diagnoses, e.g. acute appendicitis, ectopic pregnancy, aortic
The stone often causes some bleeding into the renal tract and this may
produce a positive result for blood on stick testing (a negative test does
not exclude the diagnosis).
If microscopy shows pyuria, this suggests infection.
Check urine pH. pH above 7 suggests urea splitting organisms such as
Proteus whilst a pH below 5 suggests uric acid stones.
MSU for microscopy, culture and sensitivities
Blood for renal function, electrolytes, calcium, phosphate and urate
Encourage the patient to try to catch the stone for analysis. This may
mean urinating through a tea strainer, filter paper such as a coffee filter
or a gauze.
Imaging of the urinary tract traditionally starts with a KUB x-ray. This is
larger than the plain abdominal x-ray as it takes in both kidneys, ureters
and bladder. Around 75% of stones are of calcium and so will be radioopaque.
Helical CT is now regarded as the gold standard for the investigation of
urinary stones. Current guidance is that the best technique is
unenhanced helical CT4 and CT is now the first line investigation in some
hospitals, in order to avoid an accumulation of radiation which occurs if
CT is performed only after an initial x-ray.
Differential diagnosis- This depends upon the position of the pain and the
presence or absence or pyrexia.
Biliary colic, usually from gall stones. Pain may radiate to the shoulder.
There may be some jaundice and dark urine.
Dissection of an aortic aneurysm: beware the patient who presents with
features of renal colic for the first time over the age of 60. This may be
dissection of aortic aneurysm leading to ruptured aortic aneurysm.
Pyelonephritis: very high temperature. Pain unlikely to radiate to groin.
Infection may co-exist.
Acute pancreatitis: pain radiates to back. There tends to be epigastric or
left upper quadrant pain and tenderness. Paralytic ileus may set in.
Vomiting occurs early in the condition.
Acute appendicitis: tender and guarding over McBurney's point. Possibly
absent if posterior appendix. Any peritonism will cause lying still, not
Perforated peptic ulcer: rigid abdomen; patient lies still.
Epididymo-orchitis or torsion of testis: very tender testis.
Sinister causes of back pain: usually tender over vertebrae.
Drug addiction: There are reports of people with fictitious stories of
renal colic, designed to obtain an injection of pethidine. These patients
tend to be abusive when offered anything other than pethidine.
Munchausen syndrome (term for psychiatric disorders known as
factitious disorders wherein those affected feign disease, illness, or
psychological trauma in order to draw attention or sympathy to
Management- Medical assessment is advisable within 30 minutes of the onset
Initial treatment- Relief of pain must be an early priority.
The usual dose of morphine sulfate is 10 mg/70 kg of body weight
intramuscularly or subcutaneously every 4 hours
For more rapid results, morphine sulfate can be administered
intravenously in doses of 4-10 mg but must be administered slowly or in
small increments to avoid excessive adverse effects and potentially
dangerous respiratory depression
Ketorolac (NSAID)- The dosage is an initial 30-60 mg IM or 30 mg IV
followed by 30 mg IV or IM every 6-8 hours. A dose of 15 mg is
recommended in patients older than 65 years.
An antiemetic may be required if there is severe nausea and vomiting,
dehydration or an opioid is given. Metoclopramide- usual dose in adults
is 10 mg IV or IM every 4-6 hours as needed. Avoid metoclopramide in
young people in view of the risk of extrapyramidal side effects.
Aggressive Medical Therapy- after an acute renal colic attack, short-term
use, for patients who can take medications reliably and can tolerate any
Ketorolac at 10 mg orally every 6 hours for 5 days
Nifedipine XL at 30 mg/d PO for 7 days
Prednisone 20 mg PO twice a day for 5 days
Trimethoprim/sulfamethoxazole DS once a day for 7 days
Acetaminophen (Tylenol) 2 tablets 4 times a day for 7 days
An oral opioid pain medication (oxycodone/acetaminophen) as needed
for breakthrough pain
Prochlorperazine suppository as needed for control of nausea
Nifedipine can also reduce muscle spasms in the ureter, which helps
reduce pain and facilitate stone passage. Ureteral smooth muscle uses
an active calcium pump to produce contractions, so a calcium channel
blocker such as nifedipine would be expected to relax ureteral muscle
Prednisone is an oral corticosteroid that acts as a potent antiinflammatory agent to reduce local edema in the ureter.
Trimethoprim/sulfamethoxazole is a urinary antibiotic used in this case
Acetaminophen is used for analgesia, Acetaminophen has no antiinflammatory activity but raises the pain threshold and reduces the need
for narcotic pain medications.
An oral narcotic (oxycodone/acetaminophen) is used as needed to
control breakthrough pain. An antiemetic suppository (prochlorperazine
25 mg) is also made available to the patient
Indications for hospital admission
People who fail to respond to analgesia after 1 hour should be admitted
People over the age of 60 years should be admitted if there are concerns
on clinical condition or diagnostic certainty (a leaking aortic aneurysm
may present with identical symptoms).
Other indications for urgent admission include:
An abrupt recurrence of severe pain
Pain is persisting for more than 24 hours
Symptoms of systemic illness or infection; fever may suggest an infected
obstructed kidney, which is a surgical emergency
Inability to take adequate fluids due to nausea and vomiting,
Known non-functioning kidney, Known solitary kidney,
Poor social support
- Urgent intervention is required for:
1) Obstructed and infected upper urinary tract
2) Impending renal deterioration
3) Intractable pain or vomiting
5) Obstruction of a solitary or transplanted kidney
- Emergency drainage is achieved by placement of a nephrostomy
catheter or ureteric stent.
- A JJ stent (called JJ stents because the top and bottom have a curled end
to prevent migration of the stent) is sometimes used to relieve any
urinary tract obstruction caused by the stone and to aid removal of the
- Extracorporeal shock wave lithotripsy (ESWL): shock waves break up the
stone, so that stone particles pass spontaneously.
- Percutaneous nephrolithotomy (PCNL) is used for stones not suitable for
ESWL (includes cystine stones, stones greater than 2 cm, and staghorn
calculi); a nephroscope is passed percutaneously into the collecting
system and the stone fragmented and extracted through the
- Ureteroscopy with a laser to break up the stone has a reported 97–100%
success rate, with a low rate of ureteric injury in experienced hands.
- Stone removal by open surgery is only required in 1–5% of people where
ESWL, PCNL, and ureteroscopy have failed, or in other situations
including skeletal deformities, severe intrarenal abnormalities and
- Complete blockage of the urinary flow from a kidney decreases GFR and,
if it persists for more than 48 hours, may cause irreversible renal
- If ureteric stones cause symptoms after 4 weeks, there is a 20% risk of
complications, including deterioration of renal function, sepsis, and
- Infection can be life threatening.
- Persisting obstruction predisposes to pyelonephritis.