NEPHROLOGY
Questions&Answers
Q-1
A 26 year old mountain biker was rescued after being trapped under heavy rocks
for almost 12 hours. His urine is dark and urine is positive for blood on dipstick.
His heart rate is 120 bpm and systolic blood presure is 100 mmHg. Lab results
show a creatinine of 35 micromol/L and urea of 15 mmol/L. What is the SINGLE
most appropriate management?
A. Dialysis
B. Intravenous normal saline
C. Intravenous dextroes
D. Intravenous KCl
E. Pain relief
ANSWER:
Intravenous normal saline
EXPLANATION:
This patient here has attained severe crush injuries which has lead to rhabdomyolysis
which results from skeletal muscle breakdown, with release of its contents, one of which
is myoglobin into the circulation. Myogloglbin has heme which results in a positive
dipstick for blood. Myoglobin is nephrotoxic and can cause a worsening acute kidney
injury. It is important to rehydrate the patient to decrease the duration of contact
between myoglobin and the kidney tubules.
RHABDOMYOLYSIS
Rhabdomyolysis results from skeletal muscle breakdown, with release of its contents
into the circulation, including myoglobin, potassium, phosphate, urate and creatinine
kinase (CK).
Aetiology
• Suden, severe crush injury
• Status epilepticus
• Severe exertion
Important presentations to remember for the exam
• Elderly patient with history of fall followed by long duration on the floor
• Mountain biker rescued from being trapped under heavy rocks for many hours
• Trapped under a fallen wardrobe for several hours
,• IV drug user found on floor not moving for a few days
• Marathon runner who just completed a long-distance run
Two complications you need to remember for rhabdomyolysis
• Acute kidney injury
• Hyperkalaemia
There is often enough pigment release in the bloodstream to cause nephrotoxicity. The
degree of toxicity is related to the duration of contact of the tubular cells with myoglobin.
This toxicity is compounded by dehydration as well. Example, a person who has run a
marathon has both myoglobin release as well as poor kidney perfusion. Both
dehydration and release of myoglobin increase the risk of acute kidney injury.
One of the most important complications to recognise for rhabdomyolysis is
hyperkalaemia and thus rhabdomyolysis is often a medical emergency.
Laboratory testing
The most important test when there has been a severe crush injury and the
rhabdomyolysis is potentially life threatening is an ECG or potassium level.
This implies that you know how a patient with rhabdomyolysis will die. Acidosis and
hyperkalemia can lead to an arrhythmia. If there are peaked T-waves on the ECG, you
will give calcium chloride or calcium gluconate.
The best initial test that is specific for rhabdomyolysis is a urinalysis in which you find a
dipstick that is positive for blood but in which no red cells are seen. This is a False +ve
dipstick haematuria. This is because myoglobin can react with the reagent on the
dipstick and come out as if there were red cells present. Hemoglobin will do the same
thing. The dipstick of the urinalysis cannot distinguish among hemoglobin, myoglobin,
and red blood cells. This is because myoglobin has heme in it.
Rhabdomyolysis is confirmed with a markedly elevated serum CPK level. Elevated
serum CPK is a biochemical marker of skeletal muscle neurosis.
Rhabdomyolysis is associated with a very rapidly rising creatinine level. This is because
of both renal failure as well as the massive release of muscle products.
Treatment
• Calcium chloride/gluconate.
o If there are ECG abnormalities from the hyperkalaemia the best initial therapy is
calcium chloride or gluconate
• Intravenous fluid rehydration
o Priority to prevent AKI.
o This decreases the duration of contact between the nephrotoxic myoglobin and
the kidney tubule.
• Intravenous sodium bicarbonate
o Used to alkalinize urine to pH >6.5, to stabilize a less toxic form of myoglobin
o Alkalinizing the urine with bicarbonate may help prevent the precipitation of the
pigment in the tubule
• Dialysis
o Only needed in severe cases
,Q-2
A 52 year old known diabetes mellitus presents to the Emergency Department
with a sudden onset of pain in the left loin and haematuria. An ultrasound scan
shows a 7 mm stone in left lower ureter. Diclofenac was administered for the
renal colic pain and nifedipine and prednisolone was prescribed as initial
treatment as part of an expulsive therapy. He returns to the emergency
department the following day with worsening pain, vomiting and a history of
having passed two stones. A repeat ultrasound scan reveals hydronephrosis in
the left ureter and the presence of stones. His renal function test indicate an
acute kidney injury. He has a heart rate of 100 beats/minute and a temperature of
38.5 C. What is the SINGLE most appropriate management?
A. Repeat a similar regimen
B. Administer an alpha blocker
C. Extracorporeal shock wave lithotripsy
D. Open surgery
E. Percutaneous nephrostomy
ANSWER:
Percutaneous nephrostomy
EXPLANATION:
This acute kidney injury and hydronephrosis are indicative of an obstructive uropathy.
Percutaneous nephrostomy would be the best intervention to temporarily decompress
the renal collecting system.
ESWL becomes extremely less effective once the stone goes upto 2-3 mm in size.
Less than 50% chance of success. This patient has AKI, a very large stone which is
clearly obstructive uropathy, and therefore urgent percutaneous nephrostomy is
indicated.
PERCUTANEOUS NEPHROSTOMY
This is used as a temporary relief of ureteric obstruction where ureteric stones fail to
respond to analgesics and where renal function is impaired due to the stone. It is an
intervention that decompresses the renal collecting system by placing a catheter,
through the skin, into the kidney, under local anaesthetic. This catheter allows the urine
to drain from the kidney into a collecting bag, outside the body. Another method that is
often used to relieve ureteric obstruction is an insertion of a JJ stent.
The function of a percutaneous nephrostomy is to bypass the ureteric obstruction and
therefore relieve the pain associated with the obstruction.
The percutaneous nephrostomy tube can restore efficient peristalsis to the ureteric wall
and in some cases this allows the stone to pass down and out of the ureter with the
nephrostomy in situ, however in many instances, it simply sits where it is and
subsequent definitive management to remove the stone is still required.
, Q-3
A 6 year old boy presents to the paediatric outpatient clinic with a two day history
of dramatic weight gain and bodily swelling, particularly in his lower limbs. He
also had bilaterally puffy eyes two days ago, which he was given some
antihistamine syrup for, but they have not improved his symptoms. He is
otherwise happy and healthy. His mother reports an uneventful pregnancy and
he was delivered via elective Caesarean section at 38 weeks of gestation. He has
no medical problems and he is on the 50th centile on all of his growth charts. He
takes no chronic medication. The mother reports no significant family history of
renal problems. Analysis of the patient’s urine sample was done and is
significant for 3+ proteinuria. What is the SINGLE next best investigation?
A. Serum albumin levels
B. Repeat urine analysis
C. Refer to nephrology
D. Refer to dietician
E. Utrasound KUB (kidneys, ureters, bladder)
ANSWER:
Serum albumin levels
EXPLANATION:
The patient’s urinalysis shows significant proteinuria and to confirm the diagnosis of
nephrotic syndrome, the next best step would be to check the serum albumin level
Questions&Answers
Q-1
A 26 year old mountain biker was rescued after being trapped under heavy rocks
for almost 12 hours. His urine is dark and urine is positive for blood on dipstick.
His heart rate is 120 bpm and systolic blood presure is 100 mmHg. Lab results
show a creatinine of 35 micromol/L and urea of 15 mmol/L. What is the SINGLE
most appropriate management?
A. Dialysis
B. Intravenous normal saline
C. Intravenous dextroes
D. Intravenous KCl
E. Pain relief
ANSWER:
Intravenous normal saline
EXPLANATION:
This patient here has attained severe crush injuries which has lead to rhabdomyolysis
which results from skeletal muscle breakdown, with release of its contents, one of which
is myoglobin into the circulation. Myogloglbin has heme which results in a positive
dipstick for blood. Myoglobin is nephrotoxic and can cause a worsening acute kidney
injury. It is important to rehydrate the patient to decrease the duration of contact
between myoglobin and the kidney tubules.
RHABDOMYOLYSIS
Rhabdomyolysis results from skeletal muscle breakdown, with release of its contents
into the circulation, including myoglobin, potassium, phosphate, urate and creatinine
kinase (CK).
Aetiology
• Suden, severe crush injury
• Status epilepticus
• Severe exertion
Important presentations to remember for the exam
• Elderly patient with history of fall followed by long duration on the floor
• Mountain biker rescued from being trapped under heavy rocks for many hours
• Trapped under a fallen wardrobe for several hours
,• IV drug user found on floor not moving for a few days
• Marathon runner who just completed a long-distance run
Two complications you need to remember for rhabdomyolysis
• Acute kidney injury
• Hyperkalaemia
There is often enough pigment release in the bloodstream to cause nephrotoxicity. The
degree of toxicity is related to the duration of contact of the tubular cells with myoglobin.
This toxicity is compounded by dehydration as well. Example, a person who has run a
marathon has both myoglobin release as well as poor kidney perfusion. Both
dehydration and release of myoglobin increase the risk of acute kidney injury.
One of the most important complications to recognise for rhabdomyolysis is
hyperkalaemia and thus rhabdomyolysis is often a medical emergency.
Laboratory testing
The most important test when there has been a severe crush injury and the
rhabdomyolysis is potentially life threatening is an ECG or potassium level.
This implies that you know how a patient with rhabdomyolysis will die. Acidosis and
hyperkalemia can lead to an arrhythmia. If there are peaked T-waves on the ECG, you
will give calcium chloride or calcium gluconate.
The best initial test that is specific for rhabdomyolysis is a urinalysis in which you find a
dipstick that is positive for blood but in which no red cells are seen. This is a False +ve
dipstick haematuria. This is because myoglobin can react with the reagent on the
dipstick and come out as if there were red cells present. Hemoglobin will do the same
thing. The dipstick of the urinalysis cannot distinguish among hemoglobin, myoglobin,
and red blood cells. This is because myoglobin has heme in it.
Rhabdomyolysis is confirmed with a markedly elevated serum CPK level. Elevated
serum CPK is a biochemical marker of skeletal muscle neurosis.
Rhabdomyolysis is associated with a very rapidly rising creatinine level. This is because
of both renal failure as well as the massive release of muscle products.
Treatment
• Calcium chloride/gluconate.
o If there are ECG abnormalities from the hyperkalaemia the best initial therapy is
calcium chloride or gluconate
• Intravenous fluid rehydration
o Priority to prevent AKI.
o This decreases the duration of contact between the nephrotoxic myoglobin and
the kidney tubule.
• Intravenous sodium bicarbonate
o Used to alkalinize urine to pH >6.5, to stabilize a less toxic form of myoglobin
o Alkalinizing the urine with bicarbonate may help prevent the precipitation of the
pigment in the tubule
• Dialysis
o Only needed in severe cases
,Q-2
A 52 year old known diabetes mellitus presents to the Emergency Department
with a sudden onset of pain in the left loin and haematuria. An ultrasound scan
shows a 7 mm stone in left lower ureter. Diclofenac was administered for the
renal colic pain and nifedipine and prednisolone was prescribed as initial
treatment as part of an expulsive therapy. He returns to the emergency
department the following day with worsening pain, vomiting and a history of
having passed two stones. A repeat ultrasound scan reveals hydronephrosis in
the left ureter and the presence of stones. His renal function test indicate an
acute kidney injury. He has a heart rate of 100 beats/minute and a temperature of
38.5 C. What is the SINGLE most appropriate management?
A. Repeat a similar regimen
B. Administer an alpha blocker
C. Extracorporeal shock wave lithotripsy
D. Open surgery
E. Percutaneous nephrostomy
ANSWER:
Percutaneous nephrostomy
EXPLANATION:
This acute kidney injury and hydronephrosis are indicative of an obstructive uropathy.
Percutaneous nephrostomy would be the best intervention to temporarily decompress
the renal collecting system.
ESWL becomes extremely less effective once the stone goes upto 2-3 mm in size.
Less than 50% chance of success. This patient has AKI, a very large stone which is
clearly obstructive uropathy, and therefore urgent percutaneous nephrostomy is
indicated.
PERCUTANEOUS NEPHROSTOMY
This is used as a temporary relief of ureteric obstruction where ureteric stones fail to
respond to analgesics and where renal function is impaired due to the stone. It is an
intervention that decompresses the renal collecting system by placing a catheter,
through the skin, into the kidney, under local anaesthetic. This catheter allows the urine
to drain from the kidney into a collecting bag, outside the body. Another method that is
often used to relieve ureteric obstruction is an insertion of a JJ stent.
The function of a percutaneous nephrostomy is to bypass the ureteric obstruction and
therefore relieve the pain associated with the obstruction.
The percutaneous nephrostomy tube can restore efficient peristalsis to the ureteric wall
and in some cases this allows the stone to pass down and out of the ureter with the
nephrostomy in situ, however in many instances, it simply sits where it is and
subsequent definitive management to remove the stone is still required.
, Q-3
A 6 year old boy presents to the paediatric outpatient clinic with a two day history
of dramatic weight gain and bodily swelling, particularly in his lower limbs. He
also had bilaterally puffy eyes two days ago, which he was given some
antihistamine syrup for, but they have not improved his symptoms. He is
otherwise happy and healthy. His mother reports an uneventful pregnancy and
he was delivered via elective Caesarean section at 38 weeks of gestation. He has
no medical problems and he is on the 50th centile on all of his growth charts. He
takes no chronic medication. The mother reports no significant family history of
renal problems. Analysis of the patient’s urine sample was done and is
significant for 3+ proteinuria. What is the SINGLE next best investigation?
A. Serum albumin levels
B. Repeat urine analysis
C. Refer to nephrology
D. Refer to dietician
E. Utrasound KUB (kidneys, ureters, bladder)
ANSWER:
Serum albumin levels
EXPLANATION:
The patient’s urinalysis shows significant proteinuria and to confirm the diagnosis of
nephrotic syndrome, the next best step would be to check the serum albumin level
