Renal/GU

Question 1

3 different categories of causes of AKI?

Answer 1

Pre-renal(70%), instrisic renal(10%) and post-renal(20%)

Question 2

Usual findings and causes of pre-renal AKI

Answer 2

Urea rise&raquo_space;creatinine rise.

causes -

• dehydration (or if severe, shock) of any cause, e.g., sepsis, blood loss
• Renal artery stenosis (AKI in RAS is often triggered by drugs (ACEI or NSAIDs) and effectively causes hypoperfusion of the kidneys and thus a prerenal picture.)

N.B. creatinine can rise with severe prerenal AKI; to differentiate this from intrinsic and obstructive AKI, multiply the urea by 10; if it exceeds the creatinine (showing a relatively greater increase in urea compared to creatinine) then this suggests a prerenal aetiology.

Question 3

Usual findings and causes of intrinsic renal AKI

Answer 3

Urea rise

Question 4

Usual findings and causes of post-renal AKI

Answer 4

Urea rise

Question 5

Give 1 differential for raised urea that is not caused by kidney injury

Answer 5

• Upper GI haemorrhage (here creatinine will be normal and Hb low)

Question 6

what is testicular torsion?

Answer 6

Testicular torsion refers to twisting of the spermatic cord with rotation of the testicle. It is a urological emergency

Question 7

presentation of testicular torsion

Answer 7

acute rapid onset of unilateral testicular pain, and may be associated with abdominal pain and vomiting. Sometimes abdominal pain is the only symptom in boys, and testicular examination to exclude torsion is essential.

Testicular torsion is often triggered by activity, such as playing sports

Question 8

examination findings in testicular torsion

Answer 8

Firm swollen testicle
Elevated (retracted) testicle
Absent cremasteric reflex
Abnormal testicular lie (often horizontal)
Rotation, so that epididymis is not in normal posterior position

Question 9

what is a bell clapper deformity

Answer 9

A bell-clapper deformity is one of the causes of testicular torsion.

Normally, the testicle is fixed posteriorly to the tunica vaginalis. A bell-clapper deformity is where the fixation between the testicle and the tunica vaginalis is absent. The testicle hangs in a horizontal position (like a bell-clapper) instead of the typical more vertical position.

Question 10

management of testicular torsion

Answer 10

Nil by mouth, in preparation for surgery
Analgesia as required
Urgent senior urology assessment
Surgical exploration of the scrotum
bilateral Orchiopexy (correcting the position of the testicles and fixing them in place)
Orchidectomy (removing the testicle) if the surgery is delayed or there is necrosis

**A scrotal ultrasound can confirm the diagnosis. However, any investigation that will delay the patient going to theatre for treatment is not recommended. Ultrasound can show the whirlpool sign, a spiral appearance to the spermatic cord and blood vessels.

Question 11

where do renal stones form>

Answer 11

renal pelvis

Question 12

most common place where renal stones get stuck?

Answer 12

vesico-ureteric junction

Question 13

two key complications of renal stones

Answer 13

Obstruction leading to acute kidney injury

Infection with obstructive pyelonephritis

Question 14

types of renal calculi

Answer 14

1. Calcium-based stones are the most common type of kidney stone. Having hypercalcaemia and a low urine output are key risk factors for calcium collecting into a stone. There are two types of calcium stones:
   Calcium oxalate (more common)
   Calcium phosphate
2. uric acid - these are not visible on x-ray
3. struvite - produced by bacteria, therefore, associated with infection
4. Cystine – associated with cystinuria, an autosomal recessive disease

Question 15

what is staghorn calculus

Answer 15

A staghorn calculus is where the stone forms in the shape of the renal pelvis. The body sits in the renal pelvis with horns extending into the renal calyces. They may be seen on plain x-ray films.

Most commonly, this occurs with stones made of struvite. In recurrent upper urinary tract infections, the bacteria can hydrolyse the urea in urine to ammonia, creating the solid struvite.

Question 16

presentation of renal stones

Answer 16

asymptomatic
renal colic -
-Unilateral loin to groin pain that can be excruciating (“worse than childbirth”)
-Colicky (fluctuating in severity) as the stone moves and settles
-Patients often move restlessly due to the pain.

There may also be:
    Haematuria
    Nausea or vomiting
    Reduced urine output
    Symptoms of sepsis, if infection is present

Question 17

investigations for renal stones

Answer 17

urgent non-contrast CT KUB - initial investigation of choice for diagnosing kidney stones
+
Urine dipstick usually shows haematuria in cases of kidney stones. also useful to exclude infection
Midstream specimen of urine for microscopy (pyuria suggests infection), culture and sensitivities.
Blood for FBC, CRP, renal function, electrolytes, calcium, phosphate and urate, creatinine.
Prothrombin time and international normalised ratio if intervention is planned.

others -
An abdominal x-ray can show calcium-based stones, but uric acid stones are radiolucent.
ultrasound KUB - less effective at identifying kidney stones but is helpful in pregnant women and children.
stone analysis

Question 18

presentation and causes of hypercalcaemia

Answer 18

presentation - 
renal stones
painful bones
abdominal groans
psychiatric moans

causes -
hyperparathyroidism
malignancy (breast, myeloma, lungs, etc.)
calcium supplementation

Question 19

management of renal stones

Answer 19

acutely -
analgesia - NSAIDs 1st line eg IM diclofenac. IV paracetamol is an alternative.
antiemetics
abx if infection present

Watchful waiting is usually used in stones less than 5mm, as there is a 50-80% chance they will pass without any interventions. It may also be suitable for patients with stones 5-10mm, depending on individual factors. It can take several weeks for the stone to pass.

Tamsulosin (an alpha-blocker) can be used to help aid the spontaneous passage of stones.

Surgical interventions are required in large stones (10mm or larger), stones that do not pass spontaneously or where there is complete obstruction or infection.

long-term lifestyle advice

Question 20

different surgical options available to manage renal stones

Answer 20

1. extracorporeal shock wave lithotripsy
2. Ureteroscopy and laser lithotripsy
3. Percutaneous nephrolithotomy (PCNL)
4. open surgery

Question 21

what advice is to be given to pts with renal stones to avoid recrrent stones

Answer 21

Increase oral fluid intake (2.5 – 3 litres per day)
Add fresh lemon juice to water (citric acid binds to urinary calcium reducing the formation of stones)
Avoid carbonated drinks (cola drinks contain phosphoric acid, which promotes calcium oxalate formation)
Reduce dietary salt intake (less than 6g per day)
Maintain a normal calcium intake (low dietary calcium might increase the risk of kidney stones)

For calcium stones – reduce the intake of oxalate-rich foods (e.g., spinach, beetroot, nuts, rhubarb and black tea)
For uric acid stones – reduce the intake of purine-rich foods (e.g., kidney, liver, anchovies, sardines and spinach)
Limit dietary protein

Question 22

medications that may be used to reduce the risk of recurrence of renal stones

Answer 22

Potassium citrate in patients with calcium oxalate stones and raised urinary calcium
    Thiazide diuretics (e.g., indapamide) in patients with calcium oxalate stones and raised urinary calcium

Question 23

RFs for urolithiasis

Answer 23

Anatomical anomalies in the kidneys and/or urinary tract
FHx of urinary tract stones
HTN
gout
immobilisation
obesity

Question 24

ddx for renal colic

Answer 24

Biliary colic.
Dissection of an aortic aneurysm (esp if pt >60)
pyelonephritis
acute pancreatitis
acute appendicitis
perforated peptic ulcer

Question 25

complications of renal stones

Answer 25

Complete blockage of the urinary flow from a kidney decreases glomerular filtration rate (GFR) and, if it persists for more than 48 hours, may cause irreversible renal damage.
sepsis
ureteric strictures
Persisting obstruction predisposes to pyelonephritis and pyelonephrosis.

Question 26

RFs for UTIs -

Answer 26

female sex
pregnancy
immunosuppresed state
sexual activity
incontinence (urinary and faecal) 
poor hygiene
abnormal urinary tract
constipation
dehydration
Urinary catheterization
diabetes
elderly
infants

Question 27

2 broad types of UTIs

Answer 27

upper UTI - pyelonephritis

LUTI - commonly cystitis

Question 28

Presentation of utis

Answer 28

Lower urinary tract infections present with:

Dysuria (pain, stinging or burning when passing urine)
Suprapubic pain or discomfort
Frequency
Urgency
Incontinence
Confusion is commonly the only symptom in older more frail patients

Pyelonephritis presents with:

Fever is a more prominent feature than lower urinary tract infections.
Loin, suprapubic or back pain. This may be bilateral or unilateral.
Looking and feeling generally unwell
Vomiting
Loss of appetite
Haematuria
confusion
Renal angle tenderness on examination

Question 29

urine dipstick interpretation and further actions to take in case of a suspected UTI

Answer 29

Do not dipstick for UTI in pregnant women.no diagnostic value in catheterized sample
Nitrites - suggest bacteria presence
leukocytes - significant rise can be the result of an infection or other cause of inflammation.
Nitrites are a better indication of infection than leukocytes. If both are present then the patient should be treated as a UTI. If only nitrites are present then it is worth treating as a UTI however if only leukocytes are present then the patient should not be treated as a UTI unless there is clinical evidence that they have a UTI.

If nitrites or leukocytes are present the urine should be sent to the microbiology lab. If neither are present the patient is unlikely to have a UTI.

Send a midstream urine (MSU) sample to the microbiology lab to be cultured and to have sensitivity testing.

**over 65 yrs MSU is no longer diagnostic and clinical asessment is mandatory

Question 30

causes of UTI

Answer 30

most commonly E.coli
others - 
    Klebsiella pneumoniae
    Enterococcus
    Pseudomonas aeruginosa
    Staphylococcus saprophyticus
    Candida albicans (fungal)

Question 31

management of LUTIs

Answer 31

1. lifestyle advice -
   stay hydrated
   avoid holding in wee
   have a healthy high fibre diet to avoid constipation
   maintain hygiene and for women - wipe from front to back
2. medical -
   An appropriate initial antibiotic in the community would be:
   Trimethoprim
   Nitrofurantoin

 Alternatives:
    Pivmecillinam
    Amoxicillin
    Cefalexin
ciprofloxacin

duration of treatment -
3 days for a simple lower urinary tract infection in women
5-10 days of antibiotics for women that are immunosuppressed, have abnormal anatomy or impaired kidney function
7 days of antibiotics for men, pregnant women or catheter related UTIs (also change the catheter in catheter related UTI)

Question 32

complications of LUTIs in pregnancy

Answer 32

pyelonephritis, premature rupture of membranes and pre-term labour.

Question 33

management of LUTI in pregnancy

Answer 33

7 days of antibiotics (even with asymptomatic bacteruria)
Urine for culture and sensitivities
First line: nitrofurantoin
Second line: cefalexin or amoxicillin
Nitrofurantoin is generally avoided in the third trimester as it is linked with haemolytic anaemia in the newborn.

Trimethoprim is generally considered safe in pregnancy but avoided in the first trimester or if they are on another medication that affects folic acid (such as anti-epileptics) due to the anti-folate effects.

Question 34

management of pyelonephritis

Answer 34

admit if features of sepsis
NICE recommend the following first line antibiotics for 7-10 days when treating pyelonephritis in the community:
    Cefalexin
    Co-amoxiclav
    Trimethoprim
    Ciprofloxacin

Question 35

causes of hyperkalaemia

Answer 35

AKI
CKD
rhabdomyolysis
tumor lysis syndrome
adrenal insufficiency
medications (potassium supplements, aldosterone antagonists, ACE inhibitors, Angiotensin II receptor blockers, NSAIDs)
metabolic acidosis (DM)
massive blood transfusion
burns

**artefactual results: Haemolysis during sampling (difficult venepuncture, pt clenched fist), contamination with potassium EDTA anticoagulant in FBC bottles (do FBCs after U&Es), thrombocythaemia, delayed analysis (particular problem in primary care settings)

Question 36

Ix for hyperkalaemia

Answer 36

U&Es - but don’t wait for lab result, do a VBG and use blood gas analyser
serum creatinine
eGFR
ECG

Question 37

ECG signs of hyperkalaemia

Answer 37

tall tented T waves
flattened or absent P waves
inc PR interval
broad QRS complexes

there can also be - sine wave patttern, asystole

Question 38

mx of hyperkalaemia

Answer 38

Follow the local policy and protocol for treating hyperkalaemia. Get help from senior doctor. Patients with significant hyperkalaemia will need close ECG monitoring to detect changes and arrhythmias. Patients with significant renal impairment should be discussed with the renal physicians.

Patients with a potassium ≤ 6 mmol/L with otherwise stable renal function and no ECG changes don’t need urgent treatment. treat underlying cause; review medications, polystyrene sulfonate resin binds K+ in gut preventing absorption and bringing K+ down over a few days.

Patients with a potassium ≥ 6 mmol/L and ECG changes need urgent treatment.

Patients with a potassium ≥ 6.5 mmol/L regardless of the ECG need urgent treatment.

The mainstay of treatment:
1. 30mL of 10% calcium gluconate IV STAT over 5-10 mins. BNF says slow IV injection?
2. Insulin (e.g. actrapid 10 units) in glucose (e.g. 50ml of 50% glucose) drives carbohydrates into cells and takes potassium with it, reducing the blood potassium. this is given over 5-15 mins.
Calcium gluconate stabilises the cardiac muscle cells and reduces the risk of arrhythmias.

Other options for lowering the serum potassium:
    Nebulised salbutamol temporarily drives potassium into cells.
    IV fluids can be used to increase urine output, which encourages potassium loss from the kidneys (but don’t fluid overload patients with renal failure).
    Oral calcium resonium draws potassium out of the gut and into the stools. It works slowly and is suitable for milder cases of hyperkalaemia.
 Sodium bicarbonate (IV or oral) may be considered on the advice of a renal specialist in acidotic patients with renal failure. It drives potassium into cells as the acidosis is corrected.
Dialysis may be required in severe or persistent cases associated with renal failure.

Question 39

normal serum potassium lvl

Answer 39

3.6 to 5.2 millimoles per liter (mmol/L)

Question 40

severe hyperkalaemia lvls?

Answer 40

K+ >6.5 mmol/L
it is a potential emergency
main worry is myocardial hyperexcitability leading to ventricular fibrillation and cardiac arrest