Nephro

Question 1

Acute Kidney Injury - Definition & Presentation

Answer 1

An acute decline in kidney function, ranging from mild kidney injury to severe kidney failure, resulting in serum creatinine to rise and/or a fall in urine output

Presentations:
- Hypotension
- Kidney Insults
- Reduced urine production

Other presentations:
-dizziness & orthostatic symptoms (happening when you sit up or lie down
- hypertension
- Altered mental status
-Pericardial/pleural rub (heard on auscultation)

Question 2

Acute Kidney Injury - Aetiology & Risk Factors

Answer 2

Can be classed into Pre-kidney, intrinsic & post-kidney causes

Pre-kidney (80% of cases):
- reduced kidney perfusion is most common:
>Hypovolaemia
>Haemorrhage
>Sepsis
>Heart failure
- Hepatorenal syndrome

Intrinsic:
- Acute Tubular Necrosis (ATN) –> Causes 45% of cases
- Interstitial nephritis
- Rapidly progressive glomerulonephritis

Post-kidney:
- Mechanical obstruction of the urinary tract
>More common in men die to prostate hyperplasia
>Tumour
>Retroperitoneal fibrosis
>strictures

Risk Factors:
- Advanced age
- Underlying kidney disease
- Sepsis
- Exposure to nephrotoxins
- Excessive fluid loss/haemorrhage
- Surgery/ Recent vascular intervention

Question 3

Acute Kidney Injury - Epidemiology

Answer 3

AKI is seen in 10-20% of patients admitted to hospital as emergencies

Question 4

Acute Kidney Injury - Differentials

Answer 4

1) CKD –> reduced kidney function w/ elevated creatinine = chronic, although there may be acute on chronic kidney disease

2) Increased muscle mass –> Would cause an elevation of serum creatinine, but is minor and typically non-acute

3) Drug side effect –> certain medications (i.e. cimetidine/trimethoprim) can lead to elevated serum creatinine

Question 5

Acute Kidney Injury - Investigations

Answer 5

1st line:
- Basic metabolic profile (including urea & creatinine and Liver function tests)
- Serum potassium
- FBC
- Bicarbonate
- CRP
- Blood culture –> Sepsis is a common cause of AKI
- Urinalysis
- Urine culture
- Urine output monitoring
- Fluid challenge –> Good response supports diagnosis of pre-kidney AKI
- VBG
- CXR
- ECG –> Assess for hyperkalaemia as it is a common complication

Question 6

Acute Kidney Injury - Management

Answer 6

Hypovolaemia:
First line:
> Fluid Resuscitation
–> Give a 500 mL bolus of intravenous fluid over 15 minutes.
Use a wide bore cannula to allow adequate fluid resuscitation.
–> Use normal saline (0.9% sodium chloride) instead if hyperkalaemia is present (potassium >5.5 mmol/L) or suspected (e.g., rhabdomyolysis)
–> Reassess haemodynamic status after the initial fluid bolus and consider whether further 250 to 500 mL boluses are required
–> If no improvement is seen after two fluid challenges, escalate the patient for senior review

> Treat underlying cause of AKI

> Review medications and stop nephrotoxins (i.e. NSAIDs & iodine contrast agents)

Hypervolaemia:
–> Can happen due to overaggressive fluid resuscitation or Oliguria (low urine output) due to intrinsic/post-kidney AKI
First line:
> Loop diuretic (supervised by a specialist)
–> furosemide: consult specialist for guidance on dose

> Treat underlying cause

consider:
- Renal replacement therapy

Question 7

Acute Kidney Injury - Prognosis & Complications

Answer 7

Recovery depends on cause of injury and the severity & duration of AKI

Predictors of poor prognosis:
-needing dialysis –> Mortality exceeds 50%
-Multi-organ failure

5 year survival rate from 15-35%

Complications:
- Hyperphosphatemia = high chance
- Hyperkalaemia = high chance
- Uraemia = medium chance
- Chronic progressive kidney disease = medium chance -> kidneys permanently damaged and do not return to baseline
- End-stage kidney disease = medium chance -> Some cannot recover, possibly due to comorbidities, and renal replacement therapy may be required

Question 8

Bladder Cancer - Definition & Presentation

Answer 8

Over 90% of cancers of the urinary bladder are urothelial carcinoma

Non-muscle-invasive tumours are most common

Low-grade tumours are papillary and generally easy to visualise, but often have negative cytology

High-grade tumours are often flat or in situ and difficult to visualise, but typically have a positive cytology

Presentations:
- Haematuria
- Dysuria (painful urination)

(Common Cancer Symptoms)
- Unexplained weight loss
- Fatigue
- Pain
- Night sweats

Question 9

Bladder Cancer - Aetiology & Risk Factors

Answer 9

Smoking is the most important causative factor in bladder cancer, with an attributable risk of around 50%

Risk Factors:
- Smoking
- Occupational exposure to chemical carcinogens
- painters, hairdressers, and medical and clerical personnel
- T2DM
- Increasing age

• Chronic irritation/inflammation (e.g., chronic urinary tract infection, Schistosoma infection, chronic indwelling catheters)
  –> can lead to Keratinising squamous metaplasia
  –> which can lead to squamous cell carcinoma of the bladder

Question 10

Bladder Cancer - Epidemiology

Answer 10

Bladder cancer is among the top 10 most common cancer types in the world

It is the sixth most common cancer in men and the 17th most common cancer in women

Overall, non-Hispanic white people have the highest incidence rate; however, black people have a much lower survival rate than other racial groups

Question 11

Bladder Cancer - Differentials

Answer 11

1) Benign Prostatic Hyperplasia (BPH)
-> Can cause haematuria and occurs in the same age and sex group as bladder cancer
-> BPH is associated with reduced force of stream, frequency, urgency, and nocturia, as well as enlargement of the prostate on digital rectal examination

2) Haemorrhagic cystitis
-> Acute onset of severe frequency and dysuria in a young woman, particularly if associated with low back pain and malaise, suggests haemorrhagic cystitis
-> Difficult to distinguish from bladder cancer by clinical features alone

3) Prostatitis
-> Typically occurs in men <55 years old
-> Cytology is key to the differentiating prostatitis and carcinoma of the bladder or prostate

4) UTI
-> Symptoms of urgency, frequency, dysuria, and haematuria are shared by both UTI and bladder cancer and do not aid clinical differentiation
-> Back pain, fever, and chills are common with UTI, but rare with bladder cancer
-> Positive urine culture makes bladder cancer the less likely, but does not exclude the diagnosis

5) Nephrolithiasis
-> Common cause of gross and microscopic haematuria
-> Can be distinguished by typical symptoms of renal colic
-> Look for stones w/ Non-contrast CT

Question 12

Bladder Cancer - Investigations

Answer 12

1st order:
1) Urinalysis
–> About 80% of patients present with gross or microscopic haematuria
–> pyuria may also be seen, resulting in confusion with urinary infection

Consider:
1) Urine Cytology –> positive in up to 90% of patients with carcinoma in situ or high-grade tumours

2) Cystoscopy –> To visualise bladder tumours (is it low or high grade)

3) Renal & Bladder Ultrasounds

4) CT/MR urogram –> to inspect upper urinary tract

If Muscle invasive, do:
- CXR
- CT/MRI abdo and pelvis
- FBC
- Bone scan

Question 13

Bladder Cancer - Management

Answer 13

Non-muscle-invasive tumours:
1) Transurethral resection of bladder tumour
2) Immediate post-op intravesical chemo
3) + intravesical BCG therapy (if intermediate/high risk)

Locally invasive tumours:
For T2a/b & T3a/b
1) Radical/partial cystectomy w/ pelvic lymph node dissection
-> possible pre/post-op chemo
2) Immunotherapy

For T4a/b
1) Chemo
-> possibly radiotherapy
-> possibly radical cystoprostatectomy
2) Immunotherapy

Metastatic disease:
1) Chemo
-> Possible Surgery or Radiotherapy
2) Immunotherapy

Question 14

Bladder Cancer - Prognosis

Answer 14

Most patients present with low-grade, non-muscle-invasive bladder cancer (NMIBC). These patients are at high risk for tumour recurrence but low risk for disease progression and death
–> 15-year recurrence risk of 65%, but progression occurs in <5% of patients
–> Treatment with intravesical chemotherapy reduces the 2-year risk of recurrence by up to 20%

Intermediate-risk bladder cancer, without treatment, has the risk of recurrence by 15 years approaches 90%. Intravesical chemotherapy reduces recurrence by up to 20% in the short term, but has little effect on long-term recurrence

High-grade NMIBC is a risk for both recurrence and progression

Once muscle invasion occurs, overall survival is in the range of 50% even with cystectomy

Question 15

Bladder Cancer - Complications

Answer 15

1) Prostatic urothelial carcinoma
-> by 15 years 1/4 of patients develop this when BCG maintenance is not given

2) Upper tract urothelial carcinoma
-> 1/4 of high-risk patients will develop upper tract urothelial carcinoma by 15 years and mortality is high (>30%)
-> Upper-tract carcinoma, dangerous in high-risk patients

3) Hydronephrosis
-> Tumour of the trigone, ureteral orifice, or ureter can obstruct and cause renal damage

4) Urinary retention
-> Tumours at the bladder neck can cause outlet obstruction
-> Bleeding from the tumour or post tumour resection can cause clot retention

Question 16

Chronic kidney disease - Definition & Presentation

Answer 16

Defined as abnormalities of kidney structure or function, present for ≥3 months, with implications for health

This means a glomerular filtration rate less than 60 mL/minute/1.73 m², or the presence of one or more of the following markers of kidney damage:
- Albuminuria/proteinuria
- Urine sediment abnormalities (e.g., haematuria)
- Electrolyte abnormalities due to tubular disorders
- Abnormalities detected by histology
- Structural abnormalities detected by imaging
- Hx of kidney transplantation

Presentations:
- Fatigue -> Due to uraemia or anaemia
-> Anaemia is associated with CKD due to the lack of erythropoietin produced by the kidney in kidney failure
- Oedema
- Nausea with/without vomiting
- Pruritus
- Restless legs
- Anorexia
-> Most of these thought to be due to an accumulation of toxic waste products in the circulation and under the skin, such as urea that is not excreted by the kidney

Prostate examination in men should be performed to exclude obstructive uropathy -> Can lead to enlarged prostate gland

Question 17

Chronic kidney disease - Aetiology & Risk Factors

Answer 17

The most common cause in the adult population is diabetes - It is estimated that one third of patients with diabetes will develop kidney disease

Hypertension is the second most common cause. Hypertension can be both a cause and consequence of CKD

Around one third of adults with CKD have a positive family history of CKD, which suggests genetic causation

Nephrotoxic drugs can cause/exacerbate CKD

Climate also plays a significant role in some CKD presentations. Heat stress nephropathy may represent one of the first epidemics due to global warming

Risk Factors:
- Diabetes mellitus
- Hypertension
- Age >50 years
- Childhood kidney disease

Question 18

Chronic kidney disease - Differentials

Answer 18

1) Diabetic kidney disease
-> Subtype of CKD specifically caused by Diabetes
-> glucose binds to efferent arteriole in Kidney, causing it to stiffen and blood to back up into the glomerulus, causing hyperfiltration/hypertension in glomerulus and damaging it

2) Hypertensive nephrosclerosis
-> Subtype of CKD caused by hypertension
-> High BP in glomerulus arterioles causes them to become damaged -> leads to less blood/O2 getting into nephron causing ischaemic injury

3) Ischaemic nephropathy
-> Hx of long-standing essential hypertension that is suddenly uncontrolled
-> Hx of atherosclerotic disease such as coronary artery disease or peripheral vascular disease

4) Obstructive uropathy
-> Often due to prostatic enlargement or cancer, causing urine to back up into the kidneys and cause damage this way

5) Nephrotic syndrome
-> Often associated with a more sudden onset of hypertension, or acceleration of essential hypertension and development of periorbital and peripheral oedema

6) Glomerulonephritis
-> Often associated with a sudden onset of hypertension or acceleration of essential hypertension

Question 19

Chronic kidney disease - Investigations

Answer 19

Primary Care:
- Arrange blood tests for serum creatinine and estimated glomerular filtration rate (eGFR):
-> If the eGFR is less than 60 mL/min/1.73 m2, repeat the test within two weeks
-> If the eGFR remains less than 60 mL/min/1.73 m2 on repeat, with no evidence of sudden deterioration in renal function suggesting acute kidney injury, repeat the eGFR within 3 months
-> Note: interpret the eGFR result with caution if the person has extremes of muscle mass, is pregnant, has oedema, is malnourished or uses protein supplements, or is Asian or Chinese in origin

• Arrange an early morning urine sample to measure the urinary albumin:creatinine ratio (ACR)
  -> Between 3 and 70 mg/mmol, repeat the test within 3 months
  -> 70 mg/mmol or more, a repeat test is not needed as this indicates significant proteinuria
• Arrange a urine dipstick test to check for haematuria
  -> If there is 1+ or more of blood on dipstick, arrange a mid-stream urine sample (MSU) to exclude a UTI, and manage accordingly

– If the eGFR and urine ACR tests are repeated within 3 months amd are still high, diagnose CKD

In Hospital:
- Estimate GFR
- Test for elevated serum creatinine; electrolyte abnormalities
- Urinalysis -> haematuria and/or proteinuria
- Test for high Urinary Albumin
- Renal ultrasound -> Should show small kidney size, possible kidney stones

Question 20

Chronic kidney disease - Management

Answer 20

Primary Care:
- Assess and manage risk factors and co-morbidities
(i.e. Hypertension/diabetes/nephrotoxic drugs)

• Ramipril: 1.25 mg orally once daily initially, adjust dose gradually according to response, maximum dose depends on level of impairment
• For all people with CKD, offer Atorvastatin 20 mg for the primary or secondary prevention of CVD
• Prescribe an antiplatelet drug for the secondary prevention of CVD
• Consider dapagliflozin: 10 mg orally once daily (A sodium-glucose co-transporter 2 (SGLT2) inhibitor) -> especially in those w/ Diabetes
• Ensure the person is offered immunizations for influenza and pneumococcal disease to reduce infection risk, if appropriate
• If CKD is very bad, arrange Dialysis while waiting for Kidney transplant
  -> Peritoneal dialysis is performed at home and is available to all patients
  -> Haemodialysis is usually prescribed in a treatment centre 3 times a week for approximately 4 hours each session

Advise:
- Stopping smoking if appropriate
- Drinking alcohol in moderation
- Maintaining a healthy body weight
- Eating a healthy diet and taking regular exercise
- Advise the person to avoid the use of over-the-counter NSAIDs where possible
- Advise on the increased risk of acute kidney injury (AKI) if there is severe, intercurrent illness
- Advise adults with CKD and their family members or carers information about their 5-year risk of needing renal replacement therapy

Question 21

Chronic kidney disease - Prognosis & Complications

Answer 21

CKD is mostly progressive and leads to end-stage renal disease (ESRD
Though it cannot be cured, it can be controlled and managed to a large extent
By 5 years majority of patients will need a kidney transplant

Poor Prognosis Factors:
- Decreasing estimated glomerular filtration rate (eGFR)
- Increasing proteinuria
- Poorly controlled Hypertension

Complications:
- CKD is a strong cardiovascular risk factor, and the majority of patients with CKD will die prior to reaching ESRD
- As kidney function declines, complications such as anaemia and hyperparathyroidism develop