Renal Flashcards
What are the NICE guidelines for diagnosing an acute kidney injury?
Rise in creatinine of more than 25 micromol/L in 48 hours
Rise in creatinine of more than 50% in 7 days
Urine output of less than 0.5 ml/kg/hour over at least 6 hours
State 5 risk factors that would predispose someone to developing an AKI?
Older age
Sepsis
Chronic kidney disease
Heart failure
Diabetes
Liver disease
Cognitive impairment (leading to reduced fluid intake)
Medications (e.g., NSAIDs, gentamicin, diuretics and ACE inhibitors)
Radiocontrast agents
State 3 pre-renal causes of AKI?
Dehydration
Shock (e.g., sepsis or acute blood loss)
Heart failure
State 3 renal causes of AKI
Acute tubular necrosis
Glomerulonephritis
Acute interstitial nephritis
Haemolytic uraemic syndrome
Rhabdomyolysis
State 3 post-renal causes of AKI
Kidney stones
Tumours (e.g., retroperitoneal, bladder or prostate)
Strictures of the ureters or urethra
Benign prostatic hyperplasia (benign enlarged prostate)
Neurogenic bladder
What is acute tubular necrosis?
damage and death (necrosis) of the epithelial cells of the renal tubules. It is the most common intrinsic cause of acute kidney injury. Damage to the kidney cells occurs due to:
Ischaemia due to hypoperfusion (e.g., dehydration, shock or heart failure)
Nephrotoxins (e.g., gentamicin, radiocontrast agents or cisplatin)
Recovery usually takes 1-3 weeks
How is a acute tubular necrosis diagnosed?
Muddy brown casts on urinalysis
Renal tubular epithelial cells may also be seen
What is acute interstitial nephritis?
involves acute inflammation of the interstitium (the space between the tubules and vessels). It is caused by an immune reaction associated with:
Drugs (e.g. NSAIDs or antibiotics)
Infections (e.g., E. coli or HIV)
Autoimmune conditions (e.g., sarcoidosis or SLE)
What other features can accompany AKI in acute interstitial nephritis?
Rash
Fever
Flank pain
Eosinophilia
What is the management of acute interstitial nephritis?
treat underlying cause
steroids may reduce inflammation
what investigation can be used to assess for obstruction post-renal cause of AKI?
Ultrasound of urinary tract
What are 3 ways to prevent an AKI?
Avoiding nephrotoxic medications where appropriate
Ensuring adequate fluid intake (including IV fluids if oral intake is inadequate)
Additional fluids before and after radiocontrast agents
What supportive management options are there for an AKI?
IV fluids for dehydration and hypovolaemia
Withhold medications that may worsen the condition (e.g., NSAIDs and ACE inhibitors)
Withhold/adjust medications that may accumulate with reduced renal function (e.g., metformin and opiates)
Relieve the obstruction in a post-renal AKI (e.g., insert a catheter in a patient with prostatic hyperplasia)
Dialysis may be required in severe cases
State 4 complications of AKI
Fluid overload, heart failure and pulmonary oedema
Hyperkalaemia
Metabolic acidosis
Uraemia (high urea), which can lead to encephalopathy and pericarditis
What defines kidney disease as chronic?
chronic reduction in kidney function sustained over three months
State 3 factors that can speed up a decline in kidney function
Diabetes
Hypertension
Medications (e.g., NSAIDs or lithium)
Glomerulonephritis
Polycystic kidney disease
Most patient with CKD are asymptomatic. What non-specific signs/symptoms may they have?
Fatigue
Pallor (due to anaemia)
Foamy urine (proteinuria)
Nausea
Loss of appetite
Pruritus (itching)
Oedema
Hypertension
Peripheral neuropathy
What investigations are done in CKD?
eGFR
urine:creatinine ratio (proteinuria)
Urine dipstick/microscopy (haematuria)
renal ultrasound (obstructions)
RF: BP, HbA1c, Lipid profile
When can a diagnoses of CKD be made?
when there are consistent results over three months of either:
Estimated glomerular filtration rate (eGFR) is sustained below 60 mL/min/1.73 m2
Urine albumin:creatinine ratio (ACR) is sustained above 3 mg/mmol
What are the stages of CKD?
G1 = Over 90
G2 = 60-89
G3a = 45-59
G3b = 30-44
G4 = 15-29
G5 = Under 15
A1 = Under 3 mg/mmol
A2 = 3-30 mg/mmol
A3 = Above 30 mg/mmol
What is accelerated progression of CKD?
sustained decline in the eGFR within one year of either 25% or 15 mL/min/1.73 m2
State 4 complications of CKD
Anaemia
Renal bone disease
Cardiovascular disease
Peripheral neuropathy
End-stage kidney disease
Dialysis-related complications
what can be used to estimate the 5-year risk of kidney failure requiring dialysis?
Kidney Failure Risk Equation
When should you refer someone with CKD to a specialist?
eGFR less than 30 mL/min/1.73 m2
Urine ACR more than 70 mg/mmol
Accelerated progression (a decrease in eGFR of 25% or 15 mL/min/1.73 m2 within 12 months)
5-year risk of requiring dialysis over 5%
Uncontrolled hypertension despite four or more antihypertensives
what is the blood pressure target in patients under 80 with CKD and an ACR above 70 mg/mmol.
less than 130/80
State 2 medications that can slow disease progression of CKD
ACE inhibitors (or angiotensin II receptor blockers)
SGLT-2 inhibitors (specifically dapagliflozin)
State 2 factors that can reduce the risk of complications in someone with CKD
Exercise, maintain a healthy weight and avoid smoking
Atorvastatin 20mg for primary prevention of cardiovascular disease (in all patients with CKD)
What management options are their for treating the complications of CKD?
Oral sodium bicarbonate to treat metabolic acidosis
Iron and erythropoietin to treat anaemia
Vitamin D, low phosphate diet and phosphate binders to treat renal bone disease
What are the management options for end-stage renal disease?
Special dietary advice
Dialysis
Renal transplant
what needs monitoring in a patient with CKD on ACE inhibitors?
serum potassium as both can cause hyperkalaemia
ACE inhibitors should be offered to all patients with:
Diabetes plus a urine ACR above 3 mg/mmol
Hypertension plus a urine ACR above 30 mg/mmol
All patients with a urine ACR above 70 mg/mmol
When should Dapagliflozin be offered for CKD?
Diabetes plus a urine ACR above 30 mg/mmol
what type of anaemia does CKD cause and why?
normocytic normochromic
reduced production of erythropoietin
How should anaemia in CKD be managed?
Iron replacement first then erythropoiesis-stimulating agents
What is raised/low in renal bone disease?
High serum phosphate
Low vitamin D activity
Low serum calcium
why can you get secondary hyperparathyroidism in CKD?
Chronic kidney disease leads to less vitamin D activity and low serum calcium, parathyroid glands react to the low serum calcium and high serum phosphate by excreting more parathyroid hormone
what is the characteristic sign on x-ray of renal bone disease?
Rugger jersey spine
What are the management options for renal bone disease?
Low phosphate diet
Phosphate binders
Active forms of vitamin D (alfacalcidol and calcitriol)
Ensuring adequate calcium intake
What are the indications for short-term dialysis?
A – Acidosis (severe and not responding to treatment)
E – Electrolyte abnormalities (particularly treatment-resistant hyperkalaemia)
I – Intoxication (overdose of certain medications)
O – Oedema (severe and unresponsive pulmonary oedema)
U – Uraemia symptoms such as seizures or reduced consciousness
What is the main indication for long-term dialysis?
End-stage renal failure (CKD stage 5)
What are the 2 options for long-term dialysis?
Haemodialysis
Peritoneal dialysis
What are the 2 options for longer term access in patients who have dialysis?
Tunnelled cuffed catheter
Arteriovenous fistula