renal Flashcards
what type of patients present with AKI
unwell patients with infection or following a surgery, above 65.
The NICE guidelines (2019) criteria for diagnosing an acute kidney injury are:
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
name some of the risk factors that would predispose to developing acute kidney injury
Older age (e.g., above 65 years)
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 (e.g., used during CT scans)
name the stages of renal impairment
Pre-renal causes are the most common. Insufficient blood supply (hypoperfusion) to kidneys reduces the filtration of blood. This may be due to:
Dehydration
Shock (e.g., sepsis or acute blood loss)
Heart failure
Renal causes are due to intrinsic disease in the kidney. This may be due to:
Acute tubular necrosis
Glomerulonephritis
Acute interstitial nephritis
Haemolytic uraemic syndrome
Rhabdomyolysis
Post-renal causes involve obstruction to the outflow of urine away from the kidney, causing back-pressure into the kidney and reduced kidney function. This is called an obstructive uropathy. Obstruction may be caused by:
Kidney stones
Tumours (e.g., retroperitoneal, bladder or prostate)
Strictures of the ureters or urethra
Benign prostatic hyperplasia (benign enlarged prostate)
Neurogenic bladder
what are some pre-renal kidney issues
insufficient blood flow-hypoperfusion, due to dehydration, heart failure, shock-sepsis, or acute blood loss.
what are some Renal kidney issues
Due to intrinsic factors:
- Acute tubular necrosis
- Glomerulonephritis
Acute interstitial nephritis
Haemolytic uraemic syndrome
Rhabdomyolysis
what are some post-renal kidney issues
obstruction to the outflow of urine away from the kidney, causing back-pressure into the kidney and reduced kidney function. This is called an obstructive uropathy. Obstruction may be caused by:
Kidney stones
Tumours (e.g., retroperitoneal, bladder or prostate)
Strictures of the ureters or urethra
Benign prostatic hyperplasia (benign enlarged prostate)
Neurogenic bladder
name the common cause of intrinsic renal impairments and the diagnosis of it.
Acute tubular necrosis- this is due to ischaemia and poor perfusion of the epithelial cells of the renal tubules
Nephrotoxins-gent, radiocontrast agents or cistplatin
- Urinalysis- muddy brown cast, renal tubular epithelial cells may also been seen. they can regenerate quickly so this cause is reversible 1-3 weeks.
Acute tubular necrosis cause of renal impairment is reversible. True or false?
True, epithelial cells are able to regenerate in 1-3weeks.
What are urinalysis findings for AKI
-Leukocytes and nitrites - infection
- Protein and blood suggest acute nephritis, and infection
- glucose- diabetes
other than urinalysis what other tool is used for diagnosing stages of AKI
Ultrasound of the urinary tract assesses for obstruction when a post-renal cause is suspected.
what is the management for AKI prevention?
- consider causes of 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 is the treatment plan for AKI with an (underlying cause)- consider medications, invasive management
Treating an acute kidney injury involves reversing the underlying cause avoiding medications that may worsen and also medications that may accumulate with reduced renal impairment.
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
TOM TIP: Calling ACE inhibitors nephrotoxic is incorrect. ACE inhibitors should be stopped in an acute kidney injury, as they reduce the filtration pressure. However, ACE inhibitors have a protective effect on the kidneys long-term. They are offered to certain patients with hypertension, diabetes and chronic kidney disease to protect the kidneys from further damage.
Name some complications of AKI
(electrolytes)
(blood gas)
-fluid overload- heart failure and oedema
-metabolic acidosis
hyperkalemia
uraemia: leads to encephalopathy and pericarditis
Define CKD and how long does it have to maintain to be considered as CKD.
Chronic kidney disease (CKD) describes a chronic reduction in kidney function sustained over three months. It tends to be permanent and progressive.
Name some causes of CKD
Diabetes
Hypertension
Medications (e.g., NSAIDs or lithium)
Glomerulonephritis
Polycystic kidney disease
What are the presentations of CKD. (consider the synthesis of kidney, fluid status
Mostly Asymptomatic,
Pallor due to Anemia: erythropoetin is the hormone synthesised by the kidney for RBC formation.
- Fatigue
- foamy urine
-nausea
loss of appetite
oedema
pruritus
hypertension
peripheral neuropathy
what is the EGFR based on
The estimated glomerular filtration rate (eGFR) is based on the serum creatinine, age and gender. It estimates the glomerular filtration rate (the rate at which fluid is filtered from the blood into Bowman’s capsule).
Which investigation tool is used for proteinuria
Quantified with a urine albumin:creatinine ratio (ACR).
Which investigation tool is used for Haematuria
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Haematuria (blood in the urine) can be assessed with a urine dipstick or microscopy. Microscopic haematuria is when blood is identified on testing but not visible on inspection. Macroscopic haematuria refers to visible blood in the urine. Haematuria can indicate infection, malignancy (e.g., bladder cancer), glomerulonephritis or kidney stones.
what tool can be used to look for obstruction in the kidneys
Renal ultrasound helps identify obstructions (e.g., kidney stones or tumours) and polycystic kidney disease.
name some other investigations necessary to identify risk factors for CKD (consider common AKI causes)
Blood pressure (for hypertension)
HbA1c (for diabetes)
Lipid profile (for hypercholesterolaemia)
what are the components to classifying CKD?
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
The G score is based on the eGFR. The A score is based on the albumin:creatinine ratio.
Accelerated progression is a sustained decline in the eGFR within one year of either 25% or 15 mL/min/1.73 m2.
G5- UNDER 15
A3- ABOVE 30MG/MMOL
What are the values of accelerated progression in CKD
Accelerated progression is a sustained decline in the eGFR within one year of either 25% or 15 mL/min/1.73 m2.
what are the complications of CKD
Anaemia
cardiovascular disease
Renal bone disease
end stage kidney diseases
dialysis related complications
peripheral neuropathy
what tool ‘equation’ can be used to estimate risk of kidney failure requiring dialysis and how many years does it estimate?
The Kidney Failure Risk Equation can be used to estimate the 5-year risk of kidney failure requiring dialysis.
The NICE clinical knowledge summaries (May 2023) suggest referral to a renal specialist when:
(consider hypertension issues, dialysis, accelerated progression, EGFR ACR) (5)
(EGFR AND ACR- 100)
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
Treating the underlying cause of CKD involves:
Optimising diabetic control
Optimising hypertension control
Reducing or avoiding nephrotoxic drugs (where appropriate)
Treating glomerulonephritis (where this is the cause)
What are the BP and ACR findings in patients under 80
The blood pressure target is less than 130/80 in patients under 80 with CKD and an ACR above 70 mg/mmol.
Medications that help slow the disease progression in CKD are:
ACE inhibitors (or angiotensin II receptor blockers)
SGLT-2 inhibitors (specifically dapagliflozin)
Decrease ACR RATIO
Reducing the risk of complications in CKD involves (consider meds used to treat common cause of AKI:
cardio input
Exercise, maintain a healthy weight and avoid smoking
Atorvastatin 20mg for primary prevention of cardiovascular disease (in all patients with CKD)
Management of complications of CKD involves: (blood gas impairment, blood status, renal bone disease)
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
Management of end-stage renal disease involves:
Special dietary advice
Dialysis
Renal transplant
ACE inhibitors are offered to all patients with (consider common cause of AKI, ACR levels :
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
what electrolyte imbalance is associated with CKD and ACE inhibitors
hyperkalaemia- monitor serum potassium
Patients with diabetes and CKD are offered what type of medications
Dapagliflozin is the SGLT-2 inhibitor licensed for CKD. It is offered to patients with:
Diabetes plus a urine ACR above 30 mg/mmol
Dapagliflozin is considered for patients with:
Diabetes plus a urine ACR or 3-30 mg/mmol
Non-diabetics with an ACR of 22.6 mg/mmol or above
What type of anaemia does CKD cause and state the cause of this?
Healthy kidneys produce erythropoietin, a hormone that stimulates the production of red blood cells. CKD results in lower erythropoietin and a drop in red blood cell production. It causes a normocytic (normal sized) normochromic (normal colour) anaemia.
treated with erythropoiesis-stimulating agents: recombinant human erythropoietin.
Blood transfusions can sensitise the immune system (allosensitization), increasing the risk of future transplant rejection.
Iron deficiency is treated before using erythropoietin. Intravenous iron is usually given, particularly in dialysis patients.
what are the treatments for Anaemia in chronic kidney disease?
Anaemia may be treated with erythropoiesis-stimulating agents, such as recombinant human erythropoietin. Blood transfusions can sensitise the immune system (allosensitization), increasing the risk of future transplant rejection.
Iron deficiency is treated before using erythropoietin. Intravenous iron is usually given, particularly in dialysis patients.
How does CKD cause renal bone disease?
consider the function of kidneys in bone synthesis
- high serum phosphate as a result of poor excretion
- low vitamin D due to kidney’s inability to metabolise vitamin D into active vitamin D which is essential for calcium absorption in the intestines and reabsorption in the kidneys. It is also responsible for regulating bone turnover and promoting bone reabsorption to increase the serum calcium level. Chronic kidney disease leads to less vitamin D activity and low serum calcium.
what type of deficiency does CKD cause?
Chronic kidney disease leads to less vitamin D activity and low serum calcium.
which glands are responsible for responding to low calcium serum as a result of VitD in CKD?
The parathyroid glands react to the low serum calcium and high serum phosphate by excreting more parathyroid hormone, causing secondary hyperparathyroidism. Parathyroid hormone stimulates osteoclast activity, increasing calcium absorption from bone.
what is the term used to describe the increased turnover of bones without adequate calcium supply
osteomalacia
***** occurs when the osteoblasts respond by increasing their activity to match the osteoclasts, creating new tissue in the bone. Due to the low calcium level, this new bone is not properly mineralised.
OSTEOSCLEROSIS
What is the finding on spinal x-ray for patients with renal bone disease as a result of CKD.
Rugger jersey spine is a characteristic finding on a spinal x-ray. This involves sclerosis of both ends of each vertebral body (denser white) and osteomalacia in the centre of the vertebral body (less white). The name refers to the stripes found on a rugby shirt.
