Chronic Kidney Disease Flashcards
What is chronic kidney disease (CKD)?
A slow decline in kidney function or structure (months to years)
To label someone as having chronic kidney disease they should have two readings taken at least 90 days apart
This term now replaces chronic renal failure
Patients may not develop symptoms until an advanced stage
How is CKD staged?
Using a measured or estimate of the glomerular filtration rate
5 stages of CKD
What is eGFR?
Estimated glomerular filtration rate
Requires age, sex, serum creatinine and ethnicity
What are the causes of CKD?
- Congenital and inherited disease
- Glomerular disease
- Vascular disease
- Tubulo-interstitial disease
- Acute kidney injury
- Urinary tract obstruction
- Hypertension
- Diabetes
- Infections
- Trauma
What is a congenital/inherited kidney disease?
Autosomal dominant polycystic kidney disease
What are examples of glomerular disease?
1ary: e.g. membranous nephropathy
2ary: diabetes, lupus nephritis
What are examples of vascular disease?
Renovascular disease
What is tubulo-interstitial disease commonly caused by?
Allergic reaction to drugs
What are examples of urinary tract obstruction?
Renal stone disease
Prostatic disease
What are symptoms of CKD?
Nausea Lethargy Insomnia Nocturia Pruritis Paraesthesia Restless legs Bone pain Oedema
What is nocturia caused by?
Decreased ability to concentrate urine
What is bone pain caused by?
Metabolic bone disease
How can urinalysis be used to investigate CKD?
Looking for blood and/or protein suggestive of glomerular disease
What are U&E results in CKD?
Elevated urea and creatinine
What are calcium and phosphate results in CKD?
Hypocalcaemia
Hyperphosphataemia
What are results of haematology in CKD?
Anaemia associated with renal disease
How can immunology be used to investigate CKD?
Myeloma screen (immunoglobulins, serum electrophoreseis, urine for Bence Jones Protein)
How can radiology myeloma screen be used to investigate CKD?
Renal tract ultrasound scan (USS) to rule out obstruction
How can hyperkalaemia associated with CKD be treated?
- Reduced dietary intake
- Potassium binding resins
How can acidosis associated with CKD be treated?
Sodium bicarb tablets
How can metabolic bone disease associated with CKD be treated?
Phosphate binders (tablets taken with meals that bind to phosphate from food in the gut and allow it to be excreted and not absorbed)
Vitamin D tables
How can anaemia associated with CKD be treated?
Subcutaneous erythropoietin therapy
What do some patients go on to develop?
End stage kidney disease (ESKD)
What is treatment for ESKD?
- Renal replacement (dialysis)
- Renal transplant
- Symptom control (palliative care)
What must eGFR be for CKD?
> 60ml/min
Along with other signs of kidney damage
- Urine abnormalities (protein, blood)
- Structural abnormalities
- Electrolyte abnormalities due to tubular disorders
- Genetic disease
- Kidney transplant
- Histological abnormalities
What is CKD strongly associated with?
CV complications
Which ethnic minorities is CKD more prevalent in?
South asians (DM), black people (HTN)
How can diabetes lead to CKD?
Diabetic kidney disease induces structural changes, including thickening of the glomerular basement membrane
How can raised intra-glomerular pressure lead to CKD?
Nephrons scar and drop out
Compensatory adaptation of remaining nephrons. Increased blood flow per nephron and hyperfiltration
Can lead to changes in capillary wall permeability (leads to proteinuria)
What can raised intra-glomerular pressure lead to?
Glomerulosclerosis: scarring of glomeruli which can lead to proteinuria as filtration doesn’t occur properly
expansion of glomerular mesangium and deposition of EC matrix??
Tubulointerstitial fibrosis: tubular atrophy, interstitial inflammatory cell infiltrate, deposition of EC matrix in the interstitium
Loss of renal cortex
Shrunken kidneys
What are the structural and functional changes in kidneys as we get older?
Renal mass declines and glomerulosclerosis leads to a decrease in renal weight.
Reduced glomeruli number.
Decrease in renal blood flow
Redistribution of blood flow which favours renal medulla. Shunting of blood from afferent to efferent
How to test for CKD?
- Bloods: eGFR
- Urinalysis: blood/protein, uACR annually
- Blood pressure
Who to test for CKD?
- Diabetes
- Hypertension
- AKI
- CVD
- Structural renal tract disease e.g. bladder outflow obstruction, recurrent renal calculi or prostatic hypertrophy
- Multisystem diseases with potential kidney involvement e.g. SLE, myeloma
- Family history of stage 5 kidney disease
- Hereditary kidney disease
- Opportunistic detection of haematuria (urologically unexplained) or proteinuria
- Chronic nephrotoxin use e.g. NSAIDs, lithium
CKD can lead to uraemia. What can this lead to?
Pericarditis (=>cardiac tamponade)
Encephalopathy (reduced GCS, impaired cognition, confusion, coma, seizures)
Uraemic frost (urea and urate deposits on skin)
What can a renal ultrasound present?
Structural information; PKD
Urinary tract obstruction
Chronicity - renal size
What is PKD?
Polycystic kidney disease
A genetic disorder that causes many fluid-filled cysts to grow in your kidneys. Unlike the usually harmless simple kidney cysts that can form in the kidneys later in life, PKD cysts can change the shape of your kidneys, including making them much larger
What can cause kidneys to become enlarged?
Hyperfiltration (seen in diabetes)
What is blood pressure typically like in CKD?
Almost always elevated
Raised BP = increased glomerular filtration pressure = increased proteinuria z
What is a higher degree of urinary protein excretion associated with?
More rapid decline in kidney function
What is hyperphosphataemia?
There is an elevated level of phosphate in the blood. Most people have no symptoms while others develop calcium deposits in the soft tissue. Often there is also low calcium levels which can result in muscle spasms.
Why do patients with CKD tend to develop hyperphosphataemia?
Kidneys usually remove extra phosphorus in blood
What is effect of high phosphorus levels on calcium?
High phosphorus lowers calcium levels, which activates parathyroid glands (this pulls extra calcium out of bones)
What can hyperphosphataemia lead to?
Calcium phosphate deposition –> interstitial fibrosis and tubular atrophy
Why does metabolic acidosis occur?
Less reabosorbtion and less production of bicarb
Increased acid secretion (as ammonia not present to excrete endogenous acid in form of ammonium)
How do sodium bicarbonate buffers work?
- Buffer acid
- Prevent oesopenia
- Prevent muscle wasting (acidosis promotes catabolism by induction of proteolysis and resistance to growth hormones)
How can CKD lead to anaemia?
Erythropoeitin deficiency
BUT there are also other causes so be sure to look for other causes of iron deficiency
- Nutritional deficiency
- Accumulation of inhibitors of erythropoeisis
- Increased bleeding tendency from uraemia induced platelet dysfunction (blood loss)
What are symptoms of anaemia?
Fatigue, muscle cramps, dizziness
What is CKD-MBD?
CKD mineral bone disorder
How can CKD lead to MBD?
A normal kidney will hydroxylate 25-hydroxyvitamin D (which has already been to the liver)
In CKD, there is reduced renal hydroxylation of 25-hydroxyvitamin D
This, along with hyperphosphataemia, leads to reduced calcium absorption which stimulates 2ary hyperparathyroidism
What is treatment for CKD-MBD regarding phosphate levels?
Dietary restriction, phosphate binders, dialysis
What are other treatments for CKD-MD?
- Vit D replacement
- Calcium supplements
- Parathyroidectomy
What is hyperparathyroidism triggered by?
Low Ca, high phosphate
What is calcitrol?
Used to treat and prevent low levels of calcium and bone disease in patients whose kidneys or parathyroid glands are not working normally.
How can CVD associated with CKD be treated?
- Antiplatelets
- Antihypertensives
- Statins
How can volume overload associated with CKD be treated?
- Fluid and salt restriction
- Diuretics
- RRT
What are the indicators that RRT is required?
- Uraemia
- Severe metabolic acidosis
- Hyperkalaemia
- Fluid overload
How can hypertension affect kidneys?
Uncontrolled high blood pressure can cause arteries around the kidneys to narrow, weaken or harden (scarring). These damaged arteries are not able to deliver enough blood to the kidney tissue.
- Nephrons don’t receive the oxygen and nutrients they need to function well.
- Kidneys are not able to remove all wastes and extra fluid from your body.
Extra fluid in the blood vessels can raise your blood pressure even more.
What is diabetic nephropathy?
Diabetes that leads to kidney disease
Affects about 20-30% of diabetics
How can diabetes lead to nephropathy?
High blood glucose can damage the blood vessels in your kidneys. Many people with diabetes also develop high blood pressure, which can also damage your kidneys.
What is an easy test used to confirm diabetic nephropathy?
Urinalysis –> proteinuria
What does proteinuria reflect?
Glomerular injury and increased glomerular permeability to macromolecules
Why is it important to examine feet in diabetic patients?
Peripheral arterial disease (PAD) and/or sensory neuropathy affecting diabetic patients
Don’t feel when they injure feet –> lead to ulcers
What is C Reactive protein?
A substance produced by the liver in response to inflammation.
What is a C reactive protein test used for?
A high level of CRP in the blood is a marker of inflammation or infection.