Flashcards in Chronic Kidney Disease Deck (49):
What is the traditional definition of chronic renal failure?
Irreversible and significant loss of renal function
How do we assess for kidney disease?
-Glomerular Filtration Rate (eGFR from creatinine blood test)
-Check for presence of blood or protein in urine
What is the problem with the relationship between serum creatinine and GFR (for measuring eGFR)?
Creatinine will not be raised above the normal range until 60% of total kidney function is lost
What effects serum creatinine levels?
-Ethnicity (African Americans)
Give some formulae to estimate GFR from serum creatinine
MDRD 4 variable equations
What crosses the GBM?
What crosses the GBM but is reabsorbed in the proximal tubule?
Low molecular weight proteins (a2-microglobulin)
What doesnt cross the GBM?
Cells (RBC, WBC)
High molecular weight proteins (albumin, globulins)
How much blood or protein should you be able to measure in a normal kidney?
Should be no blood or protein measurable in urine if filtering properly
How can you test for protein or blood in urine?
-Protein creatinine ratio (PCR)
What is the current chronic kidney disease definition?
Chronic kidney disease is defined by either the presence of kidney damage (abnormal blood, urine or x-ray findings) or GFR /= 3 months
What is the prevelence of CKD?
Increases with age
About 8-12% in UK
Mostly stage 3
Give some of the complications of chronic kidney disease
Death and dialysis
How much does CKD cost?
About £35,000pa for 1 patient
Around £6,500 drug costs
What is the aetiology of CKD?
Polycystic kidney disease
-And all the causes of that
What is the clinical approach to CKD?
Detection of the underlying aetiology
-Treatment for specific disease
Slowing the rate of renal decline
Assessment of complications related to reduced GFR
-Prevention and Treatment
Preparation for Renal replacement therapy
What are you looking for in terms of previous evidence of renal disease in a CKD history
Raised urea/ creatinine
What systemic diseases do you need to keep an eye out for in a CKD history?
Collagen vascular diseases:
-SLE, Scleroderma, Vasculitis
-Myeloma, Breast, lung, lymphoma
Sickle cell disease
What drugs are you keeping an eye out for in CKD history?
ACE inhibitor/ ARBs
What uraemic symptoms may you be looking for in a CKD history?
Nausea, anorexia, vomiting
Weakness, fatigue, drowsiness
What are some of the clinical signs of depleted volume status?
Skin turgor/ temperature
What are some of the clinical signs of fluid overload?
What chemistry investigations may you want to carry out to look for CKD aetiology?
U&E (Na, K, Cl)
Total protein, albumin
Liver function tests
Immunoglobulins, serum protein electrophoresis
What haematology investigations may you want to carry out to look for CKD aetiology?
-% hypochromic RBCs
What will be included in a coagulation screen you may want to carry out?
What imaging may you want to carry out to find the aetiology of CKD?
CT Nuclear medicine
When can pathology be useful for finding the aetiology in CKD?
Unexplained renal failure and Normal sizes kidneys
How can you slow the rate of renal decline?
Reverse other contributing factors - treat causes
-Dietary proetin restriction
What investigations can you carry out to assess complications related to reduced GFR?
Blood count and Film
Calcium Phospate Albumin PTH
- ?Renal bone disease
Urine Protein excretion (Pr:Cr)
- ?Degree of proteinuria
When does anaemia usually manifest in CKD?
Describe the anaemia resulting from CKD?
Reduced erythropoietin production
Reduced red cell survival
Increased blood loss
How do you treat anaemia due to CKD?
Usually treat if
When is metabolic acidosis usually seen in CKD?
When is metabolic acidosis most marked?
Nor usually seen until GFR
What are the symptoms of metabolic acidosis due to CKD?
Exacerbates renal bone disease
How do you treat metabolic acidosis in CKD?
Treat with oral Na Bicarbonate
-Care with volume overload
How does CKD result in bone disease?
Reduced GFR leads to hyperphosphataemia
Loss of renal tissue leads to lack of vitamin D
-(indirect reduction in Ca absorption)
Low Calcium and raised phosphate
Secondary hyperparathyroidism (elevtaed PTH)
May progress to tertiary hyperparathyroidism
How does CKD effect activation of vitamin D?
Vitamin D, derived from sunlight or diet, requires to be hydroxylated to be active - 1,25 (OH) 2 D
The 1a hydroxylation is catalysed by 1a hydroxylase in the kidney
CKD -> low 1a hydroxylase, so low activation of vitamin D
How does low vitamin D lead to low calcium?
Reduced intestinal absorption
Reduced tubular reabsorption
Resulting stimulation of PTH secretion (i.e. secondary hyperparathyroidism)
What does high phosphate levels cause?
Reduced 1a hydroxylase therefore low vitamin D
Stimulates PTH production
Associated with vascular and cardiac calcification
How do you manage renal bone disease?
---CaCO3, Ca Acetate, Sevelamer, lanthanum
Normalise Calcium and PTH
-Active Vit D analogues (Calcitriol)
---Parathyroidectomy and Calcimetics (Cinacalcet)
Why does CKD result in Hyperkalaemia?
Normally excreted by exchange with Na+ in distal tubule
Reduced delivary of Na+ to distal tubule as GFR falls
Other factors include underlying disease, drgs and diet
How do you treat acute hyperkalaemia?
Stabilise cardiac membrane
Shift K+ into cells
Remove calcium from body:
How do you treat chronic hyperkalaemia?
When does fluid/ volume overload become problomatic in CKD?
How does CKD lead to fluid/ volume overload?
Unable to excrete an excess Na+ load
Na+ and water retention
Oedema and hypertension
How do you treat fluid overload in CKD?
How do you tackle hypertension in CKD?
Treatment as per slowing rate of progression
Most imporatnt in proteinuric renal disease
ACEI may offer additional advantage
Otherwise tailored therapy
What drugs should by be weary of in CKD?
The main effect of kidney disease is reduced excretion of drugs and their toxins
-Beware antibiotics, morphine, digoxin, metformin amongst others
In those with CKD certain drugs and agents can cause acute kidney injury on top of CKD:
-Contrast agents, antibiotics