Chronic Kidney Disease Flashcards
How can chronic kidney disease be defined?
Abnormal structure, biochemistry or function of the kidneys for at least 90 days
What is eGFR based upon?
- Serum creatinine levels
- Age
- Sex
- Race
How many stages of CKD exist?
5
What are the stages of CKD?
- G1
- G2
- G3 and G3b
- G4
- G5
What is G1 CKD?
Normal kidney function
Urine findings, structural abnormalities or genetic trait point to kidney disease
(eGFR > 90ml/min)
What is G2 CKD?
Mildly reduced kidney function
Urine findings, structural abnormalities or genetic trait point to kidney disease
(eGFR = 60-89ml/min)
What is G3 CKD?
Moderately reduced kidney function
G3a = eGFR = 45-59ml/min
G3b = eGFR = 30-44ml/min
What is G4 CKD?
Severely reduced kidney function
(eGFR = 15-29ml/min)
What is G5 CKD?
Established renal failure
(eGFR < 15ml/min)
What is ACR and what is its purpose?
Albumin creatinine ratio
Estimates level of protein in urine
(more convenient vs 24 hour collection and compensates for hydration level)
What are the different cut offs for ACR?
- A1 < 3mg/mmol
- A2 3-30mg/mmol
- A3 > 30mg/mmol
(Nephrotic > 300mg/mmol)
Why should a patient with AKI be monitored for many years after?
Incidence of developing CKD is higher than normal
(remaining nephrons work harder and burn out sooner as they must take on work of lost nephrons)
Why is eGFRcystatinC more accurate than eGFRcreatinine?
Creatinine is excreted by both the kidneys and GI tract
CystatinC is excreted only by the kidneys
How can accelerated progression of CKD be diagnosed?
Sustained decrease in GFR of 25%+ and change in GFR category within 12 months
or
Sustained decrease in GFR of 15ml/min per year
Which risk factors exist which can contribute to CKD progression?
Other illness
- Cardiovascular disease/Hypertension
- Proteinuria
- Diabetes
- Untreated urinary outflow obstruction
Ethnic origin
- African
- Afro-Carribean
- Asian
Lifestyle
- Smoking
Dysmorphic red cells are often due to what?
Glomerular bleeding
What are the blood pressure targets in CKD?
<140/90mmHg (CKD only)
<130/80mmHg (CKD and diabetes or ACR of >70mg/mmol)
The dose of RAAS system antagonists should not be modified in which instances?
GFR decrease from pre-treatment is <25%
or
Serum creatinine increase from pre-treatment is <30%
In patients with CKD what should be prescribed for either the primary or secondary prevention of CVD?
Atorvastatin 20mg
(dosage may be altered in more severe cases)
What are the two most common causes of CKD?
- Hypertension (most common)
- Diabetes
What is the basic process behind why hypertension causes CKD?
- Renal artery walls thicken to withstand pressure
- Less blood and O2 delivered to glomeruli causing ischaemia
- Macrophages enter ischaemic area and release TGF-B plus other growth factors
- GFs cause mesangial cell regression to mesangioblasts (secrete extracellular structure matrix)
- This causes glomerulosclerosis (scarring and hardening of tissue)
- Blood filtering capability is diminished
What is the basic process behind why diabetes causes CKD?
- Excess glucose causes glycation of blood proteins
- Efferent arteriole stiffens due to hyaline arteriosclerosis
- Glomerular pressure increases leading to hyperfiltration
- Mesangial cells secrete more and more extracellular structural matrix
- Glomerulosclerosis develops over many years
Which vascular conditions can cause CKD?
- Renal artery stenosis
- Nephrosclerosis (hypertensive or ischaemic)
- Thrombotic thrombocytopenic purpura (TTP)
- Haemolytic-uremic syndrome (HUS)
- Small vessel vasculitis
What are the clinical signs of CKD?
- Anaemic (pallor)
- Weight loss
- Advanced uraemia
- Lemon yellow, uraemic frost (rare)
- Encephalopathy (flapping tremor, confusion)
- Pericardial rub (or haemorrgaic pericardial effusion)
- Kussmaul breathing (metabolic acidosis)
What are the renal consequences of CKD?
- Local - pain, haemorrhage, infection
- Urinary - haematuria, proteinuria, nocturia, oliguria
- Impaired salt and water handling (hypertension)
- Electrolyte imbalanaces - hyperkalaemia
- Acid base disturbance
What are the main extra-renal complications of CKD?
- CVD
- Renal osteodystrophy
- Anaemia
What are the options for end stage renal disease?
- Haemodialysis
- Peritoneal dialysis (can be done at home)
- Transplant
- Palliative care
What is the name of the condition when urea builds up in CKD?
Azotaemia
What symptoms can azotaemia cause?
Usually just nausea, vomiting and loss of appetite
Higher concentrations of urea can lead to:
- Pericarditis
- Bleeding risk (clotting ability diminishes)
- Encephalopathy, asterixis, coma, death
- Uraemic frost
What is uraemic frost?
Develops in severe cases of CKD with azotaemia
Urea crystals precipitate in skin and appear like snow crystals
CKD will cause an ________ in potassium and a _________ in calcium
CKD will cause an increase in potassium and a decrease in calcium
For which reasons does hypocalcaemia occur in CKD?
Kidneys become less efficient at activating vitamin D
Activated vitamin D increases gut absorption of calcium
This happens less so hypocalcaemia occurs
When hypocalcaemia occurs in CKD, how does the body compensate?
PTH secretion increase in reponse to low serum calcium
The bones will lose calcium in order to boost serum calcium levels
This causes weak and brittle bones
This is called renal osteodystrophy
How can renal osteodystrophy be treated?
Alfacalcidol (active vitamin D)
Phosphate binders
Cinacalcet (calcimimetic)
Why does anaemia occur in patients with CKD?
The kidneys produce erythropoietin
This induces RBC production in the bone marrow
As kidney production decreases, RBC production will also decrease
Decribe how the RAAS is involved in a vicious circle of CKD
Decreased fluid filtration in the kidneys will normally induce renin production to raise BP
In CKD, a rise in BP will worsen the CKD as hypertension is the main cause of CKD
What is the target Hb level in CKD?
100-120g/L
How is renal anaemia treated?
Oral iron
IV iron (if oral fails)
