(SYNOPTIC) Renal - CKD Flashcards
Define CKD
abnormalities of kidney function or structure present for more than 3 months, with implications for health
Why are patients with CKD referred late to nephrology and what is the impact of this?
because early CKD is asymptomatic causing late referral, which leads to increased mortality and morbidity
How is CKD measured?
GFR is measured against ACR
What is ACR and how is it measured?
- ACR = Urine Albumin Creatinine Ratio
- To measure ACR = Urine sample + dipstick, which is then used to compare Albumin leaked out to creatinine
What are the different stages of CKD, their eGFR results and what this means?
SEE TABLE ATTACHED
What is the main difference between stages 1,2&3 when compared to stages 4&5 of CKD?
- Stage 1,2&3 = Kidney functions can still filter waste
- Stages 4&5 = More severe disease, so kidneys may stop working completely
What is the general trend between eGFR and kidney function?
Lower eGFR = Lower kidney function
What are the risk factors associated with CKD?
- Diabetes (nephropathy is a complication of diabetes)
- Hypertension (high blood pressure pushes kidneys, causing more damage)
- Kidney disorders (genetic)
- Cardiovascular disease
- AKI (especially if treated late or poorly managed/repeated AKI)
- Infections (especially UTIs/recurrent infections e.g. Pyelonephritis)
- HIV or Hepatitis C
- Medications (e.g. NSAIDs, Lithium)
- Malignancy
- Age
- Family history of CKD
How is CKD diagnosed?
Diagnosing CKD is done according to the classifications (blood creatinine levels + ACR) as well as certain prompts:
- Persistent microalbuminuria (albumin in urine)
- Persistent proteinuria
- Persistent haematuria (blood in urine), after excluding other causes
- Ultrasound or biopsy
What are the 3 main functions of the kidneys and explain each one
- Homeostasis - Filtration, absorption, secretion, removal of waste products (e.g. urea), regulating pH of blood, removing potassium and regulating blood pressure
- Hormone function - Release of Renin & Epoetin, activates vitamin D to active form
- Metabolic function - Removal of drugs from the body
What are the clinical complications of CKD?
- Acidosis (acidic blood - kidneys can’t regulate H+ ions can’t get rid of H+ ions)
- Anaemia (lack of Epoetin, EPO, or iron)
- Dyslipidaemia (abnormal lipid metabolism in CKD)
- Fluid overload (kidneys can’t regulate blood pressure, water or Na+ ions - less secretions = more accumulation, causing oedema in hands and legs)
- Hyperkalaemia (kidneys can’t clear potassium as well as it used to)
- Hypertension (kidneys can’t regulate blood pressure as well as before)
- Mineral and bone disorder (vitamin D, calcium and phosphate)
- Uraemia (kidneys are less able to excrete urea, causing build up)
Define acidosis
a condition in which the blood becomes too acidic, with an abnormally low pH level
What is the cause of acidosis in CKD?
- Normally, kidneys maintain the pH of blood by reabsorbing/excreting HCO3- (bicarbonate) and H+
- As CKD progresses, the kidneys are less able to excrete H+/reabsorb HCO3- = acidic blood
What is the long-term maintenance treatment for acidosis?
PO sodium bicarbonate 1g TDS (long-term treatment)
What is the acute treatment for acidosis in a medical emergency?
IV sodium bicarbonate (acute treatment)
What is the main side effect of sodium bicarbonate and why?
fluid retention (swelling of body parts due to trapped fluid) due to secondary increase in sodium because wherever sodium goes, water follows
What is renal anaemia?
Quality/ quantity of RBCs is below normal
Define anaemia
when the quality or quantity of red blood cells are below normal
(2) Lack of erythropoietin
What are the 2 causes of renal anaemia?
- lack of circulating iron (not enough RBCs)
- lack of erythropoietin (EPO)
What are the benefits of correcting renal anaemia?
Increased:
- Quality of life
- Exercise capacity
- Endocrine function
- Immune function
- Muscle metabolism
- Sleep patterns
- Cognitive function
- Nutrition
Decreased:
- Bleeding tendency
- Transfusions
- Depression
- Hospitalisation
What are the causes of a lack of circulating iron?
- Increased blood loss → Haemodialysis (HD)/blood samples
- Dietary inadequacy → many patients are on a renal diet to restrict phosphate intake
- Poor iron absorption due to uraemia (uric acid) or use of phosphate binders
- Reduced or impaired erythropoiesis due to lack of erythropoietin or iron
What is the treatment for a lack of circulating iron in pre-dialysis patients?
- Oral iron OD usually for 3 months maximum
- E.g. Ferrous sulphate or ferrous fumarate
- If no improvement in oral iron, give IV iron
What are the side effects of PO iron?
- GI irritation
- Black stools
- Constipation
- Diarrhoea
(2) Black stools
What is the treatment for a lack of circulating iron in dialysis patients?
- V iron given after a dialysis session
- Many different type of iron IV but usually given Ferinject
What is Erythropoietin (EPO) and its function?
- Erythropoietin (EPO) is a naturally occurring hormone produced by the kidneys
- It stimulates the bone marrow to produce red blood cells
What are the levels of Erythropoietin (EPO) in CKD patients like?
patients have low or no circulating EPO
What is ESA?
Erythropoietin stimulating agents
What are the treatment options for a lack of Erythropoietin (EPO) in CKD?
Multiple treatment options known as Erythropoietin stimulating agents (ESA):
- Eprex - recombinant human EPO
- can be given s/c once weekly (usually self administered by patient)
- can also be given IV 3x weekly to dialysis patients usually at the end of the dialysis session
- Aranesp - novel erythropoiesis stimulating protein (longer half-life than Eprex)
- given IV to dialysis patients usually at the end of the dialysis session
- can be given once weekly due to longer half-life
- Mircera (longest half-life that provides continuous activity)
What ESA has the longest half-life?
Mircera > Aranesp > Eprex
Why can Aranesp be given only once a week?
Longer half-life than other ESAs
What is dyslipidaemia?
the imbalance of lipids such as cholesterol, low-density lipoprotein cholesterol, (LDL-C), triglycerides, and high-density lipoprotein (HDL)
- Mainly hypertriglyceridaemia
What is the treatment for dyslipidaemia in CKD?
Atorvastatin 20mg OD (can be on a higher dose if already taking statins for other cardiovascular conditions)
What is the cause of fluid overload (oedema) in CKD?
occurs due to the kidneys decreased ability to maintain sodium/fluid balance in CKD
What is the treatment for oedema in CKD?
- restrict dietary sodium
- restrict fluid intake (need to balance as patient can become dehydrated, developing AKI on top of CKD)
- offload fluid with diuretic therapy - Thiazides
- if CrCl <20ml/min = Loop diuretic in higher doses (e.g. Furosemide)
- if medication ineffective → dialysis
Define hyperkalaemia
High levels of potassium in blood