CKD Flashcards
What is the role of the kidney? (5).
(1. ) Excretion of by-products of metabolism
- Drug metabolites- Creatinine
- K+, Urea, Phosphate excretion
- Keep in plasma proteins, cells
(2. ) Vitamin D activation: Ca and PTH regulation, important for bone, vasculature, nerve health
(3. ) Fluid balance and BP: RAAS
(4. ) Epo production: RBC production
(5. ) Acid-base pH homeostasis
- drop in pH sensed by kidney -> cells excrete acid and absorb bicarbonate to correct pH
What is CKD and RF?
- Irreversible deterioration in renal function over years
- Initially it manifests as biochemical abnormalities then loss of excretory, metabolic, endocrine function of the kidney leads to clinical Sx and signs of renal failure
- Ultimately without RRT it leads to chronic stage 5, ESRD
RF - HTN, DM, vascular disease - >65y - using nephrotoxics e.g. ibroprofen These are high risk groups and should be targeted for screening
Pathophysiology of CKD (note: this is a simplified answer) (6)
(1. ) Nephron damage:
- GFR drops causing RAAS activation
- inc BP and systemic resistance thus HTN
- pedal & pulmonary oedema
(2. ) Reduced excretion:
- Uremic, hyperkaliaemic (late stage)
- Drug toxicity
- Albuminuria
(3. ) Reduced PO excretion and vitamin D activation
- Low serum Ca
- PTH excreted (in response to hi serum PO, low Ca)
- secondary hyperparathyroidism, which inc bone resorption & can lead to renal osteodystrophy (CKD-MBD)
(4. ) High serum PO and HTN causes endothelial damage and calcification. This inc BP and CVD risk
(5. ) Reduced intercalated cells available means there’s reduced bicarbonate in relation to H+, so become acidotic.
(6. ) Reduced EPO production means less RBC are formed -> anaemic
Aetiology of CKD
- DM
- HTN/atheroma/renovascular (renal-CVD)
- Glomerulonephritis
- Unknown
- Infective
- Obstructive
- Cystic or congenital e.g. POK
- Others: Medication, Myeloma
Dx of CKD
KDIGO criteria:
- Abnormalities of the kidney structure or function
- Present for >3m with implication for health
Therefore, Dx requires:
- Abnormal function = either GFR <60ml or albuminuria (urine ACR >3mg/mmol)
- Abnormal structure = histological or radiological evidence
What is staging of CKD based on?
- GFR and albuminuria
Clinical features of CKD
(1. ) Asymptomatic usually
- Raised creatinine & urea found accidentally
- Low GFR but <30ml at this point
(2. ) Nocturia
(3. ) Tiredness, Breathlessness: due to renal anaemia or fluid overload
(4.) Sx of further deterioration: Pruritus, anorexia, wt loss, N+V
(5. ) Sx of advanced deterioration
- Kussmaul breathing: due to metabolic acidosis
- Muscle twitching
- Drowsiness
- Coma
CKD Ix
Approach
- Hi Creatinine & urea requires rapid investigation, repeat in 2w
- identify cause, exacerbating factors e.g. HTN, obstruction
- screen for complications (CVD, bone etc)
(1. ) U&E, electrolytes: hyperkalaemia? acidosis?
(2. ) Urinalysis: quantify proteinuria, haematuria may indicate GN
(3. ) Ca, phosphate, PTH, 25(OH)D: renal osteodystrophy?
(4. ) FBC, Albumin, glucose, lipids:
- anaemia?
- nephrotic syndrome?
- CV risk
(5. ) Renal US
(6. ) Hepatitis, HIV Serology
Aims of CKD Management (4.)
Aims of Mx in CKD is to:
(1. ) Monitor renal function
(2. ) Slow down further renal damage and limit complications
(3. ) Treat CVD RF
(4. ) Prepare for RRT if appropriate
CKD Management (5.)
(1.) Monitor renal function every 6m in stage 3,4,5 CKD. Predict when ESRF would be reached
(2. ) Reduce rate of progression:
- ACEi, ARBs: reduce proteinuria
(3. ) Tx of complications
(a. ) Electrolyte & fluid imbalances = reduce dietary protein, K, Na, fluid. Consider diuretics.
(b.) Acidosis: Na bicarbonate supps
(c. ) CKD-MBD:
- Reduce dietary PO
- Active vitamin D supps
(d. ) Anaemia: iron supps, ESA
(e. ) Glycaemic Control
(4. ) Tx of CVD risk
- healthy lifestyle, wt loss, exercise, smoking cessation, statin
(5. ) Renal Replacement Therapy RRT:
- Haemodialysis
- Peritoneal dialysis
- Kidney Transplant
What are non-modifiable and modifiable factors that affect CKD progression?
Non-modifiable
- underlying cause of renal disease
- race (CKD progresses faster in black than white)
Modifiable
- BP
- Proteinuria
- Nephrotic use
- Underlying disease activity
- Further renal insults
- Dyslipidaemia
- Inc phosphate
- Acidosis
- Anaemia
- Smoking
- Glycaemic control if diabetic
What does RRT not do? (2)
- Activate vitamin D
- Produce EPO
- So pts still required - active Vit D, EPO injections
When is Dialysis indicated? (4)
- Fluid overload
- Hyperkalemia
- Uraemia
- Metabolic acidosis
When is kidney transplant contraindicated? (4)
active malignancy
vasculitis
CVD
high risk of renal failure
