Approach to & Management of Chronic Kidney disease in SA Flashcards
what is chronic kidney disease
often smoulders for months/years before becoming clinically apparent
loss of functional renal tissue due to prolonged process (generally >2 months)
usually progressive and irreversible
what is chronic renal failure
end stage process
azotemia and reduced urine concentrating ability
what are degenerative causes of CKD (2)
- chronic interstitial nephritis
- renal infarcts
what are developmental causes of CKD (2)
- familial renal dysplasia
- polycystic kidney disease
what are metabolic causes of CKD (1)
- hypercalcemia
what are neoplastic causes of CKD (2)
- renal lymphoma
- renal carcinoma
what are iatrogenic causes of CKD (2)
- vitamin D supplementation
- nephrotoxic drugs
what are idiopathic causes of CDK (2)
- renal amyloidosis
- primary glomerulopathies
what are immune mediated causes of CKD (1)
- immune complex mediated glomerulonephritis
what are infectious causes of CKD (2)
- pyelonephritis
- borreliosis (lyme nephropathy)
why is it important to stage CKD
CKD often progresses from initial non-azotemic stage to end-stage uremia (CKD –> CRF)
progression can take years
patient management varies substantially as disease progresses
prognosis changes as stage changes
what is the IRIS CKD classification
stage 1-4
what is stage I CKD in dogs
non-azotemic
creatinine <125
what is stage II CKD in dogs
mild renal azotemia
creatinine 125-180
what is stage III CKD in dogs
moderate renal azotemia
creatinine 181-440
what is stage IV CKD in dogs
severe renal azotemia
>440
what is stage I CKD in cats
non-azotemic
<140
what is stage II CKD in cats
mild renal azotemia
creatinine 140-250
what is stage III CKD in cats
moderate renal azotemia
251-440
what is stage IV CKD in cats
severe renal azotemia
creatinine >440
what is the pathophysiology of CKD
normal animals have more nephrons than necessary
CKD leads to nephron damage (glomeruli, tubules, interstitial tissue and/or vessels)
kidneys have limited ways of responding
as nephrons are lost, remaining nephrons have to filter more blood –> glomerular hypertension & hyperfiltration
what does prolonged injury in the kidney lead to
- infiltration of inflammatory cells
- profibrotic cytokine production
- hypoxia –> further injury
nephrons cannot regenerate or replicate
what are the early pathophysiology changes in CKD
nephrons hypertrophy & single nephron GFR increase –> compensation
what are the later pathophysiology changes in CKD
compensation is overwhelmed –> clinical kidney disease
what % of nephron loss causes urine concentrating ability to become impaired
1/3
what % of nephron loss causes azotemia to develop (CRF)
1/4
what are the physiological consequences of CKD (10)
- azotemia and uremia: due to reduced GFR
- PUPD: due to tubular damage & fewer nephrons
- hyperphosphatemia
- increased PTH (renal secondary hyperparathyroidism)
- hypokalemia
- anemia
- hemorrhage
- hypertension
- proteinuria
- metabolic acidosis
why does CKD lead to hyperphosphatemia
phosphate excreted via filtration through glomeruli
reduced GFR –> phosphate retention
what are the effects of hyperphosphatemia (2)
unlikely to cause clinical signs BUT
- drives renal secondary hyperparathyroidism (increased PTH) –> disease progression
- leads to reduced survival
what are the effects of high PTH (3)
- likely uremic toxin –> depression
- can cause osteopenia and tooth loosening and pathological features
- renal cell tubular damage
how does decreased GFR lead to increase PTH
why does hypokalemia occur in CKD (3)
- reduced intake
- reduced renal potassium reabsorption
- renal tubular acidosis
what does hypokalemia (6)
- neuromuscular weakness
- arrhythmias
- metabolic acidosis
- anorexia and impaired protein synthesis –> weight loss
- hypokalemic nephropathy
- promotes PUPD
what type of anemia is present in CKD
non-regenerative, normocytic, normochromic anemia
why does CKD cause anemia (5)
- erythropoietin deficiency (synthesized in kidneys)
- reduced RBC lifespan
- nutritional abnormalities
- chronic GI hemorrhage
- iron deficiency
what are the effects of anemia (3)
- lethargy
- inappetance
- may cause progression of disease due to renal hypoxia
what is hemorrhage due to in CKD (2)
- acquired platelet dysfunction (thrombocytopenia, impaired platelet adhesiveness to subendothelium)
- GI hemorrhage secondary to ulceration
what is hypertension due to in CKD (2)
- impaired excretion of sodium
- activation of renin-angiotensin-aldosterone system (RAAS)