CKD - amboss Flashcards
define CKD
abnormality of kidney structure of function that persists > 3 months
common causes include diabetes, hypertension, and glomerulonephritis
pathos of diabetic nephropathy
hyperglycaemia causes varying degrees of damage to all types of kidney cells
pathos of hypertensive nephropathy
caused by protective autoregulatory vasoconstriction of preglomerular vessels
benign nephrosclerosis (sclerosis of afferent arterioles and small arteries
decreased perfusion
ischaaemic damage
pathos of glomerulonephritis
noninflammatory GN eg. membranous nephropathy, focal segmantal glomerulosclerosis
inflammatory GN eg. lupus nephritis, post streptococcal GN, rapid progressive GN, haemolutic uraemic syndrome
pathophys of CKD
reduced GFR causes decreased production of urine which leads to increase in extracellular fluid volume and total body volume overload
decrease in excretion of waste products eg. urea, drugs
decrease in excretion of phosphate causes hyperphosphataemia
decreased maintenance of acid base balance leads to metabolic acidosis
decrease in maintenance of electrolyte concentration causes electrolyte imabalances eg. Na retention
reduced endocrine activity in CKD
decrease in hydroxylation of calcifediol causes decreased production of calcitriol - decreased serum Ca
decreased in erythropoetin excretion causes decreased stimulation of erythropoiesis
reduced gluconeogenesis causes increased risk of hypoglycaemia
clinical features of CKD
patients are often asymptomatic until later stages due to the exceptional compensatory mechanisms of the kidneys
hypertension, heart failure, pulmonary oedema and peripheral oedema due to Na and H2O retention
define uraemia
accumulation of toxic substances due to decreased renal excretion. These toxic substances are mostly metabolites of proteins such as urea, creatinine, β2 microglobulin, and parathyroid hormone.
uremia symtpoms
constitutional: fatigue, weakness, headaches
GI symptoms: nausea and vomiting, loss of appetite, ammonia breath
derm: pruritis, skin colour changes, uremic frost
serositis: uremic pericarditis, pluritis
neuro: asterixis, uremic encephalopathy, peripheral neuropathy
haematologic: anaemia, leukocyte dysfunction, increased bleeding tendancy
uremic fetor
characteristic ammonia or urine like breath odour
uremic frost
uraemia leads to high levels of urea excreted in the sweat, the evaporation of which results in yellow white urea deposits on the skin
serositis
An inflammation of any serous surface such as the pericardium, pleura, or peritoneum. Usually associated with autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis.
uraemic pericarditis
complicaation of chronic kidney disease that causes fibrinous pericarditis
clinical features include chest pain worsened by inhalation
physical examination findings include friction rub on auscultation, ECG changes that would normlly be seen in non uremic pericarditis are not usually seen
signs of uraemic encephalopathy
seizures
somnolence
coma
criteria for chronic kidney disease
GFR < 60 for 3 months
define end stage renal disease
irreversible kidney dysfunction with GFR < 15 mL
manifesttions of uraemia requiring chronic renal transplant therapy with either dialysis or renal transplantation
likely death by cardiovascular disease
how do people with end stage renal disease usually die
Most likely due to associated complications (e.g., anemia of chronic kidney disease) and increased cardiovascular risk factors (e.g., hypertension)
CGA classification of chronic kidney disease
classified according to GFR and albuminuria
higher stages correlate with poorer prognosis
determining albuminuria category
Spot UACR: The ratio of urine albumin concentration to urine creatinine concentration. An ACR < 30 mg/g is considered normal to mildly increased; an ACR 30-300 mg/g for more than 3 months indicates likely chronic kidney disease. An ACR > 300 mg/g is severely increased.
other urine studies for CKD
Spot UPCR: The ratio of total protein to total creatinine in the urine. The UPCR obtained from a single urinary sample (i.e., spot urine) can be used to estimate 24-hour protein excretion (assuming creatinine is excreted at a constant rate). A spot UPCR value typically approximates the number of grams of protein excreted in the urine in a 24-hour period (e.g., a spot UPCR of 3.0 can be used to estimate proteinuria of ~ 3.5 g/day).
urine dipstick: may show hematuria or proteinuria
urine microscopy: may show abnormal urine sediment
US of kidneys and urinary tract
first line imaging technique for the assessment of kidney structure
conider obtaining for all patients to further support the diagnosis and help determine the etiology