Chronic Kidney Disease Flashcards
Chronic Kidney Disease
A long-standing, progressive deterioration of renal function
○ Results from the decline of GFR over months to years
○ Renal insufficiency, may progress to renal failure or end-stage renal disease (ESRD)
Most common causes of CKD
● Diabetic nephropathy
● Hypertensive nephrosclerosis
● Glomerulopathies
Over 70% late stage CKD cases (Stage 5/ESRD) are due to ____
DM and HTN/vascular disease
Chronic Kidney Disease causes an increased risk of _____
CV disease
Kidney Resiliency
● Despite renal injury or progressive destruction to the nephrons, the kidney has
an innate ability to maintain GFR
○ The remaining healthy nephrons manifest hyperfiltration and compensatory
hypertrophy
Plasma levels of substances such as urea and creatinine will start to show
measurable increases only after total GFR has decreased to _____
50%
Chronic Kidney Disease Etiology
● May result from any cause of renal dysfunction of sufficient magnitude (Prerenal, intrinsic and postrenal)
● DM and HTN account for > 2/3 of cases
CKD may also result from abnormalities of kidney structure or function, if present for more than ___ months
3
○ Kidney damage or decreased
GRF < 60 mL/min/1.73m2
Why is staging for CKD important?
● Provides a baseline for monitoring
● Improves communication among
providers
● Helps anticipate/facilitate interventions at different stages of disease
T/F CKD In Stage 1 and 2 & reduced GFR alone is diagnostic for CKD
F
One of the following markers must also be present
● Albuminuria (> 30mg/24 hours or Albumin:Creat ratio (ACR) >30 mg/g)
● Abnormal urine sediment
○ i.e. hematuria or broad waxy casts (dilated, hypertrophic nephrons)
● Electrolyte abnormalities due to tubular disorder
● Histologic pathology
● Structural pathology on imaging
● Any h/o kidney transplantation – low threshold to monitor these patients
What Albumin:Creatinine ratio (ACR) is concerning for CKD?
> 30 mg/g)
Must also be present >3 months
Chronic Kidney Disease Screening
● Early detection may slow or prevent the progression to ESRD
● Testing involves checking for albumin in a urine sample and a blood test
(BMP/CMP)for creatine to estimate GFR
MDRD
(Modification of Diet in Renal Disease)
○ The most commonly used estimate equation
○ Estimates using body surface area
○ Uses a standardized serum creatinine assay
■ More accurate than creatinine clearance from 24 hr urine
Gold standard for GRF determination
○ Gold standard is inulin (but is cumbersome to navigate)
○ Creatinine used instead
CKD-EPI
(Chronic Kidney Disease-Epidemiology Collaboration)
○ Developed to provide a more accurate estimate of GFR among
individuals with normal or only mildly reduced GFR
○ More accurate of the two in groups with eGFR > 60
■ As accurate as MDRD in eGFR < 60
Leading cause of CKD
Diabetes
Diabetic Nephropathy =
albuminuria with known DM
○ Diabetic nephropathy can also cause secondary HTN due to abnormal
renal function
■ HTN can worsen existing renal microvascular disease
Diabetic Kidney Disease (DKD) =
albuminuria and/or decreased eGFR with DM
○ Does not indicate a specific kidney disease
○ Typically a clinical (or presumptive) diagnosis; renal biopsy is rare
3 major changes occur in the glomeruli caused by Diabetic Nephropathy
- Mesangial expansion (fibrosis within the kidneys) – directly induced by hyperglycemia
- Glomerular Basement Membrane (GMB) thickens
- Glomerular Sclerosis – caused by intraglomerular hypertension (more to come)
HTN negatively impacts both _____
CKD and CVD
Hypertensive Nephrosclerosis has two important effects
- Glomerular Ischemia: Chronic hypertension narrows pre-glomerular arteries and arterioles
■ Reducing blood flow, causing ischemic changes - Glomerulosclerosis
○ Glomerular HTN → glomerular hyperfiltration → progressive glomerular sclerosis
CKD Presentation
● Asymptomatic in early stages – “Silent Disease”
● Hypertension is them most common finding
○ Partially due to impaired sodium excretion
■ ↓Na excretion → ↑ECF → ↑ Blood pressure
■ Later stages may present with sign of volume overload (hypervolemia)
Skin changes with CKD
○ Pale skin – Anemia
○ Bruising/hematoma – platelet dysfunction
○ Uremic Frost – Urea crystallization (fine white powder)
○ Calciphylaxis – Calcium deposits in vessels → ischemia → skin necrosis