Alex: Chronic Kidney Disease (Epidemiology and Adaptations)

Question 1

What are a the functions of he kidney

Answer 1

Making/Concentrating urine

Elimination of Nitrogenous waste

Water and electrolyte balance

Endocrine activity (Vitamin D, erythropoietin, renin, prostaglandins

Produce vasoactive compounds (ie. prostaglandins, nitric oxide, angiotensin II, endothelin).

Question 2

Define Chronic Kidney Disease (CKD)

Answer 2

Kidney damage for >3 months, as defined by structural or functional abnormalities of the kidney, with or without decreased GFR, manifest by either :

1.Pathological abnormalities of the kidney
OR
2.Markers of kidney damage, including abnormalities in the composition of the blood or urine or abnormal imaging tests of the kidneys

OR (Alternatively)

GFR 3 months, with or without markers of kidney damage

Question 3

What are some examples of STRUCTURAL abnormalities seen in CKD ?

Answer 3

Multiple renal cysts

Presence of only one kidney

Question 4

What are some examples of FUNCTIONAL abnormalities seen in CKD ?

Answer 4

Microalbuminuria (Diabetes, HTN, Obesity)

Proteinuria (Large amounts of protein)

Hematuria (RBC)

Question 5

How can you differentiate CKD from Acute Kidney Injury ?

Answer 5

AKI: Serum Creatinine > 0.3 mg/dl (days to weeks)

CKD: Decrease in GFR or signs of renal injury (>3 months duration)

Question 6

The Cockcroft and Gault formula takes into account which variables when estimating GFR ?

Answer 6

Age and Weight

Question 7

the MDRD Formula takes into account which variables when estimating GFR ?

Answer 7

Age, Sex and Weight.

Question 8

Males typically have a ______ GFR than females. Why ?

Answer 8

Higher

Increased Muscles Mass

Question 9

Younger patients typically have a _______GFR than older patients. Why

Answer 9

Higher

Increased Muscles Mass

Question 10

African American patients typically have a ______ GFR than caucasians . Why ?

Answer 10

Higher

Increased Muscles Mass

Question 11

Stage O Kidney disease

Answer 11

GFR > 90 with CKD risk Factors

Question 12

Stage I Kidney disease

Answer 12

GFR >90 , Chronic Kidney damage with normal GFR

Question 13

Stage II Kidney disease

Answer 13

GFR 60-89 , Mild GFR decrease

Question 14

Stage III Kidney disease

Answer 14

GFR 30-59 , Moderate GFR Decrease

Question 15

Stage IV KD

Answer 15

GFR 15-29, Severe GFR Decerase

Question 16

Stage V KD

Answer 16

Kidney failure, GFR < 15 or Dialysis

Question 17

List 6 risk factors for CKD

Answer 17

Ethnic (African Americans)
Systemic HTN
Diabetes Mellitus
Family History 
Autoimmune Disease 
Elderly

Question 18

When does the rate of GFR typically begins to increase ?

Answer 18

As you age, around age 40.

Question 19

The incidence of CKD is rising for all age groups but is most pronounced in which group ?

Answer 19

The Elderly.

Question 20

What stage of Kidney Disease is this patient in : A patient with autosomal dominant polycystic kidney disease with cysts in the kidneys by ultrasound and a GFR of 100 ml/min

Answer 20

Stage I (GFR is over 90 but there is evidence of chronic kidney damage)

Question 21

What stage of Kidney Disease is this patient in: A patient with IgA nephropathy with increased echogenicity of the kidneys on ultrasound and a GFR of 70 ml/min

Answer 21

Stage II (GFR 60-89) with kidney damage.

Question 22

What stage of Kidney Disease is this patient in : A patient with long-standing HTN, 8 cm kidneys by ultrasound (small) and a GFR of 32 ml/min

Answer 22

Stage III (GFR 30-59)

Question 23

What are the 4 key issues in the management of CKD

Answer 23

1. Treat any reversible causes of renal dysfunction (ie. volume depletion, AKI)
2. Prevent or slow the progression of disease
3. Treat the complications of kidney failure
4. Prepare the patient for renal replacement therapy (ie. dialysis or transplantation)

Question 24

The Initial Evaluation of CKD involves 7 Steps. List them

Answer 24

1. Obtain serum creatinine to calculate eGFR
2. Measure protein/creatinine ratio or albumin/creatinine ratio in first AM (morning) or random urine
3. Examine the urine sediment for RBCs, WBCs, and cellular casts
4. Imaging study of kidneys- Ultrasound (always!)
5. Serum electrolytes (Na, K, Cl, HCO3,) and chemistries (calcium, phosphorous)
6. Check hemoglobin
7. Measure parathyroid hormone level (PTH)

Question 25

One of the reversible factors leading to a reduction in kidney function is to dehydration. What can cause this ?

Answer 25

Decreased Fluid Intake Increased Fluid Output (Use of diuretics, Diabetes Insipidus)

Question 26

Including Dehydration, what are the 5 reversible factors that can lead to a reduction in kidney function ?

Answer 26

1. Dehydration 2. Accelerated HTN 3. Heart Failure with poor renal perfusion 4. Nephrotoxic substances (IV contrast, NSAIDs) DO NOT USE CONTRAST (if you can help it) 5. Urinary tract infection/obstruction

Question 27

End Stage Renal Disease is also known as ...

Answer 27

Stage V CKD requiring Dialysis or Transplant

Question 28

It the maintenance of the volume and composition of the ECF well conserved or impaired until late in the course of CKD ?

Answer 28

Surprisingly, it is well preserved

Question 29

What occurs to allow for compensation in response to loss of functioning nephrons in CKD ?

Answer 29

Nephron hypertrophy and hyper function (combine to compensate for the loss of functioning nephrons) THERE IS NO HYPERPLASIA ..no ability to create new nephrons.

Question 30

Adaptive changes in the nephron may lead to ....

Answer 30

maladaptive long-term consequences The effort of the kidney to correct a low GFR may eventually lead to progression of renal failure

Question 31

In order for the remaining nephrons to compensate for the lost ones, what three things must be achieved by the available nephrons ? (Intact Nephron Hypothesis)

Answer 31

1.Increase its own GFR (Single nephron GFR) This process is called Compensatory Hyperfiltration.... 2.Increase its own net acid (H+) secretion (ammonium generation- ammoniagenesis) Limits metabolic acidosis 3.Increase its own sodium and water excretion

Question 32

Where in the nephron will the adaptions needed to achieve increased sodium, H20 and ammonium excretion (Intact Nephron Hypothesis) occur ?

Answer 32

The Tubules (tubular hypertrophy)

Question 33

Where in the nephron will the adaptions needed to achieve increased Urea excretion occur ?

Answer 33

At the glomerulus Only an increase in the GFR of that single nephron will permit more BUN excretion

Question 34

What occurs at the level of the glomerular capillaries to allow for increased sodium, H20 and ammonium excretion ?

Answer 34

Increased Vasodilation of the Afferent Arteriole Increased Vasoconstriction of the Effertent Arteriole. Overally this will lead to increased intraglomerular pressure and GFR

Question 35

What molecules are responsible for increased Afferent Arteriole Vassodilation ?

Answer 35

``` Vasodilatory prostaglandins (PGE2 / PGI2) Nitric Oxide ```

Question 36

What molecule is responsible for Efferent Arteriole Vasoconstriction ?

Answer 36

Angiotensin II

Question 37

The overall effect of the Intact Nephron Hypothesis is maladaptive ......

Answer 37

Intraglomerular HTN

Question 38

Intaglomerular hypertrophy will lead to glomerular stretch/growth and hypertrophy. This will cause...

Answer 38

Increased GFR

Question 39

What occurs in nehphrons who undergo long term HTN and hypertrophy ?

Answer 39

Long term effect is to develop progressive scarring of the mesangium / glomerulus Increases wall stress on the vessels and mesangium results in increased production of matrix and collagen to prevent overstretching of the glomerulus

Question 40

due to Impaired renal ammonia genesis and Reduced filtration of titratable acids, what will occur in all CKD patients over time ?

Answer 40

Metabolic Acidosis !

Question 41

Although increased ammoniagenesis is good for short term prevention of metabolic acidosis, what is the long term effect ?

Answer 41

Ammonia is highly inflammatory to the renal interstitium Results in complement activation and Progressive deposition of collagen and matrix leading to interstitial fibrosis

Question 42

Once renal adaptation to CKD (Intraglomerular HTN, Glomerular hypertrophy, increased ammonia genesis) is initiated can you halt progression by fixing the original disease ?

Answer 42

NO renal function continues to decline even if the original disease or cause of injury is not present any longer

Question 43

With nephron loss, what molecule will be increased to help the tubules deal with an increased Na+(fluid) load ?

Answer 43

Atrial Naturetic Peptide

Question 44

Why are patients with CKD unable to concentrate their urine ?

Answer 44

increased water and solute excretion and loss of the medullary concentrating gradient from fibrosis lead to dilute urine.

Question 45

What is the Urine Specific Gravity associated with the decreased urine concentrating ability of the nephron ?

Answer 45

Urine Specific gravity = 1.010 (isosthenuria)

Question 46

What occurs to most patients with CKD at night ?

Answer 46

Nocturia

Question 47

List the Anatomic Renal Adaptations in CKD

Answer 47

Hypertrophy of surviving structures, both glomeruli and tubules

Question 48

List the Funtional Adaptations seen in CKD

Answer 48

Glomerular hyperfiltration and intraglomerular hypertension | Tubular: Decreased fractional reabsorption (ie. increased fractional excretion)