A-Introduction To Renal Dysfunction

Front 1

Renal Dysfunction

What is the definition of polyuria?

Back 1

Production of more than 3000ml/hr of urine

Front 2

Renal Dysfunction

How many RBC's in the urine requires a greater workup?

Back 2

Either three urine samples with greater than 3 RBC's/hpf or one urinalysis with > 100 RBC's.

Front 3

Renal Dysfunction

What is pyuria?

When does this occur? (2)

Back 3

Pyuria: WBC's in urine.

WBC casts occur in pyelonephritis and acute interstitial nephritis.

Front 4

Renal Dysfunction

What stain do you use to see eosinophils?

Back 4

Wright stain

Front 5

Renal Dysfunction

When do you see tubular casts?

Why does this occur?

Back 5

Tubular casts can be seen in dehydration as well as in acute tubular necrosis where they may be described as epithelial, granular, or muddy brown casts.

Why? Dehydration pushes out protein

Front 6

Renal Dysfunction

What is the normal amount of urine protein excretion (total protein and albumin) over a 24 hr period?

Back 6

NL: < 150mg/day of total protein

and 30mg/day of albumin

Front 7

Renal Dysfunction

What amount of total protein in the urine (over 24hrs) signifies NEPHROTIC syndrome?

Back 7

Nephrotic:
3.5gm or greater per 24 hrs

Front 8

Renal Dysfunction

In nephrotic syndrome: is the main problem glomerular filtration (lack thereof) or massive protein leak across the glomerular basement membrane?

Back 8

Nephrotic: leak across the basement membrane

Nephritic: glomerular infiltration

Front 9

Renal Dysfunction

What are Tamm Horsfall proteins?

Back 9

Proteins made in the thick ascending limb and form the matrix of urinary casts.

Front 10

Renal Dysfunction

What is Bence Jones proteinuria?

Back 10

Proteins in the urine that are found in patients with multiple myeloma. They are immunoglobulin light chains and are caused by defective platelet function.

Front 11

Renal Dysfunction

What is azotemia?

Back 11

Azotemia: is the presence of urea (product of nitrogen waste products) in the blood

Front 12

Renal Dysfunction

Is the relationship between serum creatinine and GFR linear?

Back 12

No, you can have a large reduction in GFR and only small increases in creatinine.

For example, creatinine could increase from 0.6-1.2 mg/dl and still be "normal" but the GFR has decreased by 50%.

Front 13

Renal Dysfunction

Explain why differences in serum creatine would exist between a young man and an old man?

Back 13

Since serum creatinine is dependant on muscle mass, a large muscular man may have a creatinine of 1.0mg/dl and have a nL GFR but an old man with little muscle mass may also have a creatinine of 1.0mg/dl, indicating a poor GFR

Front 14

Renal Dysfunction

In general, way isn't creatinine a perfect test?

Back 14

Creatinine is insensitive in the lower range so poor glomerular filtration can be easily obscured.

Front 15

Renal Dysfunction

What is the formula for creatinine clearance?

Back 15

VIP

Ccr: (urine creatinine x urine volume) / (plasma creatinine x 1440)

Note: urine creat is in mg/dl; urine vol = ml/min; plasma creatinine = mg/dl

Front 16

Renal Dysfunction

What is the calculation needed to estimate CCr?

Back 16

Estimated CCr = [(140-age) x (IBW in kg)] / (72 x Pcr)

Multiply total by 0.85 for women

Front 17

Renal Dysfunction

In renal dysfunction what are the four most common electrolyte abnormalities?

Back 17

1. hyperkalemia
2. hypercalcemia
3. hyperphosphatemia
4. decrease in serum bicarbonate (caused by an accumulation of organic anionns, resulting in metabolic acidosis)

Front 18

Renal Dysfunction

If a patient presents with pyuria (WBC's in the urine), fever, and flank pain - what is the Dx?

Back 18

Pyelonephritis

Front 19

Renal Dysfunction

What are four signs of uremia?

Back 19

1. neuropathy
2. pericarditis
3. confusion
4. pruritus

Front 20

Renal Dysfunction

Explain how chronic kidney disfunction causes anemia and bone disease:

Back 20

Anemia: chronic renal dysfunction can caused by the loss of erythropoietin (cytokine for RBC precursors that is made in the kidney)

Bone disease: kidney produces 1,25(OH) Vitamine D3. When Ca is low the parathyroid gland will send out PTH to bone and kidney.

Without Vit D you get osteomalacia.

Front 21

Renal Dysfunction

What is the most common cause of intrinsic renal disease?

Back 21

Acute tubular necrosis: this is caused by the effect of low blood pressure (ischemic injury) or nephroTOXIC injury (ex. IV contrast material)

Front 22

Renal Dysfunction

What is the most common cause of acute interstitial nephritis?

Back 22

Medications, especially sulfa drugs and beta-lactam antibiotics (ie methicillin induced interstitial nephritis)

Front 23

Renal Dysfunction

One major example of a disease that causes rapidly progressive glomerulonephritis?

Back 23

Goodpasture's syndrome

Front 24

Renal Dysfunction

What disease can, over time, give a patient chronic glomerulonephritis?

What gross kidney finding would be seen?

Back 24

CHF

Causes the formation of small shrunken kidney from fibrosis and sclerosed glomeruli

Front 25

Renal Dysfunction

Does nephrotic or nephritic syndromes give you a higher risk of thrombosis and/or infection from encapsulated organisms?

Back 25

Nephrotic:
- these patients often have hypercoagulability and are predisposed to renal vein thrombosis

-Hypogammaglobulinemia that can occur with Nephrotic syndrome increases risk for infection from encapsulated organisms.

Front 26

Renal Dysfunction

Is nephrotic syndrome caused by primary renal disease or a systemic process?

Back 26

BOTH!

Front 27

Renal Dysfunction
VIP
Why does Alports disease cause hematuria?

Back 27

Alport's disease is caused my a mutation in alpha 5 gene of collagen IV causing the basement membrane of the kidney to be irregularily formed.

WIKI: GBM can't filter product from blood and protein and blood end up in the urine. Eventual fibrosis occurs. This causes thickening of GBM and splitting of the lamina densa (since type IV collagen forms the lamina densa of the GBM)

Front 28

Renal Dysfunction

5 ways to differentiate acute vs. chronic renal disease

Back 28

1. take history (meds? hx of radiologic studies? hx of other diseases?)
2. see old lab results (if available)
3. determine kidney size with ultrasound (though nL size does not rule OUT chronic disease)
4. look for radiographic evidence of renal induced bone disease
5. rarely do a renal biopsy

Front 29

Renal Dysfunction

How do eliminate obstruction as a cause for elevated BUN/creatinine?

Back 29

Get a renal ultrasound and (esp for men) catheterize bladder to make sure it is not full.

If renal ultrasound shows small kidneys without obstruction --> most likely chronic renal failure.

If ultrasound shows hydronephrosis --> refer to urologist.

Front 30

Renal Dysfunction

If the normal then the differential diagnosis is between prerenal azotemia and acute tubular necrosis, how do you differentiate between them?

Back 30

USE FRACTIONAL EXCRETION OF SODIUM: FeNa

In prerenal azotemia there is little Na excreted as the kidney reabsorbs Na avidly and the urine is extremely concentrated with high urine osmolality (and specific gravity) -- FeNa < 1%

In ATN, the kidney cannot reabsorb or concentrate urine as effectively leading to a higher FeNa -- > 1% and a dilute urine.

Front 31

Renal Dysfunction

What is the calculation for fractional excretion of sodium?

Back 31

FeNa = (U/P)na x (P/U)cr x 100

U = urine na or cr
P = plasma na or cr

Front 32

Renal Dysfunction

What are six causes of prerenal azotemia?

Back 32

Prerenal azotemia = caused by a decreased renal perfusion

1. CHF
2. excessive diuresis
3. blood loss
4. diarrhea
5. vomiting
6. drugs like ACE inhibitors

Front 33

Renal Dysfunction

Eosinophils in the urine =

Back 33

Interstitial nephritis

Front 34

Renal Dysfunction

Bacteria in the urine =

Back 34

Pyelonephritis

Front 35

Renal Dysfunction

RBC's in urine with OUT casts =

Back 35

Can be renal artery or vein occulusion

Front 36

Renal Dysfunction

RBC's in urine WITH casts =

Back 36

Glomerulonephritis or vasculitis (definitive diagnosis can require a renal biopsy)

Front 37

Renal Dysfunction

Top 3 most common causes of end stage renal disease?

Back 37

ESRD:
1. diabetes
2. hypertension
3. glomerulonephritis

Front 38

Renal Dysfunction

What interventions can slow loss of renal function in CRF?

Back 38

1. Control of BP < 140/90 (often through use of ACE inhibitors in diabetic nephropathy)

2. avoidance of nephrotoxic drugs like NSAID's!!

3. controlling hyperphosphatemia to avoid secondary hyperparathyroidism

4. decreasing dietary protein

5. control of acidosis

Front 39

Renal Dysfunction

What must a diabetic on ACE inhibitors be ware of?

Back 39

ACE inhibitors can cause hyperkalemia

Front 40

Patient with Acute renal failure

What three things can cause acute interstitial nephritis?

Back 40

Intertitial inflammation caused by:
1. drugs (allergic interstitial nephritis): Classic triad of eosinphils in urine, fever, and rash
2. infections
3. collagen-vascular disease

Front 41

Patient with acute kidney injury:

Three main causes of intrinisic tubular obstruction and examples of each:

Back 41

1. Protein in tubule: Myeloma kidney (bence-jones proteins)
2. Pigment: Rhabdomyolysis (myoglobin)
3. Crystallis: Tumorolysis syndrome (uric acid) & drugs (indinavir and acyclovir)