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41 Cards in this Set

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  • Back
Renal Dysfunction

What is the definition of polyuria?
Production of more than 3000ml/hr of urine
Renal Dysfunction

How many RBC's in the urine requires a greater workup?
Either three urine samples with greater than 3 RBC's/hpf or one urinalysis with > 100 RBC's.
Renal Dysfunction

What is pyuria?

When does this occur? (2)
Pyuria: WBC's in urine.

WBC casts occur in pyelonephritis and acute interstitial nephritis.
Renal Dysfunction

What stain do you use to see eosinophils?
Wright stain
Renal Dysfunction

When do you see tubular casts?

Why does this occur?
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
Renal Dysfunction

What is the normal amount of urine protein excretion (total protein and albumin) over a 24 hr period?
NL: < 150mg/day of total protein

and 30mg/day of albumin
Renal Dysfunction

What amount of total protein in the urine (over 24hrs) signifies NEPHROTIC syndrome?
3.5gm or greater per 24 hrs
Renal Dysfunction

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

Nephritic: glomerular infiltration
Renal Dysfunction

What are Tamm Horsfall proteins?
Proteins made in the thick ascending limb and form the matrix of urinary casts.
Renal Dysfunction

What is Bence Jones proteinuria?
Proteins in the urine that are found in patients with multiple myeloma. They are immunoglobulin light chains and are caused by defective platelet function.
Renal Dysfunction

What is azotemia?
Azotemia: is the presence of urea (product of nitrogen waste products) in the blood
Renal Dysfunction

Is the relationship between serum creatinine and GFR linear?
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%.
Renal Dysfunction

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

In general, way isn't creatinine a perfect test?
Creatinine is insensitive in the lower range so poor glomerular filtration can be easily obscured.
Renal Dysfunction

What is the formula for creatinine clearance?

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
Renal Dysfunction

What is the calculation needed to estimate CCr?
Estimated CCr = [(140-age) x (IBW in kg)] / (72 x Pcr)

Multiply total by 0.85 for women
Renal Dysfunction

In renal dysfunction what are the four most common electrolyte abnormalities?
1. hyperkalemia
2. hypercalcemia
3. hyperphosphatemia
4. decrease in serum bicarbonate (caused by an accumulation of organic anionns, resulting in metabolic acidosis)
Renal Dysfunction

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

What are four signs of uremia?
1. neuropathy
2. pericarditis
3. confusion
4. pruritus
Renal Dysfunction

Explain how chronic kidney disfunction causes anemia and bone disease:
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.
Renal Dysfunction

What is the most common cause of intrinsic renal disease?
Acute tubular necrosis: this is caused by the effect of low blood pressure (ischemic injury) or nephroTOXIC injury (ex. IV contrast material)
Renal Dysfunction

What is the most common cause of acute interstitial nephritis?
Medications, especially sulfa drugs and beta-lactam antibiotics (ie methicillin induced interstitial nephritis)
Renal Dysfunction

One major example of a disease that causes rapidly progressive glomerulonephritis?
Goodpasture's syndrome
Renal Dysfunction

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

What gross kidney finding would be seen?

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

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

Is nephrotic syndrome caused by primary renal disease or a systemic process?
Renal Dysfunction
Why does Alports disease cause hematuria?
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)
Renal Dysfunction

5 ways to differentiate acute vs. chronic renal disease
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
Renal Dysfunction

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

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

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.
Renal Dysfunction

What is the calculation for fractional excretion of sodium?
FeNa = (U/P)na x (P/U)cr x 100

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

What are six causes of prerenal azotemia?
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
Renal Dysfunction

Eosinophils in the urine =
Interstitial nephritis
Renal Dysfunction

Bacteria in the urine =
Renal Dysfunction

RBC's in urine with OUT casts =
Can be renal artery or vein occulusion
Renal Dysfunction

RBC's in urine WITH casts =
Glomerulonephritis or vasculitis (definitive diagnosis can require a renal biopsy)
Renal Dysfunction

Top 3 most common causes of end stage renal disease?
1. diabetes
2. hypertension
3. glomerulonephritis
Renal Dysfunction

What interventions can slow loss of renal function in CRF?
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
Renal Dysfunction

What must a diabetic on ACE inhibitors be ware of?
ACE inhibitors can cause hyperkalemia
Patient with Acute renal failure

What three things can cause acute interstitial nephritis?
Intertitial inflammation caused by:
1. drugs (allergic interstitial nephritis): Classic triad of eosinphils in urine, fever, and rash
2. infections
3. collagen-vascular disease
Patient with acute kidney injury:

Three main causes of intrinisic tubular obstruction and examples of each:
1. Protein in tubule: Myeloma kidney (bence-jones proteins)
2. Pigment: Rhabdomyolysis (myoglobin)
3. Crystallis: Tumorolysis syndrome (uric acid) & drugs (indinavir and acyclovir)