acute and chronic renal failure Flashcards
What are the three main ways to approach renal disease?
1) HOW
-Duration, UA (+/- protein), GFR
2) Type of azotemia?
3) Duration
acute (hours and days)
chronic (months to years)
How much time can elapse before collection and analysis of UA?
No more than 1 hour!
heavy proteinuria and lipiduria
Nephrotic syndrome
hematuria, RBC casts, and mild proteinuria
glomerulonephritis
WBC, WBC casts, and mild proteinuria
interstitial nephritis
WBC alone suggests
pyelonephritis
Pyuria suggests
UTI (lower)
What might an albumin spike be suggestive of?
an abnormality in glomerular basement membrane
What conditions might elevate serum creatinine?
Ketoacidosis, drugs such as cefoxitin, aspirin, cimetidine, trimethoprim
What conditions decrease creatinine?
Advanced age, cachexia, liver disease
What causes an increase in BUN?
Dehydration, GI bleed, steroid use, CHF
What causes a decrease in BUN?
liver disease
What imaging studies are indicated in renal failure?
U/S, IVP, CT (for neoplasms)
What are contraindications for IVP contrast?
DM with Cr>2.0
chronic renal failure with Cr>5.0
MM
What is used in place of CT when contrast is contraindicated?
MRI
What is the main indication for percutaneous needle biopsy?
Unexplained renal failure, proteinuria, lesions
A or C RF: Which has elevated Cr? In which is BUN and Cr elevated?
Acute; Chronic
A or C RF: Which has minimal proteinuria? More proteinuria?
Acute; Chronic
A or C RF: Which has elevated PTH with high calcium and alkalne phosphatase? Which has normal PTH?
Chronic; Acute
A or C RF: Which presents with anemia? Which has a normal CBC?
Chronic, Acute
A or C RF: Which has a small kidney? Which has a normal sized kidney?
Chronic; Acute
A or C RF: Which presents with oliguria? Which has gradual fluid retention?
Acute (sudden); Chronic
ACF presentation
Sudden increase in BUN or Cr oliguria N/V malaise, confusion pericardial effusion, friction rub \+/- rales in the lung
ACF labs
+/- hyperkalemia, anemia from decreased erythropoietin
What is the most common cause of acute renal failure?
Prerenal azotemia (due to HYPOPERFUSION)
What causes decreased renal perfusion?
a decrease in IV volume, a change in vascular resistance (sepsis, ACE-I, NSAIDs, Epi), low cardiac output (CHF, PE, arrhythmias)
What should you do in the very beginning of diagnosing prerenal azotemia?
Do a careful assessment of volume status (mucosal membranes), drug usage, and cardiac function (orthostatic, edema)
UA prerenal azotemia
volume depletion, tubular casts
Labs prerenal
high BUN/Cr,
in what cause of prerenal azotemia will urine sodium be low? high?
Volume depletion; acute tubular necrosis
What is the least common but most important cause of ACF?
post renal azotemia due to urine flow obstruction
What is the most common cause of Postrenal azotemia in men? What are other causes?
BPH; anticholinergic drugs, stones
What are signs and symptoms of ACF?
Lower abd pain, distended bladder
What are labs in ACF?
High urine osmolality, low urine sodium, high BUN/Cr
If you suspect postrenal as a cause of ACF, which studies should you do?
1) bladder U/S or catheterization.
If normal, consider CT or MRI
What constitutes 50% of renal failure? What must you exclude before you diagnose this as the cause?
Intrinsic renal failure; exclude prerenal and postrenal causes
What accounts for 85% of intrinsic renal failure? What are the major causes of this?
Acute tubular necrosis; Ischemia and exogenous toxins
What is the origination of ischemia that might cause acute tubular necrosis?
When prerenal azotemia is not corrected, i.e. hypotension, hypoxemia, dehydration, shock or sepsis
What is the origin of toxins that might cause ATN?
AGs, some cephalosporins, contrast media (esp in DM), cyclosporine for transplant rejection
What are some endogenous toxins that can cause ATN?
Myoglobinuria, hemoglobin, bence jones protein
What will labs of intrinsic renal failure show?
UA shows brown urine and pigmented granular casts, may see hyperkalemia and hyperphosphatemia (increased reabsorption)
What is the main goal of treatment of acute tubular necrosis?
Avoid volume overload and hyperkalemia, try loop diuretics and restriction of dietary protein
When do you think of dialysis for a patient with ATN?
With a life threatening electrolyte disturbance, no response to diuresis, worsening acidosis (tried insulin and glucose for entry of hyperkalemia and it’s not working…)
What is the prognosis for ATN?
20-50% in medical illness, 70% in surgery. Increased mortality with advanced age and comorbidities
What percentage of interstitial nephritis is caused by drugs?
70%, usually PCN, cephs, sulfas, NSAIDs, allopurinol
What infections can cause interstitial nephritis?
strep, CMV, histoplasmosis
What are the signs and symptoms of interstitial nephritis?
Fever (infectious origin), rash, arthralgias
What will labs show with interstitial nephritis?
Peripheral blood eosinophila, +/- RBCs WBCs and white cell casts
Proteinuria if NSAIDS are the cause
What is the treatment for interstitial nephritis?
removal of offending agent and short term, high dose prednisone, good prognosis
What is an uncommon cause of RF that presents with HTN, periorbital and scrotal edema, hematuria, proteinuria, and red cell casts? What is the treatment?
Glomerulonephritis; high dose steroids (unless it’s post strep)
What is a cause of ARF that is a/w high ASO titer and cola-colored urine?
Post-infectious glomerulonephritis
What is the most common form of glomerulonephropathy in the US? In whom is it see? What is its common presenting complaint?
IgA nephropathy; children and young adults; gross hematuria is most common presenting complaint
What other signs are seen in IgA nephropathy?
cola-colored or red urine, asymptomatic hematuria, serum IgA increase in 50%
How do you diagnose IgA nephropathy? What is the prognosis?
Renal biopsy; 33% enter remission, 40-50% progress to renal insufficiency
What are two types of membranous nephropathies?
Immune-mediated and amyloidosis
What are some causes of immune-mediated membranous nephropathy?
hep B, endocarditis, SLE, thyroiditis, CA
Where does amyloidosis originate? What is the prognosis?
enter ESRD in 2-3 years, 5 year survival is less than 20%
What are the two most common causes of chronic renal disease?
DM>HTN
What is one additional sign of CRD as opposed to ARD
Uremic fetor as BUN increases (fishy odor on breath)
What is the key to treatment in any pt with renal failure?
Identify and correct all possibly reversible causes, i.e. UTI HTN CHF Toxins
Labs of CRF
elevated BUN and Cr
Imaging and diagnosis of CRF
U/S reveals bilat small kidneys
Complications of CRF
Hyperkalemia from endogenous or exogenous causes
Metabolic acidosis from limiting production of ammonia for H+ excretion in the kidney
HTN from salt and water retention
CHF from ECF overload
Treatments for CRF
Protein restriction
salt and water restriction
potassium restriction
What is the major complication of standard dialysis?
Hypotension
What is the major complication of peritoneal dialysis?
Peritonitis
What are the indications for dialysis in CRF?
Uremic symptoms appear, fluid overload unresponsive to diuretics, refractory hyperkalemia, severe metabolic acidosis, neuro symptoms
Nephrotic syndome
urine protein >3.5g/24 hours, albumin <3 grams, and peripheral edema
What is the CP of nephrotic syndrome?
Edema due to sodium retention, dyspnea due to pulmonary edema, pleural effusions, or ascites
HYPERLIPIDEMIA
When do you get a biopsy for nephrotic syndrome?
Anytime DM or amyloid IS NOT the cause
treatment for nephrotic syndrome
moderate protein restriction to avoid negative nitrogen balance
dietary salt restriction and probs diuretic tx (thiazide or loop) if hypoalbuminemia, may need to increase diuretic dose
What should you do to treat nephrotic syndrome if serum albumin is less than 2 grams?
May need AC therapy due to losses of antithrombin III, Protein C, and Protein S
What is the most common cause of ESRD in the US?
Diabetic nephropathy
What can be used to prevent diabetic nephropathy?
microalbuminuria screens, strict glycemic control and treatment of HTN, ACE inhibitors
You have all signs of CRF plus UA hematuria. What is at the top of your differential?
Acute tubulointerstitial disease
What do you need to diagnose acute tubulointerstitial disease?
U/S, CT, maybe MRI
What is the cause of chronic tubulointerstitial disease?
obstructive uropathy, vesicoureteral reflux, analgesics, or heavy metals
What are the most common causes of obstructive uropathy leading to chronic tubulointerstitial disease?
prostatic disease, bilateral uterteral calculi,
CA of cervix, colon, or bladder
Kid with chronic UTI. What is it and how do you diagnose?
vesicoureteral reflux; U/S or IVP
What are the effects of aspirin, NSAIDs, and acetaminophen on the kidneys?
Chronic tubulointerstitial disease–decreases medullary blood flow
What do you see with tylenol, ibuprofen, and aspirin overdoses?
hematuria, mild proteinuria, polyuria, or anemia
DO AN IVP
signs and sx of tubulointerstitial dz
polyuria due to damage to tubular area causing inability to concentrate urine
hyperkalemia (aldosterone resistance)
hyperchloremic acidosis due to reduced ammonia
simple cyst in 50% of people over age 50. What is it, how do you diagnose/differentiate?
cystic disease of the kidney, must do an ultrasound or CT to differentiate from malignancy
How to qualify as a simple cyst?
echo-free, sharply demarcated with smooth walls, an enhanced back wall
PKD can cause CRF. Sx?
50% in ESRD by 60. abdo or flank pain with hematuria
MM protein can’t be detected on a dipstick. Why?
light chain
Primary manifestation of sickle cell dz
proteinuria
Why do more adverse side effects occur in older population?
altered Vd, altered drug half life, altered elimination
