Renal Failure - GU

Question 1

Acute Renal Failure

Answer 1

• Worsening of renal function over hours to a few days
• Retention of nitrogenous wastes such a urea nitrogen and creatinine in the blood
• This is called azotemia
• Oliguria: urine output <400 ml/day
• 5% of hospital admissions and 30% of ICU admissions have acute renal failure
• Sudden decrease in renal function resulting in an inability to maintain fluid and electrolyte balance and to excrete nitrogenous wastes
• Serum Creatinine acutely increases by more than 0.5mg/dL and more than 50% over baseline levels

Question 2

Chronic Renal Failure

Answer 2

• Loss of renal function over months to years
• Typically see anemia in the setting of chronic renal failure
• Small kidneys

Question 3

Signs and Symptoms of ARF

Answer 3

• Nausea
• Vomiting
• Malaise
• Altered sensorium
• Arrhythmias in setting of hyperkalemia
• Pericardial Effusion
• Nonspecific abdominal pain
• Evaluate BUN (blood urea nitrogen) and creatinine
• Decreased GFR (glomerular filtration rate)
• Hyperkalemia

Question 4

3 Categories of ARF

Answer 4

• Prerenal Azotemia
• Postrenal Azotemia

-Intrinsic Renal Disease
Acute Tubular Necrosis
Acute Glomerulonephritis
Acute Interstitial Nephritis

Question 5

Prerenal Azotemia

Answer 5

-Most common cause of ARF

Due to renal hypoperfusion

• Decrease in intravascular volume
• Change in vascular resistance
• Low cardiac ouput
• common in heart failure patients

Sxs: tachycardia and hypotension

Question 6

Causes that change Vascular resistance

Answer 6

-Sepsis
-Anaphylaxis
-Anesthesia
After-loading medications:
-Ace-inhibitors (lisinopril) ARB’s (losartan)
-NSAID’s
-Renal Artery Stenosis
Low cardiac output is a state of hypovolemia
-Cardiogenic Shock
-CHF (congestive heart failure)
-Pulmonary Embolus
-Pericardial tamponade
-Arrhythmias and Valvular Disease

Question 7

Prerenal AzotemiaLab Findings

Answer 7

Serum BUN:Cr Ratio >20:1

Fractional excretion of sodium is low 500

Decreased urine sodium

Question 8

Treatment of Prerenal Azotemia

Answer 8

• Depends on the cause
• Maintain euvolumic state
• Monitor potassium levels
• Avoid nephrotoxic medications

-Monitor cardiac function, volume status, and medication usage

Question 9

Postrenal Azotemia

Answer 9

-Least common cause of acute renal failure
-Occurs when urinary flow from both kidneys is obstructed
Causes:
-Urethral obstruction
-Bladder Dysfunction or obstruction
-Obstruction of both ureters or renal pelvis
-In men, BPH (benign prostatic hypertrophy) is common
-Bladder, prostate or cervical cancers

Question 10

Lab Findings with postrenal azotemia

Answer 10

• Serum BUN:Cr ratio > 20:1
• Urine Osmolality <400
• Urine sediment: normal or red cells, white cells, or crystals

Question 11

Treatment for postrenal azotemia

Answer 11

Evaluate and treat obstruction promptly and this can result in complete reversal of the acute process

Question 12

Intrinsic Renal Failure

Answer 12

• Accounts for 50% of all cases of ARF
• Consider this after you have ruled out pre and postrenal azotemia
• Acute tubular Necrosis
• Acute Glomerulonephritis
• Acute Interstitial Nephritis

Question 13

Acute Tubular Necrosis

Answer 13

-ARF due to tubular damage

Causes:
-Ischemia: causes tubular damage from state of prerenal azotemia
-Nephrotoxin exposure (aminoglycosides, contrast):
Nephrotoxins (exogeneous):
-Aminoglycosides (gentamicin)
-Amphotericin B
-Vancomycin
-Cephalosporins
-Contrast Dye (usually occurs 24-48 hours after contrast)
Nephrotoxins (endogenous)
-myoglobinuria as a consequence of rhabdomyolysis (Rhabdomyolysis occurs with an elevated serum creatine kinase)
-Bence Jones protein seen in conjunction with multiple myeloma

Question 14

Lab Findings in Acute Tubular Necrosis

Answer 14

• Brown urine
• Serum BUN:Cr <20:1
• Urinary sediment shows granular casts
• Urinary osmolality 250-300

Question 15

Treatment of ATN

Answer 15

-Loop Blocking Diuretics

Dialysis indications:

- life threatening electrolyte disturbances

- volume overload unresponsive to diuresis
- worsening acidosis
- uremic complications: encephalopathy, pericarditis, seizures

Question 16

Interstitial Nephritis

Answer 16

• Interstitial inflammatory response with edema
• Can occur in infectious diseases(streptococcal, CMV, histoplasmosis) or immunologic disorders (SLE, Sjogren’s, sarcoidosis, cryoglobulinemia)

-Medications can also be a cause:
Penicillins, cephalosporins, sulfa drugs, NSAIDs, rifampin, phenytoin, and allopurinol

• This is interstitial inflammation and renal tubular cell injury
• It is often associated with hypersensitivity reaction to a medication or an immunological disease

Question 17

Intersitial Nephritis - Signs and Symptoms and treatment

Answer 17

• Fever
• Rash
• Arthralgias
• Peripheral blood eosinophils
• Proteinuria (especially seen in NSAID-induced)

Tx: Usually a good prognosis
33% of people require acute dialysis

Question 18

Glomerulonephritis

Answer 18

• Uncommon cause of ARF
• Serum BUN:Cr ratio 20:1
• Urinary Sediment: dysmorphic red cells and red cell casts
• Urinanalysis: hematuria, moderate proteinuria
• 60% of cases are in children 2-12 years of age

Question 19

Glomerulonephritis - Signs and Symptoms and Treatment

Answer 19

• Hypertensive
• Edematous, face and eyes
• Abnormal urinary sediment
• Hematuria, urine is often tea colored

tx:
- High dose steroids
- Cytotoxic agents (cyclophosphamide)
- Dietary management: salt and fluid intake should be decreased.
- Ace inhibitors are renoprotective in GN.

Question 20

Which renal disease can eosinophils appear in the urine?

Answer 20

Interstitial Nephritis

Question 21

Which of the following is the most common cause of intrinsic renal failure?

Answer 21

Acute Tubular Necrosis

Intrinsic or intrarenal disorders affect the renal parenchyma and the most common is ATN.

ATN may be ischemic (hypoperfusion, sepsis or embolism) or toxic (drug-induced, contrast)

Question 22

A patient is hospitalized for a swollen left leg, and a gram negative UTI. On admission, a venogram was negative for DVT. A foley catheter was inserted with a residual urine volume of 30cc followed by normal urinary volumes. The patient was started on IV gentamicin and responded well. Admit labs were BUN 30, and creatinine of 1.0. Labs remained stable until the 8th day in the hospital, then the BUN is 40 and creatinine is 2.6. What is the most likely cause?

Answer 22

Aminoglycoside Toxicity

Aminoglycoside nephrotoxicity is the result of an accumulation of the drug in the renal cortex. A rise is seen in day 5-7 after initiation and usually recovers, but can take weeks to months.
This patient had normal urine volumes so no to volume depletion
Contrast will typically cause an elevation in creatinine levels within 24 hours of procedure and peak at day 3-7 and then improve

Question 23

A patient presents with abrupt onset of edema, azotemia, proteinuria and tea colored urine, what is the most likely diagnosis?

Answer 23

Acute Glomerulonephritis

This is associated with sudden onset of hematuria, proteinuria, and azotemia.

Question 24

A patient just finished a course of IV methicillin for a staph infection. She did well for the following 10 days. She then redeveloped fever and a mild rash. Her creatinine level was elevated and eosinophils on blood smear. UA shows hematuria, pyuria, white blood cell casts, and eosinophilia. What is your likely diagnosis?

Answer 24

Interstitial Nephritis

• Methicillin has been found to have a strong association with interstitial nephritis
• Interstitial nephritis is most often associated with hypersensitivity reaction to a drug, especially the penicillin and cephalosporin families.
• Acute pyelo, UTI and tumors are not associated with eosinophilia or rashes

Question 25

A 65 year old patient with generalized atherosclerosis 2 days after cardiac catheterization and angioplasty develops an increase in BUN 38, creatinine 2.5 with his baseline 20 and 1.3 respectively. He complains of vague abdominal pain. On exam, his lower extremities are mottled with several darkended areas of the toes. The most likely diagnosis is?

Answer 25

Renal atheremboli Generally seen in patients with athersclerotic disease. It results from occlusion of the small renal vessels with cholesterol containing microemboli. The emboli was likely dislodged at the time of the cath. Radiocontrast ATN differs from atheroemboli in that the creatinine increase is steady, peaks, and then improves to baseline usually within several days to weeks.

Question 26

Chronic Renal Failure

Answer 26

- Over 50% of the cases are due to diabetes mellitus and hypertension - Progressive azotemia over months to years - Hypertension - Bilateral small kidneys on ultrasound - Rarely reversible and leads to progressive decline in renal function Causes: - Diabetes - Hypertension - Glomerulonephritis - Polycystic kidney disease

Question 27

Signs and Symptomsof CRF

Answer 27

- Typically asymptomatic initially (until GFR is <10-15mL/min) - Fatigue, malaise, weakness - Dyspnea - Pruritus - Hiccups - Nausea and vomiting - Metallic taste in mouth

Question 28

CRF Lab Findings

Answer 28

- Elevated BUN and Creatinine - Low GFR (glomerular filtration rate)-this is the gold standard - Proteinuria - Hyperkalemia - Hyperphosphatemia - Anemia - Hypocalcemia - Metabolic Acidosis Small kidneys <10cm via ultrasound

Question 29

Complications of CRF

Answer 29

``` Hyperkalemia: -Generally is intact until GFR is <10 -Caused by medications or salt substitutes Treatment includes: -Cardiac monitoring (peaked T waves) -IV gluconate or calcium carbonate ``` Acid-Base Disorders: -Damaged kidneys are unable to excrete the 1meq/kg/d of acid that is generated by metabolism of dietary protein. Anemia: - Normochromic and normocytic - Due to decreased erythropoetin production - Many patients have iron deficiency anemia - Coagulopathy: -Caused by platelet dysfunction Endocrine: - Circulating insulin levels are higher because of decreased renal insulin clearance. - In Diabetic patients, they typically require decreased doses of hypoglycemic agents. - Decreased libido and impotence are common.

Question 30

Treatment of CRF

Answer 30

Dietary Management - Protein restriction - Salt and water restriction - Potassium restriction (salt substitutes, bananas, OJ, potatoes) - Phosphorus restriction - Magnesium restriction (avoid laxatives and antacids) -Dialysis: Hemodialysis, Peritoneal dialysis Kidney transplantation - Erythropoieten, iron supplements, and antiplatet therapy should be considered to maintain hemoglobin and bleeding time. - Ace-inhibitors/ARB’s: can be used to control blood pressure which can reduce renal vascular damage - This are especially good to use in diabetic patients to reduce intraglomerular pressure and decreasing proteinuria

Question 31

Dialysis

Answer 31

Indications: - Uremic symptoms such as pericarditis, encephalopathy, or coagulopathy - Fluid Overload that is unresponsive to diuresis - Refractory hyperkalemia - Severe metabolic acidosis pH < 7.20 - Neurological symptoms: seizures, neuropathy

Question 32

Hemodialysis

Answer 32

- Diffusion and convection allow the dialysate to remove unwanted substances from the blood while adding back needed components - Vascular access if typically via AV fistula, but can also be a prosthetic shunts - It takes approximately 6-8 weeks following surgery for the AV fistula to be able to use it - Infection, thrombosis, and aneurysm formation are complication seen more often with shunts than fistula - Dialysis requires 3 days per week for 3-5 hours each day to be dialyzed

Question 33

Peritoneal dialysis

Answer 33

- Peritoneal membrane is the “dialyzer” - Fluids and solutes move across the capillary bed that lies between the visceral and parietal layers; it is typically continous - Permits per patient autonomy - Most common complication is peritonitis, typically Staphylococcus.

Question 34

Kidney Transplantation

Answer 34

- About 50% of end stage renal disease patients are suitable for transplant - Two thirds of transplant kidneys are from cadavers - Average wait for a cadaveric transplant is 2-4 years. - Aside from medication use, the life of a transplanted patient return to near normal - The expected remaining lifetime for the age group of 55-64 is 22 years, whereas that of end stage renal disease population is 5 years

Question 35

You have a diabetic patient with hypertension and BP is not controlled, his creatinine is 1.5, BUN of 22, what would you use to treat his blood pressure?

Answer 35

ACE-Inhibitor (lisinopril) Ace-Inhibitors and ARB’s medications are recommended in diabetic patients to control blood pressure and reduce vascular damage. They decrease proteinuria In patients with diabetes, blood pressure goal is 135/85 and less.

Question 36

The leading cause of chronic renal failure is?

Answer 36

Diabetes Diabetic nephropathy is the major cause of end-stage renal disease and is the etiology of renal failure in approximately 35% of patients on dialysis

Question 37

A reduction in what hormone produced by the kidney contributes to anemia in renal failure?

Answer 37

Erythropoietin - Erythropoieten is a hormone produced by cells in the kidney. - It acts to stimulate maturation of red blood cells in the bone marrow. - In renal failure, decreased production of erythropoieten is the main cause of anemia

Question 38

``` Findings that may indicate the chronicity of renal failure include all of the following except? Azotemia for at least 3-6 months Bilaterally small kidneys by ultrasound Hematuria Broad casts in urinary sediment anemia ```

Answer 38

Hematuria and proteinuria are frequently present but are nonspecific in regard to the chronicity of renal disease.

Question 39

``` The most common complication of peritoneal dialysis is peritonitis. What is the organism that is most likely the causative agent? Candida E.coli Streptococcus Pseudomonas Staphyloccus ```

Answer 39

Staphylococcus Most common organism that causes peritonitis with peritoneal dialysis Improper technique by the patient in making catheter connections during dialysis exchanges is the entry source.