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IPAP GU - Exam 1 - 9)Acute Renal Failure & CKD

Terms in this set (159)

1) Sudden increase in BUN or serum creatinine
2) Oliguria often associated
3) Symptoms and signs depend on cause
4) **Most common symptom is decreased urine output
What are the essentials of diagnosis of Acute Renal Failure (ARF)?
Decreased urine output
What is the most common symptom of Acute Renal Failure (ARF)?
Acute Kidney Injury (AKI)
What is another name for Acute Renal Failure (ARF)?
A condition in which the glomerular filtration rate is abruptly reduced, causing a sudden retention of endogenous and exogenous metabolites (urea, potassium, phosphate, sulfate, creatinine, administered drugs) that are normally cleared by the kidneys
What is Acute Renal Failure (ARF)?
Acute Renal Failure (ARF)
What are the majority of nephrology consults?
The urine volume is usually low (under 400 ml/d) which is the case in Acute Renal Failure (ARF)?
What is oliguria?
When the renal concentrating mechanisms impaired, the daily urine volume may be normal or even high
What is high-output or nonoliguric renal failure?
No
Is is no urine output at all (anuria) common in Acute Renal Failure (ARF)?
It will typically increase by 1-1.5 mg/dl daily
Serum creatinine is a good marker for assessing Acute Renal Failure (ARF). IN the absence of functioning kidneys, how much does the serum creatinine rise?
The Azotemia (increased urea/BUN levels) or its underlying cause
What causes the symptoms of Acute Renal Failure (ARF)?
1) Initially patient may only have weight gain and peripheral edema

2) Azotemia can cause nausea & vomiting, malaise, and altered sensorium

3) May also see hypertension and arrythmias (with hyperkalemia)
What are the symptoms of Acute Renal Failure (ARF)?
1) Prerenal azotemia
2) Postrenal azotemia
3) Intrinsic renal disease
Acute renal failure can be divided into three categories. What are they?
Identifying cause (Prerenal azotemia, Postrenal azotemia, Intrinsic Azotemia)
What is the first step in managing my Acute Renal Failure Patient?
Prerenal Azotemia
What is the most common cause of acute renal failure?
Renal hypoperfusion
What causes Prerenal Azotemia?
Yes
In Prerenal Azotemia, can renal parenchyma damage be prevented if there is restoration of appropriate blood flow
Ischemia can result
In Prerenal azotemia, what happens if hypoperfusion persists
1) Decrease in intravascular volume
2) Change in vascular resistance
3) Low cardiac output
Decreased renal perfusion can occur in one of three ways. What are they?
1) Hemorrhage
2) GI losses
3) Dehydration
4) Excessive diuresis
5) Pancreatitis
6) Burns
7) Trauma
8) Peritonitis
What are causes of a decrease in intravascular volume?
1) Sepsis
2) Anaphylaxis
3) Anesthesia
4) Afterload-reducing drugs
What are the causes of change in vascular resistance (systemically)?
1) Cardiogenic shock
2 Congestive heart failure
3) Pulmonary embolus
4) Pericardial tamponade
5) Arrhythmias and valvular disorders can also reduce cardiac output
What are the causes low cardiac output?
1) Dehydration due to renal or extrarenal fluid losses...from diarrhea, vomiting, excessive use of diuretics
OK so we talked about a lot of things that can cause "Prerenal Azotemia" leading to Acute Renal Failure, what is the most common?
1) Thirst
2) Dizziness
3) Fluid Loss/Weight Loss
What will patient complain of with Prerenal Azotemia?
1) Decreased skin turgor
2) Collapsed neck veins
3) Dry mucous membranes
4) Orthostatic blood pressure and pulse
In a patient with Prerenal Azotemia, what will the patient exhibit on Physical Exam?
1) BUN:creatinine ratio > 20:1
2) Elevated urine osmolality
3) Urinary sediment: benign or hyaline casts
4) UNA (mEq/L): <20 (An appropriate response to conserve Na+)
5) FENa (%): < 1
6) RFI (renal failure index): <1%
What will labs show in a patient that has prerenal azotemia?
FENa (%) (Fractional excretion of sodium)
***What is the MOST accurate screening test to differentiate between Prerenal azotemia & Acute Tubular necrosis (ATN)?
< 1
What must the FENa (%) be in a patient with Prerenal azotemia?
When the patient is not putting out enough urine to measure contents by conventional means
When is FENa (%) (Fractional excretion of sodium) used?
ADMIT!!
What is the treatment for Prerenal Azotemia?
1) Maintenance of euvolemia
2) Attention to serum potassium
3) Avoidance of nephrotoxic drugs are benchmarks of therapy
What are the benchmarks of therapy with a patient once we have admitted them for prerenal azotemia?
Yes (good fluid intake = good urine output)
Do we do a fluid a challenge for patients with Prerenal Azotemia?
Postrenal Azotemia (Least common cause of ARF)
What is the LEAST common cause of ARF?
When urinary flow from both kidneys, or a single functioning kidney, is obstructed...usually a urologic problem
When does Postrenal Azotemia occur?
Each nephron has an elevated intraluminal pressure, causing decrease in GFR
What happens to the nephrons in Postrenal Azotemia?
1) Urethral obstruction
2) Bladder dysfunction or obstruction
3) Obstruction of both ureters or renal pelvises
What causes the obstruction which leads to Postrenal Azotemia?
Prostatic hyperplasia
In men specifically, what can cause an obstruction that leads to Postrenal Azotemia?
Anticholinergic drugs
What type of drugs can a patient take that puts them at a higher risk for Postrenal Azotemia?
True
T or F. Bladder, prostate, and cervical cancers as well as retroperitoneal processes and neurogenic bladder can lead to obstruction causing Postrenal Azotemia
1) Blood clots
2) Bilateral ureteral stones
3) Urethral stones or stricture
4) Bilateral papillary necrosis
What are less common cause of obstruction that lead to Postrenal Azotemia?
True
T or F. In Postrenal Azotemia, Patients may be anuric or polyuric, and may c/o lower abdominal pain
AND
Obstruction can be constant or intermittent, and partial or complete
Exam may reveal enlarged prostate, distended bladder, or mass palpable with pelvic exam
What would I note on pelvic exam for a patient with Postal Renal Azotemia?
1) BUN:creatinine ratio > 20:1

2) Urinary sediment: normal, or red cells, white cells, or crystals

3) UNA (mEq/L): variable, usually > 20

4) FENa (%): variable, usually > 1

5) RFI: usually >1%
What would the labs show for a patient with Post Renal Azotemia?
< 1
**Prerenal Azotemia FENa (%) =
Variable, usually > 1
**Post Renal FENa (%) =
>1-2
**Acute Tubular Necrosis FENa (%): =
Admit & Find the cause
1) Obtain bladder and/or renal ultrasound
2) Bladder catheterization
3) CT
4) MRI/PRN
*Not necessarily in this order
What is the treatment of Post Renal Azotemia?
Relieve the obstruction ASAP! Catch it within a few days, and you may be to completely reverse the condition
Whats the main treatment with Post Renal Azotemia?
Intrinsic Renal Disease
We talked about Prerenal Azotemia, Postrenal Azotemia, what is the left?
Intrinsic (parenchymal) dysfunction is considered after prerenal and postrenal causes have been excluded
When do we use Intrinsic Renal Disease as a cause of Acute Renal Failure (ARF)?
1) Tubules
2) Interstitium
3) Vasculature
4) Glomeruli
What are the sites of injury affected by Intrinsic Renal Disease?
1) Acute tubular necrosis
2) Acute interstitial nephritis
3) Acute glomerulonephritis
What are examples of Intrinsic Renal Disease?
1) Acute renal insufficiency
2) Clinical scenario consistent with diagnosis (ischemia or toxic insult)
3) Urine sediment with pigmented granular casts and renal tubular epithelial cells
What are the essentials of diagnosis for Acute Tubular Necrosis (ATN)?
Patients may present with generalized swelling, nausea & vomiting, oliguria, decreased LOC, uremic tongue, anorexia, GI bleeding, muscle weakness and/or twitching. Check for pulmonary edema
How may a patient present with Acute Tubular Necrosis (ATN)?
1) Ischemia (May be a continuation of prerenal azotemia)
2) Nephrotoxin exposure
ARF due to tubular damage is termed acute tubular necrosis (ATN) and accounts for 85% of intrinsic ARF. What are the sub-categories of ATN?
Causes tubular damage from states of low perfusion and is often preceded by a state of prerenal azotemia
How does Ischemia cause Acute Tubular Necrosis?
NO! It is also characterized by inadequate blood flow to maintain parenchymal cellular formation
Is Ischemic ARF only characterized by inadequate GFR?
Occurs in the setting of prolonged hypotension or hypoxemia such as dehydration, shock, sepsis, major surgery, or trauma
In what setting does ATN caused by Ischemia occur?
Exogenous is more common
With ATN caused by Nephrotoxin exposure. Is exogenous or endogenous more common?
1) Aminoglycosides, Vancomycin, and several cephalosporins
2) Radiographic contrast media
3) Cyclosporin
4) Antineoplastics (Cancer medications), such as cisplatin
5) Heavy metals, such as lead, mercury, cadmium, and arsenic
What are the exogenous causes of nephrotoxin?
1) Heme-containing products
- Myoglobin, hemoglobin
2) Uric acid
3) Paraproteins
- Bence Jones (multiple myeloma)
What are the endogenous causes of nephrotoxin?
1) Urine brown in color, with proteinuria and low pH
2) Low urine osmolality, < 400 = severe impairment
3) Active sediment with "muddy brown" granular casts
4) Renal tubular epithelial cells & tubular cell casts often present
5) BUN:creatinine ratio < 20:1
6) UNA (mEq/L): >20
7) FENa (%): >1-2
9) RFI: >1%
10) CBC for anemia
11) Hyperkalemia and hyperphosphatemia common
What are the labs associated with ATN?
"Muddy Brown" Granular Casts
Wait what kind of sediment is associated with ATN?
Admit to the ICU!!!!
What is the treatment of ATN?
Avoid volume overload
- Diuretics
- Monitor for Pulmonary Edema
What should I avoid in ATN?
1) Nutritional Support (Protein Restriction)
2) Phosphate-binding agents
3) Indications for dialysis
Other than avoiding volume overload, what else is indicated while a patient is in the ICU for ATN?
1) Life-threatening electrolyte disturbances (hyperkalemia)
2) Volume overload unresponsive to diuretics
3) Worsening acidosis, and uremic complications (encephalopathy, pericarditis, seizures)
What are the indications for dialysis?
The clinical course of ATN often divided into three phases:
1) Initial injury
2) Maintenance
3) Recovery
What is the course and prognosis of ATN?
- It Is either oliguric or nonoliguric.
- Nonoliguric ATN has better outcome.
- This phase is 1-3 weeks.
- Cellular repair and removal of debris occurs
What is included in the maintenance phase of ATN?
Diureses
What is included in the recovery phase?
Infection
What is the most common cause of death in ATN?
1) Fever (> 80% of cases)
2) Transient maculopapular rash
3) Acute renal insufficiency
4) Pyuria (eosinophils)
5) WBC casts, and hematuria
What are the essentials of diagnosis in Acute Interstitial Nephritis?
Drugs
But
Acute interstitial nephritis is also associated with:
1) Infectious Diseases
2) Immunological Disorders
3) Idiopathic condition
What accounts for the most (> 70%) of cases of Acute interstitial Nephritis?
1) BUN:creatinine ratio <20:1
2) UNa (mEq/L): variable
3) FENa (%): variable...usually > 1
4) Urinalysis with red cells, white cells, and WBC casts
5) Wright or Hansel stain to eval for eosinophils
6_ Proteinuria (<1gm/day)
7) ****Peripheral blood eosinophilia in 80% of cases
What will a patient with Acute Interstitial Nephritis present with?
Good! WIth recovery usually within weeks to months
What is the prognosis with Acute Interstitial Nephritis?
Rarely
Do patients with Acute Intersitial Nephritis progress to ESRD?
1) Supportive bu removing the inciting agent
2) If renal failure persists, give a short course of steroids
What is the treatment of Acute Interstitial Nephritis?
1) Hematuria
2) Dysmorphic RBCs
3) RBC Casts
4) Mild Proteinuria
5) Dependent edema and HTN
6) Acute renal insufficiency
What are the essentials of diagnosis in Acute Glomrulonephritis?
1) When oliguria is present
2) Advanced patient age
3) There is multiple organ failure
Generally speaking, when is the prognosis of ARF poor?
1) Progressive azotemia over months to years
2) Symptoms and signs of uremia when nearing end-stage disease
3) Hypertension in majority
4) Isosthenuria and broad, waxy casts in urinary sediment are common
5) Bilateral small kidneys on US (unless PKD)
What are essentials of diagnosis for Chronic Kidney Disease (CKD)?
1) Evidence of renal damage
Based on abnormal urinalysis [proteinuria, hematuria] or structural abnormalities found with US
or
2) GFR < 60 mL/min for 3 or more months!!!
What does the National Kidney Foundation (NKF) defines CKD as:
1) Diabetes mellitus
2) Hypertension
3) Coronary vascular disease
4) FHx of CKD
5) Age > 60 yrs
What are the most common risk factors for CKD?
1) Coronary vascular disease
2) Progression to renal failure
3) Development of complications of impaired renal function, such as anemia, disorders of mineral metabolism, and secondary hyperparathyroidism
What are the Major outcomes of CKD?
Reduced clearance of certain solutes principally excreted by the kidney results in their retention in the body fluids. The solutes are end products of the metabolism of substances of exogenous origin (food) or endogenous origin (catabolism of tissue)
Bottom line what happens in CKD?
CKD is rarely reversible and leads to progressive decline in renal function!
Is CKD reversible?
hypertrophy of the remaining nephrons with hyperfiltration, and the glomerular filtration rate in these nephrons is transiently at supranormal levels.
What does the Reduction in renal mass leads to?
progressive glomerular sclerosis and interstitial fibrosis, suggesting that hyperfiltration may worsen renal function
What do the adaptations on the remaining nephrons cause?
Until renal failure is far-advanced:

(GFR < 10-15 ml/min)
***Symptoms of CKD develop slowly, and patients remain asymptomatic until what point?
1) Fatigue
2) Malaise
3) Weakness
4) Pruritis
When a patient reaches a GFR < 10-15 ml/min, what are their symptoms?
Anorexia, nausea & vomiting, metallic taste and hiccups are common
What are the GI symptoms of CKD?
include irritability, difficulty concentrating, insomnia, and forgetfulness
What are the neurologic symptoms of CKD?
Menstrual irregularities, infertility, and loss of libido are also common as condition progresses
What are the sexual symptoms of CKD?
1) Exam reveals a chronically ill-appearing patient
2) Look for possible underlying cause (DM, SLE)
3) Hypertension is common
4) Skin may be yellow, with evidence of easy bruising.
5) May have nail changes (Mee's lines)
6) Uremic fetor (fishy breath) may be present
7) Cardiopulmonary and mental status changes are also frequently noted...CMDT
What is noted on Physical Exam of a patient with CKD?
Fishy breath
What is uremic fector in CKD?
Nail changes
What are "Mee's Lines" in CKD again?
By documenting elevations of BUN and serum creatinine concentrations
**How is the diagnosis of CKD made?
evidence of LOSS of tubular concentrating ability
I said that on Urinalysis, there would be broad, waxy casts in CKD. But what does this mean?
True
T or F. Persistent proteinuria is suggestive of CKD regardless of GFR level?
Evidence of previously elevated BUN and creatinine, abnormal prior urinalysis, and stable but abnormal serum creatinine on successive days is most consistent with a chronic process
Hmmmmm, so since I may see anemia, metabolic acidosis, hyperphosphatemia, hypocalcemia, and hyperkalemia...with both acute and chronic renal failure
Finding of small echogenic kidneys (<9 cm)
What supports diagnosis of CKD/irreversible
disease
Osteodystrophy
-Check phalanges of hands
-Also check clavicles
What is another radiological finding that supports CKD?
Cardiovascular (over 50% of deaths in pts with ESRD)
Hyperkalemia
Acid-base disorders (tendency to retain hydrogen ions)
Hematologic
Neurologic
Disorders of mineral metabolism
Endocrine disorders
What are the complications of uremia?
HTN
What is the most common cardiovascular complication of CKD that leads to ESRD?
Initial RX to include ACE inhibitor or angiotensin II receptor blocker (ARB). Recheck serum potassium and GFR in one week
In treating HTN, what is the initial prescription for cardiovascular problems?
<130/80 mm
What is the BP Goal for a patient with CKD?
< 125/75 mm Hg
What is the BP Goal for a patient with CKD AND proteinuria > 1-2 g/d
Stop smoking
What can the patient do to really help me out
Pericarditis is an absolute indication for initiation of hemodialysis
Pericarditis is a cardiovascular complication in CKD. But what is unique about Pericarditis
Hell Yes!!
Is CHF a complication of CKD?
True
T or F. Patients with ESRD tend toward a high cardiac output
True
T or F. There is an increased rate of atherosclerosis
LVH and dilation
What causes the CHF in a patient with CKD?
1) Loop diuretics
2) ACE inhibitors
3) Regulation of salt /water
What is the treatment of CHF in a patient with CKD?
True. So don't just focus on CKD. treat the Cardiovascular disease and other risk factors as well
T or F. CKD Patients, especially those with DM, are more likely to die from cardiovascular disease than to progress to ESRD/dialysis!
Hyperkalemia
In CKD, Potassium balance usually remains intact until GFR < 10-20 mL/min. Then what happens?
1) Cardiac monitoring
2) IV calcium chloride or gluconate
3) Insulin with glucose
4) Bicarbonate, and sodium polystyrene sulfonate
What is the treatment of acute hyperkalemia?
Dietary potassium restriction, sodium polystyrene PRN
How is chronic hyperkalemia treated?
Damaged kidneys (Shrunken) are unable to excrete the 1 mEq/kg/d of acid generated by metabolism of dietary proteins.
In CKD, how does the body end up in metabolic acidosis (Acid-base disorders)?
Maintain serum bicarb level at > 20 mEq/L
Alkaline supplements include sodium bicarb, calcium bicarb, sodium citrate
What is the treatment of Acid-base disorders in CKD?
pH > 7.20
BOTTOM LINE, WHAT DO I NEED TO KEEP THE BODY pH AT?
Normochromic, normocytic
- Due to decreased erythropoiesis and RBC survival
OK so the RBCs look normal but my patient is anemic. What kind of anemia does he have?
Recombinant erythropoietin (epoetin alfa) used in patients whose hematocrits are < 33%. Some recommend start with iron supplement and then possibly add ESA (erythroproeitin stimulating agents..Procrit/Epogen)
What is the treatment of a patient that has anemia as a result of CKD?
Platelet dysfunction (Platelet counts only mildly decreased, but bleeding time is prolonged)
In a patient with CKD, what causes coagulopathy?
Petechiae, purpura, and increased bleeding during surgery
What does a patient with coagulopathy from CKD present with?
Yes but it doesn't normalize it
Does dialysis improve bleeding time?
Hematocrit increased to 30%
What is the treatment goal for a patient with coagulopathy?
Uremic encephalopathy does not occur until GFR falls below 10-15 mL/min
In patients with CKD, when does a neurologic complication such as Uremic encephalopathy occur?
Symptoms begin with difficulty concentrating and can progress to lethargy, confusion, and coma
What are the symptoms of Uremic encephalopathy?
Earlier initiation of dialysis may prevent peripheral neuropathies
What are the ways to prevent Uremic encephalopathy?
renal osteodystrophy
In CKD, what are mineral metabolism disorders of calcium, phosphorus, and bone are referred to as
osteitis fibrosa cystica
What is the most common mineral metabolism disorder?
bony changes of secondary hyperparathyroidism
What happens in osteitis fibrosa cystica?
The lesions are lesions most prominent in phalanges and lateral ends of clavicles
- Look for subperiostial erosions
Where would I see radiographical changes (lesions) as a result of mineral metabolism in CKD?
Osteomalacia or adynamic bone disease
What are other bone disorders caused by CKD?
Bony pain, proximal muscle weakness, and spontaneous bone fractures
What do all of the Disorders of mineral metabolism, that I just mentioned cause as far as symptoms?
Dietary phosphorus restriction, oral phosphorus-binding agents such as calcium carbonate or Renogel, and vitamin D
What is treatment of disorders of mineral metabolism in CKD?
With calcitriol or Sensipar
How is Hyperparathyroidism treated in CKD patients?
Because of decreased renal insulin clearance
Why are circulating insulin levels higher in CKD?
Glucose intolerance can occur in chronic renal failure when GFR is < 10-20 mL/min. This is mainly due to peripheral insulin resistance
When does glucose intolerance occur in CKD?
1) STOP SMOKING!
2) ACE/ARB to slow progression of proteinuria and CVD
What are the two major things in reducing the effects of CKD?
- Potentiates hyperkalemia...
REPEAT SERUM CREATININE & POTASSIUM IN ONE WEEK!!!!
What may be the negative effects of treatment with an ACE/ARB?
Keep HgA2C < 7
In a patient with CKD, I need to maintain tight glucose control. How do I do that?
Place the patient on a statin
What should I do to lower cholesterol?
Use diuretics such as Lasix PRN
What should I do to avoid fluid overload?
is to keep the patient OFF dialysis!
I need to refer my CKD patients to CKD clinics, but why, what is their goal?
Malnutrition very common secondary to anorexia, decreased intestinal absorption/digestion...
Why should every CKD patient be referred out to a dietician?
1 g/kg/d!
In general, what should a patients protein intake NOT exceed?
2 g/d of sodium is an initial recommendation
In regards to salt and water restriction, what is the initial recommendation for the non-dialysis patient approaching ESRD
1) Hemodialysis
2) Peritoneal dialysis
3) Kidney transplantation
When conservative management of ESRD is inadequate, what are my alternatives?
Dialysis should be started when patient has GFR of 10 mL/min or serum creatinine of 8 mg/dL
***When should dialysis be started?
When GFR reaches 15 mL/min or serum creatinine is 6 mg/dL
***When should dialysis be started on a diabetic patient?
1) Uremic symptoms such as pericarditis, encephalopathy, or coagulopathy
2) Fluid overload unresponsive to diuresis
3) Refractory hyperkalemia...>7
4) Severe metabolic acidosis (pH < 7.20)
5) Neurologic symptoms such as seizures or neuropathy
6) BUN > 100
Other than the GFR, what are other indications for dialysis?
Hemodialysis
What type of dialysis is the most common for patients in the US?
Staphylococcus aureus
With Hemodialysis, Infection, thrombosis, and aneurysm formation are complications seen more often in grafts than fistulas. What is the most common causative agent?
Patients typically require hemodialysis 3 times per week...sessions last 3-5 hrs each
About how often does a patient need dialysis?
Peritoneal dialysis
- Most common type is continuous ambulatory peritoneal dialysis (CAPD)
- Continuous cyclic peritoneal dialysis (CCPD) utilizes a cycler machine to automatically perform exchanges at night
What is a much more inexpensive form of dialysis?
Peritonitis
What is the most common Peritoneal dialysis complication?
S aureus
What is the most common pathogen?
When their GFR is < 15
When are patients placed on the kidney transplant list?
Living donors (One year survival rate is approximately 98% and five year survival rate is approximately 70-80%)
What is the best option for kidney transplants?
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