Acute Kidney Injury And Chronic Kidney Disease

Question 1

What is acute kidney injury (AKI)?

Answer 1

Increase in serum creatinine +/- decrease in urine output over hours to days

Question 2

What are the effects of AKI?

Answer 2

Electrolyte disturbances
Acid-base disturbances (metabolic acidosis)
Inability to excrete nitrogenous waste
Intravascular volume overload

Question 3

20 y/o F student presents to ER after fainting. She awakened immediately after passing out. She had recurrent episodes of dizziness the past 24 hrs and has had N/V for past 2 days. No diarrhea. General body aches since GI symptoms started but no specific abdomen pain. She denies menstrual changes or vaginal drainage. LMP was 4 weeks ago. No OTC, no meds, NKDA, no tobacco/alcohol/drugs. Negative PMH, PSH, FH

Initial assessment for acute mental status change?
A. Migraine Variant
B. Seizure disorder
C. Cardiac arrhythmia 
D. Drug ingestion 
E. Orthostatic hypotension

Answer 3

A. Migraine Variant - no headache, no neuro deficits
B. Seizure disorder - no apparent risk factors, immediately awakened on change in position
C. Cardiac arrhythmia - no FH or exam findings to support
D. Drug ingestion - awakened immediately, no history, neuro intact
E. Orthostatic hypotension
-dehydartion (volume contraction or extracellular volume depletion (ECVD) - due to fluid losses from N/V

Question 4

20 y/o F student presents to ER after fainting. She awakened immediately after passing out. She had recurrent episodes of dizziness the past 24 hrs and has had N/V for past 2 days. No diarrhea. General body aches since GI symptoms started but no specific abdomen pain. She denies menstrual changes or vaginal drainage. LMP was 4 weeks ago. No OTC, no meds, NKDA, no tobacco/alcohol/drugs. Negative PMH, PSH, FH

In addition to urine studies, which diagnostics would help?
A. Ab xray
B. Fingerstick glucose
C. Arterial blood gases
D. ECG
E. Serum electrolytes, BUN, & creatinine

Answer 4

A. Ab xray - no suggestion of blockage or mass on exam
B. Fingerstick glucose - no history of diabetes, no diaphoresis or tachypnea, immediately awakened
C. Arterial blood gases - no resp distress, duration only 2 days, less likely metabolic compoment ot acid/base
D. ECG - cardiac exam normal, no chest pain, no prior histoy
E. Serum electrolytes, BUN, & creatinine
-urine (sodium, potassium, chloride levels that can be affected by dehydration)
BUN/CR will tell if retaining nitrogenous waste and retaining creatinine, indicating AKI

Question 5

What is fractional excretion of sodium (FeNa)?

Answer 5

Calculated using a random urine sample close to time of blood draw
Helps sort between pre-renal and intrinsic renal
(Una/Pna)/(Ucr/Pcr)X100

Question 6

What does 1-2% FeNa mean?

Answer 6

1-2% means tubular function not intact

Question 7

What are the ways to categorize renal disease?

Answer 7

Pre-renal vs intrinsic (renal) vs post-renal
Tubular vs glomerular: based on first areas affected. Ultimately all of kidney will be affected
Underlying etiology, hypertensive nephropathy, diabetic nephropathy

Question 8

What is the significance of pre-renal determination?

Answer 8

Pre-renal origin suggests that tubules and glomeruli were not initial location of pathology, though they will eventually become affected and possibly permanently

Question 9

Describe BUN/Creatinine in AKI

Answer 9

Elevation in serum creatinine (Cr) by 50% (if baseline known) or by 0.5-1.0 mg/dL (affected by muscle mass available to generate Cr)
Blood urea nitrogen (BUN) also elevated due to retention of nitrogenous wastes
-elevated BUN=azotemia
-elevated BUN plus confusion = uremia

Question 10

Describe GFR

Answer 10

Can be estimated by prediction equations that take into account not only serum creatinine but also age, gender, race, and body size
Prediction equations:
-children: Schwartz & Counahan Barrett
-adults: MDRD & Cockcroft-Gault

Question 11

Describe pre-renal causes

Answer 11

Anything that compromises renal perfusion

1. Hypovolemia: dehydration, viral syndromes, acute pancreatitis, diuretics
2. Low cardiac output: CHF
3. Altered renal/SVR ratio: sepsis, cirrhosis
4. Renal hypoperfusion with impaired autoregulation: NSAIDs
5. Hyperviscosity syndrome (rare): myeloma

Question 12

What is effective volume depletion?

Answer 12

3rd spacing

Results in decreased kidney perfusion as seen in pre-renal

Question 13

What is the treatment for prerenal?

Answer 13

For hypovolemia:

• fluid replacement IV
• as always, treat underlying cause

Even with effective (rather than true) volume depletion such as pancreatitis, large quantities of IV fluids are indicated, with close monitoring for systemic volume overload

Question 14

Describe causes of intrinsic renal failure

Answer 14

1. Renovascular obstruction: renal artery obstruction, eg, embolism, dissecting aortic anuerysm
   (Renal artery stenosis can be pre-renal or intrinsic renal)
2. Disease of glomeruli or microvasculature: accelerated HTN
3. Acute tubular necrosis (ATN): iodinated contrast dye.
   -used with CT’s, vascular studies, IVP’s (intravenous pyelograms)
4. Interstitial nephritis: acute pyelonephritis, NSAIDs, also can be contrast dye induced, other drugs
5. Intratubular deposition & obstruction: myeloma
6. Renal allograft rejection

Question 15

72 y/o F presents to ER with midsternal chest pain that radiates into L shoulder, has lasted an hour, resting helps, worse with increased activity. No similar previous episodes. Initially cold sweats and trouble breathing. DM-2 controlled on oral agent, hyperlipidemia controlled on oral statin, HTN controlled on thiazide diuretic. NKDA.
Cardio took her for cardiac cath and was able to stent LAD artery. She tolerated procedure well and had no apparent changes through the night. BP remained controlled, but urine seems darker/more concentrated. In the morning, her BUN and creatinine are over 50% increased compared to her ER results.

In addition to dipstick, which on urine micro would point to diagnosis?
A. red cell casts 
B. TNTC bacteria
C. Transitional cells 
D. Urate cyrstals
E. Muddy brown casts

Answer 15

A. red cell casts - (dysmorphic red cells) indicate glomerular damag; contrast dye poses risk of more likely tubular damage
B. TNTC bacteria - indicates infection. Pt not febrile
C. Transitional cells - line the bladder
D. Urate cyrstals - no history of gout
E. Muddy brown casts
-tubular damage is most likely initial insult to kidneys after contrast, esp larger volumes of contrast
As much as 300-400 ml for ventriculogram, instead of approx 40-75 cc to examine vessels
May have had normal lab prior to this, but her HTN & DM even though controlled still increase her risk for renal compromise

Question 16

72 y/o M present with intermittent pink-tinged urine and R mid-back pain for past month. No pain, burning, or change in stream w/urination. PMH: prostatic hypertrophy, peripheral vascular disease, HTN, hyperlipidemia, controlled on current meds and follows for labs every 4 moths. NKDA. + R flank tenderness to percussion. Remainder ab exam normal.

10 months ago
-Normal dipstick and negative microscopic

4 months ago
-BUN/Cr 16/1.0

Current:

• dipstick + for blood
• micro verified few RBC’s
• BUN/Cr 18/2.5

Which would be your next step?
A. Cytoscopy
B. IVP (intravenous pyelogram)
C. CT of pelvis
D. MR angiogram
E. US abdomen (attn kidneys)

Answer 16

A. Cytoscopy - though bladder cancer can have hematuria, other diagnostics indicated before sending to urology
B. IVP (intravenous pyelogram) - iodinated contrast involved
C. CT of pelvis - won’t show kidneys
D. MR angiogram - though peripheral vascular disease, no bruits on abdominal exam, and expensive test reserved for later if necessary
E. US abdomen (attn kidneys) - non-invasive, more affordable and accessible, and can determine kidney size, hydronephrosis, and possible masses

Question 17

Describe causes of post-renal blockage

Answer 17

1. Ureteric:
   - calculi (stones), blood clot, sloughed papilla, cancer, external compression (tumor, retroperitoneal fibrosis)
2. Bladder neck:
   - neurogenic bladder, prostatic hypertrophy, calculi, cancer, blood clot
3. Urethra
   - stricture, congenital valve, phimosis

Question 18

What if AKI is unresponsive to conservative measures?

Answer 18

Consider temporary hemodialysis in following:
Volume overload refractory to diuretics
Hyperkalemia
Encephalopathy otherwise unexplained
Pericarditis, pleuritis
Severe metabolic acidosis compromising respiratory or circulating function

Question 19

What is chronic kidney disease (CKD)?

Answer 19

Long-standing, irreversible impairment of renal function
Uremia: clinical syndrome resulting from profound loss of renal function
-vs azotemia = elevated BUN

Question 20

How can GFR be measured?

Answer 20

Ccr (creatinine clearance): 24 hr urine sample measured for creatinine in addition to obtaining serum creatinine
-actual measured value obtained on 24 hr urine more closely approximates actual GFR than using serum Cr alone

Can use inulin as substance to measure but has to be given IV and assay for inulin not available in most labs

Question 21

What are the 5 stages of CKD?

Answer 21

1. Kidney damage with normal or increase GFR >/= 90
2. Mild decrease in GFR 60-89
3. Moderate decrease in GFR 30-59
4. Severe decrease in GFR 15-29
5. Kidney failure (ESRD)

Question 22

Describe the early stage of CKD.

Answer 22

Usually symptom free
Overall function intact
Reserve function diminished
BUN/Cr may even be in normal range

Question 23

58 y/o F presents to clinic for ongoing care after moving. History of sarcoidosis with intermittent HTN and steroid related hyperglycemia. Lab normal. After a year, she has remained stable, on no meds, and no HTN. Her eGFR is 80. CKD stage 2

Which would you recommend?
A. Continue to monitor every 6 months
B. Beta blocker
C. Alpha blocker
D. Diuretic
E. ACE inhibitor

Answer 23

E. ACE inhibitor

-poses kidney protection to delay progression of CKD even if blood pressure does not need treatment

Question 24

Describe later stages of CKD

Answer 24

Azotemia and accompanying symptoms/signs
Reserve decreases sufficiently, so sudden stress can induce further compromise
-infection
-urinary obstruction
-dehydration
-nephrotoxic drugs

Question 25

Describe effects of uremic toxins on cellular function

Answer 25

Reduction in transmembrane voltage - increased intracellular Na - decreased intracellular K - inhibition of Ca flux Uremia and its effects are largely reversible with dialysis Normal erythrocytes incubated in uremic serum demonstrate similar changes

Question 26

Describe effects of uremic toxins on whole body composition

Answer 26

Osmotically induced overhydration of cells Increased extracellular volume Malaise, anorexia, N/V/D - protein & calorie malnutrition - negative nitrogen balance - profound loss of lean body mass & fat deposits

Question 27

Describe effects of uremic toxins on metabolism

Answer 27

Hypothermia (decreased active Na transport) Intracellular deficits of K Metabolic acidosis

Question 28

Describe effects of uremic toxins on nitrogen and lipids

Answer 28

Protein intolerance - increased catabolism in uremia - decreased elimination Hypertriglyceridemia, decreased HDL, normal cholesterol - decreased removal by lipoprotein lipase - increased lipogenesis - possibly increased production by liver and intestine

Question 29

Describe effects of uremic toxins on sodium and volume homeostasis

Answer 29

Total body content of Na and water are increased modestly: in stable CKD ``` Excessive salt ingestion can lead to CHF HTN Ascites Edema ```

Question 30

Describe effects of uremic toxins on Na and Water

Answer 30

Excessive water ingestion - hyponatremia - weight gain Recommended fluid intake pre-dialysis -urine output plus 500 ml/day

Question 31

Describe potassium effects in chronic renal disease

Answer 31

Normal until late stages -adaptation in renal distal tubule and colon = sites where aldosterone enhances K secretion Increased K: cardiac arrhythmias

Question 32

What are drugs that can increase serum potassium?

Answer 32

Antikaliuretic drugs - spironolactone - triamterene - amiloride - trimethoprim - pentamidine Others: - ACEIs - beta-blockers

Question 33

Describe how extrarenal fluid loss also contributes to CKD

Answer 33

Impaired renal mechanisms to conserve Na and water in CKD Vomiting, diarrhea, fever: volume depletion - dry mucous membranes, dizziness, syncope - tachycardia, decreased JVP - orthostasis - cardiovascular collapse

Question 34

What is the most common complication of ESRD?

Answer 34

HTN as a result of primary renal disease or effects on kidney from systemic disease Chronic dialysis pts also have a higher incidence of accelerated atherosclerosis which contributes to HTN

Question 35

If no HTN on clinical exam of ESRD pt, what should you also consider?

Answer 35

Salt wasting form of renal disease causing CKD - polycystic or medullary cystic disease - chronic tubulointerstitial disease - papillary necrosis Volume depletion On antihypertensive therapy at the time

Question 36

Describe pulmonary congested associated with CKD

Answer 36

Unique form, even in absence of volume overload - normal or mildly elevated intracardiac or pulmonary capillary wedge pressures - chest x-ray: butterfly wing distribution (peripheral vascular congestion) - -increased permeability of alveolar capillary membranes

Question 37

Describe pericarditis associated with CKD

Answer 37

Less frequent with early dialysis -thought to be secondary to metabolic toxins If occurs in well dialyzed, likely viral infection or systemic disease Effusion often hemorrhagic TX: pericardiocentesis, pericardiectomy

Question 38

Describe hematologic anemia associated with CKD

Answer 38

Normocytic, normochromic anemia Hemolysis: uremic pts GI, chronic dialyzer blood loss Hyperspenism: occasional

Question 39

Describe hematologic abnormal hemostasis associated with CKD

Answer 39

Prolonged bleeding time Decreased platelet factor III activity Abnormal platelet aggregation and adhesiveness Impaired prothrombin consumption

Question 40

Describe enhanced susceptibility to infection associated with CKD

Answer 40

Lymphocytopenia Atrophy of lymphoid structures Neutrophil production relatively unimpaired Uremia impairs function of all leukocytes

Question 41

Describe bone changes with uremia

Answer 41

Renal rickets: widened osteoid seams at growth margins Osteitis fibrosis cystica: due to secondary hyperparathyroidism - osteoclastic bone resorption - subperiosteal erosions - terminal phalanges, long bones, and distal clavicles Osteosclerosis

Question 42

Describe bone changes in long term dialysis

Answer 42

Adynamic or aplastic bone disease Aluminum-induced osteomalacia Dialysis-related amyloidosis (DRA) - carpal tunnel syndrome - tenosynovitis of hands - shoulder arthropathy - bone cysts - cervical spondyloarthropathy - cervical pseudotumors

Question 43

42 y/o F presents with increasing fatigue, dyspnea, and poor appetite. Developing elevated BP, lipids, and swelling of extremities. Lab showed hematuria, RBC casts, increased potassium, low albumin, and eGFR of 20 FH positive for multiple members with kidney problems and several on dialysis (most diabetics with 2 sisters already deceased) What is your initial diagnosis?

Answer 43

Idiopathic nephrotic syndrome since no diabetes and no prior HTN However renal biopsy showed FSGS which comprises 15% of nephrotic syndromes Progresses to CKD in 5-10 yrs. No proven therapy.

Question 44

What are signs and symptoms of CKD?

Answer 44

Severity depends on - magnitude of loss in renal function - rapidity of loss ``` Anorexia Weight loss Dyspnea Fatigue Pruritus Sleep & taste disturbance Confusion, possibly other forms of encephalopathy ```

Question 45

What will PE show with CKD?

Answer 45

``` HTN JVD Pericardial +/- pleural friction rub Muscle wasting Asterixis Excoriations & ecchymoses ```

Question 46

What will labs show with CKD?

Answer 46

Potassium phosphate, uric acid all high Calcium, albumin, and hemoglobin all low Metabolic acidosis

Question 47

What are treatments for CKD?

Answer 47

Aggressive control of HTN Eliminate volume overload (diuretics, volume intake restriction) EPO (rHuEPO): recombinant human erythropoietin Phosphate binders: Ca carbonate or acetate Restrict dietary potassium Sodium polystyrene sulfonate binds potassium ACEIs: diabetes, signficant proteinuria (>1 gm/d) Dietary protein restriction

Question 48

What are indications for dialysis?

Answer 48

``` Unresponsive to conservative measures Volume overload refractory to diuretics Hyperkalemia Encephalopathy otherwise unexplained Pericarditis, pleuritis Severe metabolic acidosis compromising respiratory or circulatory function Need for fluids/drugs also consideration ```

Question 49

Describe dialysis methods

Answer 49

PD (peritoneal dialysis) cycler vs dwell time then drain IHD (intermittent hemodialysis) - most common type used for AKI - many CKD pts maintained on 3x/wk Night-time dialysis - in-center hemodialysis - in-home hemodialysis CCRT (continuous renal replacement therapy) - if intolerant to IHD - may see in extremely unstable ICU pts

Question 50

Describe complications of peritoneal dialysis

Answer 50

``` Peritonitis Hyperglycemia Hypertriglyceridemia Obesity Hypoproteinemia Dialysis-related amyloidosis Insufficient clearance due to vascular disease or other factors ```

Question 51

What are complications of hemodialysis?

Answer 51

``` Hypotension Accelerated vascular disease Rapid loss of residual renal function Access thrombosis Access or catheter sepsis Dialysis-related amyloidosis Protein-calorie malnutrition Hemorrhage Dyspnea/hypoxemia Leukopenia ```

Question 52

Describe absolute contraindication for renal transplant

Answer 52

``` Active glomerulonephritis Active bacterial or other infection Active or very recent malignancy HIV Hep B surface antigenemia Severe comorbidity (vascular disease) ```

Question 53

What are relative contraindications of renal transplant?

Answer 53

``` Age>70 yrs Severe psychiatric disease Moderately severe degrees of comorbidity Hep C w/chronic hepatitis or cirrhosis Noncompliance with dialysis or other tx ``` Primary renal diseases: - primary focal sclerosis with prior recurrence in transplant - multiple myeloma - amyloid - oxalosis

Question 54

What are complications of renal transplant?

Answer 54

Rejection Immunosuppression -infection -neoplasm