Acute and Chronic Kidney Injuries Flashcards
A 69-year-old male presents to the emergency department for sudden shortness of breath that
came on while he was sleeping. He currently is short of breath, but denies any chest pain, arm
pain, or jaw pain. The patient has a past medical history of hypertension, obesity, diabetes, and
GERD. The patient states he has not filled his prescriptions for any of his medications in
months and cannot remember what his medications are. A chest radiograph is obtained and is
seen in Figure B. Lab values at admission are below:
Serum:
Na+: 139 mEq/L, K+: 4.0 mEq/L
Cl-: 100 mEq/L, HCO3-: 24 mEq/L
BUN: 22 mg/dL, CREATININE: 0.9 mg/dL
Glucose: 72 mg/dL, Ca2+: 9.9 mg/dL, Mg2+: 1.5 mEq/L
The patient is started on appropriate treatment and
his symptoms resolve. He is recovering on the medicine floor.
His laboratory values are ordered and are below:
Serum:
Na+: 137 mEq/L, K+: 3.5 mEq/L
Cl-: 100 mEq/L, HCO3-: 26 mEq/L
BUN: 39 mg/dL, CREATININE: 1.5 mg/dL
Glucose: 70 mg/dL, Ca2+: 9.7 mg/dL, Mg2+: 1.5 mEq/L
The patient states that he has not urinated in the past 24 hours. Which of the following is the
most likely cause of this patient’s current presentation?
Acute kidney injury caused by too high dose of loop diuretic
A 20 year old male presents with complaints of tea/coke colored,
cloudy urine, 2 days following a sore throat. He is otherwise
healthy. Urine analysis reveals:
WBCs: 1-2 /hpf
RBCs: 100 /hpf
Protein: 2+
Sugar: nil
Red cell casts: present
What type of AKI is the most likely diagnosis?
AKI caused by bacterial infection spread
how do we diagnose CKI?
GFR less than 60 for over 3 months or kidney damage for over 3 months
is CKI reversible?
no
Acute kidney injury id characterized by?
rapid loss of renal function and accumulation of nitrogen waste products
electrolyte abnormalities (hyperkalemia)
acid/base imbalance
if AKI has lasted over 2 weeks, what phase of AKI would the patient be in?
oliguric or anuric phase
after 3 weeks from AKI, what is the phase called?
polyuric phase
what is normal BUN?
10
what is normal creatinine?
1
what are the common values we obtain to diagnose kidney injury?
serum BUN/Cr
urinalysis
Fe Na (fraction of excretion of Na)
urine osmolarity
urine volume
when would you perform a renal ultrasound to diagnose kidney injury?
if we think the injury is obstruction related
what is normal Creatinine clearance?
100
what are the 2 main kidney function tests we use?
serum creatining and E-GFR
what is considered normal GFR?
~125ml/min
if plasma creatinine concentration increases from 1-2, what is the correlated GFR level?
~60
what is the Cockcroft and Gault Equation?
{ (140-age) * weight/ (72 * SCr) } * 0.85 (if female)
when should the Cockcroft and Gault Equation not be used?
-serum creatinine is changing rapidly
-unusual diet such as strict vegetarian
-low muscle mass
-obesity
what are the drugs that increase serum creatinine without affecting GFR?
THRU
Secretion
Inhibition
Action
On
Tubules
Trimethoprim
H2 blocker (Cimetidine)
Ranolazine
Uricosuric
Salicylate
Imatinib
Amiodarone
Olaparib
Telaprevir
A 78-year-old man is admitted to the hospital with an acute
upper GI bleed and resulting hypotension. (POD1 scr 1.0) After
initial stabilization treatment and colonoscopic evaluation, the
patient underwent a colectomy because of multiple bleeding
diverticula. He became hypotensive while in the OR and
developed acute tubular necrosis. (POD 2: scr 2 )
*** Post-operatively, the patient developed congestive heart failure and
underwent continuous venovenous hemodiafiltration (POD 3 Scr 2.5).
What other patient specific data would like to know here?
Calculate this patient’s eGFR [Wt: 65 kg]
We cannot calculate eGFR b/c pt has AKI (SCr is rapidly changing)
**serum urea is not an accurate way to determine if patient has kidney damage
.
what does silver or milky urine indicate?
pus, bacteria, or epithelial cells
what does reddish brown urine indicate?
blood in urine
what does orange, green, blue, or red urine indicate?
change in color caused by medications
when does the kidney produce urinary casts?
in certain disease states
where are urinary casts formed?
in the distal convoluted tubule and collecting ducts
what does the Fe Na value tell us about what’s wrong with the pt?
can help differentiate if pt has a prerenal injury or has acute tubular nephrosis
if Fe Na is less than 1%, what does this indicate?
what if it is over 1%?
why can’t we use Fe Na to diagnose if pt is using a diuretic?
less than 1% means prerenal
over 1% means acute tubular nephrosis
diuretics affect sodium excretion
A 65-year-old man with gastrointestinal malignancy undergoes a laparotomy
for resection followed by ileostomy. Intravenous normal saline is given at a
rate of 100 ml per hour to compensate for the excessive losses from ostomy.
Initially, his urine output is approximately 40 ml per hour but drops to 20 ml
per hour on post-op day 4. An arterial blood gas is remarkable for a pH of
7.21 and PCO2 of 28 mmHg. Serum sodium is 130 mEq/L, potassium is 5.6
mEq/L, BUN is 90 mg/dL, and creatinine is 3.0 mg/dL. Urine sodium is 35
mEq/L, and urinary creatinine is 90 mg/L. Which of the following is the next
most appropriate step in establishing the underlying pathology leading to
deranged renal function?
A. Urine for dysmorphic RBCs
B. Fractional excretion of sodium
C. Ultrasound abdomen and pelvis
D. Renal biopsy
B
what is the main cause of prerenal injury?
hypoperfusion
what happens inside the kidney in the prerenal stage of AKI and why?
intrarenal vasoconstriction due to low perfusion
what are extrarenal factors that occur during prerenal injury that may lead to renal injury if not treated?
vomiting, diarrhea, burns, sweating, blood loss
why should we be concerned if patient is dehydrated while taking a diuretic?
may indicate diuretic overuse which should be discontinued in order to rehydrate the pt
what is the leading cause of renal injury (glomerulonephritis)?
diabetes
what are other causes of renal injury (glomerulonephritis)?
hypertension
vasculitis
lupus
post infection
what is a typical cause of cola colored urine?
IGA nephropathy
what medications can cause interstitial nephritis?
NSAIDs, antibiotics- ((especially penicillins), sulfonamides, cephalosporins, cipro, and rifampin), and proton pump inhibitors
which antiviral can cause interstitial nephritis?
acyclovir
what can cause tubular nephritis?
ischemia from prolonged hypotension
exogenous toxins such as aminoglycosides (gentamicin, tobramycin, vancomycin…)
endogenous toxins such as rhabdomyolysis, hemolysis, tumor lysis
what is the main cause of postrenal injury?
an obstruction
which two antivirals can cause crystal formation in the kidney?
acyclovir and indinavir
what are intrarenal things that can cause postrenal injury?
stones, crystals, tumors, clots
what are the two factors that indicate prerenal AKI?
dehydration and hypoperfusion
what Serum BUN:Cr ratio do we typically see in prerenal AKI?
> 20:1 due to hypoperfusion
what fraction of excretion of sodium indicates prerenal AKI?
if it is less than 1% (less fluid excreted = less sodium excreted)
when would hyaline casts be present in the urine?
from prerenal AKI
what are the signs that indicate a postrenal AKI?
obstruction causing sudden decrease in renal function and abdominal pain
what Serum BUN:Cr ratio do we typically see in postrenal AKI?
same as prerenal > 20:1
how do we classify a kidney injury as acute tubular nephrosis?
ischemia (reduced blood flow to kidney)
nephrotoxins are causing the injury
if the fraction of excretion of sodium is greater than 1%
typically we will see muddy brown casts in the urine
how do we treat patients with acute tubular nephrosis?
provide a lot of hydration and stop their diuretic/hypertension meds
how do we classify a kidney injury as acute interstitial nephritis?
injury caused by an allergic reaction or adverse reaction to a drug
if patient is positive for eosinophils in urine (penicillin is usually the cause)
when does the patient’s kidney injury become acute tubular necrosis?
if the prerenal AKI is not treated fast enough, the tubular cells start to die
which drugs can cause a bladder neck obstruction?
tricyclic antidepressants and ganglion blockers
what are the 2 most common drugs that cause acute interstitial nephritis? (allergic rxn)
penicillin and its derivatives and cephalosporins
what are the 2 most common indicators of acute interstitial nephritis? (allergic rxn)
oliguria (low urine production) and rising serum creatinine
define anuric
when your kidneys don’t have enough blood or fluid supply
A 39-year-old woman is brought to the emergency department in a
semi-unconscious state by her neighbor, who saw her lose
consciousness. There is no apparent injury on the primary survey. The
patient is not currently taking any medications. She has had loose stools
for the past 3 days and a decreased frequency of urination. No further
history can be obtained. Blood pressure is 94/62 mm Hg, the
temperature is 36.7°C (98.0°F), the pulse is 105/min, and the respiratory
rate is 10/min. The patient’s skin appears dry. The routine basic
metabolic panel, urine analysis, urine osmolality, and urine electrolytes
are pending. Which of the following lab abnormalities would be
expected in this patient?
A. Urine Na+ > 40 mEq/L
B. Fractional excretion of sodium (FENa) > 2%
C. Serum blood urea nitrogen/creatinine (BUN/Cr) > 20
D. Serum creatinine < 1 mg/dL
C
