kpmle2
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A 45-year-old white woman with type 2 diabetes
mellitus originally admitted for a pulmonary
embolism develops a cough and fever
while in the hospital. She was admitted 4 days
ago and had started warfarin the day prior to
the onset of her cough and fever. On day two
of admission she was advanced to a normal
diet and maintenance intravenous fluids were
discontinued. The nurses say she has been eating
and drinking normally. On examination
she is febrile, her neck veins are flat, her skin is
warm to the touch, and her blood pressure is
80/40 mm Hg. Urine output was 20 mL/hr for
the last 3 hours. A CT is ordered and shows a
right lower lobe pneumonia. Laboratory work
also shows a blood urea nitrogen (BUN) of 35
mg/dL and creatinine of 4.3 mg/dL. Her BUN
and creatinine the day before had been 23
mg/dL and 1.5 mg/dL, respectively. WBC
count is 25,000/mm3 and blood cultures grow
Pseudomonas aeruginosa. There is tenderness
upon palpation of the costovertebral angle region.
Which of the following mechanisms
would most likely account for the worsening
kidney function?
(A) Contrast administration during the course
of her treatment in the hospital
(B) Diabetic kidney failure secondary to angiotensin
II–induced vasoconstriction
(C) Hematogenous spread of the pulmonary
infection to the kidney leading to
pyelonephritis
(D) Insufficient intravascular volume secondary
to discontinuation of maintenance
intravenous fluids
(E) Respiratory acidosis secondary to pulmonary
infection
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| Eagle_303
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B/C ratio is indicative of Renal azotemia.
She is in sepsis Option C is looks to be correct.
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| nightflight1945
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(C) Hematogenous spread of the pulmonary
infection to the kidney leading to
pyelonephritis
Pyelonephritis does not cause renal dysfunction in a normal functioning kidney , However it can cause renal failure in a patient with underlying renal disease.
However there is a problem in the question , even in acute renal failure Cr doesn't change more than 1-1.5 per days however in this case it has changed 4.3-1.5=2.7 in one days that is incorrect.
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| Eagle_303
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nightflight1945 wrote:
(C) Hematogenous spread of the pulmonary
infection to the kidney leading to
pyelonephritis
Pyelonephritis does not cause renal dysfunction in a normal functioning kidney , However it can cause renal failure in a patient with underlying renal disease.
However there is a problem in the question , even in acute renal failure Cr doesn't change more than 1-1.5 per days however in this case it has changed 4.3-1.5=2.7 in one days that is incorrect.
nightflight ! you are really a knowledgeful person.
I need reference for both of informations you put in the post. Please do not quote only the book but also topic underwhich it is discussed.Better if you can copy paste in case you have some ebook edition.
As far your first statement is concerned ,CMDT says:
"
Interstitial Nephritis
Essentials of Diagnosis
Fever. Transient maculopapular rash. Acute renal insufficiency. Pyuria (including eosinophiluria), white blood cell casts, and hematuria.
General Considerations
Acute interstitial nephritis accounts for 10–15% of cases of intrinsic renal failure. An interstitial inflammatory response with edema and possible tubular cell damage is the typical pathologic finding. Cell-mediated immune reactions prevail over humoral responses. T lymphocytes can cause direct cytotoxicity or release lymphokines that recruit monocytes and inflammatory cells.
Although drugs account for over 70% of cases, acute interstitial nephritis also occurs in infectious diseases, immunologic disorders, or as an idiopathic condition. The most common drugs are penicillins and cephalosporins, sulfonamides and sulfonamide-containing diuretics, NSAIDs, rifampin, phenytoin, and allopurinol.
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| nightflight1945
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Thank you a bunch Eagle.
The following is from emedicine :
link : www.emedicine.com/med/topic1595.htm
Blood urea nitrogen and serum creatinine The ratio of BUN to creatinine is an important finding because the ratio can exceed 20:1 in conditions in which enhanced reabsorption of urea is favored (eg, in volume contraction) and suggests prerenal AKI. BUN may be elevated in patients with GI or mucosal bleeding, steroid treatment, or protein loading. Assuming no renal function, the rise in BUN over 24 hours can be roughly predicted using the following formula: 24-hour protein intake in milligrams X 0.16 divided by total body water in mg/dL added to the BUN value. Assuming no renal function, the rise in creatinine can be predicted using the following formulas: For males: weight in kilograms X [28 – 0.2(age)] divided by total body water in mg/dL added to the creatinine value For females: weight in kilograms X [23.8 – 0.17(age)] divided by total body water added to the creatinine value As a general rule, if serum creatinine increases to more than 1.5 mg/dL/d, rhabdomyolysis must be ruled out
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| nightflight1945
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Acute uncomplicated pyelonephritis in adults rarely progresses to renal functional impairment and chronic renal disease. Repeated upper tract infections often represent relapse rather than reinfection, and a vigorous search for renal calculi or an underlying urologic abnormality should be undertaken. If neither is found, 6 weeks of chemotherapy may be useful in eradicating an unresolved focus of infection.
Repeated symptomatic UTIs1 in children and in adults with obstructive uropathy, neurogenic bladder, structural renal disease, or diabetes progress to chronic renal disease with unusual frequency. Asymptomatic bacteriuria in these groups as well as in adults without urologic disease or obstruction predisposes to increased numbers of episodes of symptomatic infection but does not result in renal impairment in most instances.
Harrison's Principles of Internal Medicine 16th Edition . page 1720
The prognoses of uncomplicated cystitis and pyelonephritis are generally good, and there are no deaths unless a patient with pyelonephritis is left untreated, in which case sepsis may develop and lead to death. Also, secondary complications are rare in these patients. In patients with complications such as renal scars from childhood pyelonephritis, chronic pyelonephritis or glomerulonephritis, or other chronic renal diseases, acute pyelonephritis may lead to further reduction of renal function. As mentioned above, infections with Proteus spp. or other ammonia-producing organisms may lead to formation of calculi or aggravation of existing ones.
Cecil Textbook of Medicine 22nd edition , page 1911
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| Eagle_303
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Interstitial nephritis no matter cause is infection ,autoimmunity or drug is a well known and documented cause of ARF .
The answer is in your own post .
In Your first post you said:
Pyelonephritis does not cause renal dysfunction in a normal functioning kidney
In your reference it is clear that it can occur though rarely.
Acute uncomplicated pyelonephritis in adults rarely progresses to renal functional impairment and chronic renal disease.
Best of luck
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| Eagle_303
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nightflight1945 wrote:
Thank you a bunch Eagle.
The following is from emedicine :
As a general rule, if serum creatinine increases to more than 1.5 mg/dL/d, rhabdomyolysis must be ruled out
Great information ;Thanks a lot.
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| nightflight1945
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rarely is the key point in my post!
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| Eagle_303
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Rarely = uncommon but possible
Does not = never happens
Best of luck
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| nightflight1945
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Rarely doesnot mean uncommon . Please don't be picky .Pyelonephritis rarely cause renal failure in normal functioning kidney means Pyelonephritis doesnot cause renal failure in normal functioning kidney , it is your option to take it or reject it .
GL
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| Oussama77
Forum Junior
Topics: 9
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Ok.
Pyelonephritis left untreated, infection can sometimes resolve on its own but, if it persists, it may lead to scarring and damage of the kidneys.
Damaged kidneys can cause other conditions, such as high blood pressure or even chronic renal failure, requiring frequent medical attention for the rest of one's life.
With the clinical picture of pyelonephritis:
Suggesting answer C).Hematogenous spread of the pulmonary
infection to the kidney leading to
pyelonephritis
http://www.diagnose-me.com/cond/C159020.html
___________________
And those who were seen dancing were thought to be insane by those who could not hear the music. FWN
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| ngaybinhyen
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you have the answer, Kpmle2?
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| DrAlex_76
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this pt has preexisting renal dysfunction due to her Creatinin level at day of admission = 1.5 ( also Creatinin clearance estimated around 45-50 )
She had normal range of BUN/ Cre at day of ad around 15.
She has now creatinin clearance around 1/3 compare to that of the 1st day ( 15-18) also BUN/Cre ratio < 10 which she could be in stage of intra-renal disease.
base upon above things, we can rule out B and D options. ( prerenal disease )
It can't be E because Pneumonia likely causes res alkalosis.
So now it only A or C.
Favor the option C because she is in septicemia with Pseu and Pseudo is usually seen in hematogenous spread.
contrast induced nephritis usually has postprocedural serum creatinine > 5mg/dL and serum creatinine peak at day 3-5 postprocedure.
Some silly thoughts, pleasure to be corrected.
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| kpmle2
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Posts: 512
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Ans is (C) Hematogenous spread of the pulmonary
infection to the kidney leading to
pyelonephritis
Will post the explanation later .
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| kpmle2
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The correct answer is C. Patients with urinary
tract infections and hospital-acquired pneumonias
can quickly become bacteremic. With
hematogenous spread, the infecting agents can
potentially infect other organs. In this case, the
sudden onset of fever, bacteremia, x-ray findings,
and acute kidney failure are suggestive of
sepsis. The costovertebral angle tenderness
also suggests pyelonephritis.
Answer A is incorrect. Contrast nephropathy
may be contributing, as it can occur a few days
after the administration of contrast and is more
likely in patients with diabetic nephropathy,
but it would not explain the clinical picture of
fever and low blood pressure. Had hypotension
and decreased urine output immediately followed
the administration of intravenous contrast,
it would be characterized as an anaphylactoid
reaction due the activation of mast
cells.
Answer B is incorrect. Diabetic nephropathy
causes a more chronic renal failure. Given the
patient’s baseline creatinine of 1.5 mg/dL, it is
likely that diabetic nephropathy is the etiology
of her underlying chronic renal insufficiency.
This patient presents with acute renal failure.
Answer D is incorrect. Insufficient intravascular
volume may cause acute renal failure(prerenal
azotemia). Although maintenance fluids
had been discontinued, the patient was not restricted
to nothing by mouth and presumably
was eating and drinking normally. While still a
possible explanation, this is less likely, as there
is an infectious source as well as clinical find-
ings compatible with pyelonephritis. Furthermore,
classically, the blood urea nitrogen:creatinine
ratio in prerenal azotemia is > 20; here
the ratio is < 10. Further tests to determine the
etiology of the renal failure would be urine osmolality,
urine sodium, and fractional excretion
of sodium.
Answer E is incorrect. Acidosis will not explain
the costovertebral angle tenderness or
the entire clinical picture. Furthermore, the
most common acid-base disturbance in sepsis
is combined metabolic acidosis and respiratory
alkalosis.
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