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Old 06-01-2012
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Question metabolic acidosis question

A 75-year-old man has had increasing shortness of breath with exertion during the past 2 weeks. He has a 25-year history of hypertension well controlled with diuretics. Two months ago, serum urea nitrogen and creatinine concentrations were within the reference ranges. His pulse is 98/min, respirations are 19/min, and blood pressure is 180/100 mm Hg. The lungs are dull to percussion at the bases, and crackles are heard one third of the way up bilaterally. Cardiac examination shows increased jugular venous pressure, an S3 gallop, and no murmur. There is 3+ pitting edema of the lower extremities. Serum studies show:
Na+126 mEq/L
K+5.4 mEq/L
Cl− 108 mEq/L
HCO3−16 mEq/L
Urea nitrogen 75 mg/dL
Creatinine3 mg/dL


This patient most likely has which of the following types of acid-base disturbance?
(A) Metabolic acidosis
(B) Metabolic alkalosis
(C) Respiratory acidosis
(D) Respiratory alkalosis

By process of elimination, i figured the answer is (B).
but what exactly does this guy have? i know am missing the bigger picture...
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Old 06-01-2012
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seems like he has a lung problem thats causing right heart failure.
say history of hypertension so maybe he has a thickened LV and thats causing congestion thats backing up into the lungs and then the right heart.

he's on diuretics.
maybe thats why he has low sodium and high K+ (K-sparing diuretic?)

he's respirations are slightly higher (19) but i dont think enough to cause an acid-base disturbance.

he's kidney's are messed up as indicated by the BUN and Cr

He's bicarb level is low

how this all relates, im having trouble determining. cant exact draw the connection.

all i see is low bicarb, so all i can think of is A. Metabolic Acidosis?

hmmm Where am I going wrong?
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Old 06-01-2012
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oh God. I meant A. Sorry!
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but thats my problem as well..cant make a clear relationship.
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Old 06-01-2012
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He's got severe CHF (from the hypertension) and renal failure, the CHF leads to fluid in the lungs causing the crackles and dullness. Since got hyperkalemia as well, furosemide is the best option. Gotta treat the severe CHF even if it means compromising the kidney function.
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Last edited by slowpoke; 06-01-2012 at 06:17 PM. Reason: clarifying
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Old 06-01-2012
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Quote:
Originally Posted by Dr.NickRiviera View Post
say history of hypertension so maybe he has a thickened LV and thats causing congestion thats backing up into the lungs and then the right heart.
Wouldn't that cause an S4 and not a S3 ? I forgot..

This patient has congestive heart failure I think to the point where he has right sided heart failure due to left sided heart failure. It also seems like he has renal failure because he cannot pump enough blood to keep the kidneys perfused and since he's on diuretics, the Renin-Angiotensin-Aldosterone system probably isn't effective ?

His anion gap is below normal as well, it's at 2

It's for sure Metabolic Acidosis but not sure what this patient has.
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Quote:
Wouldn't that cause an S4 and not a S3 ? I forgot..
You're right, S4 is true of HCM, and S3 means DCM. So this patient has dialated CHF. But the reason for it?? probably renal failure leading to increased volume.
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Old 05-04-2014
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Default Solid Reasoning.

Good explanations so far Thank you. Another forum attributed Spironlactone meds for HTN for the sodium/potassium disturbance in place, so ur left with renal failure and low HCO3- as the driver of met acidosis (A).

This guy has severe CHF originating from LV, Hx of HTN, and he's old as dirt so renal function is particularly susceptible to v.blood supply.

An academic question though: I'm assuming the Cl- is driven by the acidosis, otherwise diuretics would lower this, ya? I guess we should mostly ignore Cl- as a poor indicator for diagnosis in this case.
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Old 05-04-2014
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Well he could be suffering from metabolic acidosis due to renal failure that worsened over the past 2 weeks. Or he could be having RTA4 from spironolactone which is basically a type of metabolic acidosis.
I would consider renal failure more. These are the two things I can think of. Can someone please provide us with a definitive answer!!
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Old 07-15-2014
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Patient might have had LHF(long standing HTN, although mentioned , is well controlled by diuretics))--> RHF-->raised jugular vein/ pitting limb edema.Broadly speaking, CHF , leading to hypoperfusion of vital organs i.e renal--> causing raised BUN and creatinine and decreased ability to reabosrb Bicarbs---> METABOLIC acidosis, High K ion also support metabolic acidosis-- H+ exchange with Intracellular K, raising serum K levels.
So best and correct should be Metabolic acidosis.
One more thing, hypoperfusion may lead to RAAS activation--> sodium and water retention ---> HTN & edema

Please correct me if i am wrong.
Thanks
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