View source for WBR0904

 {{WBRQuestion
|QuestionAuthor= {{Rim}}
|ExamType=USMLE Step 2 CK
|Prompt=A 70 year old male patient is hospitalized for pneumonia requiring an IV course of antibiotics. On the third day of hospitalization, the patient reports less dyspnea and shows overall clinical improvement. His vital signs are: temperature of 37.2 degrees celsius, blood pressure of 120/68 mmHg and heart rate of 70 bpm.  The patient has a previous history of myocardial infarction and hypertension.  His medications include aspirin, statin and ACE inhibitors.  His electrolytes ordered in the morning show the following results: <br>
Sodium: 139 mEq/L <br>
Potassium: 5.5 mEq/L <br>
Calcium: 10 mg/dl <br>
Phosphorus: 3.9 mg/dl <br>
Magnesium: 1.68 mg/dl <br> <br>
Which of the following is a first step in the management of the patient?
|Explanation=The patient has a potassium level >5.5 mEq/L consistent with [[hyperkalemia]].  Hyperkalemia often has no symptoms. Occasionally, people may experience irregular heartbeat, [[nausea]], slow, weak, or absent pulse.  Extreme degrees of hyperkalemia are considered a medical emergency due to the risk of potentially fatal arrhythmias. A detailed history taking is very helpful in diagnosing the cause of hyperkalemia. The first step in the management of hyperkalemia is to rule out pseudohyperkalemia. 

Shown below is an algorithm summarizing the first steps in the management of hyperkalemia:

[[ File:Hyperkalemia.PNG]]

The management of the patient depends on the presence or absence of EKG changes, level of increase in potassium lvel and the hemodynamic status of the patient.  The management of the patient should target the following:<br>
1. Myocardial stabilization ( if [[EKG]] changes are present)<br>
2. Shift potassium from blood into cells<br>
3. Lower total body potassium

Educational objective: 
The first step in the management of hyperkalemia is to rule out pseudohyperkalemia by rechecking the electrolytes level.
|AnswerA=Repeat blood test
|AnswerAExp=The first step in the management of hyperkalemia is to rule out pseudohyperkalemia by rechecking the electrolytes level.  Pseudohyperkalemia can be an artifact or caused by [[hemolysis]], elevated [[WBC]], elevated [[RBC]], elevated [[platelet]]s)
|AnswerB=Administer IV saline
|AnswerBExp=IV saline is not the first step in the management of a patient having an elevated potassium level.  The first step in the management of hyperkalemia is to rule out pseudohyperkalemia by rechecking the electrolytes level.
|AnswerC=Order an EKG
|AnswerCExp=Once the blood test to confirm for potassium levels is ordered, EKG should be done to check the any EKG changes.  The management of the patient depends on the presence or absence of EKG changes and the hemodynamic status of the patient.  If EKG changes are present, the management of the patient should target the following:<br>
1. Myocardial stabilization<br>
2. Shift potassium from blood into cells<br>
3. Lower total body potassium
|AnswerD=Administer calcium gluconate
|AnswerDExp=If EKG changes are present, the management of the patient should include the administration of [[calcium gluconate]] for myocardial stabilization.  However, the administration of calcium gluconate should be preceded by a repeat potassium level and an [[EKG]].
|AnswerE=Discontinue his hypertension medication
|AnswerEExp=[[ACE inhibitor]]s might cause hyperkalemia.  However, the medication should not be discontinued before confirming hyperkalemia.  In order to confirm hyperkalemia, a repeat potassium level should be done.
|RightAnswer=A
|WBRKeyword=hyperkalemia, pseudohypokalemia
|Approved=No
}}