An 82-year-old man comes to the emergency department because of sudden onset back pain. He denies any lower extremity weakness, bowel or bladder incontinence, muscle cramps, or paresthesias. He has no fever or chills. He has a history of chronic lymphocytic leukemia and hyperlipidemia. He has not received any chemotherapy for his leukemia and lost follow-up with physician appointments. He does not take any prescription medications. He denies tobacco, alcohol, or illicit drug use.
His blood pressure is 140/76 mm Hg, pulse is 72/min, and respirations are 14/min. Examination shows cervical lymphadenopathy and splenomegaly. He has point tenderness at the L2 level. The remainder of the examination is within normal limits.
The patient's labs reveal:

An electrocardiogram is normal. Spinal imaging shows a compression fracture at the level of L2.
Which of the following is the next best step in the management of his hyperkalemia?

Question

An 82-year-old man comes to the emergency department because of sudden onset back pain.  He denies any lower extremity weakness, bowel or bladder incontinence, muscle cramps, or paresthesias.  He has no fever or chills.  He has a history of chronic lymphocytic leukemia and hyperlipidemia.  He has not received any chemotherapy for his leukemia and lost follow-up with physician appointments.  He does not take any prescription medications.  He denies tobacco, alcohol, or illicit drug use.
His blood pressure is 140/76 mm Hg, pulse is 72/min, and respirations are 14/min.  Examination shows cervical lymphadenopathy and splenomegaly.  He has point tenderness at the L2 level.  The remainder of the examination is within normal limits.
The patient's labs reveal:

An electrocardiogram is normal.  Spinal imaging shows a compression fracture at the level of L2.
Which of the following is the next best step in the management of his hyperkalemia?

Quizplus · Accepted Answer

11ec193a_96a7_32ad_853d_ab4e86331d24_MD0002_00 Hyperkalemia is a potentially life-threatening condition, with the causes listed in the above table. The first step is to evaluate the systemic effects of hyperkalemia on EKG such as peaked T waves, increased PR interval, absent P waves, prolonged QT interval, and a widened QRS complex. A normal EKG in the setting of a serum potassium level of more than 7 to 8 mEq/L raises the possibility of laboratory error or spurious (pseudo-) hyperkalemia, which is most commonly due to potassium movement from damaged red blood cells after a blood draw. The force of the vacuum tubes or suction at drawing causes potassium release from lysed red cells, and the free hemoglobin causes a red or pink tint to the serum. Very high white blood cell (> 50,000 cells/µL) and platelet counts (> 600,000 cells/µL) are also associated with significant pseudohyperkalemia due to the mechanical stress of the blood draw releasing potassium from diseased or fragile white blood cells and platelets. In this situation, it is recommended to obtain arterial blood (no tourniquet or shaking, stored on ice, and promptly analyzed) to document the serum potassium and confirm the diagnosis of pseudohyperkalemia. Failure to recognize this entity could lead to incorrect treatment of presumed hyperkalemia and result in significant hypokalemia. (Choice B & C) Insulin plus glucose and calcium gluconate are not indicated for spurious hyperkalemia. (Choice D) Tumor lysis syndrome can occur in patients with significant bulky tumors undergoing chemotherapy, but this patient has no other biochemical manifestations of tumor lysis syndrome (increased uric acid, phosphorus, and creatinine) and would likely not benefit from aggressive hydration. (Choice E) Chronic lymphocytic leukemia is associated with development of autoimmune hemolytic anemia, which can cause an extravascular site of red blood cell destruction without hyperkalemia. While corticosteroids can be used to treat autoimmune hemolytic anemia, there is no evidence of hemolysis in this patient or any indication for corticosteroids. Educational objective: Almost all patients with a serum potassium > 8 mEq/L have EKG changes. Significant hyperkalemia in the absence of EKG changes should suggest the possibility of pseudohyperkalemia. The presence of significant leukocytosis or thrombocytosis is associated with spurious hyperkalemia, and the patient should have a redraw of arterial blood with care to prevent hemolysis (i.e. no tourniquet or shaking, stored on ice, and promptly analyzed). __________ References: Pseudohyperkalemia in serum: a new insight into an old phenomenon. (http://www.ncbi.nlm.nih.gov/pubmed/18591376) Pseudohyperkalemia in Patients with Chronic Lymphocytic Leukemia (http://www.ncbi.nlm.nih.gov/pubmed/21603111)

An 82-Year-Old Man Comes to the Emergency Department Because of Sudden