WBR1090
| Author | [[PageAuthor::Mohamed Moubarak, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 3 |
| Main Category | MainCategory::Emergency Room |
| Sub Category | SubCategory::Cardiovascular, SubCategory::Electrolytes |
| Prompt | [[Prompt::A 65-year-old male comes to emergency department complaining of chest pain, sweating, and fatigue. He is a newly diagnosed lung cancer patient, and undergoes his first round of cisplatin. He has insignificant past medical history. On examination, his BP is 90/60 mmHg, irregular heart rate 50 beat per minute, temperature 37 C (98.6 F), respiratory rate is 19/minute. His laboratory tests are:
Which of the following is the best urgent step in the management of this patient?]] |
| Answer A | AnswerA::IV atropine |
| Answer A Explanation | [[AnswerAExp::Incorrect
IV atropine does not stabilize the myocardium from the effects of hyperkalemia.]] |
| Answer B | AnswerB::IV calcium gluconate |
| Answer B Explanation | [[AnswerBExp::Correct
Calcium gluconate is necessary to help stabilize the myocardium from the effects of hyperkalemia]] |
| Answer C | AnswerC::Oral kayexalate |
| Answer C Explanation | [[AnswerCExp::Incorrect
Kayexalate binds potassium in the large intestine and helps remove total body potassium; however, this is not immediately helpful in treating life-threatening hyperkalemia because of the increased time to onset of action.]] |
| Answer D | AnswerD::Subcutaneous insulin |
| Answer D Explanation | [[AnswerDExp::Incorrect
Insulin is given in conjunction with dextrose, as the first-line treatment for hyperkalemia. It will promote the movement of potassium intracellularly, but will not protect the myocardium from the effect of hyperkalemia.]] |
| Answer E | AnswerE::IV glucagon |
| Answer E Explanation | [[AnswerEExp::Incorrect
IV glucagon does not stabilize the myocardium from the effects of hyperkalemia.]] |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::The patient has tumor lysis syndrome. The destruction of malignant cells by chemotherapeutic agents will lead to the release of intracellular contents, including potassium, phosphorus, and uric acid (from nucleic acids). This can result in hyperkalemia, hyperuricemia, and hyperphosphatemia.
This patient is having hemodynamic instability because of life-threatening hyperkalemia.
Calcium gluconate, in this case, is necessary to help stabilize the myocardium from the effects of hyperkalemia, although it will not have an effect on the serum potassium itself. Intravenous insulin, given in conjunction with dextrose (in order to prevent hypoglycemia), is the first-line treatment for hyperkalemia, as it will promote the movement of potassium intracellularly. Albuterol is also effective in the treatment of hyperkalemia, as a beta agonist will promote the cellular uptake of potassium. Kayexalate binds potassium in the large intestine and helps remove total body potassium; however, this is not immediately helpful in treating life-threatening hyperkalemia because of the increased time to onset of action. |
| Approved | Approved::No |
| Keyword | [[WBRKeyword::Tumor lysis syndrome]] |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |