WBR0829

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Author PageAuthor::Vendhan Ramanujam
Exam Type ExamType::USMLE Step 3
Main Category MainCategory::Inpatient Facilities, MainCategory::Emergency Room
Sub Category SubCategory::Endocrine, SubCategory::Electrolytes
Prompt [[Prompt::A 28 year old African-American male presented to the emergency department with complaints of lethargy and vomiting for the past one day. He is a known type 1 diabetes mellitus patient. He had a gastrointestinal disturbance before two days following which he restricted his food intake and skipped his insulin doses. He also played soccer with his friends last evening. Physical examination revealed a confused, dehydrated, tachypneic male with vital signs like heart rate of 120 beats/min, blood pressure of 98/58 mmHg, respiratory rate of 35/minute and oral temperature of 37.2 C. A rapid finger glucose test revealed plasma glucose of 638 mg/dL, thus confirming diabetic ketoacidosis. He was started on 0.9% normal saline while waiting for the following laboratory tests


Serum sodium: 130 mEq/L
Serum potassium: 5.2 mEq/L
Serum chloride: 87 mEq/L
Serum bicarbonate: 12 mEq/L
Serum BUN: 32 mg/dL
Serum creatinine: 1.5 mg/dL
Blood glucose: 700 mg/dL
Blood pH: 7.08
PaCO2: 25 mmHg

Urinary Ketones turned out to be positive. Meanwhile he was transferred to the intensive care unit. What is the next best step in line of management of this patient?]]

Answer A AnswerA::Continuous infusion of intravenous regular insulin and isotonic 0.9% normal saline
Answer A Explanation AnswerAExp::'''Incorrect'''-Since the patient’s serum potassium has gone below 5.3 mEq/L, potassium should be added to the continuous infusion of intravenous regular insulin and isotonic 0.9% normal saline.
Answer B AnswerB::Continuous infusion of intravenous regular insulin and hypertonic D5 normal saline
Answer B Explanation AnswerBExp::'''Incorrect'''-Hypertonic D5 normal saline should replace the isotonic normal saline only when blood glucose falls below 200 mg/dL.
Answer C AnswerC::Continuous infusion of intravenous regular insulin, hypertonic D5 normal saline and potassium
Answer C Explanation AnswerCExp::'''Incorrect'''-Hypertonic D5 normal saline should replace the isotonic normal saline only when blood glucose falls below 200 mg/dL.
Answer D AnswerD::Continuous infusion of intravenous regular insulin, isotonic 0.9% normal saline and potassium
Answer D Explanation [[AnswerDExp::Correct-The first line of management of diabetic ketoacidosis (DKA) is starting the patient on a continuous infusion of intravenous regular insulin and isotonic 0.9% normal saline. Potassium is supplemented when serum potassium falls below 5.3 mEq/L.]]
Answer E AnswerE::Continuous infusion of intravenous regular insulin, isotonic 0.9% normal saline, potassium and sodium bicarbonate
Answer E Explanation [[AnswerEExp::Incorrect-Sodium bicarbonate can be administered only when acidosis (<7) is accompanied by a severe (<5 mEq/L) fall in serum bicarbonate level and life threatening hyperkalemia. Otherwise, sodium bicarbonate infusion can lead to neurological deterioration, slowing of the rate of recovery of ketosis and post treatment alkalosis.]]
Right Answer RightAnswer::D
Explanation [[Explanation::The first line of management of diabetic ketoacidosis (DKA) after confirming with a simple rapid finger glucose test and relevant serum biochemistry, urine analysis and arterial blood gas analysis tests will be starting the patient on a continuous infusion of intravenous regular insulin and isotonic 0.9% normal saline. The only indication for delaying insulin therapy will be serum potassium below 3.3 meq/L since insulin will worsen hypokalemia by driving potassium into the cell. Isotonic saline will rapidly correct the extracellular volume depletion, lower the plasma osmolality in the hypoosmotic patient, and reduce the serum glucose concentration both by dilution and by increasing urinary losses as renal perfusion is increased. Most patients are switched at some point to one-half isotonic saline to replace the free water loss induced by the glucose osmotic diuresis. When this should occur is uncertain, because of concern about the possible development of cerebral edema if the plasma osmolality is reduced too rapidly. Intravenous potassium chloride is supplemented when serum potassium falls below 5.3 mEq/L and intravenous sodium bicarbonate can be supplemented when acidosis (<7) is accompanied by a severe (<5 mEq/L) fall in serum bicarbonate level and life threatening hyperkalemia. Blood glucose should be monitored every one hour and other parameters every 4 to 6 hours. This regimen will be continued until the patient’s anion gap corrects to normal (3-11 mEq/L).

Educational Objective: The first line of management of diabetic ketoacidosis (DKA) after confirming with a simple rapid finger glucose test and relevant serum biochemistry, urine analysis and arterial blood gas analysis tests will be starting the patient on a continuous infusion of intravenous regular insulin and isotonic 0.9% normal saline. Potassium can be supplemented when serum potassium falls below 5.3 mEq/L and sodium bicarbonate can be supplemented when acidosis (<7) is accompanied by a severe (<5 mEq/L) fall in serum bicarbonate level and life threatening hyperkalemia.
Educational Objective:
References: ]]

Approved Approved::Yes
Keyword WBRKeyword::Diabetic ketoacidosis
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