A 22-year-old woman is hospitalized after a car accident. She sustained a hip fracture, fracture of several ribs, and a blunt abdominal injury that required a laparotomy. The laparotomy revealed a liver laceration and extensive hemoperitoneum. In the early postoperative period, the patient is noted to have hyperactive deep tendon reflexes. Which of the following electrolyte abnormalities may be responsible for this condition?

Question

A 22-year-old woman is hospitalized after a car accident.  She sustained a hip fracture, fracture of several ribs, and a blunt abdominal injury that required a laparotomy.  The laparotomy revealed a liver laceration and extensive hemoperitoneum.  In the early postoperative period, the patient is noted to have hyperactive deep tendon reflexes.  Which of the following electrolyte abnormalities may be responsible for this condition?

Quizplus · Accepted Answer

Explanation: Hypocalcemiais the most probable diagnosis in this patient. Hypocalcemia can occur during or immediately after surgery, especially in patients undergoing major surgery and requiring extensive transfusions (as likely occurred in this patient with multiple fractures, a liver laceration, and hemoperitoneum). Usually, hypocalcemia occurs due to volume expansion and hypoalbuminemia, and is therefore asymptomatic; however, sometimes it may manifest as hyperactive deep tendon reflexes, muscle cramps and, rarely, convulsions. The etiology of hypocalcemia with massive blood transfusion is related to the large amounts of citrate used to anticoagulate the blood; the citrate chelates with calcium, leading to hypocalcemia. Hypomagnesemia may mimic hypocalcemia but is associated with heavy alcohol use, prolonged nasogastric suction or diarrhea, and diuretic use. (Choice E) Mild hypermagnesemia results in decreased deep tendon reflexes. A severe form causes loss of the deep tendon reflexes and muscle paralysis, thereby leading to flaccid quadriplegia, decreased respiration, and eventual apnea. (Choice B) Hyperkalemia typically results in gastrointestinal disturbances (nausea, vomiting), ECG changes, and asystole, if severe. It may be associated with severe burns, crush injuries, and renal insufficiency. (Choices A and C) Hypokalemia and hyponatremia are unlikely to manifest as hyperactive deep tendon reflexes. Educational objective: Hypocalcemia can occur during or immediately after surgery, especially in patients undergoing major surgery and requiring extensive transfusions. Hyperactive deep tendon reflexes may be the initial manifestation. Hypermagnesemia, on the other hand, results in loss of the deep tendon reflexes.

A 22-Year-Old Woman Is Hospitalized After a Car Accident