A 67 year old woman with metastatic squamous cell cancer presents to the emergency department having been found on the floor by a family member. She lived alone and cared for herself and was apparently given to heavily imbibing in solutions containing two carbon fragments.
She was clearly quite ill, hypothermic, and confused. She was very weak and had difficulty moving her extremities. Her blood pressure was 95/55, and her temperature was 34 degrees centigrade. Her 12 lead ECG revealed this:
A closer look at leads V1 through V3 is found here:
What is your interpretation, and what do you think that this patient’s electrolyte panel would show?
We knew going in that this patient had metastatic cancer and that she was weak and hypothermic. If you’ll look at lead V3, you’ll see that there is a “sine wave look” to the ST and T wave areas. The machine read the QTc interval as 518. What you’re seeing is a missing ST segment PLUS a flattened T Wave PLUS a large U wave. The missing ST segment is what you see in hypercalcemia, and the flattened T Wave PLUS a large U wave is what you see in severe hypokalemia. This patient’s serum calcium was 15.9 and the serum potassium level was 2.0.
So, severe hypercalcemia: Short QT interval (the ST segment is actually associated with calcium influx; high serum calcium, brisk calcium influx, and short QT).
And, severe hypokalemia: Flattened T wave and prominent U wave.
This is an unusual case of dual marked electrolyte disorders! Amal Mattu says, “The ECG is your best test!"