Welcome to PICU Doc On Call, A Podcast Dedicated to Current and Aspiring Intensivists.
I'm Pradip Kamat and I'm Rahul Damania and we are coming to you from Children's Healthcare of Atlanta - Emory University School of Medicine in Atlanta, GA.Today we are going to present a case of a 3 year old presenting with bilateral hyper-flexed wrists.
Here is Rahul with our case:
A 3 yo previously healthy M presents to the emergency department after his mother noted his wrists becoming completely stiff and flexed. Despite several attempts to stretch out his wrist, his mother was unable to place them back into position. She brought him to the ED for further evaluation. Importantly, mother denies any trauma or injury. Mom notes that this happened once before one month ago. The episode lasted 10 min and self-resolved. She did not seek medical attention at that time. Patient has no history of bleeding, bruising or chronic medical conditions. His immunizations are UTD. Family hx was relatively unremarkable however the mother states that she gets admitted to the hospital for Kidney Stones 4-5 times per year. She usually follows with a urologist. Though she is on diuretic therapy for recurrent renal stones, she denies that her son has any access to these medications & also denies any ingestion. She does state that patient is a picky eater and does not drink milk but will eat cheese often with 4-5 cups of juice. Mother denies any recent upper respiratory tract symptoms, vomiting, constipation, urinary abnormalities or changes in gait.
Upon presentation to the ED, his vital signs were stable. His physical exam is normal except for Bilateral hands in flexion with digits on flexion as well. After some resistance the examiner was able to extend hands. There were no abrasions or signs of cutaneous injury in his bilateral hands. Full range of motion of elbow and shoulder as well as full range of motion of ankle and knee as well as hip. Prior to drawing blood for a diagnostic work-up the patient undergoes an EKG which shows some artifact but is notable for a prolonged QTc interval of 560.
To summarize key elements from this case so far, we have a toddler with
Pradip, I would love to hear more about the emergency room diagnostic work-up in this patient...
OK to summarize, we have:
Before we go into diagnostic management, I want to particularly highlight some physiologic aspects of Ca homeostasis:
Only 1% of totally body Ca is in the extracellular volume. 99% of the body's calcium is in the bone. the ECF ca exists as protein bound (mostly albumin) (~40%), 10% as chelated and 50% as ionized. Ionized Ca is the active form of Ca.
Serum Ca is tightly regulated by PTH, vitamin D, and calcitonin by their action on the gut, kidneys and bone.
Actions of PTH: In the kidney PTH inhibits phosphate reabsorption (remembered as Phosphate Trashing Hormone) and promotes phosphaturia. This loss of phosphate shifts flow of Ca from bone to the ECF.
PTH also facilitates distal tubular reabsorption of filtered Ca. PTH also production of 1,25-dihydroxy Vitamin D to facilitate intestinal absorption of calcium and phosphate. Thus PTH helps increase serum ca and decrease serum phosphate.
Calcitonin: secreted in response to increased serum ca, helps divert Ca to the bones (remembered by "tones the bones"). It promotes calciuria and phosphaturia.
An increase in serum pH of 0.1 unit can cause ionized Ca++ to fall by 0.16mg/dl. The total ca will drop 0.8mg/dL fro every 1gm/dL decreases in serum albumin. The change in total Ca and ionized ca are independent of each other.
Alright to summarize today's take home points — remember that when you have hypocalcemia you care going to be twitchy. Remember the mnenonic CATS go NUMB which reviews the symptoms of hypocalcemia — namely, convulsions, arrhythmias, tetany, and numbness. You also want to correlate 5 major values with in disorders of calcium regulation — namely iCa, Total Ca, Phosphorus, PTH, and Vitmin D levels. Finally, have a multi-discplinary model to your approach to hypoca with help from not only the PICU team but also pediatric endocrinology and nutrition!
This concludes our episode on hypocalcemia. We hope you found value in our short, case-based podcast. We welcome you to share your feedback, subscribe & place a review on our podcast! Please visit our website picudoconcall.org which showcases our episodes as well as our Doc on Call management cards. PICU Doc on Call is co-hosted by myself Dr. Pradip Kamat and Dr. Rahul Damania. Stay tuned for our next episode! Thank you!