Hypercalcemia in the Pediatric Patient in your ED.

I would confidently announce that we, generally, order less reflexive blood work in the pediatric ED.  I would like to think that this is because we have consciously and carefully considered the utility of the tests that we order; however, I know that it is just as likely that we pause to consider the labs we order more carefully simply because it is more difficult to obtain that blood to run the test on.  Nevertheless, we do obtain less habitual chemistry panels on our pediatric patients compared to their adult counters.

Certainly, though, there are times when we do need to obtain chemistry panels and may obtain values that cause us to reach back into the recesses of our medical school minds in order to develop a working differential diagnosis.  Hypercalcemia is one of those findings that causes my synapses to fire a little slower than normal (sadly, that is pretty slow).  So, let’s recap a few useful Morsels regarding Hypercalcemia in the pediatric patient in your ED.

Hypercalcemia Basics

• Less commonly encountered in pediatric patients than in adult patients (partially due to more habitual bloodwork in adults)
• More likely to be of clinical significance in pediatric patients than in adults.
• Levels governed by Parathyroid Hormone, which is produced in an inverse proportion to the circulating level of Ca.
  • PTH acts on target cells in the bone and kidney
    • Leading to increased osteoclastic activity and increase renal absorption.
  • PTH also stimulates Vit D conversion to calcitriol, which increases GI transport of Ca.
• Baseline Ca levels are age dependent and higher in younger children than adults

Symptoms of Hypercalcemia

• Symptoms can be very nonspecific
  1. Often discovered during work up for Failure to Thrive of an neonate or infant.
  2. Lethargy, Weakness, hypotonia – proximal myopathy
• Symptoms often are dependent upon Ca Level
  1. Mild elevations may be asymptomatic
  2. May lead to Polyuria, polydipsia and Dehydration – Volume Contraction
  3. Constipation and anorexia
  4. Generalized weakness
  5. Encephalopathy, Coma
  6. Seizures (rarely)
  7. Arrhythmia

Abridged Differential to Consider for Pediatric Patient with Hypercalcemia

•  Neonates and Infants (essentially weird stuff)
  
  • Phosphate Depletion (today, likely due to TPN poorly constructed – iatrogenic)
  • Inborn Error of Metabolism
    • Bartter Syndrome
    • Lactase deficiency
    • Hypophosphatasia
  • Vitamin A Toxicity
  • Hypervitaminosis D
  • Hyperparathyroidism
    • Congenital parathyroid hyperplasia
    • Maternal hypoparathyroidism
  • Subcutaneous Fat Necrosis
  • Williams Syndrome
  • Down Syndrome
• Older Children 
  • Hyperparathyroidism
    • Usually due to single adenoma
    • Often present with nephrolithiasis, pancreatitis or bone involvement
    • Can also be due to autosomal dominant disorder (MEN Type I)
  • Immobilzation(“Disuse Osteoporosis”)
    • Common cause
    • Kids have high bone turn-over… when immobilized, the osteoblastic bone formation reduces
  • Malignancy
    • Hypercalcemia does not accompany malignancy in children (<1%) as much as it does in adults.
    • Due to:
      • Direct bone invasion and destruction
      • Increased osteoclastic activity from factors produced by the tumor cells.
    • Has been seen with rhabdomyosarcoma, leukemia, lymphoma, myeloma, neuroblastoma, hepatocellular carcinoma, ovarian carcinoma, and brain cancers.
  • Hypervitaminosis D or Vitamin A toxicity

Initial Treatment

• Main goal is to increase urinary excretion of calcium.
• Hydration with normal saline
  • This will restore intravascular volume, dilute serum Ca level, and enhance renal excretion of Ca.
• Furosemide and other loop diuretics are not often required in pediatric patients (more often needed in adults).
  • If using, must monitor intravascular volume, as the diuretics can worsen this and lead to decreased glomerular filtration and worsen hypercalcemia.
• Then determination of the etiology! (recalling that hypercalcemia, particularly in the young, is usually clinically significant.
  • PTH level
  • Phosphate level
  • Vitamin D Level
  • PTH-related Protein Level

 

Hopefully this will help knock the dust off some of those synapses and help solidify a plan to help care for the child with Hypercalcemia.

 

 

McMahon G. Hypercalcemia in Children. The New England Journal of Medicine; NOW@NEJM; February 11th, 2011.

 

Lietman SA, Germain-Lee EL, Levine MA. Hypercalcemia in Children and Adolescents. Curr Opin Pediatr. 2010 August; 22(4): 508–515.