ZSFG Endocrine report: hypoglycemia

Thank you to Lisa Murphy for acting as our endocrine consultant today AND presenting a fascinating case of recurrent hypoglycemia found to be panhypopituitarism with adrenal insufficiency
When developing a framework for hypoglycemia, think about the physiologic response to low glucose. Disorders at every point in this complex chain can lead to hypoglycemia. Most commonly due to problems with impaired gluconeogenesis, impairment of the neurohormonal response to hypoglycemia, increased glucose utilization, too much insulin and/or decreased glycogen stores
Because hypoglycemia usually results from derangement at multiple checkpoints, I find it easier to organize my ddx by organ system as opposed to by MOA. But you can find your own hypoglycemia bliss
Ddx of hypoglycemia by organ system
  • Infections
    • classically bacterial or fungal
    • usually in association with severe sepsis
  • endocrine causes
    • diabetes
      • Many mechanisms, including insulin overdose, impaired clearance of insulin/hypoglycemic meds due to new renal failure
      • Lisa Pearl: people with pancreatitis-induced diabetes are particularly prone because they can’t make glucagon
    • hypothyroidism
    • adrenal insufficiency
    • growth hormone deficiency
    • insulinoma
      • lisa pearl the catecholamine surge is rare in patients with insulinoma. Their primary presenting symptom is neuroglycopenia.
  • renal causes
    • Three mechanisms
      • decreased insulin clearance
      • BUN suppresses gluconeogenesis
      • 20% of gluconeogenesis happens in the kidneys and declines linearly with renal function
  • hepatic causes
    • anything that impairs hepatic function including cirrhosis
  • other
    • med effect
      • surreptitious or accidental use of insulin or sulfonylurea
        • no case of ZSFG hypoglycemia should go by without talking about street drugs laced with sulfonylureas. These days, most commonly street benzodiazepines.
      • pentamadine
    • low glycogen reserves
      • this is very hard to do on your own! But more common in conjunction with other causes, like liver disease
What should your initial workup be for hypoglycemia?
  • cbc, chem 10, LFTs, coags
  • TSH, T4
  • cortisol
    • a random cortisol will be helpful if low because it will rule out the  but non-diagnostic if normal.
  • When to send an insulin and c peptide?
    • only helpful when hypoglycemic! Can be sent in the ED if hypoglycemia has not yet been detected.
    • otherwise, 72 hour fast is necessary to induce enough hypoglycemia to send these tests correctly
Two bonus pearls
Concurrent hypothyroidism and adrenal insufficiency?
  • ALWAYS give steroids first! Hypothyroid patients hypo metabolize their cortisol. Giving thyroid hormone will stimulate cortisol metabolism, which can trigger a life threatening adrenal crisis.
Prolactinoma pearl
  • A prolactin level >100 in a non-pregnant human, even in a patient getting psych meds, should make you concerned that they may have a pituitary tumor.

Evernote: https://www.evernote.com/l/AMCsjRpDMr5Ly4OcOP07xJuXpPCz_q74ITI

Cryer PE, Axelrod L, Grossman AB, Heller SR, Montori VM, Seaquist ER, Service FJ, Endocrine Society Evaluation and management of adult hypoglycemic disorders: an Endocrine Society Clinical Practice Guideline.

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