USMLE Internal Medicine Review 11 03 Myxedema Coma

USMLE Internal Medicine Review 11 03 Myxedema Coma

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Let’s start our USMLE Review with Hypothyroidism and Hyperthyroidism from the Gold Standard USMLE Foundations of Medicine Audio Review program.

 

Play USMLE Audio MP3 11 03 Myxedema Coma Below

 

Begin 11 03 Myxedema Coma Transcription

Is myxedema coma to be treated as a regular hospital admission?

  • Myxedema coma is an acute medical emergency and should be treated in intensive care.

Blood gases must be monitored regularly and the patient usually requires which two other procedures?

  • The myxedema coma patient usually requires intubation and mechanical ventilation. In treating myxedema coma associated illnesses like infections and heart failure need to be indentified and treated appropriately.

What is another caution to observe regarding IV fluids and water intake?

  • In treating myxedema coma, intravenous fluid should be administered cautiously and excessive free water intake avoided.

Is Levothyroxine in the treatment of myxedema coma administered orally or intravenously and why?

  • Because patients with myxedema coma absorb all drugs poorly, it’s crucial to give Levothyroxine intravenously.

Why is it advisable to start the myxedema patient with an additional loading dose of Levothyroxine?

  • Myxedema coma patients have marked depletion of serum Thyroxine and so need the initial Levothyroxine load. The loading dose then followed by smaller daily Levothyroxine doses.

What are typical loading and daily doses for the adult myxedema coma patient in micrograms?

  • Remember administration is always IV. A typical adult loading dose is 300 to 400 µg Levothyroxine IV followed by 50 µg IV daily.

Student doctor please pause the tape and summarize initial treatment measures for myxedema coma. Please include initial procedures, associated illnesses, fluid management, and Levothyroxine administration and dosing.

  • Myxedema coma is an acute medical emergency and should be treated in intensive care if at all possible. Blood gases should be monitored regularly and intubation and mechanical ventilation are usually needed. Associated illnesses like infections or heart failure need to be identified and treated appropriately. Intravenous fluids should be administered cautiously and excessive free water intake avoided. Because myxedema coma patients absorb all drugs poorly it is crucial to give any or all Levothyroxine doses intravenously. Myxedema coma patients have marked depletion of serum Thyroxine so an initial loading dose of Levothyroxine 300 to 400 µg IV is given to restore balance before reducing to an average daily dose of 50 µg IV.

What are probably the two most telling clinical signs of improvement in the myxedema coma patient?

  • Clinical guides to improvement of the myxedema coma patient are a rise in body temperature and a return to normal cerebral and respiratory function.

In recovering from myxedema coma, under what circumstances is adrenal support recommended? Please pause the tape.

  • If the patient had normal adrenal function before the myxedema coma developed, adrenal support is probably not necessary. If adrenal history is unknown, the possibility of adrenal insufficiency does exist due to autoimmune adrenal disease or pituitary insufficiency.

In this case, plasma level of which steroid hormone should be checked diagnostically?

  • If adrenal history of the hypothyroid myxedema coma patient is unknown it is a good idea to check plasma Cortisol levels for clues to the possible presence of adrenal problems.

And if time allows which additional test is a useful diagnostic tool for adrenal function?

  • Cosyntropin stimulation test can be performed. It takes about 30 minutes.

If full adrenal support is needed, which hormonal steroid agent secreted by the adrenal cortex should be administered?

  • Hydrocortisone Hemisuccinate.

What should be the route of administration of Hydrocortisone Hemisuccinate, and at what dose?

  • Hydrocortisone Hemisuccinate 100 mg IV followed by 50mg IVQ 6h tapering over 7 days.

With what result on plasma Cortisol screening and Cosyntropin stimulation test can adrenal support be withdrawn earlier than 7 days?

  • Go ahead and pause the tape. With a plasma Cortisol of 20 µg/dL or greater and/or a normal Cosyntropin stimulation test result, adrenal support for the myxedema patient can be withdrawn.

Student doctor please pause the tape and summarize clinical guide to improvement in the myxedema coma patient and the need for adrenal support. Please also include plasma Cortisol and Cosyntropin stimulation tests.

  • Clinical guides as to improvements of a myxedema coma patient include a rise in body temperature and return to normal cerebral and respiratory function. If the patient had normal adrenal function before myxedema coma developed, then adrenal support is probably unnecessary. If adrenal history is not documented, it’s a good idea to test for adrenal insufficiency from either autoimmune adrenal disease or pituitary insufficiency. Test for this include plasma Cortisol and Cosyntropin stimulation test. If indicated full adrenal support should be administered with Hydrocortisone Hemisuccinate 100 mg IV initially followed by 50mg IVQ 6h tapering over 7 days. Adrenal support can be withdrawn sooner if plasma Cortisol tests greater than 20 µg/dL or if Cosyntropin stimulation test is normal.

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