Thyroid
Best Panel for Critically Ill
TSH, Total T4, T3 Uptake or
TSH, Total T4, Free T4
Confirmatory tests (normal T4 and suppressed TSH or Amiodarone patients): get Total/Free T3
Hyperthyroid Storm
fever, tachycardia, tremor, systolic flow murmur, A-Fib
can also be from exogenous thyroid replacement hormone
ask about stressors: thyroid manipulation, med changes, trauma, infections, exertion, anesthesia, iodinated contrast
Diagnosis
>45 is almost surely storm, 25-44 is suggestive, <25 is unlikely
(Endocrinol Metab Clin North Am. 1993 Jun;22(2):263-77.) do not give ASA
Rx
Step I
Start a beta blocker
PO propanolol if stable
Esmolol drip if not
Step II
Antithyroid meds
PTU 1000 mg PO load then 250 mg Q4-6 (1200 mg per day)
OR
MMI 20 mg PO or PR Q4 hours
AND
Dexamethasone 2 mg IV Q6
Step III
then iodide (at least 1 hr after PTU/MMI)
Propylthiouracil PO/NG/PR 1 g x1 Blocks Gland formation and conversion 250 mg Q4-6 MMI PO/NG/PR 20 mg Q4 hrs Iopanoic Acid PO 1 G Q8 SSKIPO/NG 8 Drops Q6 Lugol’s Solution PO/NG 8 drops Q6 Blocks hormone release Potassium Iodide PO/NG 1 Tab QD Blocks hormone release Lithium Carbonate PO/NG 300 mg Q6 Propranolol PO/NG 40-80 mg Q 4-6 Blocks peripheral effects IV 1 mg Q2 PRN Max 10 mg Atenolol PO/NG 25-100 mg QD Blocks peripheral effects IV 5 mg Over 5 min Esmolol IV .5/kg bolus .05-.1 mg/kg/min Blocks peripheral effects Reserpine IM 1-2.5 mg Q6 Hydrocortisone IV 100 mg Q8 Blocks Peripheral Conversion Dexamethasone PO/IV 2 mg Q6 Blocks Peripheral Conversion Prednisone PO/NG 1 mg/kg QD Blocks Peripheral Conversion
may need hemodialysis
high dose propranolol may not be the most clever move as the patient may have a longstanding cardiomyopathy from the thyroid and when pt’s hormones go down, they can crash from the long beta blockage. Esmolol is probably the most 2nd most clever way to go.
From EM:RAPDx
1. Hyperthyroid History
2. Fever, pt’s can’t vasodilate
3. Cognitive Changes
4. Something that predisposes to sympathetic response
Young people handle this worse b/c they have more receptors
Always screen for infection
CBC, T4, TSH, Pan Cx
May have a low Cr because they can’t convert creatine to Cr
Low PLt
Hb in the range of 12
PTU 150 Q8
1 hour later, 10 drops of KI
Decadron 4 mg IV Q6
Inderal IV only has 1/2 life of 5 min
give 1 mg test dose
then give in 1-2 mg increments
then start on 3-5 mg/hr
shoot for HR of 90-100
beta 3 receptors effect metabolic rate
Review
Hypothyroidism
Hypothermia, weight gain, constipation
5% of carpal tunnel is hypothyroid
500 mg T4 orally or IV, give stress does of steroids as well.
Myxedema Coma
Rx:
Supportive Care
Levothyroxine 300 to 500 ug IVPB then 50 to 100 ug IV OD
T3 25 ug IV/PO Q8
Consider Hydrocortisone 100 mg IV Q8 before thyroid replacement (Draw Cortisol first if possible)
Thyroid hormone The optimal mode of thyroid hormone therapy in patients with myxedema coma is controversial, largely because the condition is so rare that there are no clinical trials comparing the efficacy of different treatment regimens. While increasing serum thyroid hormone concentrations rapidly carries some risk of precipitating myocardial infarction or atrial arrhythmias, this risk must be accepted because of the high mortality of untreated myxedema coma. There is disagreement about the preferred thyroid hormone regimen, but both very high and very low doses seem less effective than intermediate doses [14]. Some experts favor administration of triiodothyronine (T3), because its biologic activity is greater and its onset of action is more rapid than T4. An additional consideration is that the conversion of T4 to T3 is impaired due to both hypothyroidism and any concurrent nonthyroidal illness. Proper dosing is important. High serum T3 concentrations during treatment have been correlated with mortality [13]. Others prefer T4, which should be given intravenously because gastrointestinal absorption may be impaired [15]. The first dose should be large: 200 to 400 mcg (0.2 to 0.4 mg), with the exact dose being dependent upon the patient’s weight and age and the likelihood of complications such as myocardial infarction or an arrhythmia. In one randomized trial of 11 patients, those who received a 500 mcg loading dose followed by 100 mcg daily had a lower mortality than those treated with 100 mcg daily without a loading dose; however, the difference did not reach statistical significance [16]. Thus, the dose should be reduced in lighter and older patients and those at risk for cardiac complications. Daily doses of 50 to 100 mcg are given thereafter, initially intravenously and, when feasible, orally. (See “Treatment of hypothyroidism” for a discussion of chronic therapy). We prefer to give both hormones [17]. T4 is given in a loading dose of 200 to 300 mcg followed by 50 mcg daily. T3 is given simultaneously in a dose of 5 to 20 mcg, followed by 2.5 to 10 mcg every eight hours depending upon the patient’s age and coexistent cardiac risk factors. T3 is continued until there is clinical improvement and the patient is stable. Supportive measures Supportive measures are extremely important in the treatment of patients with myxedema coma and, in the first day or so, may make the difference between survival and death. These measures include treatment in an intensive care unit, mechanical ventilation if necessary, judicious administration of intravenous fluids including electrolytes and glucose, correction of hypothermia, and treatment of any underlying infection. Dilute fluids should be avoided in hyponatremic patients to prevent a further reduction in the plasma sodium concentration. Hypotension, if present and not caused by volume depletion, will be corrected by thyroid hormone therapy over a period of hours to days. Severe hypotension that does not respond to fluids should be treated with a vasopressor drug until the T4 has had time to act. Passive rewarming with a heating blanket is preferred for correction of hypothermia. Active rewarming carries a risk of vasodilatation and worsening hypotension. As with any critically ill, comatose patient, empiric administration of antibiotics should be considered until appropriate cultures are proven negative.
Myxedema almost always has a cpk>500
winter months
sed/hyp and psych drugs
amiodarone
diuretics
labs to send tsh, free t4, total t4delayed dtr, low wbc with lymphocytic predominencethey will all have altered mental status of some ilk if they are myxedematous, better to call it decompensated hypothyroidismgive 500 mcg of T4mostly anemicfluid downgive hydrocortisone firsthyponatremiagive betablockers for thyroid paralysis
Euthyroid Sick Syndrome
thyroid function abnormality from illness or stress without underlying thyroid disease.
Probably from cytokine interactions
Initially low levels of T4 and T3 with normal TSH, eventually TSH will decline as well
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