April 9th - MHH - Thyrotoxicosis

Today at Morning Report a Patient with Thyrotoxicosis was presented

So what does this mean?
Hyperthyroidism is the general term for increased thyroid function
Thyrotoxicosis is sometimes used as a synoynm, but generally refers to increased circulating levels of T3/T4. 
Thyroid Storm is a serious complication, usually in untreated patients with infection/surgery/trauma and others







Causes:
Graves Disease
Toxic Multinodular Goiter
Thyroiditis
Thyroid Adenoma
Factitious
Also - Struma Ovarii, which is rare

Some physical signs/symptoms with thyrotoxicosis:
General & Vitals: Tachycardia, Fevers, Heat intolerance, Weight Loss, Anxiety, Insomnia, AMS
HEENT: Graves opthalmopathy ("foreign body sensation," periorbital edema, conjunctival injection, increased lacrimation.  Diploplia and Proptosis can be present as well
Neck: Goiter (Look for bruit in patient with Graves)
Cardiovascular: Tachycardia, Systolic Flow Murmur on Exam.  Patient may have irregular rhythm due to atrial fibrillation.  Remember that thyrotoxicosis can exacerbate/cause CHF or exacerbate CAD
Pulmonary:  Dyspnea
GI: Increased stool frequency
GU: Oligomennorhea
Neuro: Tremors and Hyperreflexia (rapid relaxation phase)
Skin: Moist and warm, palmar erythema may be present, pretibial myxedema
Nails: onycholysis

Caveat for the Elderly - There is a term called apathetic hyperthyroidism.  Instead of presenting "classically," the elderly can have a complaint of just weakness, weight loss and/or atrial fibrillation

Workup/Diagnosis
Send a Serum TSH.  A level <0.1 is consistent, and a Free T4 should then be sent.  If the T4 is normal then T3 should be measured, as there are instances of this alone.  If the TSH is low in the setting of a Normal T4 or T3 then the patient may have either "subclinical hyperthyroisism" (which would technically be a misnomer if the patient presented with the above signs/symptoms) or Sick Euthyroid Syndrome due to underlying disease.  Note in Sick euthyroid syndrome the T4 is common'y either low or normal. You can confirm this state with an elevated reverse T3.

One can order a RAIU to differentiate the causes of hyperthyroidism/toxicosis.
High RAIU States include: Graves Disease, Toxic Multinodular Goiter and Adenoma
Low RAIU States include: Thyroiditis and Factitious Causes

Usually this testing is not always needed as physical findings of Graves disease are obvious in most causes.  The presence of eye findings and/or pretibial myxedema is almost always Graves.  If the patient has either a diffusely nontender goiter OR a non-palpable thyroid usually have Graves as well

Also - workup the causes of what may have exacerbated the thyroid state - i.e. infection

A Note About Thyroid Storm
This can be caused by infection, surgery, trauma, DKA, Pregnancy
Patients will be very tachycardic (or have atrial arrythmias), fevers, N/V, tremors and AMS and can progress to a comatose state.  See below for scoring system:

Treatment for Acutely Ill/Serious Thyrotoxicosis/Storm
PTU 300mg po q6 hours
SSKI 1-2 Drops po q12 hours
Propanolol 40mg po q6hours and titrate if needed



See this link for an article from Endocrinology clinics regarding thyroid storm, with the scoring system:
http://www.scribd.com/doc/6837836/Thyrotoxicosis-and-Thyroid-Storm