AM Report 1/3/17: Thyrotoxicosis

EKG findings with Atrial Fibrillation:

  • Irregularly irregular rhythm (no RR repetitive pattern)
  • No distinct P waves
  • f waves (small, irregular waves indicating rapid atrial activity ~150-300 bpm)

Common etiologies of Atrial Fibrillation:

  • Ischemic heart disease
  • Hypertension
  • Thyrotoxicosis
  • Drugs (sympathomimetics)
  • PE
  • Valvular heart disease (esp. mitral stenosis / regurgitation)
  • Electrolyte abnormalities (hypokalemia, hypomagnesaemia)
  • Cardiomyopathies (dilated, hypertrophic)

Different Classifications of Atrial Fibrillation:

  • Paroxysmal: AF that terminates spontaneously or with intervention within 7 days of onset
  • Persistent: sustained AF that lasts > 7 days
  • Long-standing persistent: sustained AF that lasts > 12 months
  • Permanent: persistent AF with either treatment failure or a decision to not pursue treatment

CHADS2 versus CHA2DS2VASc:

CHADS2 = CHF (1), HTN (1), Age ≥ 75 years (1), DM (1), Stroke/TIA (2)

CHA2DS2VASc = CHF (1), HTN (1), Age ≥ 75 years (2), DM (1), Stroke/TIA (2), Vascular disease (1), Age 65-74 (1),  Female sex (1)

  • Treat with anti-coagulation is score >2
  • Treatment options include: warfarin (goal INR 2-3), dabigatran, rivaroxaban, apixaban

Rate versus Rhythm Control:

AFFIRM trial

  • In patient’s with non-valvular AF, there is no survival benefit between rate and rhythm control
  • A non-significant trend towards decreased mortaility was associated rate control

Strict versus Lenient rate control:

RACE II trail

  • Among patients with permanent atrial fibrillation, lenient rate control (HR <110 bpm) is as effective as strict rate control (HR < 80 bpm) in preventing cardiovascular events
  • Of note, the strict group met resting targets in 78% of cases (compared with 98% in lenient) and required 9 times as many visits (684 vs. 75)

Physical Exam of Thryotoxicosis:

Skin: warm/moist skin, thin/fine hair, pretibial myxedema (Grave’s disease), thyroid acropachy (digital clubbing, swelling of digits)

Eyes: stare (lid retraction), lid lag, exophthalmos, periorbital/conjunctival edema, limitation of eye movement

CV: tachycardia, atrial fibrillation, systolic hypertension, high output CHF

GI: increased appetite, hyperdefecation

Neuro: fine tremor, hyperreflexia, proximal muscle weakness

Psych: anxiety, agitation, psychosis, depression, insomnia, mania

Thyroid: diffuse thyromegaly, thyroid bruit (specific for Graves)

Graves’ Disease Toxic adenoma / TMNG Subactue Thyroiditis
Epidemiology Females between 20-50 yo TA – 40-50 yo; TMNG > 50 yo Female > Male; young > old
Pathophysiology Antibodies against TSH receptors (TSI or TRAb) stimulate autonomous production of T4/T3 Autonomous production from activating mutations in TSH receptor Leakage of hormone from gland
Clinical Course / Physical Exam Exophthalmos,

Pre-tibial myexedema, Thyroid bruit

Hyperthyroid symptoms;

Palpable nodule(s)

Often preceded by URI, painful thyroid palpation, initially hyperthyroid => hypothyroid => normalizes
Diagnosis / Tests Low TSH, High FT4/T3, TSI, TBII; RAIU with markedly increased activity TSH, FT4, RAIU, thyroid US TSH, FT4

RAI – low uptake

Thyroid US – diffuse enlargement

Treatment Thionamides (PTU, methimazole); RAIA (avoid with ocular findings), surgery Thionamides (toxic patients), surgery for compression, RAIA NSAIDs, supportive care; prednisone if poor response, BB for symptom management

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