Hyperthyroidism

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Clinical causes
Clinical manifestations
Diagnosis
Treatment
Preoperative management
Intraoperative management
Postoperative mangement

Clinical causes:

-Graves Disease
-exogenous administration
-thyroiditis
-toxic multinodular goiter
-adenoma of thyroid
-tumor of pituitary

Clinical manifestations:

-weight loss
-muscle weakness
-nervousness
-heat intolerance
-diarhea
-reflex (hyper-reflexia)

Diagnosis:

Throid Function Test:
-increased T3
-increased T4 (bound and unbound)
-decreased TSH

Treatment:

Medical treatment
-propylthiouracil
-methimazole
-sodium iodide
-potassium
-propranolol
-radioactive iodine (not for pregnant females)

Surgical treatment
-subtotal thyroidectomy

Indication:
-large toxic multinodular goiter
-solitary toxic adenoma

Preoperative management

Elective surgery:
-euthryoid with medical treatment
-normal thyroid function test
-resting heart rate < 85 bpm
-continue antithyroid medications till a.m of surgery

Emergency surgery:
-attempt for CVS stability with esmolol infusion

Intraoperative management

Induction:
-induction agent of choice : thiopental
may have an exaggerated hypotensive response to induction due to:
-hypovolemia
-vasodilated

Intubation:
intubate patient when deeply anesthetized to avoid:
-tachycardia
-hypertension
-ventricular dysrhythmia

Systemic precautions:
-ophthalmology: exopthalmus: therefore avoid corneal abrasions
-airway: avoid kinking, compression or obstruction of ETT: may require armored ETT
-thyroid mass: head elevation approx 15 - 20 degree to promote venous drainage and reduce amount of bleeding
-cardiac: avoid tachycardia, hypertension, ventricular dysrhythmias
-hepatic: increased drug metabolism therefore more prone to hepatic injury ex. halothane hepatitis
-renal: may be prone to renal toxicity ex. enflurane
-NMJ: hyperthyroidism may be associated myopathies, myasthenia gravis

Postoperative management:

Observe for potential postoperative complications:
-thyroid storm
-recurrent laryngeal nerve (RLN) palsy
-hematoma
-hypoparathyroidism
-pneumothorax

Thyroid storm:
-change in mental status (agitation, delirium, coma)
-tachycardia (treat with esmolol infusion or propranolol 0.5 mg IV increments until heart rate is less than 100bpm)
-hyperpyrexia (treat with cooling blanket)
recurrent laryngeal nerve palsy: acute
-unilateral: hoarseness
-bilateral: stridor, aphonia, flacid paralysis adduction of vocal cords

Hematoma:
-may create tracheal/airway compression and obstruction