Thyroid Physiology

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Electrolyte Imbalance

• Hyponatremia ↓ [Na] (<135) </aside>

Classifications

Primary Hypothyroidism

• Congenital: agenesis/dysgenesis, through Ontario Newborn Screening
• Hashimoto Thyroiditis (most common cause of thyrodism in Canada, esp. in middle aged women)
• Subacute Thyroiditis

Secondary Hypothyroidism - Rare

• Anterior Pituitary Diseases
• Iatrogeni causes

Tertiary Hypothyroidism

• Hypothalamic Disease

Peripheral Resistance

• Defective T3 receptor

Additional Complications

• Myxedema Coma → Coma (GCS ≤ 8)
• Hyperprolactinemia ↑ and Galactorrhea → High level of TSH stimulate prolactin production
• Haematological instability (in severe cases)
  • ↓Bradycardia
  • Hypotension ↓(<90/60) with increased dBP (rare, unless severe)

Investigation

Decision Process (linear):

Clinical Pearl

In Older Adult > 65 (RF)

• Incidence 1-17% (common)
• Symptoms can be confused with symptoms of aging
  • Dementia, Confusion
• More likely to be subclinical
• More likely in Female
• Medication: “Start Slow, Go Slow”