thyroid pathway

• Graves' disease


  • Epidemiology: genetic, women
  • Etiology: autoimmune due to TSH receptor antibodies stimulating thyroid gland growth and hormone synthesis
  • Clinical presentation: ophthalmopathy - decreased eye movement, irritation, inflammation, swelling, light sensitivity, proptosis, incomplete lid closure/corneal ulceration, optic nerve compression, blindness, pretibial myxedema
  • Labs: normal/high radioiodine uptake, TSH low/undetectable, free T4 elevated, thyroid stimulating antibodies present
  • Treatment: antithyroid drugs, beta blockers, radioactive iodine ablation, thyroidectomy
• Hashimoto's disease


  • Epidemiology: women, pediatrics
  • Etiology: autoimmune destruction of thyroid tissue
  • Clinical presentation: goiter/thyroid atrophy
  • Labs: low free T4, low TSH
• Workup for hypothyroidism and hyperthyroidism

  • EKG
  • Laboratory tests
  • Diagnostic imaging
• Hypothyroidism


  • Epidemiology: women, older, iodine deficiency
  • Signs/Symptoms: fatigue and weakness, weight gain, cold intolerance, cognitive dysfunction, constipation, growth failure, dry skin, hoarseness of voice, myalgias and paresthesias, depression, menorrhagia, pubertal delay, goiter, coarse hair, slow movement and slow speech, delayed relaxation of deep tendon reflexes, bradycardia, decreased cardiac output, myxedema, high cholesterol, macrocytic anemia, elevated CK
• Hyperthyroidism


  • Signs/Symptoms: sweating, heat intolerance, weight loss, increased appetite, oligomenorrhea, anxiety, increased frequency of bowel movements, tachycardia/arrhythmia (atrial fibrillation, supraventricular tachycardia), widened pulse pressure, hypertension, increased cardiac output, osteoporosis, dyspnea, tachypnea, resting tremor, hyperreflexia, wide staring gaze with lid lag
• Hyperthyroidism lab findings


  • Normal/high radioiodine uptake, TSH low/undetectable, free T4 elevated, thyroid stimulating antibodies present
• Hypothyroidism lab findings


  • Elevated TSH, low free T4
• Hyperthyroidism treatment


  Antithyroid drugs, beta blockers, radioactive iodine ablation, thyroidectomy
• Hypothyroidism treatment


  Thyroxine replacement (levothyroxine), may not need treatment if TSH <10
• Thyroid storm


  • Epidemiology: complication of hyperthyroidism (super high levels of thyroid hormones)
  • Etiology: infection, trauma, illness, surgery
  • Signs/Symptoms: fever, diaphoresis, tachycardia, atrial fibrillation, heart failure, tremors, nausea/vomiting
  • Treatment: ICU admission, treat underlying problem, cooling, propylthiouracil/methimazole, propranolol, corticosteroids
• Thyroid gland produces hormones that regulate metabolism, growth, and development, while the parathyroid gland regulates calcium and phosphate levels in the blood
• Hyperparathyroidism

  Primary means gland problem, secondary can be from renal failure, decreased calcium intake, calcium malabsorption, renal calcium loss
• Primary hyperparathyroidism


  Parathyroid adenoma
• Hypoparathyroidism


  Destruction of parathyroid glands, abnormal gland development
• Hyperparathyroidism


  • Asymptomatic, kidney stones, "bones, stones, moans and psychic groans"
  • Bones: osteopenia, osteoporosis, bone pain, fractures
  • Stones: kidney stones, polyuria, polydipsia, nephrogenic diabetes insipidus, renal insufficiency
  • Abdominal moans: anorexia, nausea/vomiting, constipation, pancreatitis
  • Psychic groans: poor concentration, confusion, fatigue, altered mental status, coma, depression, psychosis
  • Other: bradycardia, hypertension, arrhythmia, vascular and valvular calcification, muscle weakness
• Laboratory findings in hyperparathyroidism

  Elevation of plasma calcium, PTH, hypophosphatemia, serum creatinine/eGFR, 24hr urinary calcium, 25(OH)D, DEXA scan, imaging of kidneys, spinal imaging
• Treatment of hyperparathyroidism


  Monitor calcium/creatinine/bone density/increase activity, avoid things like thiazide diuretics, lithium carbonate, volume depletion, prolonged bed rest/inactivity, high calcium diet (100mg/day), cinacalcet/bisphosphonate if can't do surgery
• Secondary hyperparathyroidism


  Hyperphosphatemia, vitamin D deficiency, hypocalcemia
• Hypoparathyroidism


  • Acute symptoms: prolonged QT, tetany (Trousseau's sign/Chvostek's sign)
  • Basal ganglia manifestations (parkinsonism), cataracts, dry/coarse skin, brittle hair/nails, transverse grooves in nails, increased bone mineral density
• Laboratory findings in hypoparathyroidism


  Persistent hypocalcemia, low or normal parathyroid hormone, elevated phosphorus, no hypomagnesemia
• Treatment of hypoparathyroidism


  IV calcium + calcitriol, oral calcium/vitamin D, teriparatide