Thyroid Disorders

Conditions 

• Hyperthyroidism
  Graves’ Disease: The most common form of hyperthyroidism (accounting for approximately 85% of hyperthyroidism) is Graves' disease. Graves' disease is an autoimmune condition in which the thyroid TSH receptors are continually stimulated by antibodies. This causes the thyroid gland to overproduce thyroid hormone. TSH production is regulated by a negative feedback loop, so if the thyroid is overactive, the pituitary gland will produce less TSH. Patients with normal t3 and t4, and suppressed TSH are usually considered to have a subclinical hyperthyroidism. However, current research indicates patients with Graves’ disease also have auto antibodies to thyrotropin receptor sites, thus resulting in TSH suppression regardless of the levels of endogenous or exogenous thyroid hormones.
  
• Hashimoto’s Disease: Another form of autoimmune thyroiditis, Hashimoto’s disease can also become hyperthyroid, although typically it causes hypothyroidism only. When Hashimoto’s is associated with hyperthyroidism, it usually waxes and wanes as opposed to Graves’ disease, which usually progresses.
  
• Toxic Multinodular Goiter: This is a third cause of thyrotoxicosis and is treated similarly to Graves’ disease.
  
  Hypothyroidism
  
• Hashimoto's Thyroiditis: Autoimmunity is one of the main factors contributing to low thyroid function. Chronic lymphocytic thyroiditis (Hashimoto’s) is characterized by an autoimmune goiter typically followed by hypothyroidism. It affects women more than men (8:1) and begins usually between 30 and 50 years of age. Treatment usually includes thyroid hormone replacement, which suppresses the thyroid gland function and in turn the autoimmune process, but is rarely curative. The use of desiccated thyroid is controversial, as some patients are unable to tolerate it due to the antigenicity of the thyroid substance, while in others it is thought that the antigenic properties stimulate blocking antibodies and thereby reduce the autoimmune process.
  
• Wilsons Temperature Syndrome: This is low metabolic syndrome with the hallmark signs of low body temperature. Although patients are usually biochemically euthyroid, they have all low thyroid symptoms, which resolve with the use of T3 thyroid hormone preparation doses in a cyclic fashion.
  
  

  Associated Syndromes and Etiologies 

• Chronic Fatigue Syndrome
• Fibromyalgia
  
  

  Signs and Symptoms

  Hyperthyroidism
• Heart palpitations
• Insomnia
• Weight loss
• Fatigue
• Chest pain
• Breathing difficulties
• Anxiety
• Fever
• Tachycardia
• Insomnia
• Increased bowel motility
• Excess sweating
• Autoimmune manifestations: exophthalmos, periorbital edema, swollen conjunctivi, diplopia, onycholysis, and pretibial dermopathy
  
  

  Hypothyroidism

  Symptoms
• Fatigue
• Depression
• Poor concentration
• Intolerance to cold
• Weight gain
• Constipation
• Muscle cramps
• Paresthesias
• Joint pain
• Vertigo
  
  Signs
• Fluid retention
• Menstrual irregularities
• Dry skin, hair loss
• Lateral eyebrow thinning
• Muscle weakness
• Hoarse voice
• Hypertension
• Slow deep tendon reflex (especially slow Achilles relaxation phase)
• Carotene deposits around mouth and on palm
• Low basal body temperature
• Infertility 
•  Increased PRL
• Normocytic anemia
• Hyponatremia
• Hyperlipidemia (especially, increased LDL and total cholesterol)
  
  

  Medical History
  

• Family and personal history of thyroid disorders
• Exposure to excess halogens (fluoride, chlorine) and lack or excess iodine intake
• Exposure to ionizing radiation to the head or neck can affect the thyroid and pituitary
• Excess ingestion of goitrogens
• History of stress
• Heavy metal exposures
• Pregnancies
• Pharmaceutical use should also be investigated
  
  

  Physical Examination 

• Visual inspection of the anterior neck region for signs of masses

• Manual palpation of the thyroid for size, tenderness, masses, nodules, consistency

• Patients can be instructed to turn their heads or swallow. The thyroid gland moves down when swallowing

• Auscultate the thyroid for bruits (blood flow is increased in hyperthyroidism).

  
  

  Laboratory Tests

• TSH, Total T4, Free T4, and Free T3 are the most common laboratory tests to address thyroid function.
• Autoantibodies, such as anti-thyroglobulin (anti-TBG), anti-thyroid peroxidase (anti-TPO), are measured if autoimmune disease is suspected.
• Anti TSH receptor antibodies (TSH-R Ab) are present in Graves’ disease.
• A radioactive iodine uptake (RAIU) scan is used to assess thyroid gland metabolism.