Thyroid Dysfunction

Kristopher Maday, MS, PA-CProgram Director/Associate Professor

University of Tennessee Health Science CenterPhysician Assistant Program

Target Tissue Effect Mechanism

HeartChronotropic Increase number and affinity of β-

adrenergic receptors

Inotropic Enhance responses to circulating catacholamines

Adipose Tissue Catabolic Stimulate lipolysis

Muscle Catabolic Increase protein breakdown

BoneDevelopmentalMetabolic

Promote normal skeletal development, accelerates bone turnover

Nervous System

Developmental Promote normal brain development

Gut Metabolic Increase rate of carbohydrate absorption

Lipoprotein Metabolic Stimulates LDL receptor formation

Metabolism CalorigenicIncreases metabolic rate by stimulating O2 consumption of metabolically active tissues

Thyroiditis• Infectious– Staphylococcus, streptococcus– Signs and Symptoms• Rapid onset• Neck pain, fever, chills, dysphagia

– Ultrasound to evaluate for abscess– Treatment• IV antibiotics PO after 2-3d defervescence

Thyroiditis• Subacute– 2 main causes• Post-viral infection (2-8 weeks)• Autoimmune

– Signs and Symptoms• Enlarged, tender thyroid

– Laboratory• Elevated ESR or CRP• (+) thyroglobulin or thyroperoxidase• Variable thyroid panel

Thyroiditis• Treatment

T3, T4

Hyperthyroidism - Causes• Grave’s Disease–Most common cause of hyperthyroidism

is US– Autoimmune disease• High association with other autoimmune

diseases– Female:Male 8:1– Onset in 20s-40s

TSH-Receptor

Anti-thyroperoxidase

Hyperthyroidism - Causes• Toxic adenoma– Single – Plummer’s Disease–Multiple– Non-tender enlargement of thyroid

Hyperthyroidism - Causes

Hyperthyroidism - Causes

Signs and Symptoms of Hyperthyroidism

Signs and Symptoms of Hyperthyroidism

Signs and Symptoms of Hyperthyroidism

TFTs in Hyperthyroidism

TSH

TSH

T3T4

T3T4

Hyperthyroid - Treatment

Hyperthyroid - TreatmentThianamides

Methimazole Propylthiouracil

Onset Faster Slower

Compliance Better Worse

Cost Cheaper More expensive

Initial Dosing 5-20mg TID 100-300mg TID

Maintenance Dosing 5-15mg daily 30-50mg TID

Pregnancy No Yes

Thyroid Storm

T3, T4

Hyperthyroidism - Causes• Hashimoto’s Thyroiditis–Most common cause of hypothyroid in

iodine sufficient countries– Thyroperoxidase and thyroglobulin

antibodies

Hypothyroidism - Causes

Signs and Symptoms of Hypothyroidism

Signs and Symptoms of Hypothyroidism

Signs and Symptoms of Hypothyroidism

TFTs in Hypothyroidism

TSH

TSH

T3T4

T3T4

Hypothyroidism - Treatment

Initial Dosing1.6 mcg/kg/day

Levothyroxine

Recheck TSH in 6 weeksIncrease by 12.5-25 mcg/day

Temp – 93o F (33.8o C)

HR – 50 bpm

RR – 10 bpm

Sodium – 130 mg/dLTSH – 258 mu/L

T4 – 0.01 ng/dL

Myxedema Coma - Treatment

Thyroid HormonesLevothyroxine Triiodothyronine

Load – 200-400 mcg Load - 5-20 mcgMaintenance – 1.6 mcg/kg/day

Maintenance – 2.5-10 mcg TID

Fluid resuscitationStress dose steroids

Rewarming

Thank You!

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