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Thyroid Disorders - Coggle Diagram
Thyroid Disorders
Hypothyroidism
Labs
Early: High TSH normal free T4
Later: High TSH, and low free T4:
Do TSH First: if high Suspect primary hypothyroidism, if Low free T4, overt hypothyroidism, and if normal free T4, subclinical hypothyroidism
Symptoms
Fatigue, decreased exercise tolerance, hair intolerance, loss of nails/skin, hair, non pitting edenma of eyelids, face legs
Signs
Bradycardia, Diastolic hypertension, proximal muslce weakness, goitre or small/rubbery
Causes
Hashimoto's Thyroiditis
Caused by anti-TPO antibodies, and thyroid is initially enlarged but becomes atrophied and rubbery
Iodine Deficiency
Not enoguh substrate to produce thjyroid hormone -> Increased TSH -> Increased growth of thyroid -> large goitre
Will typically improve with iodine supplementation
Iodine Excess
Wolff Chaikoff effect
With excess iodine intake -> thyroid gland will downregulate thyroid hormone biosyntehsis as a protective mechanism
Medications
Amiodarone: High Iodine content, Lithium: Concentrated in gladn adn prevents iodine uptake, inteferon: induces thyroid autoimmunity, Cancer immunotherapy: Causes thyroiditis, Graves Disease treatment
Central Hypothyroidism
Physiology
Insult to the pituitary gland that injures TSH producing cells, resulting in less stimualtion to thyroid
Labs: low free T4 and low/normal TSH
Causes
Rare condition resulting from pituitary adenoma or tumors that damage pituitary destruction
Treatment
Levothyroxine: Syntehtic T4
T3 is active hormone and T4 is converted to T3 by deoidoises
Syntehtic T3 is availabel but needs to be dosed BID
Severe Hypothyroidism: Myxedema Coma
Due to severe prolonged hypothyroidism and trigger, presents with signs/symtposm of hypothyroidism, hypoglycemia, bradycardia
Treatment
Glucocorticoids, Levothyroxine, Supportive measures, Treat underlying cause
Hyperthyroidism
Primary Hyperthyroidism
Excess thyroid hormone in circulation leading to suppresion of TSH
Labs
TSH being low suggests hyperthyroidism
If TSH is low, order Free T4 and free T3
Normal Free T4/t3 means subclinical hyperhtyroidism, and if they are high, overt hyperthyroidism
Thyroid scan and iodine uptake, and TSH receptor Antibodies (TRAb)
Symptoms
Anxiety, palpitations, Sweating, heat intolerence, weight loss, increased appetitie, Lid Lg, lid retraction, murmur, muscle weakness, brisk reflexes
Causes
Graves Disease
Most common cause of hyperthyroidism
TSH receptor antibody stimulates TSH receptor -> TSH continuously grows
Signs
Orbitopahty, Acropachy, Pretibial myxedema, Thyroid bruit, Diffusely enlarged thyroid gland
Thyroid Scan
Diffuse uptake on Thyroid scan
Treatment
Beta Blocker for symptoms
ANti-thyroid drugs to reduce Free T4 over weeks/months
Radioactive iodine ablation
Surgery: Mostly for patents who cannot do either or compression from goiter
Toxic Nodule
Small part of thyroiod tissue gained autonomous production of thyroid hormone
Treatment
Symptomatic therapy (beta blockers), anti-thyroid drugs (methimazole, PTU), radioactive iodine ablation, surgery
Iodine and Hyperthyroidism
Jod-Basedow Phenomenom
Autonomous thyroid tissue sees excess iodine -> more subtrate -> more T4
In presence of hyperthyroid disorder, iodine can exacerbate or trigger hyperthyroidism
Gestational THyrotoxicosis
TSH and hCG are similar as they have similar compositions, and hCG levels peak in pregnancy leading to suppresssed TSH, but hCG can activate TSH receptor
TSH-oma
Pituitary adenoma secreting excess TSH
Diagnosis
Elevated FT4 with elevated TSH
Thyroiditis
Infilammation of thyroid: Leads to spilling of pre-formed hormone
Subacute
deQuervain's thyroiditis
Viral infection of thyroid
Transient hyperthyroidism -> Transient hypothyothyroidism
Painless
Similar to subactue but no neck pain or symptoms
Autoimmune insult to thyroid can cause a spilling of hormones
Postpartum
Similar to painless but occurs within 1 year post-partum
Scan: Low RAIU uptake
Exogenous: Patients may be taking thyroid hormone intentionally, or uninstentionally, which results in thyroid scan is completly suppressed
Subclinical: Low TSH normla Free T4 and free T3, same causes and same investigations
Thyroid Storm
Rare life-treatening state of severe decompensated thyrotoxicosis
Treatment
Need to acutely stabilize
ABCs, Stabolize vitals, block T4-> T3 conversion (high dose PTU/Glucocorticoids), Decrease T3 action on tissyues , Decrease T4/T3 production (PTU and iodine)
Symtposm: Hyperpyrexia, large fluid loss, conusion, seiure, coma, tachycarida, nausea, vomiting, dirrhea, hepatic dysfunction
