Thyroid Flashcards
Risk Factors for hyperthyroidism
Family history.
History of ordering disorders.
History of type one diabetes.
Diffuse not going to
Medication, such as iodine, lithium, amiodarone
Aetiology of hyperthyroidism
Graves’ disease most common.
Toxic multicar goiter.
Toxic adenoma
Thyroiditis
Treatment induced.
Thyroid, tumor, or ovarian tumour that produces thyroid hormone
Types of thyroiditis
Subacute thyroiditis usually resolves in eight months. Usually caused by infections.
Lymphocytic, thyroiditis or postpartum thyroiditis.
Investigations for hyperthyroidism
Nose screening less patient high risk.
TSH, free, T4.
Low, TSH, high, T4, then radio iodine and uptake.
If high, TSH, high, T4, then MRI of the brain to rule out pituitary adenoma.
Consider cardiac evaluation such as ECG, echo, Holter, myocardial, perfusion studies
Baseline,. Hemoglobin, WBC, ALT, AST, bilirubin.
Hyperthyroidism investigation algorithm
Elevated DSH elevated T4: secondary hyperthyroidism. MRI of the pituitary.
Low TSH elevated T4: radio iodine uptake.
Radio iodine, uptake, low: thyroiditis, exogenous, thyroid hormone, ectopic, thyroid hormone.
Radio ID update high: diffuse them, graves or Hashimoto. nodular uptake then, multinodular or toxic adenoma based on picture. FNAC, if nodular, but no update.
Treatment of primary hyperthyroidism
Beta blocker
Methimazole or PTU
Radioactive iodine.
Sub total thyroid ectomy
Treatment of sub clinical hyperthyroidism
Treatment not needed unless TSH less than zero point one or the patient is elderly, postmenopausal not on HRT, has osteoporosis or coronary artery disease
Treatment of hyper thyroidism in pregnancy
Treatment of choice is subtotal thyroid ectomy in the second trimester
PTU is preferred over methimazole during pregnancy and breast-feeding.
Methimazole is contraindicated  in the first trimester
Symptoms and treatment of thyroid storm
Symptoms of thyroid storm include fever, Cardia, CNS agitation, G.I. disturbance, CHF.
Fever is the cardinal symptom.
Bloodwork will show increased WBC, increased glucose, increased calcium, increased LFTs, increased three T4, decreased, TSH, decreased hemoglobin.
Treat withbeta blocker, methimazole, potassium, iodide, and glucocorticoids, along with fluids, oxygen cooling
Aetiology of primary hypothyroidism
Chronic auto immune thyroiditis.
Postpartum thyroiditis.
Thyroid agenesis or dysgenesis
Subacute granulomatous thyroiditis
Thyroid surgery, radiation, radioiodine treatment.
Thyroid infiltration with cancer or sarcoidosis
Causes of secondary or central hypothyroidism
Pituitary adenoma.
Pituitary damage with tumor, metastasis haemorrhage and necrosis and aneurism or surgery or trauma.
Pituitary infiltration with sarcoidosis tuberculosis
Risk Factors for hypothyroidism
Pregnant vivid in the first trimester
postpartum the first six weeks to six months
Age 45 to 50+
We’ve been trying to conceive next nine in history of the disease in the family or immune disorder in the family next nine history of personal auto immune disease.
Prior neck radiation
Medication such as a lithium or iodine
Investigations for hypothyroidism
TSH
T4
T3 only if undetectable TSH and normal free T4 and high suspicion of hypothyroidism.
Thyroid peroxidase antibodies plus thyroglobulin plus thyroid receptor antibodies.
Hemoglobin macrocytic anemia may be present.
Lipids.
If goitrePresent: radioiodine, uptake, or thyroid, scan, or MRI/ct of the thyroid
Ultrasound of the thyroid only if palpable abnormality of the thyroid gland
What is the management of hypothyroidism?
Levothyroxine titrate every 4 to 6 weeks until TSH in target. And then every year after.
Take levothyroxine at least 30 minutes before breakfast or walk two hours after dinner
Avoid taking with caffeine, alcohol, other medication, as that may impair absorption
At what time is treatment for hypothyroid warranted?
If TSH greater than 10, and patient is symptomatic
TSH between 5 to 10 and either presence of thyroid peroxidase antibodies or patient is pregnant or has strong family history of autoimmune disease or has a goitre
If patient has viral infection, followed by painful enlarged thyroid, as well as symptoms of hypothyroidism. What is the diagnosis and what treatment should be given
Most likely acute granulomatous thyroiditis. Treatment would be NSAID. Usually self resolving
management of hypothyroidism, diagnosed pregnancy
Stabilized TSHASAP.
Monitor every 2 to 3 weeks as compared to 4 to 6 weeks.
Take prenatal vitamins at different time than thyroxin
Will lead to decrease dose of levothyroxine postpartum
Management of hypothyroidism, diagnosed prior to pregnancy
TSH less than 2.5 prior to conception
Check TSH as soon as pregnancy is confirmed.
May need to increase thyroxin dose by 30 to 40% in the first 4 to 6 weeks.
Monitor regularly during pregnancy
When should the patient with hypothyroidism be referred?
Refer if patient has.
Central hypothyroidism.
Myxedema,
CAD.
Arrhythmia
Risk factors for malignancy, in a thyroid nodule
Rapid growth of nodule with the presence of dysphasia, dyspnea, dysphonia, personal history of MEN, FAP, history of neck, radiation, family, history of thyroid cancer
Physical findings in a thyroid nodule, indicative of malignancy
Size greater than 4 cm
Irregular, farm.
Fixed.
Associated lymphadenopathy.
Vocal cord palsy
Investigation of thyroid nodule on exam
T4.
Thyroid ultrasound.
Radio iodine uptake
FNAC if greater than 1 cm or less than 1 cm and concerning findings on ultrasound If AFLAC non diagnostic. Repeat in one to four weeks. Benign follow up in six months. If concerning refer for surgery.
Ultrasound, findings of thyroid nodule that are concerning for malignancy
Nodule that is taller than white
Presence of microcalcifications
Presence of calcified rim
Irregular border
Extending beyond the thyroid.
Lymph node involvement
Symptoms and management of myxedema coma
It is an emergency.
Patient will be drowsy, confused, comatose, will have bradycardia, hypertension, bradypnea, hypothermia, decrease reflexes.
Treat with levothyroxine, liothyronine, glucocorticoid, IV fluids, oxygen, other supportive measures as needed
