Thyroid nodules/hyperthyroid Flashcards
Thyroid Nodules
General
Disordered growth ofthyroid cells that form a lump or amass
Discrete nodule or a multinodular goiter
Extremely common
Palpated by the patient or clinician or discovered incidentally on imaging studies
Palpable nodule in 4-7% of adults in the United States
90% are benign adenoma, colloid nodules, or cysts
Primary thyroid malignancy
Metastatic malignancy
Prevalence increases with age
♀>♂
thyroid nodule
Individuals Risk for Malignant nodules(6)
Male
Young age (< 30 years old)
History of head-neck radiation
Family history of thyroid cancer
Personal history of another malignancy
Large, firm, solid solitary nodule or “cold” nodule
Associated cervical lymphadenopathy
thyroid nodules
Clin Man
Asymptomatic
Symptoms:
Nodule or multinodular goiter that is visible
Anterior neck discomfort
Hoarseness
Dysphagia
Ipsilateral recurrent laryngeal nerve palsy
Hypothyroidism
Hyperthyroidism
thyroid nodule
incidental finding
Thyroidnodules often present as an incidental finding on radiologic tests obtained for different purposes:
Carotid ultrasound
Neckor chest CT
PET
No symptoms or observable lesion by exam → thyroid cancer needs to be ruled out
Thyroid nodule
Whenever to do further testing
Nodule ≥ 1 cm requires further testing
Nodules < 1 cm in a patient at high risk for thyroid cancer requires further testing
All thyroid nodules should be initially evaluated with a thyroid ultrasound
Nodules ≥ 1 cm and/or high-risk patient
TSH and free T4
May be low, normal, or high
Majority of patients are euthyroid
thyroid nodule
Ultrasound
benign and high-risk features(5)
Thyroid ultrasound
Determinesnodule size and characteristics (including adjacent structures)
Benignfeatures:
Purelycystic, without solid components
High-risk features:
Solid
Hypoechoic - indicated a solid mass of dense tissue
Microcalcifications
Irregular margins
Extrathyroidal extension
can also assess vasculature
thyroid nodule
Radionuclide thyroid scan
Performed when TSH levels are low
Goal is to examine if the nodule is functioning
Nonfunctioning – cold nodule
Iodine uptake less than surrounding tissue
Fine-needle aspiration biopsy (FNAB)
Hyperfunctioning – hot nodule
Iodine uptake more than surrounding tissue
Likely benign
thyroid nodule
Fine-needle Aspiration (FNA) Biopsy
indications
Best method for assessing for malignancy
Indications:
≥ 1 cm nodule and:
Elevated/normal TSH + suspicious ultrasound findings
Low TSH + suspicious ultrasound findings + cold or indeterminatenodule(s)
Largenodule ≥ 1.5 cm
Thyroidnodule of any size with risk factors:
Young age
Family historyofthyroid cancer
History ofradiation
thryoid nodule
Tx of a Benign lesion
Repeat ultrasound every 6 months initially
Stable lesion – repeat ultrasound yearly
Repeat FNA biopsy if growth occurs
> 2 mm of growth per year – higher likelihood of malignancy
Suppression therapy with levothyroxine
Nodules < 2 cm and/or ↑ TSH
Starting dose of 50 mcg PO daily
thyroid nodules
Other treatments for benign lesions that are greater than 3cm or toxic (hyper)
Radiofrequency ablation for lesions ≥ 3 cm
Radioiodine therapy for hyperthyroid patients with toxic thyroid adenomas or multinodular goiter
thryoid nodule
Tx of Cancerous lesion
Total thyroidectomy
Goiter
general
Chronic enlargement of the thyroid gland due to non-neoplastic growth
Can be an overall enlargement or irregular cell growth that forms one or more nodules
Goiter
Types (3)
- Toxic – associated with hyperthyroidism
- Nontoxic – associated with euthyroidism
- Hypothyroid – commonly seen in Hashimoto’s thyroiditis
Hypothalamic-Pituitary-Thyroid Axis
Complex neuroendocrine web that determines the set point of thyroid hormone production
Negative feedback
Production of Thyroid Hormones
Two biologically active thyroid hormones:
Tetraiodothyronine (T4 or thyroxine)
Triiodothyronine (T3)
Most metabolically active
Derived from modification of tyrosine (amnio acid)
Hyperthyroidism
general
Typical age of onset
Excessivethyroid hormones (T4 and T3) produced and released by thethyroid gland
♀>♂
Typical age of onset is 20-40 years of age
hyperthyroid
causes
Causes:
Increased synthesis of thyroid hormones
Excessive passive release of thyroid hormones
Extrathyroidal source
Pituitary adenoma (secondary hyperthyroidism)
Toxic multinodular goiter
general
More common in?
Second most common cause of hyperthyroidism in the United States (15% of cases)
Thyroid has multiple hyperfunctioning areas
More common in elderly patients (>50 years)
More common in patients that smoke
Highest incidence is in iodine-deficient area
Graves Disease
general
Most common cause of hyperthyroidism in the United States (60-80% of cases)
Autoimmune disorder in whichantibodiesagainst thethyroid-stimulating hormones (TSH) receptors cause thethyroidgland to hyperfunction (primary hyperthyroidism)
Thyroid develops diffuse hypertrophy and hyperplasia of the follicular cells with lymphoid infiltrates (toxic goiter)
Graves Disease
RF(6)
Female
Family history of thyroid disease
Personal or family history of an autoimmune disease
Under the age of 40
Stress
Smoking
Left: normal thyroid
Right: thyroid of a patient with hyperthyroidism; irregular follicles that have decreased colloid (the fluid within the follicles that contains thyroglobulin)
Graves’ disease
Clin Man
Variable: Asymptomatic → thyroid storm
Palpitations/Tachycardia
Heat intolerance/diaphoresis (vasodilation)
Weight loss due to increased metabolic rate
Exophthalmos/preorbital edema/excessive lacrimation
Fine tremors and hyperreflexia
Diarrhea
Weakness of proximal muscles
Psychosis/anxiety
Goiter
-Graves – smooth, symmetric, nontender with a thrill or bruit on auscultation (due to increased blood flow)
Pretibial myxedema
-Swelling over the tibia with the skin assuming a peau d’orange appearance
Left, top: exophthalmos
Left, bottom: pretibial myxedema
Right: multinodular goiter
Graves Disease`
Labs
TSH, t3/t4, anything else?
↓ TSH (Graves and toxic multinodular goiter)
↑ T4 and T3
↑ thyrotropin receptor antibodies (Graves disease)
Graves
Radioactive Iodine Uptake (RAIU) and Thyroid Scan
Helps to determine the cause of hyperthyroidism
Uptake is a percentage of an radioactive iodine (I-123) tracer dose taken up by the thyroid at 24 hours
High uptake = Graves disease or toxic multinodular goiter
Thyroid scan shows the distribution of the radiotracer
Homogeneous = Graves disease
Multiple areas of accumulation = toxic multinodular goiter
cant use during pregnancy
Graves
Ultrasound
Ultrasound ofthe thyroid gland
Detect diffuse enlargement, solitary or multiple nodules, and increased vascularity of the gland
Primary imaging modality used during pregnancy and lactation
graves
Beta blockers
Used to control adrenergic symptoms (palpitations, tremor, heat intolerance)
Very useful in those with impendingthyroid storm
Propranolol (nonselective)
Immediate release: 10-40 mg PO every 8 hours
Extended release: 80-160 mg PO once daily
Atenolol (selective)
25-100 mg PO once or twice daily
Safer for use in patients with asthma or COPD
be prepared to pick depending on underlying issues. if someone has lung issue, use selective blocker
propanolol typically used for treating.
graves
Antithyroid medication and protocol before initiation
Inhibit oxidation and organic binding of thyroid iodideby inhibiting thyroid peroxidase
Inhibiting extrathyroidal conversion of T4 → T3
Requires a baseline CBC and liver function before initiation (agranulocytosis)
Monitoring - Free T4 and T3 obtained 4 weeks after initiation and every 4-8 weeks with dosage adjustments
graves
Antithyroid medications
And dosages
methimazole (Tapazole) 10-30 mg PO QD
Preferred except during the first trimester of pregnancy (birth defects)
propylthiouracil (PTU) 100 mg PO TID
Used in the 1st trimester of pregnancy and in thyroid storm
Black box warning from the FDA (severe liver damage)
- once in 2-3rd trimester then switch back to methimiazole
graves
Radioactive iodine (I-131) ablation of the thyroid
Most common treatment in the United States
Capsule or solution ofsodiumiodine-131 (I-131,radioactive iodine (RAI)) taken orally
I-131 concentrates in thethyroid→ progressivethyroidcell destruction
graves
Radioactive iodine (I-131) ablation of the thyroid
Contraindications
Contraindicated in pregnancy and breastfeeding
Most patients develop permanent hypothyroidism between 2-6 months after radioactive iodine ablation and require thyroid hormone replacement
graves
Total thyroidectomy is preferred when
Preferred in patients with compressive symptoms and those with contraindications to radioactive iodine ablation or failure with antithyroid medication
Thyroid Storm
General
Rare, life-threatening emergency
More unbound thyroid hormone in the blood
Tissues might become more sensitive to the thyroid hormone
Body might become more sensitive to catecholamines → activating the sympathetic nervous system
Occurs in patients previously undiagnosed or inadequately treated for hyperthyroidism
thryroid strom
precipitating factors
Precipitating factors: major stress (surgery, childbirth), trauma, illness, taking too much thyroid hormone
thyroid strom
clin man
Fever
Delirium
Nausea and vomiting
Anxiety → seizures
Cardiovascular manifestations: atrial fibrillation with rapid ventricular response, hypotension
thyroid storm
Tx
Supportive therapy – oxygen, airway maintenance
Antithyroid medication (TPU/methimazole)
Propranolol to control adrenergic symptoms
Oral or IV sodium iodide to decrease thyroid hormone release
Glucocorticoids to block the conversion of T4 to T3
Plasmapheresis
Blood plasma is removed, thyroid hormone can be removed, and the remaining plasma is returned to the patient
Hypothalamic-Pituitary-Thyroid Axis
