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)