Thyroid Flashcards
What is the incidence of false positives with FNA of thyroid nodules
0.04
What % of the normal population will have a positive Chvostek’s sign
0.1
What is the mean age of presentation of MTC in patients with MEN Ila
27
What % of patients with Hurtle cell carcinoma present with distant metastases
???
The local recurrence rate is higher after subtotal than after total thyroidectomy. True.
???
What % of thyroid nodules are malignant
What % of thyroid cancers are well-differentiated
>90%.
What level of TSH is optimal during suppression therapy
0.1 - 0.5 miU/L.
What is the incidence of permanent recurrent laryngeal nerve injury after total thyroidectomy
1 - 4%.
What % of nodules diagnosed as having follicular or Hurtle cells, are malignant
10- 20%.
What % of the population has more than 4 parathyroid glands
10%.
What % of cases of primary hyperparathyroidism are due to diffuse hyperplasia
14-16%.
What is the average lag time between radiation exposure and development of thyroid cancer
15 - 25 years.
What is the incidence of permanent hypoparathyroidism after total thyroidectomy
1-5%.
What % of malignant nodules are suppressible by exogenous TSH
16%.
What % of nodules with an indeterminate FNA are malignant
16.7%.
What % of cold, warm/cool, and hot nodules are malignant
17%, 13%, and 4%, respectively.
In a non-acute setting, what is the maximum useful amount of calcium supplementation
2 grams of calcium/day.
What % of parathyroid glands are located in the mediastinum
2%.
What % of a parathyroid gland is composed of fat
20-30%.
What % of benign nodules are suppressible by exogenous TSH
21 %.
What % of FNAs of thyroid nodules are either nondiagnostic or suspicious
27%.
What % of cases of primary hyperparathyroidism are due to carcinoma
3%.
What % of the population has only 3 parathyroid glands
3%.
What % of thyroid nodules are malignant in patients with a history of radiation exposure
30 - 50%.
What is the optimal TSH value prior to radioiodine therapy
30 mU/L.
What % of patients have had well-differentiated cancer before developing anaplastic thyroid cancer
47%.
What is the false-negative rate of the RET analysis
5%.
What % of solitary thyroid nodules in children are malignant
50%.
What % of MTCs secrete CEA
50%.
What % of patients have had benign thyroid disease before developing anaplastic cancer
53%.
After ablation therapy, how often are repeat scans performed
6 - 12 months after ablation, then every 2 years.
What % of MTC occurs sporadically
70 - 80%.
What percentage of patients with papillary carcinoma (greater than 1 em) are found to have multicentric disease on pathologic examination of the entire thyroid
70 to 80%.
What study should be performed prior to re-operation for persistent or recurrent hyperparathyroidism
99Tc sestamibi is 85% sensitive in experienced centers; more accurate is patient is placed on cytomel to suppress the thyroid.
What infectious diseases can cause chronic thyroiditis
Actinomycosis, TB, and syphilis.
What are the indications for parathyroid exploration in patients with asymptomatic or minimally symptomatic hyperparathyroidism
Age less than 50. Serum calcium I mg/ml above the upper limits of normal for the lab. Creatinine clearance reduced by 30°/o or more compared with age-matched normal persons. 24-hour urinary calcium excretion >400mg. T -score at lumbar spine, hip, or distal radius
What factor best correlates with the presence of lymph node metastases in papillary carcinoma
Age.
What are the indications for adjuvant thyroid hormone in patients with well-differentiated thyroid carcinoma
All patients with well-differentiated carcinoma should be treated with thyroid hormone to suppress TSH for life, regardless of the extent of their surgery.
What is another cause of bone disease in patients with renal failure that should be ruled out prior to parathyroidectomy
Aluminum bone disease.
Which cardiovascular medication will interfere with radioiodine scanning
Amiodarone.
What antibodies are specific for Hashimoto’s thyroiditis
Antimicrosomal and antithyroglobulin.
What test should be ordered in a patient with an elevated TSH
Antimicrosomal antibody (antithyroperoxidase level) to rule out Hashimoto’s thyroiditis.
What are the characteristics of familial MTC
Autosomal dominant inheritance pattern; not associated with any other endocrinopathies.
What laboratory workup is necessary in patients with MTC
Basal and pentagastrin stimulated calcitonin levels, serum calcium, 24-hour urine catecholamines, VMA, and metanephrine, +/ CEA.
Which of these is lethal prenatally
Blomstrand’s chondrodystrophy.
What are the indications for parathyroidectomy in patients with secondary hyperparathyroidism
Bone pain (most common indication), intractable pruritus, calcium-phosphate product over 70 despite medical treatment, calciphylaxis, and osteitis fibrosa cystica.
What is the most common site of metastasis from follicular thyroid cancer
Bone.
When is prophylactic thyroidectomy recommended in patients with the RET mutation
By age 5 or 6.
How is the definitive diagnosis of follicular thyroid cancer made
By demonstration of capsular invasion at the interface of the tumor and the thyroid gland.
What is the difference in the Ca/Cr clearance ratio in someone with FHH and someone with primary hyperparathyroidism
Ca!Cr clearance 0.02 in primary hyperparathyroidism.
What are the histologic features of papillary thyroid cancer
Calcified laminated bodies called psammoma bodies, elongated, pale nuclei with a ground glass appearance (Orphan Annie-eyes).
What lab test should be obtained in patients with a family history of medullary thyroid cancer
Calcitonin.
What is the appropriate calcium supplementation if the maximum amount of calcium has already been given and the patient is still hypocalcemic
Calcitriol or other vitamin D preparations should be added.
What are the advantages of ultrasound in the evaluation of thyroid nodules
Can detect nodules as small as 2 - 3 mm, can differentiate between solid, cystic, or mixed nodules with >90% accuracy, can detect presence of lymph node enlargement.
What are the disadvantages of ultrasound in the evaluation of thyroid nodules
Cannot accurately distinguish benign from malignant nodules.
What is the best treatment for primary non-Hodgkin ‘s lymphoma of the thyroid gland
Chemoradiation.
Which cell is most commonly proliferated in diffuse parathyroid hyperplasia
Chief cell.
What are the 3 types of cells comprising the parathyroid glands
Chief cells, clear cells, and oxyphil cells.
Which cells produce PTH
Chief cells.
What is the pathophysiology behind secondary hyperparathyroidism from chronic renal failure
Chronic hypocalcemia results from decreased production of 1 ,25(0H)2 vitamin 0 3, bone resistance to PTH, and decreased clearance of PTH and phosphate, resulting in parathyroid hyperplasia and increased levels of PTH.
What is the most common cause of secondary hyperparathyroidism
Chronic renal failure.
What are the indications for calcium supplementation after thyroid or parathyroid surgery
Circumoral paresthesias, anxiety, positive Chvostek’s or Trousseau’s sign, tetany, ECG changes or serum calcium less than 7.1 mild I.
What are the histochemical characteristics of MTC
Congo red dye positive, apple-green birefringence consistent with amyloid; immunohistochemistry positive for cytokeratins, CEA and calcitonin.
What is the significance of elevated preoperative levels of alkaline phosphatase in patients with chronic renal failure undergoing parathyroidectomy
Correlates with a good chance of amelioration of bone pain after parathyroidectomy.
Why is measurement of the C-terminal of PTH not accurate for diagnosis of secondary hyperparathyroidism
C-terminal fragments are cleared by the kidney; elevation may indicate either renal insufficiency or hyperparathyroidism.
What are the histologic features of follicular thyroid cancer
Cuboidal epithelial cells with large nuclei in a well-structured follicular pattern.
What is the appropriate management for a patient with an anaplastic thyroid carcinoma
Debulking and tracheostomy may be performed for palliation of airway obstruction.