Endocrine Disorders Flashcards
What is the risk of thyroid cancer after radiation exposure?
What is the most common form of cancer following radiation to the neck?
past history (10-25 years) of low-dose ionizing radiation « 2000 rad) to the neck carries a 40% risk of thyroid cancer; the most common cancer following radiation is papillary carcinoma
Which parts of the history are important to rule out thyroid cancer?
Radiation exposure, family history, thyroid nodule pattern, depressive symptoms.
And a patient with a 1 cm right thyroid nodule and history of radiation exposure, what is the next step?
Proceed directly to thyroidectomy
A patient has a family history of medullary cancer. How could you test for this type of cancer?
- autosomal dominant trait, and
- testing for the existence of a point mutation of the RET gene in a family can establish a diagnosis.
What voice and airway symptoms would suggest a malignancy?
history of hoarseness as well as the
- presence of a hard, fixed nodule
- dyspnea
-dysphagia - cervical lymph node enlargement; and
- vocal cord paralysis suggest malignancy
What is the risk of malignancy for a solitary nodule versus a dominant nodule in a multinodular gland?
Solitary nodule – 15%
Dominant nodule in a multinidular gland – 5%
What is the management of a thyroid cyst?
cyst necessitates complete aspiration and follow-up. If it is large (>4 cm) or recurs several times following aspiration, removal to eliminate the risk of malignancy (up to 15% in large cysts) is required.
Management of a colloid nodule?
Benign
Medical management of thyroid suppression
Papillary carcinoma
Surgery
Medullary carcinoma
Malignant highly invasive. Surgery
Psammoma bodies
Precursors for papillary carcinoma. Surgery recommended.
Amyloid deposits
substance and calcitonin staining suggest medullary cancer, and a total thyroidectomy is mandatory.
Undifferentiated cells
indicates an anaplastic cancer, and either chemotherapy and radiation or salvage operative therapy is appropriate.
Hurthle cells
Hurthle cells signifies either an adenoma or a low-grade cancer.
Therefore, lobectomy is indicated. If cancer is present, a total thyroidectomy is indicated.
Follicular cells
nondiagnostic result does not exclude cancer, so a thyroid lobectomy is usually performed for diagnostic purposes.
Lymphocytic infiltrate
lymphoma or chronic lymphocytic thyroiditis, which can be differentiated by flow cytometry. Lymphomas are radiosensitive, so radiation is approp
You should advise your patient of which serious complications of thyroid surgery?
Serious complications following thyroid surgery include injury to the recurrent laryngeal, or external branch of the superior laryngeal nerves as well as to the parathyroid, with resultant hypocalcemia and hyperphosphatemia.
Incidence of papillary cancer. What age is it typically diagnosed? What percentage of patients diagnosed will already have distant spread?
Most common thyroid cancer.
30–40 years old
5%
Management of papillary cancer with a nodule less than 1 cm in size.
– Patients with a previous history of radiation: total thyroidectomy
– Patients with no history of radiation: thyroid lobectomy and isthmusectomy
Incidence of follicular cancer? Where is this cancer more prevalent? What is the peak age of incidence?
Follicular cancers, which represent 15%-20% of thyroid cancers, are more prevalent in iodine-deficient areas. Peak incidence occurs about 40-50 years of age.
Treatment for follicular carcinoma
Formal lobectomy and isthmusectomy is appropriate for excision of a well-circumscribed lesion that is defined as a microinvasive follicular carcinoma. However, total thyroidectomy is necessary for microinvasive lesions greater than 4 cm.
How this follicular carcinoma usually spread?
Vascular route. Lymph node spread not as likely
What percentage of thyroid cancers does medullary cancer account for? What are the two forms?
Medullary cancer constitutes 5%-10% of all thyroid cancers. There are two forms: 80% are sporadic, and 20% are familial (MEN).
Describe the histology of medullary cancer cells
tumors feature hyperplasia of C cells (parafollicular) with amyloid.
The prognosis of papillary cancer depends on what variables?
One prognostic method uses a scale that includes age 40 years), pathologic grade, extent of disease, and size of tumor (mnemonic: AGES).
Prognostic factors in follicular cancers?
presence of vascular invasion worsens the prognosis. Survival is approximately 80% for favorable lesions and 60% for unfavorable lesions at 10 years. Postoperative adjuvant therapy centers on J131 ablation treatment.
What is the prognosis of medullary cancer?
Prognosis is related to the extent of disease, with an overall survival of 80% at 10 years, but less than 45% with lymph node involvement. Patients may be monitored by measuring serum calcitonin and carcinoembryonic antigen (CEA) levels.
What is the postoperative treatment for medullary carcinoma?
TreatmentwithJ131andthyroidsuppressionpostoperativelyarenotuseful,becausethe tumor arises from C cells.
Rx for undifferentiated thyroid cancer?
prognosis is extremely poor. However, multimodality therapy: Chemo + Radiation
65 year old F presents with hypercalcemia (14 mg/dL), hand demonstrated bone reabsorption (osteitis fibrosa cystica). She also complains of generalized fatigue. What labs should you also order?
- PTH
- Alkaline phosphatase
- Phosphate levels
How do you know if someone has hyperparathyroidism?
Hypercalcemia and elevated PTH suggest the diagnosis of primary hyperparathyroidism
Most likely cause of hyperparathyroidism?
Parathyroid adenomas are the most common lesions leading to primary hyperparathyroidism.
Incidence of parathyroid carcinoma?
Parathyroid carcinoma is present in less than 2% of cases.
After making a diagnosis of hyperparathyroidism. What is the next step in management?
- Surgery: explore the neck to examine the parathyroid glands.
No preoperative studies to further localize or characterize the disease are necessary. - alternative: sestamibi scan, which typically demonstrates enlarged parathyroid glands, is used to determine the site of the adenoma. Small localized incision (minimally invasive parathyroid surgery)
Common presenting symptoms of hyperparathyroidism
Muscle weakness 2/3 Myalgia 1/2 Arthralgia 1/2 Nephrolithiasis 1/3 Constipation 1/3 Polyuria 1/3
most common location for a missing inferior gland
thymus
Patient undergoes surgery to remove parathyroid. 3 normal glands and 4th is missing. Persistent calcium el evation has occurred postoperatively. How would you manage this situation?
persistent hyperparathyroidism. Management usually involves local ization studies, including sestamibi scan, ultrasound, computed tomography (CT), mag netic resonance imaging (MRI), angiography, or venous sampling.
reexploration through a neck or a lateral direct approach is necessary. In cases where a persistent intrathymic parathyroid is found, a thymectomy through a cervical incision or a median sternotomy is warranted.
Asymptomatic patient with hypercalcemia. Next step in management?
Many clinicians recommend parathyroid exploration once the serum cal cium exceeds 1 1 mEq/L to avoid the complications of hypercalcemia.
most common benign cause of hypercalcemia.
parathyroid adenoma
Acute treatment for hypercalcemia.
- Hydration with normal saline
- Calciumdiuresiswithfurosemide
- Initiation of bisphosphonates
- Treatment of underlying cause
When should an asymptomatic incidentaloma be excised?
> 6 cm in size - often malignant, 25% malignant
don’t operate: <4cm - less than 2% are malignant
4-6 cm require careful decision
What is secondary hyperparathyroidism? What causes it?
Patients with chronic renal failure retain phosphate as their glomerular filtration rate de creases. Hyperphosphatemia causes hypocalcemia, which elevates serum PTH, and this syndrome is termed secondary hyperparathyroidism. Calcium absorption from the gut and vitamin D metabolism are also impaired.
What are the surgical indications for secondary hyperparathyroidism?
bone pain, fractures, intractable pruritus, or ectopic calcifications in the soft tissues (calcium tachyphylaxis) are present.
Leave 50 mg of parathyroid behind, arm is easier as not to injure neck anatomy (nerves) if later resection needed?
Common operative finding when operating on patient with secondary hyperthyroidism?
hyperplasia of all glands
Indications for surgery for hormonally active adrenal tumors?
Symptoms - Surgery for all (Cortisol, aldosterone, pheo)
Abnormal lab studies - Cortisol - Surg; aldo spironolactone vs surg; Pheo - surg.
tertiary hyperparathyroidism
High serum calcium s/p renal transplant: parathyroids do not respond to return of renal function and overproduce PTH
Indication for surgery for tertiary hyperparathyroidism
If hypercalcemia persists for > 1 year and homeostasis does not occur, a 3 and 1/2 gland resection is indicated.
34 y/o M undergoes neck exploration for primary hyperparathyroidism but becomes uncontrollably hypertensive. What do you advise?
experiencing a catecholamine release from an undiagnosed pheochromocytoma.
- End surgery
- Transfer to ICU
- Use combined beta and alpha blockade. Never use beta blockade alone (may be fatal)
Lab findings in pheo
90% of pheochromocytomas result in elevated levels of urinary catechols, metanephrine, and vanillylmandelic acid.
nuclear I-131 metaiodobenzylguanidine (MIBG) scan
nuclear MIBG scan material selectively accumulates in chromaffin tissue, with a high sensitivity and even higher specificity for pheochromocytomas.
35-year-old woman with sudden onset tender neck mass. What is the most likely diagnosis?
de Quervain’s thyroiditis
Common lab finding in de Quervain’s thyroiditis.
Elevated ESR
Treatment for de quervains thyroiditis
analgesics and aspirin
Treatment for acute suppurative thyroiditis.
Antibiotics or antifungals with drainage if an abscess is present
hypothyroid and present with enlarged painless masses
chronic lymphocytic thyroiditis or Hashimoto’s thyroiditis
What are the lab values expected and Hashimoto’s thyroiditis?
reveal low thyroxine and triiodothyronine levels and normal TSH levels.
Is there an association with Hashimoto’s thyroiditis and other diseases?
higher incidence of malignancy is associated with Hashimoto’s thyroiditis, especially papillary carcinoma and thyroid lymphomas.
Treatment for Hashimoto’s thyroiditis
Thyroid hormone replacement therapy
Biopsy of all suspicious lesions is necessary, and patients with compressive symptoms of the trachea should undergo palliative resection to relieve the obstruction.
History of Hyperparathyroidism and Intractable Duodenal Ulcers
– R/o h. Pylori infx
– Obtain serum gastrin levels
How do you diagnose hypergastrinemia?
diagnosis of hypergastrinemia is established by an elevated unstimulated serum gastrin level or with a positive calcium or secretin stimulation test to augment the gastrin response.
Level of gastrin in hypergastrinemia?
basal serum gastrin is over 600 pglmL (>1000 pglmL is diagnostic
Gastrinoma is diagnosed in MEN syndrome. Do you recommend surgery?
Yes: surgical enucleation( preserves as much as possible) With endoscopy and ultrasound
Location of the tumor and removal of as much tumor as possible are necessary. This process includes intraoperative endoscopy to identify duodenal lesions, as well as intra operative ultrasound to isolate the mass.
How do insulinomas present?
present with the Whipple triad: fasting hypoglycemia (glucose <60 mg/ dL), symptomatic hypo glycemia, and relief by administration of glucose.
30-year-old woman presents with amyloid like material and c-cell proliferation with hypertension. What is the diagnosis?
medullary thyroid cancer associated with MEN-2, a syndrome with autosomal dominant inheritance
MEN 2A vs Men 2B
MEN-2a, the constellation of pathology involves a medullary thyroid cancer, parathyroid hyperplasia, and pheochromocytoma.
In MEN-2b, the pattern is similar, with the exception of an associated marfanoid body habitus and ganglioneuromas.
frontal pounding headaches, episodic diaphoresis, palpitations, or anxiety with hypertension
Pheochromocytoma
When is surgery indicated for an incidental adrenal mass?
5 cm or more in size, the incidence of adrenal cortical carcinoma is high, and surgery is recommended. Operative therapy usually involves a wide resection of the adrenal gland.
How should you manage an Incidental adrenal mass that is less than 5 cm?
Biochemical assessment to examine for elevated levels of catecholamines, cortisol, and serum potassium.
If any of these results indicate functional mass, surgery is indicated.
Otherwise follow with serial CT scans.
