Endocrine Flashcards
What type of malignancy is associated with hashimoto’s disease?
B cell Lymphoma
What is a brown tumour?
Mass due to excessive osteoclast activity. Bone is reabsorbed and replaced with fibrous tissue and giant cells. They are pathognomonic of hyperparathyroidism.
What is the surgical management of a thyroglossal cyst?
Sistrunk procedure
Excision of the thyroglossal duct cyst, the middle part of hyoid bone, wedge of tongue and the surrounding tissue around the thyroglossal tract.
What is the most common cause of primary hyperparathyroidosm?
Solitary adenoma of parathyroid gland (80%)
What happens to the levels of calcium, phosphate an PTH in primary hyperparathyroidism?
Ca - High
PTH - High
PO4 - Low
How do you differentiate hashimoto’s disease from hypothyroidism?
Antithyroid peroxidase antibodies will be raised in hashimoto’s disease
What are the indications for surgery in hyperparathyroidism?
Elevated serum Calcium > 1mg/dL above normal
Hypercalciuria > 400mg/day
Creatinine clearance < 30% compared with normal
Episode of life threatening hypercalcaemia
Nephrolithiasis
Age < 50 years
Neuromuscular symptoms
Reduction in bone mineral density of the femoral neck, lumbar spine, or distal radius of more than 2.5 standard deviations below peak bone mass (T score lower than -2.5)
What is the likely cause of airway compromise after surgery for large thyroid goitre?
Tracheomalacia
Extrinsic compression by enlarged thyroid previously results in normal cartilage undergoing degeneration.
What is the most common type of thyroid cancer?
Papillary thyroid cancer
more common in females, more likely to cause lymphatic spread
Where are oxyphil cells found?
Parathyroid gland
What cells secrete PTH?
Chief cells
Which thyroid cancer is most likely to metastasise to bone?
Follicular carcinoma of the thyroid
How does Carbimazole work?
Inhibition of thyroid peroxidase enzyme
What tumour marker is used to screen for recurrence of medullary thyroid cancer?
calcitonin
What type of thyroid cancer is associated with psammoma bodies? and what are they?
Papillary thyroid cancer
Areas of dystrophic calcification
Associated with orphan annuie nuclei
What cell type does medullary thyroid cancer derive from?
C cells from neural crest
What is a hurthle cell tumour?
Varient of follicular carcinoma
Oxyphil cells predominate
Which type of thyroid cancer is hashimotos associated with?
B cell Lymphoma
What substance related to thyroid function has its effects mediated by a nuclear receptor
T3 binds to a receptor on chromatin to induce protein synthesis.
What is seen on histology for hashimotos thyroiditis?
intense lymphocytic infiltrate with acinar destruction and fibrosis.
What is the lymphatic drainage of the thyroid?
Paratracheal and deep cervical nodes
How does the parathyroid regular calcium?
Secretes PTH from chief cells which:
- increase absorption of calcium from the gut
- increase reabsorption of calcium in the kidneys
- increase resorption of calcium and phosphate from bone
Negative feedback loop to hypothalamus.
Opposite action is calcitonin from c cells in thyroid.
What are the features of subacute thyroiditis?
AKA De Quervain’s thyroiditis
Follows viral illness
Symptoms of hyperthyroidism
Painful goitre
Raised ESR, decreased uptake of iodine-131
Does not need surgery, usually self limiting
What is Waterhouse - Friderichsen syndrome?
Adrenal gland failure due to diffuse haemorrhage into adrenals secondary to bacterial infection usually meningitis
What are the strap muscles?
Where should they be divided during thyroid surgery and why?
Infrahyoid muscles - Sternohyoid, Sternothyroid, omohyoid, Thyrohyoid
Should be divided in the upper half as they receive their blood supply from the ansa cervicalis which enters the muscles in the lower half.
What is histology for Graves’ disease?
Diffuse hyperplasia with hypertrophy of follicular cells
