PARATHYROID Flashcards
Can you palpate parathyroid adenoma or hyperplasia?
rarely.
Dx pseudohypoPTH
target tissues resistant to PTH -> low Ca, elevated P + defect in skeletal growth and development
Gene pseudohypoPTH
GNAS1 mutation -> encodes GCPR alpha-subunit; mutation results LOF in signaling pathway -> kidney does not respond to PTH
Indication for surgery of asymptomatic hyperPTH
- serum Ca >1mg/dL
- CrCl <60
- osteoporosis (T-score <2.5)
- poor access care or f/u
- age <50
MC sxs hyperCa
nephrolithiasis
MC aberrant locations of superior parathyroid
- retroesophageal space
- carotid sheath
MC aberrant location of inferior parathyroid
- ipsilateral mediastinal thymus
If 4 normal glands, but still hyperPTH… think? MC located…?
hypersecreting suprannumery hyperPTH gland; MC located in thymus
MC location missed parathyroid gland
normal anatomic location
MC location ectopic parathyroid gland
thymus
MCC malignancy associated w/ hyperCa
SCC (PTHrH), then breast cancer
Mgmt parathyroid cancer
en-block resection w/ ipsilateral thyroid and central neck dissection
Mgmt recurrent or widely metastatic parathyroid cancer
palliative lowering surgery + Ca-lowering drugs
Electrolyte disturbances of hyperPTH
hyperCl metabolic acidosis (Cl:P >33; phos and bicarb excretion in kidneys)
Mgmt secondary hyperPTH
- hyperP: phosphate binders + dietary mod
- Ca supp
- correction of acidosis
- vitD supp
- surgery indicated only for…
When more likely to have 4-gland involvement for hyperPTH?
MEN pts and pts w/ lithium-induced HPT
Cinacalcet
directly inhibit PTH in pts with chronic renal failure
Does bone mineral density improve after parathyroidectomy?
YES.
What type and location of bone does primary hyperPTH typically affect?
cortical bone > cancellous bone
more effect seen in femoral neck + distal radius, compared to lumbar spine
Calciphylaxis
life-threatening - painful, ischemic cutaneous wounds - tissue calcification (2/2 Ca-P precipitation, which compromises microvasc), dry gangrene, wound sepsis
Mgmt calciphylaxis
urgent total parathyroidectomy
Familial hypocalciuric hyperCa dx with calcium/Cr ratio of…?
= 0.1
Embryology: superior parathyroid arises from…? Inferior parathyroid?
Superior: from 4th pharyngeal pouch
Inferior: from 3rd pharyngeal pouch (along with thymus)
Sestamibi scans good for localization of…? But not as sensitive for..?
good for adenomas.
not as sensitive for hyperplasia.
If fail to adequately drop PTH levels after resection of one PTH, next step…?
attempt resection of ipsilateral gland first - if still no drop, then explore C/L neck and total parathyroidectomy
Embryology: inferior parathyroid glands arise from…?
3rd pharyngeal pouch (w/ thymus)
Embryology: superior parathyroid glands arise from…?
4th pharyngeal pouch (w/ lateral thyroid)
