Endocrine Flashcards
Thyroidectomy
- intubate with nerve monitor, gently extend neck
- Transverse cervical incision 1 cm inferior to cricoid cartilage, create subplatsymal flaps, separate straps and dissect them off the thyroid
- Ligate middle thyroid vein
- Take superior pole vessels as close to thyroid as possible
- Mobilize thyroid anteriorly & medially to Identify RLN in the TE groove, trace to insertion in cricothyroid membrane, keep dissection as close to thyroid as possible
- Take inferior pole vessels
- Identify and preserve parathyroids by performining capsular dissection
- Divide ligament of berry and remove thyroid from the airway
Parathyroidectomy
Know where to find missing superior & inferior adenomas
Know what to do if all parathyroids are normal ie 4 gland exploration
- Draw baseline PTH, place patient supine, arms tucked, neck slightly extended, intubated with RLN monitoring capabilities
- Transverse cervical incision 1cm inferior to cricoid cartilage
- Raise subplatsymal flaps, separate strap muscles and dissect them off the thyroid
- Ligate middle thyroid vein
- Retract the thyroid gland medially, look for parathyroid glands close to inferior thyroid artery and RLN:
- superior is deep/posteriolateral to plane of nerve,
- inferior is superficial/anteriomedial to plane of nerve - Excise the adenoma, check PTH at 5 min and 10 min to ensure 50% drop from baseline & normal levels (<55 pg/mL)
→ Missing superior adenoma is likely in retroesophageal space or carotid sheath @ bifurcation
→ Missing inferior adenoma → Thymus vs intra-lobar
For four gland exploration, identify each gland.
→ If all normal, clip & send for frozen prior to excision. Excise 3.5 glands.
→ If still doesnt drop, perform b/l thymectomy as likely extranumary gland is in thymus… then close and get more imaging if still no improvement
LEFT adrenalectomy
- Left side up, ports along costal margin, assess for mets, open w subcostal incision
- Mobilize splenic flexure, spleen, & tail of pancreas (if unable to, then enter lesser sac)
- Dissect retroperitoneal structures including Gerota’s fascia, left renal hilum, para-aortic space
- Identify, ligate, divide L adrenal vein
- Dissect L suprarenal tissues with enbloc resection of retroperitoneal fat from superior pole of L kidney to the diaphragm
RIGHT adrenalectomy
- Right side up, ports along costal margin, assess for mets, open w subcostal incision
- Mobilize triangular ligament of liver and perform medial rotation of right liver lobe to expose IVC
- Dissect R border of IVC
- Identify, dissect, clip R adrenal vein
- Dissect R suprarenal tissues with enbloc resection of retroperitoneal fat from superior pole of R kidney to the diaphragm
Bethesda system for Thyroid cytopathology & malignancy
I - nondiagnostic
II - benign
III - AUS/FLUS
IV - FN/SFN
V - suspicious for malignancy
VI - malignant
Indications for total thyroidectomy
- Extra-thyroidal disease (extends beyond capsule, clinically + nodes, mets)
- Tumor ≥4 cm
- Multicentric/bilateral
- History of XRT
Indications for MRND (LN’s I-V)
Extra-thyroidal disease (extends beyond capsule, clinically + nodes, mets)
Indications for post-op radioactive iodine at 4-6 weeks post-op (need TOTAL thyroidectomy to work, should NOT be administered to children or preggers)
- Extra-thyroidal disease (extends beyond capsule, clinically + nodes, mets)???
- Tumor ≥4 cm
- Post-op thyroglobulin > 5-10 ng/mL
- Bulky or > 5 positive lymph nodes
- Can also be used for recurrent cancer
Follow up after lobectomy/total thyroidectomy for low risk tumors & high risk/advanced tumors
LOW RISK
After lobectomy → Check TSH 6 weeks after surgery, U/S 6 months then annually
HIGH RISK
After thyroidectomy & RAI ablation →
Diagnostic whole body radioactive iodine (RAI) scan evaluate for persistent/recurrent disease
**If scan is negative with rising thyroglobulin (> 10 ng/mL), 18fluorodeoxyglucose–positron emission tomography (18FDG-PET) should be considered.
Thyroid work up - dont forget to ask & dont forget to order
Hx compressive symptoms, hyperthyroidism symptoms (anxiety, palpitations, weight loss, etc), hypothyroidism symptoms, family/personal endocrine & malignant CA
Hx radiation, Hx neck surgery
EYE symptoms! periorbital swelling, eye dryness, photophobia, etc
TSH normal or high → U/S & FNA
TSH low → TRAb & Thyroid scintigraphy
Hyperparathyroidism work up - dont forget to ask & dont forget to order
Confirm no alternative causes for hypercalcemia (ie meds)
Personal/family hx of malignancy/endocrine disorders
Kidney stones, osteoporosis/compression fracture
Vitamin D,
PTH,
phosphate,
chloride
24h urinary calcium excretion
If asymptomatic, order bone scan & b/l renal U/S
Indications for surgery in hyperparathyroidism
Symptomatic disease
Asymptomatic disease with
1. Ca > 1.0mg/dL above normal (10.3)
2. ↓ Cr clearance
3. Kidney stones
4. Substantially ↓ bone mass (densitometry T score < −2.5) or osteoporosis/compression fracture
5. Age < 50
6. Urinary calcium excretion > 400 microgram/24 hours
7. History of life-threatening hypercalcemic crisis
Parathyroid adenoma localization
U/S first, then 4D CT scan vs sestamibi scan
Adrenal mass H&P don’t forget to ask
- Personal/family history of malignancy & endocrine disorders
Symptoms of hormonal excess
2. Hypercortisolism → weight gain, bruising, HTN, hyperglycemia, muscle weakness
3. Hyperaldosteronism → HTN, hypokalemia
4. Pheochromocytoma → Tachycardia, headache, HTN, anxiety
Screening for adrenal functional tumors (do this for ALL adrenal masses)
- 1 mg LD dexamethasone suppression test: Patients take 1 mg Dexamethasone at 10PM, then have Cortisol levels drawn the next morning;
→ Normal/Negative Cortisol < 1.8
→ Hypercortisolism > 5
→ 1.8 - 5 → need 24h urinary free cortisol levels to confirm - Serum ACTH
- Serum Aldosterone & Renin
- DHEA-Sulfate (CA marker)
- Plasma free metanephrines; If elevated, need 24h urinary metanephrines testing to confirm
Adrenal mass indications for surgery
- Functioning tumor
- Enlarging tumor
- Tumors > 4 cm
- Ominous CT scan characteristics - Need adrenal protocol CT scan
→ Non-homogenous, Irregular borders. Calcifications.
→ High density > 20 HU (HU < 10 are 100% specific for benign tumor)
→ Contrast washout < 50% after 10 minutes
Hyperaldosteronism work up & management
Dx: Aldosterone:Renin >20; can also do salt load suppression test (plasma aldosterone will stay high); also need to do LD dexamethasone test, plasma metanephrines, ACTH
Need b/l adrenal vein sampling to confirm laterality regardless of lesion site; ONLY for hyperaldosteronism
Medical management if bilateral = spironolactone, nifedipine (CCB), potassium
Hypercortisolism work up & management
Bilateral adrenal hyperplasia should undergo medical management = mifepristone, ketoconazole, metyrapone
Diagnosis
1st → LD (1 mg) dexamethasone suppression test; if indeterminant, do 24h urinary free cortisol level (2 measurements); if high, go to 2nd
2nd → ACTH
- Low ACTH → Dx = Cortisol secreting lesion (adrenal adenoma/hyperplasia)
- High ACTH → Pituitary adenoma or ectopic tumor → go to 3rd
3rd → HD dexamethasone suppression test
- Suppressed cortisol → Dx = Pituitary adenoma
- Not suppressed cortisol → Dx = Ectopic ACTH-secreting tumor
NP-59 scintography can help localize tumors & differentiate adrenal adenomas from hyperplasia
Pheochromocytoma preoperative preparation
Alpha blockade with Phenoxybenzamine vs Prazosin. Then beta blockade if significant tachycardia
Work up for anyone with suspected pheochromocytoma, parathyroid hyperplasia, pancreatic tumors, MTC should include:
Calcitonin, calcium, CEA, PTH, serum metanephrines
Work up (when is staging appropriate?), management, surveillance of MTC
Labs should include calcitonin, calcium, CEA, PTH, serum metanephrines
Genetic testing for MEN
If concern for lymph node metastasis or if Calcitonin is > 500, need staging with chest CT, liver phase CT, bone scintigraphy
All MTC needs total thyroidectomy & central neck dissection vs MRND
Post op surveillance w calcitonin & CEA q3m
Central neck dissection
Identify & protect b/l RLN
Remove all fibroadipose tissue between carotid sheaths, hyoid bone, brachiocephalic vessels
Lateral neck dissection
Remove all fibroadipose tissue from lateral neck (all LN I-V , not central VI), borders defined by submandibular gland superiorly, IJV medially, trapezius laterally, clavicle inferiorly
Enlarged lateral lymph node during work up for thyroid nodule
FNA & send for cytology & thyroglobulin
If shows thyroid tissue (lateral aberrant thyroid tissue; ie. papillary thyroid CA with lymphatic spread) → Tx: total thyroidectomy, MRND, and radioactive iodine!
