| How is embryology of thyroid? | -Thyroid gland=the first of the body's endocrine glands to develop, on approximately the 24th day of gestation
- The thyroid originates from two main structures:
the primitive pharynx and the neural crest
-The median thyroid arises from the primitive pharynx
-The rudimentary lateral thyroid develops from neural crest cell
-The thyroid gland forms as a proliferation of endodermal epithelial cells on the median surface of the developing pharyngeal floor
-The site of this development lies between the tuberculum impar and the copula, and is known as the foramen cecum |
| Image of development of thyroid? | . |
| How is the migration of thyroid gland? | . |
| How is thyroid anatomy? | . |
| How is thyroid shield? | Gland weighs 25g, two lobes connected by isthmus, anterior surface of trachea just inferior to thyroid cartilage.
Larger in females than males. |
| How is thyroid blood supply? | Blood supply (From Brachiocephalic trunk : thyroid IMA artery
From right subclavian artery: inferior thyroid artery
From external carotid: superior thyroid artery.
Venous: From internal jugular superior and middle thyroid veins and from left brachiocephalic vein inferior thyroid vein giving thyroid plexus) |
| What are nodes of thyroid? | . |
| What is FNAB? | Fine needle aspiration biopsy, dx tool for solitary thyroid nodules initial evaluation, effectiveness improved w/US guidance
-Solitary thyroid nodules of 3 cm in size or greater
that have been diagnosed on FNAC as Bethesda
classification II (ie, benign) have a significant
malignancy risk
-In one study, patients with solitary thyroid nodules
sized 3 cm or more, the cancer risk was 22.8%
-The malignancy risk was greater in predominantly
cystic nodules than in predominantly solid ones |
| How is the ATA risk stratification of thyroid nodules? | . |
| How is management of thyroid nodules? | . |
| What are the main tx options for thyroid nodules and their pros and cons? | . |
| What are classifications of thyroid tumors? | . |
| what are classifications of thyroid carcinomas of follicular origins? | . |
| What is the difference between papillary and follicular thyroid carcinomas? | . |
| What are risk factors for thyrodi cancer? | Neck irradiation (only well-established risk factor for differentiated carcinoma), Genetics (FAP, Gardner's syndrome, Cowden's, MEN) Other (hx of goiter, fam hx, female gender, asian)
Age if <15 or <45 , male gender, tumor >4cm, multifocal, extrathyroid extension, high grade histology, metastasis all have unfavorable prognosis leading to carcinoma. |
| What are the main prognostic factor scales used in thyroid carcinoma? | . |
| How is ATA risk stratification of thyroid cancer and tx? | . |
| How are risks for follicular carcinoma? | . |
| How are risks for medullary carcinoma? | . |
| How is innervation of thyroid gland? | . |
| How is thyroidectomy done? | . |
| What are types of thyoridectomy? | Lobectomy/hemithyroidectomy, subtotal thyroidectomy, near total thyroidectomy, total, completion thyroidectomy |
| How is postop care after thyroidectomy? | Look for signs of bleeding, respiratory ditress
Serum calcium
Removal of drain
Reasssessment of vocal cord mobility and thyroid function test |
| What are thyroidectomy compliations? | MR in 1800 was 40% due to infection and hemorrhage, after sterile arenas and general anesthesia and improved techniques made death extremely rare.
Complications include:
Anatomy (short and thick neck)
Thyroid pathology (thyroiditis, Grave's, Substernal goiter, invasive K)
Drain
Experirence of surgeon, devices. |
| What are general complications and localized complications of thyroidectomy? | Post Op (fever, atelectasis, urine retention, MI)
Local (early [thyroid storm, seroma, bleeding, transient nerve palsy (sup and inf laryngeal), hypoparathyroidism, respiratory distress, wound infection]
Late [hypothyroidism, permenant hypoparathyroidism, permenant laryngeal nerve palsy, recurrence] ) |
| What is the thyrotoxic storm? | Unusual complication resulting from manipulation of thyroid gland during surgery in pt w/hyperthyroidism, can develop preop, intraop, postop.
S&S: Anesthetized pt (increased sympathetic output), Awake pt (nausea, tremor, altered mental status, cardiac arrhythmias, progress to coma in untreated pt
Tx: Stop procedure, admin IV BB, propylthiouracil, sodium iodine, steroids.
Use cooling blankets and cooled IV fluids reduce pt temperature, carefully monitor O2 |
| How is hypocalcemia as a complication of thyroidectomy? | Incidence (increased risk in reop, transient 1.6-83%, permenant 0-14%)
Presentation (acral numbness and parasthesia, perioral parasthesia, general muscle cramps, carpopedal spasm, seizures, cardiac arrhythmias, chvostic sign)
Potential factors (hemodilution [2ary stress w/elevation of Ca], calcitonin release, hungry bone syndrome [hyperthyroidism, osteodystrophy], autoimmune fibrosis [PTH vascularization affected]
hypoparathyroidism [2art to trauma, devascularization, inadvertent excision of 1 more more PTH gland [we preserve them by identifying them and ligating blood supply to distal vessels)
Independent risk factors for hypocalcemia: bilateral thyroidectomy, elevated fT4 level, parathyroid autotransplant |
| How is prevention of thyroidectomy complications? | Routine oral Ca and vit D supplements and autotransplantation of at least 1 PTH reduced hypocalcemia and permenant hypoPTH in total thyroidectomy |
| What is seroma complication of thyroidectomy? | Large dead space, may be followed clinically and allowed to resorb if small and asymptomatic
Large seromas may be aspirated, repeated aspirations may be necessary |
| What is hematoma complication? | 0-30% of cases (if taking AG)
Caused by inadequate hemostasis, increased venous pressure at extubation
May be superficial or deep (increase pressure in neck, compress on great veins, cause laryngeal edema)
Presentation (rapidly expanding hematoma: airway compromise and asphyxation, neck swelling and pain, airway obstruction S&S)
Evaluation (PE [examine for swelling], imaging [in case of neck swelling w/out airway compromise], Fiberoptic laryngoscopy [in pt w/out apparent wound hematoma assess vocal cord function)
Prevention (avoid thyroid tissue trauma, good intraop hemstasis, avoid neck dressings that mask hematoma, drains don't prevent them, major postop bleed need drain to block, but meticulous hemostasis is used more) |
| How is tx of hematoma? | Open wound at bed site, intubate if necessary (O2<89%), give cortisone, OR to evacuate hematoma and stop bleeding |
| What is recurrent laryngeal nerve palsy complication of thyroidectomy? | Most feared one, due to total or partial transection, traction, contusion, crush, burn, misplaced ligamture, compromised blood supply
Intraop identification of RLN is necessary
Consequences (vocal cord paresis/paralysis, transient in 2.6-10% recover w/in 6 months, permenant 0-5.5% no recovery after 6-12 months postop
Unilateral paralysis [hoarseness, breathiness, dysphagia aspiration] Bilateral paralysis after intubation [stridor, respiratory distress or both])
Tx: unilateral paralysis after 6 months go for surgery medialization
Bilateral emergency tracheotomy may be required but first endotracheal intubation, cordotomy and arytendoidectomy done to enlarge airway and permit decanulation of tracheasotomy |
| How is prevention of RLNP? | Intraop neuromonitoring (not very much, advantage over visual monitoring: prevent bilateral RLN injury, prognostic post op nerve fct, detect anatomical variations and abnormal nerve course, higher risk pts [cancer, sacrring] may benfit alot from it |
| What is superior laryngeal nerve injury complication of thyroidectomy? | Injury to nerve of Galli-Cruci external branch of SLN.
Causes ipsilateral cricothyroid muscle paralysis, career threat for singers and voice professionals (Like Galli-Cruci)
Prevention (direct trauma to cricothyroid muscle has similar presentation, dissect near this muscle to avoid electrocautry damage to it when possible)
Tx (Speech therapy |
| What is tracheomylecia? | Rare, long standing goiter compresses trachea, atrophies cartilage, when removing goiter trachea collapses.
Tx by intubation then tracheastomy |
| What are causes of respiratory distress post-thyroidectomy? | Bleeding and hematoma (tx by open wound bed site)
Bilateral recurrent laryngeal nerve injury (tx by intubation)
Tracheomylecia (tx by intubation)
Severe HypoPTH (tx by IV Ca gluconate) |
| How is thyroidectomy complications of thyroid surgery in case of surgeon experience? And Infection? | High volume surgeons (>50 thyroidectomy/year), achieve lower complications and shorter length of stay
Infection (<1-2%, periop AB not benificial, presentation [cellulitis erythema around incision, superficial abscesses, deep neck abscess produce fever, pain, leukocytosis, tachycardia)
Evaluation (send purulence from gram stain and culture, CT image exclude esophageal perforation w/deep nek abscess, gastrograffin useful w/esophageal swallow study
Tx (Cellulitis AB against G+, drain abscess, deep neck abscess broad Spectrum ABs)
Drainage not so much successful can cause inflammation |
| What are devices complications in thyroidectomy? | Less risk of RLNP, intraop blood loss, post op bleed, no difference in rates of transient RLNP, decrease operation time |
