Autonomously functioning "hot" thyroid nodules

- rate of carcinoma in an autonomously functioning thyroid nodule: 0.7%
(Mizukami et al, Am J Clin Path 1994)

Thyroid MCQ

 1)    to prove a thyroid cyst is benign:

a)     CT neck

b)    cytology and FNA

c)     US

d)    thyroid scan

2)    the best treatment for a women with a thyroid nodule which is hot on thyroid scanning and decreased TSH and increased free T4 is:

a)     radioactive iodine

b)    thyroid suppression

c)     operation

d)    FNAB to R/O malignancy

e)     Observation

3)    thyroid nodule 4cms in size:

a)     observe

b)    suppress

c)     resect

4)    what is the best initial investigation for a solid mass in the thyroid:

a)     US

b)    Thryroid function test

c)     FNA

d)    Scan

e)     serial physical exam

5)    10 yo seen by school nurse, found 3cm mass non-tender inferior aspect of the thyroid:

a)     observe and reasses in 6 months

b)    thryroid suppression

c)     radioactive iodine

d)    operate

e)     wait until puberty

6)    with regards to thyroid ca:

a)     lymphatic spread

b)    hematogenous spread

c)     may be multinodular and encapsulated

d)    mets may look normal

Complications of Thyroxine

What are the complications of Thyroxime?

Hyperthyroidism:

Surgical Management of Hyperthyroid:
- Grave's disease
- Toxic nodular goitre (single or multiple)
- Amiodarone-induced thyrotoxicosis

Preop preparation of patients required to normalize T3/T4 using thioamides.  In the past super-saturated potassium iodide or Lugol's solution used to resture thyroid function and decrease thyroid vascularity but does so only temporarily.

Medical management:
- Thioamides (propylthiouracil, methimazole): decrease thyroid hormone synthesis, takes several weeks to take effect.  Effective in 90% of patients, but relapses occur in ~80% of pts.  Complications: Agranulocytosis rare (0.5%)
- Radioactive iodine 131-I, highly effective in Grave's disease (90%), pt becomes hypothyroid.  Can worsen thyrotoxicosis
- 131-I contraindicated during pregnancy or in lactating mothers

Pemberton's Sign:
- facial plethora, inspiratory stridor, venous congestion when arms raised above head
- sign of jugular venous compression (thoracic outlet obstruction can be from large goiter)

Hyperthyroidism Questions:

1)    indications for surgery in hyperthyroidism, all except:

a)     childhood

b)    pregnancy

c)    reoperation for hyperthyroidism

d)    toxic adenoma

e)     toxic multinodular goiter

2)    a 30yo nurse presents with a 3 week history of malaise and weakness. Her thyroid gland is diffusely enlarged and tender. Her ESR is slightly elevated, and her T4 is twice normal. What should be done:

a)     total thyroidectomy

b)    radioactive iodine ablation

c)    treatment with NSAIDS and rest

d)    treatment with propanolol and PTU

e)     FNA

3)    a 35yo male has an asymmetrically enlarged thyroid gland. The ESR is 60. T4 is 180 and iodine uptake is 4%. He most likely has:

a)     Graves

b)    Ridel’s struma

c)     Haschimotos disease

d)   subacute thyroiditis

e)     toxic multinodular goitre

4)    Hashimoto’s thyroididtis may be associated with:

a)     follicular thryroid ca

b)    papillary thyroid ca

c)    lymphoma

d)    leukemia

e)     Hurtle cell tumors

5)    which of the following statements regarding Hashimoto’s thyroiditis is not true:

a)     it is the commonest type of thyroiditis

b)    there is a familial predisposition

c)     the gland is infiltrated with giant cells

d)    it occurs mostly in the middle age females

e)     antithyroid Ab may be present

Recurrent Laryngeal nerve anatomy

RLN arises from the vagus nerve
- passes beneath vessel derived from the primitive 4th aortic arch
- on the right it recurs around the subclavian artery
- on the left it recurs around the aortic arch
- 1% of patients have a retroesophageal right subclavian artery and the laryngeal nerve arises directly from vagus to the larynx

Association with the inferior thyroid artery is variable.  Most course anterior to all branches, some course between branches and a few course totally behind branches of the inferior thyroid artery.
- text advocates encircling inferior thyroid artery as it arises from carotid and lifting it up to try and help identify the RLN.

Most consistent location of RLN is its insertion between the thyroid and cricoid cartilage.  Even in cases of recurrent laryngeal nerves it inserts in this location.  Its location relative to the cornu of the thyroid cartilage is quite consistent.
- This is where DCW looks for RLN initially.

External branch of the superior laryngeal nerve runs along the cricothyroid membrane and care should be taken to avoid damaging the SLN.

Silver and Rubin Atlas of Head and Neck Surgery: pg 284

Adequate Thyroid FNA sample

Criteria for cytologic adequacy of thyroid FNA:

- 6 follicular cell groups
- each containing 10-15 cells
- from at least 2 aspirates of a nodule

Thyroid Ultrasound Characteristics suspicious for malignancy

- nodule Hypoechogenicity
- Irregular infiltrative margins
- increased intranodular Vascularity
- presence of microCalcifications
- an Absent Halo
- shape Taller than the width measured in transverse dimension

DCW Thyroid

- mark and infiltrate with 20cc local
- Transverse neck incision with scalpel
- create flaps using scalpel +/- cautery
- use russian foreceps to open linea cervicalis

- Cautery create areolar plane between straps and thyroid
- Davey-Langenbach retraction to create plane
- Finger on thyroid to roll up and out

- start at superior pole and take superior thyroid artery vessels carefully with mccabe dissector
- once near cricothyroid membrane then go work on inferior pole
- identify nerve at cricothyroid membrane along with parathyroid
- inferior para usually in the thyrothymic ligament
- save the attachement at the cricothyroid membrane for last
- clip or tie off everything
- leave a ?drain in every case - remove POD#1
- close line with vicryl
- interrupted vicryl for platysma, vicryl for skin and perfect steris

Finding the Parathyroid Glands

Superior:

Inferior:
- identify the thyrothymic ligament - inf para usually located within or adjacent to thyrothymic ligament

Non-recurrent Laryngeal nerve

- rare: 1%

- Direct laryngeal nerve that comes off the vagus.

- more common on the right

- resutls of an anomalous origin of the right subclavian artery off the descending aorta

- if not recognized will result in division thinking it is the inferior thyroid artery - and it is the reason it is important to identify the RLN before dividing vascular structures

Thyroid anatomy

Differentiating Hyperthyroid Disease States