Thyroid

Question 1

Solitary thyroid nodule differentials

Answer 1

follicular Adenoma, cyst, dominant nodule of MNG, thyroid CA

Question 2

Diffuse thyroid nodule ddx

Answer 2

Graves, simple goitre (iodine difficiency), Hashimoto thyroiditis, subacute thyroiditis, lymphoma

Question 3

multiple nodules in thyroid ddz

Answer 3

MNG, hashimotos thyroiditis

Question 4

Thyroid storm diagnosis and management

Answer 4

Burch and watofsky scoring system
- temperature, HR, AF, heart failure, CNS, GI, precipitant history

1. ABC
2. IV hydrocortisone
3. beta blocker (propranolol) - symptomatic relief
4. PTU: block TPO - production of new hormones
5. Lugol iodine soln (1hr after PTU): block release of thyroid hormones

Definitive: RAI

Question 5

Hyperthyroid causes

Answer 5

Primary - Graves, Toxic adenoma, Toxic MNG

Secondary

• TSH secreting adenoma
• gestational thyrotoxicosis
• ovarian teratoma (struma ovari), choriocarcinoma (produce both HCG and TSH)
• metastatic thyroid ca

Others - Reactive/ De Quervain (release), drugs (amiodarone, lithium), iatrogenic thyroid hormones

Question 6

Autoimmune markers for Graves and Hashimoto

Answer 6

Graves - Thyroid stimulating immunoglobulins (TSI), TSH R Ab (TRAB), anti-TPO ab
Hashimoto - anti-TPO ab, anti-thyroglobulin Ab

Question 7

Hypothyroid causes

Answer 7

Primary - Hashimoto, autoimmune (microsomal ab), iodine deficiency
- others: thyroid resection, malignant infiltration, drugs (amiodarone, lithium), genetics - pendred syndrome (b/l SNHL + goitre + hypothyroid)
Secondary - hypopituitarism, low TSH

Question 8

RF for thyroid cancer

Answer 8

General: Age, men
family history - FAP, Gardner {papillary} MENII {medullary}
Previous radiation {pap}/ occupational exposure
smoking
personal hx of thyroid dz- long standing goitre {ana}, lymphoma & Hashimoto {lymphoma}, MNG {follicular}

Question 9

Different types of MEN

Answer 9

Multiple Endocrine Neoplasia (AD inheritance)

MENI: Pituitary, parathyroid, pancreas

MENIIA (sipple): Medullary thyroid CA, phaeochromocytoma, parathyroid

MENIIB (William): Medullary thyroid CA, phaeo
(with mucosal neuromas, marfanoid habitus)

Question 10

Route of spread for follicular and papillary thyroid CA

Answer 10

follicular - blood

papillary - lymph nodes

Question 11

Poor prognostic factors for thyroid CA

Answer 11

AMES

• Age >40
• Metastasis
• Extra thyroid extension
• size > 4

MACIS

• mets
• age
• completeness of resection
• invasion
• size

Question 12

Actions and side effect of PTU and carbimazole

Answer 12

PTU

• MOA: inhibit TPO - oxidation, organification, coupling
• SE: hepatotoxicity
• not first line, but used in thyroid storm
• used in 1st T of pregnancy

Carbimazole

• MOA: inhibit TPO
• SE: agranulocytosis, rash (hypersensitivity), arthralgia, cholestatic hepatitis
• 2nd and 3rd T pregnancy

Question 13

Complications of thyroidectomy

Answer 13

Immediate:

• damage to nerves
• -> external branch of superior laryngeal nerve: inability to produce high pitch sound, voice fatigueability (divide superior thyroid artery close to gland)
• -> recurrent laryngeal artery: U/L hoarseness, B/L acute breathlessness (airway compromise KIV intubation) (divide inferior thyroid artery away from gland)
• thyroid hematoma (remove sutures holding down strap muscles)
• tracheomalacia (due to long standing large goitre compressing trachea)
• thyroid storm

Early:

• Hypocalcemia (due to hypoparathyroidism/ hungry bone syndrome)
• infection

Late

• permanent hypoparathyroidism/ hypothyroidism
• cancer/ hyperthyroid recurrence

Question 14

Follow up investigations for differentiated ca vs medullary cancers

Answer 14

differentiated (follicular, papillary): thyroglobulin

medullary: calcitonin, CEA

Question 15

Hypocalcemia symptoms

Answer 15

CATS go NUMB

• convulsions
• arrhythmia (QT elongation > torsades)
• tetany
• parasthesia

chovstek and trousseau sign

Question 16

Risk stratification of FNAC thyroid findings

Answer 16

Bethesda classification
I inconclusive
II benign
III atypia
IV suspicious for follicular neoplasm 
V suspicious for malignancy
VI known malignancy

Question 17

US thyroid features of malignancy

Answer 17

microcalcifications
internal vascularity
irregularly shaped, spiculated, infiltrative margins
hypoechoic
loss of halo
taller than wide

Question 18

More severe variant of

• papillary CA
• follicular CA
• medullary CA

Answer 18

pap: tall cell variant
fol: hurtle cell variant
med: sporadic variant

Question 19

Thyroid lymphoma most common cell type

Answer 19

non hodgekin B cell (require excision biopsy)

Question 20

Radical Neck Dissection

• what structures removed in classical sx
• what cx

Answer 20

Structures:

• sternocleidomastoid
• spinal accessory nerve
• internal jugular vein

Complications (CHIIPS)

• carotid blowout
• hematoma
• injury to nerve: vagus (VC paralysis), cervical sympathetic chain (horners), mandibular branch of facial nerve (parathesia)
• infection
• poor healing
• salivary fistula

Question 21

Total thyroidectomy - advantage and disadvantages

Answer 21

Advantages:

• reduce cancer recurrence (micro-mets)
• can use adjuvant RAI
• can use radio iodine and thyroglobulin as markers for recurrence

Disadvantage

• life long thyroid replacement
• micro-mets risk not big
• risk of b/l recurrent laryngeal nerve palsy, hypoparathyroidism

Question 22

Indications for thyroid sx (6Cs)

Answer 22

cancer, cannot be treated medically, cosmesis

compressive, compliance/ cost, child bearing

Question 23

replacement for hypocalcemia

Answer 23

PO: calcium carbonate + calcitriol
IV: 10ml of calcium gluconate 10% over 10min

Question 24

Triggers of thyroid storm

Answer 24

surgery, infection, withdrawal of drugs, radio iodine