Thyroid Flashcards
Solitary thyroid nodule differentials
follicular Adenoma, cyst, dominant nodule of MNG, thyroid CA
Diffuse thyroid nodule ddx
Graves, simple goitre (iodine difficiency), Hashimoto thyroiditis, subacute thyroiditis, lymphoma
multiple nodules in thyroid ddz
MNG, hashimotos thyroiditis
Thyroid storm diagnosis and management
Burch and watofsky scoring system
- temperature, HR, AF, heart failure, CNS, GI, precipitant history
- ABC
- IV hydrocortisone
- beta blocker (propranolol) - symptomatic relief
- PTU: block TPO - production of new hormones
- Lugol iodine soln (1hr after PTU): block release of thyroid hormones
Definitive: RAI
Hyperthyroid causes
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
Autoimmune markers for Graves and Hashimoto
Graves - Thyroid stimulating immunoglobulins (TSI), TSH R Ab (TRAB), anti-TPO ab
Hashimoto - anti-TPO ab, anti-thyroglobulin Ab
Hypothyroid causes
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
RF for thyroid cancer
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}
Different types of MEN
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)
Route of spread for follicular and papillary thyroid CA
follicular - blood
papillary - lymph nodes
Poor prognostic factors for thyroid CA
AMES
- Age >40
- Metastasis
- Extra thyroid extension
- size > 4
MACIS
- mets
- age
- completeness of resection
- invasion
- size
Actions and side effect of PTU and carbimazole
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
Complications of thyroidectomy
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
Follow up investigations for differentiated ca vs medullary cancers
differentiated (follicular, papillary): thyroglobulin
medullary: calcitonin, CEA
Hypocalcemia symptoms
CATS go NUMB
- convulsions
- arrhythmia (QT elongation > torsades)
- tetany
- parasthesia
chovstek and trousseau sign
Risk stratification of FNAC thyroid findings
Bethesda classification I inconclusive II benign III atypia IV suspicious for follicular neoplasm V suspicious for malignancy VI known malignancy
US thyroid features of malignancy
microcalcifications internal vascularity irregularly shaped, spiculated, infiltrative margins hypoechoic loss of halo taller than wide
More severe variant of
- papillary CA
- follicular CA
- medullary CA
pap: tall cell variant
fol: hurtle cell variant
med: sporadic variant
Thyroid lymphoma most common cell type
non hodgekin B cell (require excision biopsy)
Radical Neck Dissection
- what structures removed in classical sx
- what cx
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
Total thyroidectomy - advantage and disadvantages
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
Indications for thyroid sx (6Cs)
cancer, cannot be treated medically, cosmesis
compressive, compliance/ cost, child bearing
replacement for hypocalcemia
PO: calcium carbonate + calcitriol
IV: 10ml of calcium gluconate 10% over 10min
Triggers of thyroid storm
surgery, infection, withdrawal of drugs, radio iodine
