Thyroid Flashcards
Congenital Thyroid Disease
Linryology gual thyroid
Ectopic thyroid tissue
Thyroglossal cyst
Embryology
Thyroid migrates from its origin at the foramen caecum at the base of the tongue.
Passes behind the hyoid bone
Lies anterior to 3rd-4th tracheal rings in the
pretracheal fascia.
Leaves behind the thyroglossal cyst which atrophies
Persistence → thyroglossal cyst
Ectopic thyroid tissue can be found anywhere along this
descent
Goitre Differential
Diffuse Simple colloid goitre Endemic: iodine deficiency Sporadic: autoimmune, hereditary, goitrogens (e.g. sulphonylureas)
Graves’
Thyroiditis
Hashimoto’s
De Quervain’s
Subacute lymphocytic (e.g. post-partum)
(multinodular goitre c¯ nodules too small to palpate)
Multinodular
Multinodular colloid goitre (commonest)
Multiple cysts
Multiple adenomas
Solitary nodule Dominant nodule in multinodular goitre Adenoma (hot or cold) Cyst Malignancy
Thyroid lump Ix
Bloods
TFTs: TSH, fT3, fT4
Other: FBC, Ca2+, LFTs, ESR
Antibodies: anti-TPO, TSH
Imaging CXR: goitres and mets High resolution US CT Radionucleotide (Tc or I) scan (hot vs. cold)
Histology or cytology
FNAC (can’t distinguish adenoma vs. follicular Ca)
Biopsy
Laryngoscopy
Important pre-op to assess vocal cords
Simple goitre
Diffuse painless goitre Mass effects - dysphagia - stridor - SVC obstruction usually euthyroid, may be hypothyroid
Cause Endemic - iodine deficiency Sporadic - autoimmune - goitrogens (sulphonylureas) - hereditary (dyshormogenic)
Mx
thyroxine
Total or subtotal thyroidectomy if pressure Sx
Multinodular Goitre
Evolves from long-standing simple goitre
mass effects
Euthyroid (or hyperthyroid)
Causes - same as simple goitre
Mx
Thyroxine
Total or subtotal thyroidectomy if pressure Sx
Plummer’s Toxic Multinodular Goitre
Multinodular goitre
Thyrotoxicosis
Uneven iodine uptake with hot nodule
Cause
Autonomous nodule develops on background multinodular goitre
Mx
Carbimazole
radioiodine
total or subtotal thyroidectomy
Grave’s Disease
Diffuse goitre w bruit Opthalmopathy Dermopathy Thyrotoxicosis Assw other AI disease (T1DM, PA) ^uptake on radionucleotide scan
Cause - AI (T2 hypersensitivity) - anti-TSH
Mx Propanolol Carbimazole Radioiodine thyroidectomy
Hashimoto’s Thyroiditis
Diffuse goitre - may have transient thyrotoxicosis > hypothyroidism
Assw other AI Disease (T1DM, PA)
Cause - Autoimmune T2, T4 hypersensitivity
- AntiTPO, anti-Tg
Mx
levothyroxine
de Quervain’s
Diffuse painful goitre
preceding viral URTI common
Thyrotoxicosis > hypo> eu
decreased iodine uptake
Causes - Viral - coxackie common
AI
Mx - self-limiting
Subacute lymphocytic Thyroid disease
Diffuse painful goitre
may occur post-partum
thyrotoxicosis > hypo > eu
autoimune
conservative Mx
Riedel’s thyroiditis
Firm fixed irregular thyroid mass
mass effects
assw retroperitoneal fibrosis
Cause - AI fibrosis
Mx - conservative
Follicular adenoma
Single thyroid nodule +/- thyrotoxicosis (majority are cold)
May get pressure Sx
Mx - hemithyroidectomy
Thyroid cysts
solitary thyroid nodule
ASx or pressure Sx
can > localised pain due to cyst bleed
Mx - aspiration or excision
Follicular adenoma
single thyroid nodule
+/- thyrotoxicosis (majority are cold)
May get pressure Sx
Mx - hemithyroidectomy
Malignant Thyroid Disease
Pete fucked many angry ladies
Papillary
Follicular
Medullary Anaplastic
Lymphoma
Papillary Thyroid Cancer
80%
assw irradiation
20-40
Follicular cells
Tg tumour marker
Spread - nodes + lung - JDG node = lateral aberrant thyroid
often multifocal
Mx
- total thyroidectomy +/- node excision +/- radioiodine
T4 to suppress TSH
>95% 10 years
Follicular Thyroid Cancer
10% 40-60
F>M 3:1
Follicular cells
Tg tumour marker
Spread - blood > bone + lungs
Mx - total thyroidectomy + T4 suppression + radioiodine
> 95% 10 years
Medullary Thyroid Cancer
5%
30% familial (eg MEN2) >60
Parafollicular C-cells
CEA and calcitonin markers
Mx - do phaeo screen pre-op
Thyroidectomy, node clearance, consider radiotherapy
Anaplastic Thyroid Cancer
Rare >60
F>M 3:1
Undifferentiated follicular cells
Spread - rapid growth, aggressive local LN + blood
Mx - usually palliative, may try thyroidectomy + radiotherapy
<1% 10 years
Lymphoma (thyroid)
5%
MALToma in Hashi’s
Lymphocytes
Mx chemoradiotherapy
Thyroid Cancer Presentation
Non-functional (cold) Painless neck mass Cervical mets Compression Sx - dysphagia - stridor - SVC obstruction
Thyroid cancer RF for malignancy in thyroid Nodules
Solitary solid younger male cold radiation exposure
Thyroid surgery Indications
5Ms
mechanical obstruction malignancy marred beauty (cosmetic) medical Rx failure - thyrotoxicosis Mediastinal extension - can't monitor changes
Practicalities of thyroid surgery
Render euthyroid pre-op
- stop 10 days prior to surgery (they ^ vascularity)
- alternatively just give propanolol
check for phaeo pre-op in medullary carcinoma
Laryngoscopy - check vocal cords pre and post-op
Procedure - collar incision
Complications of thyroid surgery
early
Early
Reactionary haemorrhage → haematoma (<1%)
Can → airway obstruction.
Call anaesthetist and remove wound clips
Evacuate haematoma and re-explore wound
Laryngeal Oedema
Damage during intubation or surgical
manipulation
Can → airway obstruction
Recurrent Laryngeal nerve palsy (0.5%) Right RLN more common (oblique ascent) Damage to one → hoarse voice Damage to both → obstruction needing tracheostomy
Hypocalcaemia
Parathyroid dysfunction but may be permanent if parathyroids removed
Presents @ 24-48hrs
Tingling in fingers and lips
Wheeze / stridor → airway obstruction
Chvostek’s and Trousseau’s
Rx: 10ml 10% Ca gluconate IV
Thyroid Storm
- Severe Hyperthyroidism
- Rx - propanolol, antithyroid drugs, Lugol’s iodine
+ hydrocortisone sodium succinate
Complications of thyroid surgery
late
Hypothyroidism
recurrent hyperthyroidism
keloid scar
