THYROID SWELLING Flashcards
DOMINANT SWELLING
Discrete swelling with evidence of abnormality elsewhere in the gland
classify thyroid swelling
SIMPLE GOITRE(EUTHYROID)
1.diffuse hyperplastic (physiological , pubertal , pregnancy)
2. multinodular goitre
TOXIC
1. diffuse (graves disease)
2. multinodular
3. toxic adenoma
NEOPLASTIC
1. benign
2. malignant
INFLAMMATORY
1. autoimmune (hashimoto , c/c lymphocytic thyroiditis)
2. granulomatous(de Quervains)
3. fiibrosing (riedel’s)
4.infective (acute , chronic)
5. other (amyloid)
chronic infections of thyroid
TB , Syphilis
stimulus to thyroid follicles
TSH , Immunoglobulins
Stages in goitre formation
- persistent growth stimulation - diffuse hyperplasia
*later fluctuating stimulation - mixed pattern of areas of active and inactive lobules
*active lobules become more vasular and hyperplastic until hmg and necrosis occur
*necrotic lobules coalasce to form nodules - most nodules are inactive and active nodules are present only in internodular tissue
why goitre more common in females
owing to the presence of estrogen receptors in thyroid tissue
GOITROGENS
Brassica vegetables - cabbage , kale , rape (contains thiocyanates)
calcium
iodine deficiency
iodide excess(inhibits organic binding of iodine)
drugs (PAS , anti thyroid drugs)
thiocyanates , perchlorates (interfere with iodide trapping)
thiouracil , carbimazole (interfere with oxidation of iodide)
indications for surgery in simple goitres
underlying malignancy
pressure symptoms
cosmetic reasons
Dunhill procedure
aka near total thyroidectomy
total lobectomy with subtotal resection of contralateral lobe
solitary nodule thyroid
a discrete swelling in an otherwise impalpable gland
15% are malignant
modality of choice to see tracheal compression and deviation
CT
INDICATION FOR SURGERY IN SNT
RISK OF MALIGNANCY - FOLLICULAR ADENOMAS & PROVEN MALIGNANCIES
POINTS FAVOURING HIGH RISK OF MALIGNANCY
Hard with irregular borders
fixity
RLN palsy is almost pathagnomic
lymphadenopathy with IJV involvement is almost diagnostic
recurrent cysts
discrete swelling in a male
either end of age range
lifelong risk of recurrence and thyroid failure in subtotal resections
5%
upto 100% at 30 years
graves disease pathology
hypertrophy and hyperplasia due to abnormal TSH-RAb that binds to tsh receptor sites
highly vascukar
diffuse toxic goitre appearing the same time as hyperthyroidism
primary thyrotoxicosis
frequently associated with eye signs
55% have family h/o autoimmune endocrine diseases
toxic nodular goitre pathophysiology
secondary thyrotoxicosis
goitre is present long time before hyperthyroidism
usually the internodular tissue is the one that is overactive
histology in hyperthyroidism
normally acini lined by flattened cuboidal epithelium
in thyrotoxicosis , there is hyperplasia of acini, which are lined by high columnar epithelium , many are empty or with vacuolated colloid in scalloped pattern
thyrotoxicosis treatment
rest
sedation
antithyroid drugs (failure rate :55%)
surgery(rapid cure)
radioiodine(destroys thyroid cells)
disadvantages of radioiodine
isotope facilities must be available
patient must be quarantined while radiation levels are high
avoid pregnancy
avoid close physical contact especially with children
eye signs may aggravate
carbimazole block and replace regimen
doc
started 30-40 mg/day
once euthyroid - 5mh 8H with
maintenance dose of 0.1 mg thyroxine
last dose of carbimazole given the evening prior to surgery
thyroid storm treatment
iv fluids ,ice packs , oxygen ,sedation
diuretics for cardiac failure
digoxin for atrial fibrillation
iv hydrocortisone
carbimazole 10-20 mg Q6H
sodium iodide 1 g iv or lugols iodine 10 drops by mouth Q8H
proprano;o; 1mg iv or 40 mg Q6H
CLASSIFY THYROID NEOPLASM
BENIGN - Follicular adenoma
MALIGNANT –
PRIMARY
1. follicular epithelium - differentiated - follicuar(10%) , papillary(80%)
2. follicular poorly differentiated - anaplastic(5%)
3. parafollicular cells - medullary ca(2.5%)
4. lymphoid cells(2.5%)
SECONDARY 1. Metastatic 2. local infiltrates
oncogene in PTC
ret PTC3 - very aggressive short latency PTC
ret PTC1 - less aggressive
de quervains thyroiditis ? management ?
fever , malaise , irregulr firm tender swelling
T4 high normal
I123 uptake low
prednisolone 20-30 mg daily for 7 days and then gradually taper over 1 month
riedels thyroiditis
thyroid tissue is replaced by cellular fibrous tissue , which infiltrates through the capsule to muscles and adjacent organs
very hard and fixed
riedels thyroiditis treatment
high dose steroids
tamoxifen
thyroxine replacement
why diarrhea in medullary ca thryoid
5 hydroxytryptamine and prostaglandin release by tumour
mdullary ca thyroid marker
arises from parafollicular c cells, derived from neural crest cells
CEA , calcitonin
thhey are not TSH dependeny and hence do not uptake I 123
RADIOIODINE REFRACTORY DOSEASE
with advancing age and particularly if the disease is multiply recurrent , the tumour will lose iodine avidity
they can be considered for external beam radiotherapy
threos
greek - shield
father of modern thyroid surgery
theodor kocher
