Thyroid Pathology Flashcards
(27 cards)
Why are fine needle aspirates used instead of biopsies for the thyroid?
Thyroid is highly vascular therefore biopsies are dangerous
What effects does TSH have on the thyroid apart production of thyroid hormone?
Hyperplasia
Hypertrophy
Increase coroid production
What type of cells surround thyroid follicles?
Epithelial
How can you tell that a thyroid follicle is active?
Scalloping of the coroid
The columnar epithelial cells are taller
Does Hashitoxicosis cause hypothyroidism or hyperthyroidism?
Hyperthyroidism
Hypothyroidism causes what symptoms?
Hypometabolic state
– Cold intolerance; cold thickened skin; alopecia
– Weight gain (despite decreased appetite); fatigue
• Sympathetic nervous system underactivity
– Bradycardia, angina, CHF; slow-relaxing reflexes
– GI (constipation);mood, concentration; other…
- Children: developmental abnormalities, cretinism
- TSH,fT4(generally)
What are the 4 most common causes of hypothyroidism?
Iodine deficiency
Hashimoto’s thyroiditis
Iatrogenic
Thyroid removal
What are the symptoms of hyperthyroidism?
• Hypermetabolic state
– Heat intolerance; warm flushed skin; fatigue
– Weight loss (despite increased appetite); osteoporosis
• Sympathetic nervous system overactivity
– Palpitations, atrial fibrillation, cardiomegaly, CHF
– Tremor, anxiety, insomnia, emotional lability – GI (diarrhoea), MSK, ocular (lid lag), other…
Exophthalmos
Is thyrotoxicosis the same as hyperthyroidism?
No, thyrotoxicosis is excess thyroid hormones by any means not necessarily a overactive thyroid
T/F Simple goitres are usualy euthyroid
True
How do simple goitres occur?
Thyroid hormone decrease (via some mechanism eg iodine deficiency) > TSH increases > Stimulates growth of the thyroid > Normal levels of thyroid hormone are achieved
What are some causes of simple goitre?
Iodine deficiency
Goitrogen consumption
How do simple goitres appear histologically?
Hyperplastic
Follicles lined by crowded cells
Some follicles are larger than others
May have large colloid-filled cysts
How do simple goitres become multinodular?
Prolonged stimulation with TSH can cause follicles to rupture and fibrose or become large nodules
What are Toxic multinodular goitres?
Goitres nodules that have been independent of TSH and hyperactive
When don’t Toxic multinodular goitres cause hyperthyroidism?
When there isn’t enough iodine to produce the thyroid hormones
What is Pemberton’s sign?
When there is venous congestion due to the goitre
How do you treatment simple or nodular goitres?
Iodine or thyroid hormone
Surgery
What are the four histology signs of Hashimoto’s disease?
- Formation of lymphoid follicles
- Marked changes in thyroid epithelial cells
- Extensive formation of new connective tissue
- Diffuse “round cell” infiltration
What are Hürthle cells?
Thyroid cells with seen in Hashimoto’s with abundant, eosinophilic, granular cytoplasm
How does the thyroid gland appear in Hashimoto’s disease?
Pale
Firm
Tan-yellow
Nodular
What is the immune mechanism of Hashimoto’s thyroiditis?
- CD8+ cytotoxic cell-mediated cell death
- Cytokine-mediated cell death (e.g. IFN-γ, Fas)
- Maybe Antibody-dependent cell-mediated cytotoxicity
- TSH-blocking ABs further reduce thyroid function
What is the histopathology of Grave’s disease?
• Follicular cells are tall and more crowded: diffuse hypertrophy and hyperplasia
– May form papillae in follicle lumen
• Widespread scalloping of colloid
– Colloid is often paler-staining
• Lymphocytic infiltrates
What is the gross pathology of the thyroid in Grave’s?
Diffusely larger
Soft and meaty
