Thyroiditis Flashcards
1
Q
Thyroiditis
A
- Subacute (granulomatous)/Dequervain thyroiditis
- Reidel thyroiditis
- Hashimoto thyroiditis
- Lymphocytic thyroiditis
- Graves Disease
2
Q
Features of Dequervain thyroiditis
A
- probably due to viral infection/post-viral inflammatory process
- cytotoxic T cell mediated injury
- more common in women (3-5x), 30-50y
3
Q
Clinical features of Dequervain thyroiditis
A
- short history (weeks), self limiting
- pain in the neck, goitre
- mild hyperthyroidism - hypothyroidism - euthyroid
- systemic symptoms eg fever, malaise
4
Q
Morphology of Dequervain thyroiditis
A
G:
- enlarged, firm gland, uni/bilateral
- patchy appearance - firm, pale yellowish areas w intervening normal brown parenchyma
M:
- destruction of follicles, neutrophils/microabscesses (acute inflammation)
- lymphocytes, plasma cells, histiocytes around damaged follicles (chronic inflammation)
- multinucleated giant cells, engulfing pools of colloid
5
Q
Features of reidel thyroiditis
A
- rare, unknown etiology
- extensive fibrosis of thyroid & surrounding structures
- hard fixed mass in the neck
6
Q
Features of hashimoto thyroiditis
A
- more common in women (10-20x), 45-65y
- association with HLA - DR3, DR5
- familial clustering
7
Q
Pathogenesis of hashimoto thyroiditis
A
- Immune mediated cytotoxic destruction of thyrocytes
- Sensitisation of CD4+ Th cells to thyroid antigens
- cytotoxic CD8+ T cell mediated cell death
- activation of B cells - autoantibodies against thyroglobulin, TSH receptor & thyroid peroxidase
8
Q
Clinical features of hashimoto thyroiditis
A
- Painless goitre, often diffuse
- Lab tests
- low T3, T4
- high TSH
+/- preceding thyrotoxicosis
9
Q
Morphology of hashimoto thyroiditis
A
G:
- pale (lymphoid follicles overrun normal parenchyma)
- enlarged gland (mostly diffuse
- pale yellow firm cut surface +/- nodular
M:
- infiltrates - reactive lymphoid follicles, lymphocytes, plasma cells
- thyroid follicles - atrophic, Hurthle (oncocytic) cell change (metaplasmic change - normally small & cuboidal but instead large, with abundant, dense, eosinophilic cytoplasm)
- fibrosis
10
Q
Effects & complications of hashimoto thyroiditis
A
- Hypothyroidism
- Risk of other autoimmune disorders eg type 1 DM, SLE, Sjogren
- Develop to B cell lymphoma of thyroid
11
Q
Features of Grave’s Disease
A
- also a form of thyroid hyperplasia
- most common in women (7x), 20-40y, assoc w family Hx, HLA-B8, DR3
12
Q
Pathogenesis of Grave’s Disease
A
Breakdown in Th cell self tolerance to thyroid auto-antigens - resulting in production of autoantibodies to TSH receptor
13
Q
Clinical features of Grave’s Disease (5)
A
- Hyperthyroidism, lid lag
- Infiltrative Ophthalmopathy
- exophthalmos - extracellular material deposited in retro-orbital space - Infiltrative Dermopathy - pretibial myxedema
- dep of extracellular material in the shin, scaly thickening & induration, firm when palpated, discolouration
- due to lymphocytic infiltration & deposition of ecm proteins - Thyrotoxicosis
- Diffuse goitre +/- bruit (dynamic circulation - high metab)
14
Q
Tests for Grave’s Disease
A
- Biochemical - raised free T3, T4, low TSH, increased radio iodine uptake
- Serology - autoantibodies
15
Q
Morphology of Grave’s Disease
A
G:
- symmetrical diffuse enlargement
- soft, reddish (vascular) meaty cut surface
M:
- follicular cells - tall columnar crowded - pseudopapillae
- pale scalloped colloid (due to active colloid reabsorption)
- lymphoid infiltrates, reactive lymphoid follicles
