primary hyperthyroidism
thyroid gland is over functioning
secondary hyperthyroidism
gland is hyperfunctioning because it is being OVERSTIMULATED BY TSH, reflecting a primary problem in pituitary gland
Tertiary hyperthyroidism
too much TSH because there is too much hypothalamic TRH
Hyperthyroidism (signs and symptoms)
- hypermetabolism: weight loss, muscle atrophy, heart intolerance, increased appetitie
–> young female or middle age man (use a fan, use restroom a lot)
- Enhanced epinephrine effect shows as tremulousness and anxiety
–> a very fine fluttering speaks for hyperthyroidism
Lid lag
delay in downward movement of the upper eyelide as tha patient looks down
- it is enhanced by the opthalmopathy of GRAVES DISEASE
atrial fibrillation
is particularly likely to result from hyperthyroidism
(younger female)
Thyroid storm
- is the most dreaded problem in hyperthyroidism
- this development of extreme metabolism, leading to coma and death, when the hyperthyroid patient is subjected to some other major phsyiologic stress
Graves Disease***
- Autoimmune, with production of a IgG antibody directed against TSH receptor binding domain
–> TSH receptor autoantibodies (TRAb) (continuous stimulation of TSH receptor)
- HIGH T3 and T4, low TSH
- Female to male ratio: 5:1
_** DIFFUSE, SYMMETRICAL BEEFY RED GLAND**_
Symptoms of graves disease
- usual LID LAG of hyperthyroidism
- weak eye muscles
- excess collagen and ground substance behind the eyeball
** RESULTING IN PROPTOSIS/EXOPHTHALMOS** (angry eyes)
- usually antibodies against both eye mucles and the fibroblasts behind the eye
- PRETIBIAL MYXEDEMA = myxedema-like nodules confined to anterior aspects of the lower extremitiets (autoantibodies against fibroblasts) (RARE)
describe teh microscopic description of GRAVES DISEASE
**
- Hyperplastic follicles with papillary infolding (finger projections)
- Pale colloid with resorption vacuoles (SCALLOPING)
Hypothyrodism: signs and symptoms
- Slowing of mind and body is prime problem (LADIES)
- mental slowness, fatigue, irritability, and loss of interest may be mistaken for, and treated as depression
- down syndrome patients often get lymphocytic thyroiditis, and they may end up hypothyroid
- Myxedema: accumulation of hydrophilic ground substance throughout the connective tissue of the body (NO NODULES)
–> leads to coarsening of the facial features, enlargement of the tongue, puffiness around the eyes, and deepening and croaking of the voice
Cretinism signs and symptoms
- HYPOthyrodism presenting first in infancy or childhood
- CHARACTERISTICS: STUNED GROWTH (short stature), RETARDED MENTAL DEVELOPMENT, delayed bone and tooth development
- DISTICT FEATURES
–> facial swelling, puffy eyelids, protruding tongue, low hair line, altered eyebrows
Cretinism tx
- These people reamin like small children both mentally and physically throughout their lives
–> replacing thyroid hormoen later in life helps, but DOES NOT revers the damage
–> for BEST RESULTS, YOU MUST TREAT BEFORE THE 3rd WEEK
Hashimoto thyroiditis
- common, chronic, progressive thyroid disease
- Deficiency in Treg (regulatory T cells)
- can be triggered by viral infection –> induces HLA Dr antigen expression
- prototypical example of autoimmune disease
describe gross and micro anatomy of Hashimoto thyroiditis *********
- GROSS: DIFFUSELY ENLARGED THYROID, capsule is intact and well dmearcated; CUTTING SURFACE is PALE, yellow-tan, FIRM
- MICRO STRUCTURE:
- MONONUCLEAR INFLAMMATORY INFILTRATES
- Well-developed germinal centers
- Thyroid follicles are atrophic and are lined in many areas by epithelial cells distinguished by the presence of HURTHLE CELLS
Describe Hurthle cell
- abundant eosinophilic, granular cytoplasm
- metaplastic response (metaplasia) of the normal low cuboidal follicular epithelials to ongoing injury
De Quervain (subacute granulomatous) thyroiditis
- generally secondary to viral infecty by mumps, adenoviruses, echo, coxsacki
**PAINFUL******
- transient hyperthyroidism - wks to months goes away by itself
Pathology: granulomas with giant cells, macrophages, lymphocytes and destroyed thyroid follicules (low yeild)
CLINICAL: increased ESR rate, transient increase of T3/T4 and decreased TSH
GOITER***********
- THYROIDS ABILITY TO PRODUCE THYROID HORMONE IMPAIRED–> INCREASED TSH –> MAINTENANCE OF EUTHYROID STATE
- Non-nodular enlargement of gland (at first and can become nondular)
- 8:1 ratio in women vs men
- Due to LOW IODIDE, decreased T3/T4 and compensatory increase of TSH, with resulting gland growth
–> secondary to goitrogenic foods: cabbage, cauliflower, brussels sprouts, turnips
Colloid Goiter –> Multinodular goiter
- Colloid goiter is a forerunner of nodular goiter
- Multinodular goiter
–> increased size and lobulation of gland
–> must be differentiated from neoplasm (without capasule)
–> 50% of cases result in toxic nodular goiter resembles thyrotoxicosis of graves dieases without exophthalamos or dermatopathy
Pathology = colloid rich follicles of varying sizes with flattened epithelium
–> nodules, hemosiderin, hemorrhage, calcification
Describe hot and cold noduels
- Cold nodules = in the thyroid gland are palpable mass lesions that FAIL TO TAKE UP RADIOLABELED IODINE during nuclear scans
- HOT NODULES are palpable mass lesions that are hyperfunctioning and accumulate INCREASED AMOUNTS OF RADIOIODINE relative to surround normal during a scan
- FIne needle aspiration biopsy of cold nodules is commonly use to help distinguish benign thyroid conditions from more serious thyroid cancers that require surgical removal
Thyroid adenomas
- most patients are adults, and there is modest femal preponderance
- thyroid adenomas have virtually NO TENDENCY to turn malignant
- Typical adenoma is a solitary SPHERICAL ENCAPSULATED lesion that is demarcated from surrounding thyroid parenchyma by well defined, INTACT CAPSULE
describe the categories of thyroid cancer
- Papillary = large majority will NOT DIE; can be cured (65% of cancers)
- follicular = maybe 50% will eventually die of it if it is frankly invasive
- medullary = 50% 5-year mortality if sporadic
- anaplastic = ALL WILL DIE of it in short order
