Thyroid & Parathyroid Flashcards
1
Q
Thyrotoxicosis
A
- Increased free T4/T3 w/low TSH causes symptoms:
- GIT=Mal-absorption <strong>(diarrhea)</strong>
- <em><strong>Constitutional</strong></em>=Heat intolerances, weight loss, sweating
- Cardiac=Palpitation, Tachycardia, A Fib <strong>(increase Beta adrogenergic receptors)</strong>
- Thyroid myopathy <strong>(Proximal muscle weakness)</strong>
- Tremor
- Staring gaze & Lid lag
- Hyperparathyroidism (increase in I131 uptake):
- Graves (Auto-Ab)
- Toxic multinodular goiter (Plummer’s disease)
- Toxic adenoma <u>(decreased </u>uptake of I 131)
- Transient thyroiditis
2
Q
Graves Disease
A
- Age 20-40 Autoimmune condition (female common)
- Associated w/Human leukocyte Ag (HLA-DR3)
- SLE & pernicous anemia <strong>(loss of parietal cells)</strong>
- Due to Anti-TSH receptor Ab
- Thyroid stimulating Immunoglobulin <strong>(TSI)</strong>
- Thyroid growth stimulating Immunoglobulin<strong> (TGI)</strong>
- TSH receptor binding inhibitor immunoglobulin <strong>(TBIIS)</strong>
- Diffuse symmertric hyperplasias of gland
- Histo: Follicle lined by tall columnar cells, Papillary projections w/<u>scalloped appearance</u>
- Low TSH w/HIGH free T4-Diffuse increased I 131 uptake
- Symptoms:
- Opthalamopathy-exopthalmus (eye popping)
- Can be present even after accumulation of fat & immune cells behind eye
- Dermopathy-Peritibial myxedema (doughy skin)
- Thyroid storm-Brought on by stress (shock)
- Treat: Beta blockers & Thiomide (No free T3/T4 made peroxidase blocker)
3
Q
Secondary Hyperthyroidism
A
- Primary reason Pit adenoma
- TSH normal or **Elevated **
- Free T3 & T4 VERY high
- No increase in I 131 uptake
4
Q
Hypothyroidism-General
A
- Child = **Cretinism (Low T4) **
- Adult = Primary (thyroid) & Secondary (Hypopit)
- <u><strong>Secondary-</strong></u>Low Free T4/T3 w/Low TSH
- <u><strong>Secondary-</strong></u>Hypothalamic failure or Pit necrosis <strong>(Sheehan’s)</strong>
- Primary: Autoimmune or NON-autoimmune Thyroiditis
- LOW free T4/T3 w/very HIGH TSH
- Categories:
- <strong>No goiter </strong>= idiopathic <u>(most common in US)</u>
- Iodine def <u>(sub-himalayan Asia)</u> w/Goiter
- Cretinism + Goiter-<u>Umbilical hernia, protruded tongue, impaired development</u>
- <em><strong>Hashimoto’s thyroiditis </strong></em>+ Goiter
5
Q
Hypo/Hyper thyroidism-Myxedema
A
- Associated w/Severe-long standing Hypothryroidism
- Accumulation of mucopolysacs <strong>(proteoglycans) </strong>in Subcut tissue
- Also seen in Graves-Eyes & Tibia
- Symptoms:
- Mental obtundation (not alert)
- Mortality is over 50%
- Bradycardia & Hypotension present
- Hypothermia
6
Q
Primary Hypothyroidism (Autoimmune)
A
- TSH Very high <strong>(greater 10)</strong> & free T3, T4 LOW
- Brief period of increased T3/4 = **Hashitoxocosis **
- Release of thyroxin from damaged follicles
- High cholesterol & TAG lvls w/chance of coronary atherosclerosis & reduced cardiac output
- Hashimoto’s Thyroiditis:
- Age 45-65 common female
- PAINLESS diffuse symmetrical enlargement of gland
- Histo: Hurthle cells (Eosinophilic-Degenerated follicular-altered Mitochondria)
- Assoc w/HLA DR3 & DR5 (SLE, RA, Sjogren’s)
- Increased risk of non-Hodgkin’s lymphoma
- due to chornic inflammation of <u>germinal centers</u> <u>(B-cell-marginal cell lymph)</u>
- Diffuse infiltrate of lymphoid cells<u>-CD8/4</u>
- Antibodies are-marker for thyroid damage:
- Antithyroglobulin
- Antimicrosomal <u>(<strong>thyroid peroxidase</strong>-liberates iodine to thyroglobulin make T3/4)</u>
- Anti-TSH receptor Ab <strong><u>(inhibitory)</u></strong>
7
Q
Subacute Granulomatous Thyroiditis
A
- “De quervain’s disease”-Does not progress to Hypothyroidism
-
Post-Viral infection-Female 30-50
- <strong>Coxsackie, mumps, adenovirus</strong>
- Tender firm enlarged gland-“Painful”
-
Transient thyrotoxicity in progression later normalizes
- Increased WBC & ESR
- Self-limiting w/in 6-8 weeks
- Histo: large foreign body giant cells & granuloma w/inflammatory destruction of follicles
8
Q
Riedel Thyroiditis
A
- Chronic form of thyroiditis-Hypothyroidism
-
Dense fibrosis in thyroid & can spread to trachea/esophagus
- Mimics carcinoma-<em><u>Anoplastic unidffer </u>disease of elderly</em>
- Symptoms-Young women:
- Stridor, dyspnea, dysphagia
- “Hard as wood”
- Associations:
- Retroperitoneal & severe mediastinal fibrosis
- Idiopathic pulm fibrosis/scleroderma-ANAs
9
Q
Thyroid Cyst
A
-
Thyroglossal duct cyst: Midline ant neck
- Move up & down w/swallowing
- Below hyoid bone
- Remnant of thyroglossal duct
- Atrophic thyroid tissue found
- Branchial (cleft) cyst: Lateral neck
- Smooth, nontender, fluctuant masses
- Cong epi cysts
- Lined by ciliated columnar epi <strong>(resp & lymph)</strong>
- Squamous epi & lymph w/germinal follicle=<strong>Thyroglossal cyst</strong>
- Failure of obliteration of second branchial cleft
10
Q
Goiter (Diffuse non-toxic)
A
- Goiter: Diffuse enlargement of thyroid
- Prolonged iodine def (Euthyroid)
- Colloid goiter (single nodule) & Multi nodular (MNG)
- Normal free T4 w/slight increase in TSH
11
Q
Goiter (Multinodular)
A
- Non-toxic & Euthyroid (normal function)
- Complication:
- Plummer Syndrome: Nodules become toxic (make T4) develops hyperthyroidism
- Multi-focal I131 uptake (scattered)
- Can progress to Follicular carcinoma
- Morphology: Enlarged thyroid gland w/multiple colloid nodules (Tend NOT to spread)
- Histo: Follicles vary in size w/clacification & fibrosis
12
Q
Thyroid adenoma (follicular)
A
- Cold - Thyroid = Taking up LESS I 131
- Indicative of Adenoma OR Carcinoma
- Follicular adenoma:
- Single encapsulated & firm
- RARE can produce T4 (HOT) toxic adenoma (single area)
- Well formed capsule = Well circumscribed nodule
13
Q
Thyroid Carcinoma (Papillary)
A
- Most Common-Assoc w/neck radiation in early life
- Genetics-Rearrangements=tyrosine kinase receptors (RET)
- Spreads to lymphatics-regional (cervical)=<u><strong>Good prognosis</strong></u>
- Clinical-PAINLESS mass in ant neck
- Histo:
- Psammoma body (“orphan Anny”) Swirl collection of Ca+2
- Intranuclear pseudo inclusion bodies
- Papillary structure-Optically clear hypochromatic nucleus
14
Q
Thyroid Carcinoma (Follicular)
A
- Mostly Cold & rare Hot
- Males more affected (40-60)
- Genetics: Mutation HRAS, NRAS, KRAS
-
Hematogenous (blood) travels to bone/lung=BAD prognosis
- Renal cell, Hepato, Chorio
- Histo: Vascular invasion of capsule
- Invasion mediated by-
- laminin receptor in tumor
- production of Cathepsin D
- Collagenase 4
- Proteases
15
Q
Thyroid Carcinoma (medullary)
A
- Parafollicular C-cell<strong> (neuroendocrine)</strong>-Malignant
- Produces Calcitonin <strong>(Hypocalcemia-counters PTH)</strong>
- Association with MEN 2a/2b in older pt:
- MEN2a-Medullary Carcinoma + hyperparathyroid + pheochromocytoma
-
MEN2b-Medullary Carcinoma + Pheochromocytoma + Neuroma of GIT
- RET gene mutation in Young pt
- Symptoms: Flushing, diarrhea, itching
- Morphology: “Multicentric”
-
Histo: Spindle cells**+Pink **amyloid stroma
- <strong>(calcitonin deposits as amyloid)</strong>
