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PT2B3 > Lecture 87/88 -Thyroid path and thyroid disorders > Flashcards

Lecture 87/88 -Thyroid path and thyroid disorders Flashcards

1
Q

what is the fucntional unit of the thyroid? what is produced?

what other hormone is produced in the thyroid and by what cell type?

A

Follicles – produce colloid (stores of thyroid hormone)

Parafollocular cells (C cells) – Produce calcitonin

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2
Q

_____ is responsible for the formation of thyroid hormone

A

peroxidase

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3
Q

most thyroid hormone is secreted as ___- and then converted to ___ in the periphery by ____

___ is more biologically active

A

T4
T3 – more biologically active
5’ Deiodinase

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4
Q

Describe the effects of Thyroid hormone on bone, brain, CV, metabolsim?

A

○ Bone – activation of ostoclasts
§ FIRST AID: Bone growth and maturation

○ Brain – Stimulates axonal growth and development

○ Blood/CVD – Increased CO, Blood volume and Decreases SVR

§ FIRST AID: Increased B1 adrenergic receptors

Basal Metabolic Rate –
§ Liver – regulates lipid metabolism
§ Fat - increases lipolysis
§ GI – bowel regularity

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5
Q

Etiologies of primary hypothyroid disease

A 
Hashimoto's 
Post Ablative
Iodine Def 
Transient (post thyroiditis) 
Congenital
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6
Q

what is the most common cause of hypothyroid

what additional test is important to run if this is suspected?

A

Hashimoto’s

Autoantiboides: Anti-Thyroid Peroxidase, Anti Thyroglobulin

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7
Q

anticipated labs for primary hypothyroid

A

high TSH
Low T3/T4
+/- AntiTPO antibodies

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8
Q

Etiologies of Central hypothyroid

A

Aquired vs congenital deficiencies of pituitary disorders, hypothalamic disorders, TSH deficiency or TSH receptor defect

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9
Q

how can a patient with resistance to the Thyroid hormone present as either hyperthyroid or hypothyroid?

A

Mutation to the Thyroid Receptor; will depend on how diffuse the mutation is.

If only on Pitutitary – negative feedback is disrupted; pt appears hyper

If diffusely mutation in the periphery – pt not able to respond at all to hormonme; appears hypo

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10
Q

What is a Myxedema coma

what are some of the significant findings?

A

severe long stanidng hypothyroidism;

may lead to AMS, Bradycardia, heart block, prolonged QT, Hypotension, Delayed DTR relaxation, hypoventilation, Sz

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11
Q

• Hypothyroid In Pregnancy –

possible complications?

A

maternal – pre-eclampsia, hemorrhage, miscarriage, abruption,

Fetal – low weight, impaired cognition,

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12
Q

what is the gold standard of the thyroid function test?

what are the anticipiated labs for:

1) primary hypo
2) central hypo
3) Thyroid hormone resistance

A

Free T4

1) Primary hypo: High TSH, low T4
2) Central: Low TSH, Low T4
3) Resistance: High TSH, High T3/4, but no response

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13
Q

what is the difference between thyrotoxicosis and Hyperthyroid

A

○ Thyroidtoxicosis - physiologic manifestations of excessive quantities of thyroid hormone
○ Hyperthyroidism – Thyroidtoxicosis caused by d/o overproduction of thyroid hormone

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14
Q

signs and symptoms of HyperThyroid- -

what sx might be different between older and younger pts

A

younger – Sympthatic activation (anxiety, hyperactivity, tremor)

Older – CV symptoms (afib, dyspnea)

General – heat intolerance, weight loss, increased appetite, diarrhea, increased reflexes, insomina, nervousness,

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15
Q

signs and symptoms of hypothyroid

A

fatigue, lethary, somnolence, weight gain, decreased appetite, cold intolerance, dry skin, hair loss (lateral 1/3 of eye brow)

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16
Q

Most common cause of thyrotoxicosis

underlying pathophysiology

signs and symptoms

A

Grave’s Disease

Pathophys; IgG activation of the TSH receptor

signs and symptoms:
Peritibial myxedema, Exophthalmos, lid edema, Vitiligo, Dermopathy

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17
Q

Other etiologies of primary hyperthyroid

A

graves

Toxic MNG

Toxic Adenoma –

Beta HCG

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18
Q

What is the difference between toxic MNG and toxic thyroid adenoma

A

Toxic MNG – 2 or More Focal patches of Hyper-functioning follicular nodules;

Toxic Adenoma – single hyper functioning nodule

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19
Q

how can beta HCG induce hyperthroid?

A

Shared Alpha subunit homology with TSH

during pregnancy or trophoblastic tumors

20
Q

what is a thyroid storm?

is this fatal?

A

Emergency Hyperthyroid

Stress induced catecholamine surge

Some symptoms can be fatal:
tachyarrythmias, tachypnea,
other: Fevre, AMS, HTN

21
Q

etiology of secondary hyperthyroid

what other features may also be present?

A

TSH producing pituitary adenoma

Bi temporal hemianopsia

25% also produce high prolactin

22
Q

2 situations of transient hyperthyroid

A

Subactue Thyroiditis – (Quevain’s) ; hyperthyroid early in the course

Post Partum Thyroiditis – hyperthyroid for first few weeks, then hypothyroid for a few months before leveling out

23
Q

anticipated labs for:

1) primary hyperthyroid
2) secondary hyperthyroid

A

Primary – high t3/4; low TSH
+/- TSI antibodies

Secondary - -High t/3/4, high TSH

24
Q

high t3 + positive TSI is indicattive of

A

Graves disease

25
Q

first line imaging to help narrow the differentiate of hyperthyroid

what would anticpated results be for :
Graves
Toxic MNG
Thyroiditis

A

Thyroid Uptake and Scan –
Graves – uptake all over

Toxic MNG – multiple islands of increased uptake

Thyroiditis – no increased uptake (pt is hyperthyroid because inflammation has released all stores of thyroid hormone)

26
Q

Medical management of hypothyroid patients

A

§ Levothyroxin (Synthroid) – Synthetic T4 – the main treatment

§ Synthetic T3 – rarely used (much more potent)

27
Q

medical management of hyperthyroid

drugs + mechanisms

A

Non selective beta blockers (propranolol –which also exhibits some peripheral t4 conversion)

Antithyroid Drugs:
Mthimazole – blocks peroxidase

PTU - blocks peroxidase and 5’ deiodinase

28
Q

Thyroid ablation tehcniques

A

Radioactive Iodine – (I 131) –

Surgery followed by anti-thyroid meds; then followed up thyroid supplements

29
Q

patient presents with anterior midline mass which moves with swallowing. pathology reports a SCC lining. what is the dx?

A

Thyroglossal duct cyst

30
Q

Patients with Hashimotos are at increased risk for____

A

lymphoma

31
Q

patient presents with hyperthyroid symptoms 1 week after viral infection; thyroid is inflammated and tender to palpation on exam. what is the dx? what is the likely histological path

A

Dx; Subacute Thyroiditis

Histo: Patchy distribution;
early – neutrophils
later: giant cells, granulomatous; possible fibrosis

32
Q

patient presents with a multi nodular goiter and has no sx of hypo or hyper thyroid. how should you proceed?

what are the odds this is malignant?

A

FNA

Malignant –

33
Q

patient presents with a multi nodular goiter and has no sx of hypo or hyper thyroid. how should you proceed?

A

FNA

34
Q

(hot vs cold) nodules are more likely to be benign

__% of solitary thyroid nodules are malignant

more likely to be malignant if ____ patient

A

Hot nodules – more likely benign

10% solitary nodules are malignant

higher suspicion of malignancy if young male patient

35
Q

what cytologic characterisitics on FNA are used to help differentiate between malignant and benign thyroid neoplasms

how do you proceed if malignant

what other classification may be considered

A

Benign Follicular Neoplasm:
Lots of colloid, Low cellularlity, Macrofollicular

Malignant Suspicion:
Lots of cells, low colloid, Microfollicular
30% malignancy risk
(Tx - Thyroidectomy)

Atypica of Uncertain Significance (AUS);
mixed features;
5-10% risk of malignancy
Management -Repeat the FNA

36
Q

what is the most common solitary thyroid nodule

A

Follicular adenoma

37
Q

Described similar and different pathological findings between Follicular Adenoma vs Follicular Carcinoma

A

Follicular Adenoma –
Tumor is confined to a well defined thyroid capsule
mixed Macro vs Microfollicular

Follicular Carcinoma -
Tumor with thyroid Capsular and Vascular invasion
Microfollicular; uniform

Both: Hurtle Cell Changes

38
Q

prognosis and treatment of Follicular carcinoma

A

Good prognosis –

Tx - Thyroidectomy + RAI

39
Q

what is the most common thyroid carcinoma

what is the prognosis

how do you treat

A

Papillary carcinoma

prognosis: Excellent; 90% 10 year survival

Thyroidectomy + RAI

40
Q

Histological findings of Papillary carcinoma

A

Psammoma bodies;

Nuclear enalrgement, crowding and overlap

Nuclear Features: Oval Nuclei, Nuclear grooves, overlapping nuclei, Orphan Annie Eyes

41
Q

which thyroid cacncer has the poorest prognosis

A

○ Undifferentiated (Anaplastic) Carcinoma – rapidly enlarging

42
Q

○ Undifferentiated (Anaplastic) Carcinoma

who presents with this?
Common clinical symptoms
gross path
histo path

A

Older patients (mean: 65 yo)

Symptom: Hoarseness of voice

Gross: large mass invading beyond the thyroid

Histo: highly anaplastic cells, spindled, giant cells

43
Q

all thyroid cancers are dervied from _____cells, except for ____ which comes from _____

A

Follicular cells

Exception: medullary carcinoma

C cells (parafollicular)

44
Q

medullary Carcinoma –

a/w what congenital d/o –
what lab might be elevetaed
some histo findings

A

MEN2A and 2b (RET mutations)

high calcitonin

Histo: solid sheets of cells iwth amyloid deposition

45
Q

Lymphoma of the thyroid gland is associated with_____

A

hashimotos’

46
Q

tumors of what other organs can met to the thyroid

A

Lung, Esophagus, Breast, Kidney

rare overall

PT2B3 (23 decks)

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