thyroid and parathyroid Flashcards
1
Q
what is the function of the thyroid gland?
A
secrete thyroid hormone
secrete calcitonin
2
Q
Thyroglobulin
A
Protein that synthesizes and stores T3 and T4
3
Q
Thyroid hormones
A
T3 (3,5,3’-triiodothyronine)
T4 (thyroxine)*
4
Q
Hyperthalamus
A
releases TRH > TSH > T3/T4 to liver
…and
circulatory system –> which inhibits anterior pituitary gland and hypothalamus
5
Q
2 causes of hypothyroidism
A
Generalized metabolic slowing
accumulation of matrix substances
6
Q
S/s of Generalized metabolic slowing of hypothyroidism
A
Fatigue, weakness Cold intolerance Weight gain Cognitive dysfunction Constipation Slow movement/speech Delayed relaxation DTRs Bradycardia
7
Q
s/s of accumulation of matrix substances of hypothyroidism
A
Dry skin Hoarseness Edema Coarse skin Puffy facies Loss of eyebrows Periorbital edema Tongue enlargement
8
Q
other s/s of hypothyroidism
A
Decreased hearing Myalgias/arthralgias/paresthesias Depression Menstrual changes Pubertal delay Diastolic HTN Pleural and pericardial effusions Ascites Galactorrhea
9
Q
PE for pt suspected of hypothyroidism includes:
A
Vitals Skin HEENT Neck Cardiac Respiratory Abdominal GU Neuro Extremity
10
Q
PE exam findings for hypothyroidism
A
Vitals - bradycardia, HTN
respiratory - dec CO, dyspnea
skin - dry, hair loss, brittle nails, vitiligo, alopecia
abd- ascites, hypoactive bowel sounds, constipation
extremity- edema, carpal tunnel syndrome d/t edema
11
Q
Labs for hypothyroidism
A
TSH (if only for screening):
**Free T4 (most important)
T3
other: BMP (Na & Cr), lipids (elevated), drug levels
12
Q
what will TSH look like in hypothyroidism?
A
TSH will be high
upper limit of normal, usu. 4-5mU/L
13
Q
what will T4 and TSH look like in primary hypothyroidism?
A
T4 = low TSH = high
14
Q
what will T4 and TSH look like in subclinical hypothyroidism?
A
T4 = normal TSH = high
15
Q
Anti TPO antibody expected result…
A
Elevated in Hashimoto’s thyroiditis
Elevated in Grave’s disease
16
Q
Anti thyroglobulin antibody expected result…
A
Elevated in Hashimoto’s thyroiditis
Elevated in Grave’s disease
17
Q
Thyroid Stimulating Immunoglobulin (TSH Receptor Antibody) expected result…
A
Grave’s disease (65%)
18
Q
when are you NOT concerned if pt has anti-thyroid antibodies?
A
if pt is asymptomatic
19
Q
hypothyroidism etiology?
A
Autoimmune thyroiditis (Hashimoto’s) Iatrogenic (radiation, sx) Iodine deficiency or excess Meds Transient Infiltrative (rare) Congenital
20
Q
which pt’s are at increased risk for hypothyroidism?
A
Goiter History of autoimmune dz Previous radioactive iodine therapy Hx head/neck irradiation Family hx thyroid disease Meds that impair thyroid fx
also, pt’s with lab or radiologic abnormalities that could be caused by hypothyroidism
21
Q
which meds are known to impair thyroid function?
A
Lithium, amiodorone, aminoglutethimide, interferon α, thalidomide, betaroxine, stavudine
22
Q
what is the main tx & management for hypothyroidism?
A
Synthetic thyroxine (T4) replacement
to achieve and maintain euthyroid state
23
Q
what meds are used to tx hypothyroidism? and why is it a good functional med?
A
Levothroid, Levoxyl, Synthroid
High absorption, long half life
24
Q
what is the average dose for Levothroid, Levoxyl, Synthroid?
in elderly?
hx Coronary hx dz?
A
dose avg. 1.6mcg/kg/day
elderly - 25-50mc/kg/day
hx Coronary heart dz - 25mc/kg/day
25
goals of tx for hypothyroidism?
Symptom relief
Normalization of TSH secretion
If applicable, decrease in goiter size
26
how often should you monitor pt when administering new medications?
q 6weeks
27
what are other tx options available for hypothyroidism? why are they not 1st line?
T3 (Cytomel)/T4 combo therapy (bad bc highly variable w/short half life)
Dessicated thyroid extract (Armour Thyroid, Nature Throid) (absorption/metabolized variable)
28
how many pt's w/subclinical hypothyroidism progress to overt hypothyroidism?
1/3 to 1/2
29
possible assoc. with subclinical hypothyroidism?
CV disease
NAFLD
Neuropsychiatric
Reproductive
30
tx for subclinical hypothyroidism?
TSH > 10 --> supplement w/thyroid hormone
TSH ULN - 10 --> clinical presentation??
(but free T4 normal)
31
etiology of hyperthyroidism?
MC = Autoimmune thyroid disease
Autonomous thyroid tissue
TSH-mediated
hyperthyroidism
Human chorionic gonadotropin-mediated hyperthyroidism
32
what dz's are considered Autoimmune thyroid diseases?
Graves’ disease
| Hashimoto’s thyroiditis
33
what dz's are considered autonomous thyroid tissue?
Toxic adenoma
| Toxic multinodular goiter
34
what dz's are considered TSH-mediated hyperthyroidism?
TSH-producing pituitary adenoma (rare)
| Non-neoplastic TSH-mediated hyperthyroidism
35
clinical presentation for hyperthyroidism?
```
Skin changes
Stare and lid lag
**Graves’ ophthalmopathy (specific finding)
Cardiovascular (tachy, Afib)
Low total and HDL cholesterol
Impaired glucose tolerance
Dyspnea and DOE
Weight loss
Normochromic, normocytic anemia
Genitourinary
Bone changes
Neuropsychiatric change
```
36
labs for hyperthyroidism?
TSH (low), T3 & T4 (high)
other: *TSH receptor antibody
&
antithyroglobulin antibody, antithyroperoxidase antibodies, ANA, anti-dsDNA antibodies
37
diagnostic tools for hyperthyroidism?
24 hour radioiodine uptake and scan
38
Contraindications for 24 hour radioiodine uptake and scan
pregnancy & breastfeeding
39
what does high uptake and low uptake indicate on 24 hour radioiodine uptake and scan?
High uptake = increased hormone synthesis
Low uptake = inflammation/destruction of thyroid gland or extrathyroidal source of thyroid hormone
40
Tx options for hyperthyroidism?
```
Beta-blockers
Thionamides (Methimazole
Propylthiouracil (PTU))
Radioiodine ablation
Surgery
```
41
subacute thyroiditis aka...
granulomatous, de Quervain’s, giant cell thyroiditis
42
clinical presentation for subacute thyroiditis?
p/w acute symptoms or silently
Common in young/middle-aged females
assoc. w/viral illness
acutely painful glandular enlargement with dysphagia
43
who is subacute thyroiditis dx'd
clinical w/labs
44
how is subacute thyroiditis tx'd?
with anti-inflammatories (ASA, NSAIDS, prednisone) and symptom management
45
etiology of thyroiditis?
1. thyroiditis:
subacute granulomatous (de Quervain's) thyroiditis,
painless thyroiditis, postpartum thyroiditis, amiodarone-induced, radiation thyroiditis, palpation thyroiditis
2. Exogenous thyroid hormone intake: excessive replacement therapy, intentional suppressive therapy
46
during 1st trimester pregnancy, what is the preferred med in pregnancy?
propylthiouracil
47
what is a thyroid storm?
Rare, acute endocrine emergency
| w/ high mortality usu. results from an acute event
48
risk factors for thyroid storm?
```
Surgery
Trauma
Infection
Iodine adminsitration
Childbirth
Withdrawal of antithyroid meds
MI, CVA, PE
```
49
clinical presentation for thyroid storm?
```
Cardiac (tachy, CHF, hypotension, arrhythmia)
Fever
Agitation, anxiety, delirium, psychosis
Stupor, coma
N/V/D, abd pain
Hepatic failure/jaundice
Goiter
Ophthalmopathy, lid lag
Hand tremor
Warm, moist skin
```
50
diagnosis of thyroid storm?
Clinical presentation of severe, life-threatening symptoms
+
Low TSH, high free T4/T3
51
thyroid storm tx?
ICU
```
Meds:
Beta-blocker
Thionamide
Iodine solution
Glucocorticoids
Bile acid sequestrants
```
DEFINITIVE THERAPY (ablation therapy)
52
how does BB for thyroid storm work?
symptom control
53
how does thionamide for thyroid storm work?
block new hormone synthesis
54
how does iodine solution for thyroid storm work?
blocks release of thyroid hormone from gland
55
how does glucocorticoids for thyroid storm work?
reduces T4 to T3 conversion, promotes vasomotor stability, treat associated related adrenal insufficiency
56
how does bile acid sequestrants for thyroid storm work?
decrease enterohepatic recycling of thyroid hormones
57
benign etiology of thyroid nodules?
Multinodular goiter
Hashimoto’s thyroiditis
Cysts
Follicular adenomas
58
malignant etiology of thyroid nodules?
```
Papillary carcinoma
Follicular carcinoma
Medullary carcinoma
Anaplastic carcinoma
Primary thyroid lymphoma
Metastatic carcinoma (breast, renal cell)
```
59
thyroid nodule cancer concerning factors?
```
kids, men, adults <30 y/o, >60 y/o
hx of head/neck radiation
hx hematopoeitic stem cell transplant
family hx thyroid cancer
size (larger)
```
60
what is the most important lab value to evaluate w/ workup of thyroid nodules?
TSH
61
what imaging do you order if thyroid nodule found?
thyroid ultrasound
62
which is worse "hot or cold" nodule on radioactive scan?
COLD
63
next step for solitary nodule with low TSH...
thyroid scan
64
next step for solitary nodule with normal TSH...
FNA, consider US
65
what type of nodule do you NOT want to bx? (major contraindication)
if it is a "HOT" nodule
66
what is a FNA bx?
Procedure of choice to evaluate nodules and select surgical candidates
done by palpation or U/s guided in office
large nodules do multiple samples
67
what size of nodule do you do a FNA?
≥ 1 cm unless high risk hx then >5mm
68
what findings are worrisome and indicative for FNA?
lymph nodes, micro-calcifications, solid masses on u/s
69
Management of benign FNA results?
Repeat U/S 6-18 months to assess stability
| Growth > 20% - repeat FNA
70
incidence of thyroid carcinoma?
Incidence & mortality increase with age
More common in females
Worse prognosis:
< age 20
> age 45
Male gender
71
risk factors for thyroid carcinoma?
History of childhood head or neck irradiation
Thyroid cancer in first degree relative
Large nodule size (≥ 4 cm)
72
types of thyroid cancer?
```
Papillary (~85%)
Follicular (~12%)
Anaplastic (<3%)
Medullary (~1-2%)
Primary thyroid lymphoma (<2%)
Mets from other site
```
73
Tx for thyroid carcinoma
```
Surgery (near total thyroidectomy)
TSH Suppression (Levothyroxine)
Radioiodine ablation
Chemotherapy
Palliative external radiotherapy
```
74
monitoring for thyroid carcinoma post-tx management
Serum thyroglobulin level, anti-thyroglobulin antibodies
Neck ultrasound
Serum TSH level
+/- Diagnostic whole body radioiodine scan
MRI, CT, PET as appropriate
75
what is the fx of the parathyroid gland?
Parathyroid hormone secretion to help regulate calcium homeostasis
Also helps regulate phosphate
Negative feedback w/calcium sensing receptor on surface of parathyroid cells
76
slide 54
54
77
what are examples of parathyroid disease?
Hypoparathyroidism
| Hyperparathyroidism
78
MC reason for hypoparathyroidism?
Acquired, usually occurs post-thyroidectomy
other: autoimmune, congenital
79
Clinical presentation
sxs assoc. w/low Calcium
```
Tetany
Muscle cramps
Caropopedal spasm
Chvostek sign
Trousseau phenomenon
Cataracts
Thin/brittle nails
Dry, scaly skin
AMS
convulsions
```
80
hypoparathyroidism lab values...
```
serum calcium (low)
serum phosphate (high)
urinary calcium (low)
alkaline phosphatase (norm)
PTH (low)
Mg (low to norm)
```
81
Tx for hypoparathyroidism?
Emergency treatment for acute tetany:
IV calcium gluconate plus oral calcitriol (wean to oral calcium)
Airway maintenance
82
maintenance tx for hypoparathyroidism?
Oral calcium and vitamin D supplementation
Avoid hypercalcemia
2nd line tx: recombinant hPTH
83
Hyperparathyroidism etiology
Primary hyperparathyroidism
Secondary or tertiary hyperparathyroidism
Multiple endocrine neoplasia (MEN)
84
etiology for Primary hyperparathyroidism
```
Parathyroid adenoma (MC)
Parathyroid hyperplasia
Parathyroid carcinoma (rare)
```
85
Secondary or tertiary hyperparathyroidism etiology
1. Chronic renal failure
(Hyperphosphatemia and ↓renal vitamin D production → ↓ ionized calcium, which stimulates the parathyroids)
2. Renal osteodystrophy
86
clinical presentation of Hyperparathyroidism
Asymptomatic hypercalcemia
“bones, stones, abdominal groans, and psychiatric moans”
87
clinical presentation of hyperparathyroidism?
```
Renal
MSK
GI
Neurologic
CV
```
88
diagnostics for hyperparathyroidism?
Elevated calcium
Elevated serum PTH level
Urinary calcium excretion
89
Tx for hyperparathyroidism?
Surgical resection is definitive = Parathyroidectomy
```
Conservative treatment:
Physical activity
Drink adequate fluids
Avoid lithium and HCTZ
Restrict calcium intake to 1000 mg/day
Vitamin D 400-600 IU daily
Monitor
```
90
conservative tx of of Primary hyperparathyroidism?
IV bisphosphonates can temporarily ↓ hypercalcemia and treat bone pain
Zoledronic acid (Reclast)
91
Secondary or tertiary hyperparathyroidism conservative tx?
Cinacalcet (Sensipar), paricalcitol (Zemplar)
