Thyroid and Parathyroid Flashcards
1
Q
function of thyroid gland
list hormones as well
A
Secretion of hormones
- Thyroxine T4
- Triiodothyronine T3
- Reverse T3 (inactive form of T3)
- Calcitonin
Both modulate metabolism
- Energy utilization
- Heat production
Regulate/facilitate growth
Brain development
2
Q
biofeedback control of thyroid hormones
A
- Hypothalamus releases Thyroid Releasing Hormone (TRH) –> Stimulates pituitary to release TSH
-
TSH then binds to the thyroid, which then secretes T4 and T3 –> inhibit secretion of TSH
- directly and indirectly by suppressing the release of TRH
3
Q
list common dz assoc w/ hyperthyroidism
A
Graves disease (autoimmune) 60% of cases
- Autoantibodies bind to the TSH receptor –> stimulate the gland to ‘hyper function’ –> excess hormones
Toxic multinodular goiter
- Focal or diffuse follicular hyperplasia
- High level of nodularity
Toxic nodular goiter (Plummer’s disease)
- Single hyperfunctional nodule
- “Hot” on thyroid scan
Other
- Pituitary adenoma (TSH secreting)
- Meds (ex. amiodarone, lithium)
- Head/neck radiation
- Neck surgery
4
Q
si/sx of hyperthyroidism
A
- Periorbital edema
- Diplopia, Proptosis , Exophthalmos
- Tachycardia/arrhythmia (ex. palpitations)
- Irritability/nervousness
- Sweating/heat intolerance
- DEC concentration/ Fatigue
- Muscle weakness/cramps
- Weight loss despite appetite
- Skin Δ (dermopathy) on lateral aspects of shins
- Acropathy (nail clubbing)
- +/- hyperreflexia
5
Q
dx hyperthyroidism
Graves?
A
DEC TSH
INC T3 (total) /T4 (free)
+/- abs (Graves)
- Anti-thyroid perixodase antibody (Anti-TPO)
- Anti- Thyrotropin receptor antibodies 80-90%
- Thyroid-stimulating immunoglobulin (TSI)
- INC Ca
6
Q
imaging hyperthyroidism
A
US +/- doppler – FIRST line (Cyst vs. solid)
Nuclear scintigraphy w/ RAIU ( uptake)
- Technetium (Tc-99) or Iodine (I-123)
- info about size/shape of gland
- Location of functional activity within the gland
Type of functioning
- Warm/hot “functioning nodule”
- Cold “non-functioning nodule” (malignancy)
7
Q
tx graves dz
A
Thioamides (side of choice agranulocytosis)
- Methimazole –> Requires tapering down to maintenance
- Propythiouracil (PTU) –> pregnancy & Also requires tapering
Mild disease, small goiter –> Goal of remission after 1 year of treatment
- Treat additional year if still (+) antibodies
Pre-op patients –> To get them Euthyroid
Radioactive iodine – Tx of choice
Surgery (subtotal vs. total)
8
Q
Tx of Toxic multinodular goiter
A
Sub-total thyroidectomy > Radioactive Iodine (131 Iodine)
9
Q
tx of Toxic nodular goiter (Plummer’s disease)
A
Radioactive Iodine (131 Iodine) > unilateral lobectomy
10
Q
Toxic multinodular goiter
VS
Toxic nodular goiter (Plummer’s disease)
A
Toxic multinodular goiter - High level of nodularity
- Focal or diffuse follicular hyperplasia
Toxic nodular goiter (Plummer’s disease)
- Single hyperfunctional nodule
- “Hot” on thyroid scan
11
Q
on Nuclear scintigraphy w/ RAIU ( INC uptake) is a warm or cold nodule assoc w/ malignancy
A
Warm/hot “functioning nodule”
Cold “non-functioning nodule” (malignancy)
12
Q
define thyroid storm
A
Untreated hyperthyroidism - SEVERE
•Can be brought on by stress (ex. trauma, MI, infection)
13
Q
si/sx of thyroid storm
A
Exaggerated presentation of hyperthyroidism
- Tachycardiac (>140 bpm)
- HTN à CHF
- Fever (104-106°)
- AMS - Agitation, delirium, psychosis, stupor, or coma
- N/V / Abdominal pain
14
Q
tx thyroid storm
A
Beta-blocker – control HR
IV thionamide - to block new hormone synthesis
PO Lugol’s solution - to block the release of thyroid hormone
Iodinated radiocontrast- to inhibit the peripheral conversion of T4- to-T3
Hydrocortisone - ↓T4-to-T3 conversion
15
Q
define thyrotoxicosis & most commonc cause of it
define subacute thyroititis & common cause
A
16
Q
thyroid scan - diffuse uptake or irregular/diminished upstake
Graves
Toxic multinod
Toxic goiter - plummers dz
A
diffuse uptake - Graves
irregular/diminished upstake
- Toxic multinod
- Toxic goiter - plummers dz
17
Q
list types of Hypothyroidism
A
Hashimoto’s (autoimmune thyroiditis)
- B-lymphocytes invade thyroid and produce autoabs
- Hashimoto’s is #1 cause in US
- Iodine Deficiency #1 cause in developing countries
- Most common inflammatory condition of thyroid gland
- Most common cause of goiter
- ‘Body attacks thyroid’, destroys thyroidà B-lymphocytes invade the thyroid gland –> “chronic lymphocytic thyroiditis”
Other:
- Iodine deficiency
- Thyroidectomy
- Deficient HPO axis - Central hypothyroidism
18
Q
Most common inflammatory condition of thyroid gland
Most common cause of goiter
developing countries?
A
hashimotos hypothyroidism
Iodine Deficiency #1 cause in developing countries
19
Q
si/sx of hypothyroidism
A
- Fatigue/lethargy
- Cold intolerance
- Constipation
- Weight gain / Depression
- Menorrhagia
- Hoarseness
- Weakness/ Myalgias/arthralgias
- HA
- Dry skin
- Coarse, thinning hair
- Periorbital edema
- Bradycardia
- Hyporeflexia - ↓DTRS
Gland is diffusely enlarged; firm and rubbery and nodular –> atrophic and fibrotic
20
Q
dx hypothyroid
A
INC TSH
DEC T3/T4
+/- abs (Hashimoto’s)
- (+) autoantibodies (hallmark)
- High titers of abs to thyroglobulin, thyroid peroxidase
- ↑Anti-Thyroid Peroxidase (TPOAb)
- ↑Thyroglobulin antibody (TgAb)
- Thyroid Stimulating Blocking Antibodies (TSbAb)
Imaging:
- US +/- doppler
- Nuclear scintigraphy w/ RAIU –> (DEC uptake)
21
Q
tx hypothyroidism
A
Levothyroxine (Synthroid) synthetic T4
22
Q
Hyperthyroidism - ___TSH & ___ T3/T4
Hypothyroidism - ___TSH & ___ T3/T4
A
Hyperthyroidism - DEC TSH & INC T3/T4
Hypothyroidism - INC TSH & DEC T3/T4
23
Q
define Myxedema coma
A
complciation opf hypothyroidism
Medication cessation
- Impaired cognition, confusion à coma (myxedema coma)
- Most often seen in elderly and those who have stopped taking meds
24
Q
si/sx of Myxedema coma
A
- AMS
- Severe hypothermia
- Hypoventilation
- Hyponatremia
- Hypoglycemia
- Hypotension
25
Tx Myxedema coma
**IV Levothyroxine** – LARGE DOSES
**Treat hypothermia** – slowly warm to prevent cardiac events
+/- intubation/ mechanical ventilation
Monitor for infection
**+/- hydrocortisone** - Suspected concomitant adrenal insufficiency
25
Complication of hyperthyroid \_\_\_
Complication of hypothyroid \_\_\_
Complication of **hyperthyroid**: _Thyroid storm_
Complication of **hypothyroid**: _Myxedema coma_
26
2 classifications of Thyroiditis
**Painful**- Subacute granulomatous thyroiditis
**Painless**
* Med induced (ex. amiodarone, lithium)
* Hashimoto’s
27
list typea of thyroid nodules
Mostly Benign
## Footnote
* Cyst
* Follicular adenoma
* Colloid nodule
* Malignancy
28
malignnancy suspicition w/ thyroid nodule if..?
* History of head/neck radiation
* Young age
* Recent onset, rapid growth
* Family h/o medullary thyroid cancer
29
dx thyroid nodule
**RAIU scan (hot vs. cold)**
* The hotter the nodule on scan, the less likely lesion/nodule is cancerous
**Tissue Bx**
30
List types of thyroid cancer
Papillary 60%
Follicular 20%
Anaplastic 14%
Medullary 5%
31
si/sx of Thyroid cancer
**•Painless, palpable, firm/fixed nodule**
**•Rapid growth**
* Vocal cord paralysis
* Hoarseness
32
thyroid cancer dx of choice
US guided fine needle aspiration
33
type of thyroid cancer Linked to iodine deficiency
Follicular 20%
34
thyroid cancer w/
## Footnote
↑ serum calcitonin levels confirm diagnosis
Medullary 5%
35
tx of choice for what type of thyroid cancer:
## Footnote
Surgical isthmusectomy to Prevent tracheal compression
Anaplastic 14%
36
tx of thyroid cancers
## Footnote
Papillary 60%
Follicular 20%
Lobectomy on lesions \< 1.5 cm
1.5 cm lesions = near-total thyroidectomy
Life-long levothyroxine after surgery
37
thyroid cancer seen in those \>50 y/o
Anaplastic 14%
38
thyroid cancer seen families (AD)
Medullary 5%
39
dx thyroid cancer: reasons to use
## Footnote
**US guided fine needle aspiration** –
**RAIU thyroid scan** -
**+/- CT/MRI w/o contrast** -
**US guided fine needle aspiration** – dx of choice
**RAIU thyroid scan** - Can provide hint whether malignant or not
**+/- CT/MRI w/o contrast** - Evaluate soft tissue extension of large or suspicious thyroid mass
40
tx of thyroid cancer
**Surgery (subtotal vs. total)**
* Near-total’ vs lobectomy
* Depends on lesion size and type
* Modified neck dissection if evidence of lymph node metastases
**Medication**
_Post-op triiodothyronine (T3_) x 3 months
* Stop T3, 2 weeks later
_Thyroid Scan with radioactive Iodine-131_
* _uptake_…tx w/ radioactive Iodine-131
* _no uptake_…levothyroxine to suppress TSH
Annual f/u
41
tx thyroid cancer:
Thyroid Scan with radioactive Iodine-131
* uptake…tx w/ \_\_\_\_\_
* no uptake…\_\_\_\_\_\_to suppress\_\_\_\_
Thyroid Scan with radioactive Iodine-131
* _uptake_…tx w/ r**adioactive Iodine-131**
* _no uptake_…**levothyroxine** to suppress **TSH**
42
PTH monitors & regulates blood Ca++
Low Ca++ ...?
High Ca++....?
**Low Ca++** --\> _Parathyroid_ glands secrete _PTH_ --\> **↑Ca++**
**High Ca++** --\> _Thyroid_ gland release _calcitonin_ --\> **↓Ca++**
43
when do you need to correct serum Ca++
**When hypo or hyperalbuminemia**
## Footnote
Hypoalbuminemia can cause pseudohypocalcemia
Ca++ = Ca++ measured + (0.8 (4- measured albumin))
44
PTH monitors & regulate PO4 levels
Low PO4
High PO4
**Low PO4** --\> _Parathyroid_ glands secrete _PTH_ --\> **↑PO4**
**High PO4-**-\> _Parathyroid_ glands secrete _PTH_ --\> **↓PO4**
45
2 causes of Hypocalcemia (Ca+ \< 8.5)
more common cause?
**↓ calcium entering the blood-** Most common cause
* Vitamin D deficiency- may be ingesting Ca but unable to absorb from GI tract
* Hypoparathyroidism/Pseudohypoparathyroidism
**Too much calcium leaving the blood**
* Kidney failure- cannot reabsorb Ca++
* 2o Hyperparathryoidism
* Tissue injury & Inflammatory process
* Acute pancreatitis- Free fatty acids bind to free Ca++
* Too many blood transfusions- Additives bind to free Ca++
* Hyperphosphatemia- Ca++ going to bone and extra-skeletal tissue
46
pathophys of hypocalc
PTH stimulates bone resorption --\> release Ca++ from bones into blood
PTH ↑ reabsorption of Ca++ in the kidneys
PTH activates 1, 25-(OH)2 VitD (active form) from 25-(OH) VitD (storage form from diet/sunlight)
Active Vitamin D (1,25-(OH)2 Vit D= calcitriol)
* Active Vit D --\> ↑intestinal Ca++ absorption
47
si/sx of hypocalc
**Chvostek sign & Trousseaus sign**
**Hyperreflexia**
**Tetany**
**Muscle spasms**
Seizures
Abd pain
**Prolonged QTc**
48
dx hypocalcemia
**Chvostek sign & Trousseaus sign**
**ECG** (prolonged QTc)
DEC Ca
Albumin (corrected Ca)
**Dec PTH, Mg, 25-OH Vit D**
**INC PO4**
49
etiology of hypocalcemia
* (INC/DEC ) PTH- Hypoparathroidism
* (INC/DEC ) PTH- Kidney disease, Vit D deficiency, pseudohypoparathyroidism
**↓PTH**- Hypoparathroidism
**↑PTH**- Kidney disease, Vit D deficiency, pseudohypoparathyroidism
50
tx hypocalcemia
**Severe (\<7.5), symptomatic**
* Supp. Mg FIRST
* IV Ca+ gluconate
* Admit to telemetry
**Mild (\>7.5), asymptomatic**
* PO Ca+ replacement
* Vit D repletion
51
most common cause of Hypoparathyroidism
↓PTH (cannot make PTH)
* **Surgery** (thyroid or parathyroid-ectomy,
* head/neck ca.)
* Neck radiation
* Autoimmune
* Genetics
52
si/sx of Hypoparathyroidism
acute
mild-mod
severe
**Acute –** Tetany (hallmark) - neuromuscular irritability
**Mild-Mod**
* Asymptomatic
* Perioral numbness, paresthesias of the hands and feet
* Irritability, lethargy, anxiety
* Muscle cramps/spasms
**Severe**
* Carpopedal spasm (ex. Trouseau’s sign)
* Laryngospasm
* Refractory heart failure
* Seizures
53
dx Hypoparathyroidism
**↓Ca++ (**(PTH causes this to inc normally)
Cr / Albumin
**↓PTH**
Mg
25-(OH) Vit D
**↑PO4 (**PTH causes this to dec normally)
**ECG** --\> QTc prolongation
54
tx Hypoparathyroidism
severe
mild-mod
**Severe**
* IV Ca++
* IV Calcitriol (1,25-(OH)2 VitD – active form)
**Mild- Moderate**
* PO Ca++
* IV Calcitriol (1,25-(OH)2 VitD – active form)
55
define Pseudo - hypoparathyroidism
Condition associated with resistance to PTH
56
dx Pseudo - hypoparathyroidism
↓Ca++
↑PO4
**↑PTH (appropriately high due to low Ca++)**
57
common causes of Hypercalcemia (Ca+ \> 10.5)
**Too much calcium entering the blood**
* Excessive bone resorption
* _Hyperparathyroidism_
* _Malignant Tumors_
* Thyrotoxicosis
* Paget Disease, others
**Excessive calcium absorption**
* Excess Vit D
* Milk alkali syndrome
* Medications (thiazide dueretics)
**Less calcium leaving the blood**
* Adrenal insufficiency
* Adrenal failure
58
si/sx of hypecalc
**“Bones, Stones, Groans, & Psychiatric Moans”**
* **Bone pain, Muscle weakness**
* Nephrolithiasis
* Polyuria
* Fatigue/lethargy
* Confusion, hallucinations
* Anxiety/ depression
* Constipation, Nausea
* **Slow / absent reflexes**
_Calcitonin_
* Secreted from Thyroid gland
* Opposes PTH --\> ↓Ca++ in blood
59
dx hypercalc
* **ECG** (shorted QTc)
* 24-hour urine
* INC Ca
* Albumin **(↑corrected Ca)**
* _↓PTH- Malignancy_, VitD intoxication
* _↑PTH-_ 1o hyperparathyroidism, familial hypocalciuric hypercalcemia, 3o hyperparathyroidism
* DEC Mg
* INC 25-OH Vit D
60
tx hypercalc
mild
mod-severe
**Mild, asymptomatic**
* Treat underlying etiology
* Oral fluids & PO4 repletion
**Mod-severe (\>14), symptomatic**
* IV fluids
* Loop diuretics
* Calcitonin
* Bisphosphonates
* Denosumab
* Prednisone
61
complciations
hypocalc
hypercalc
hypocalc - cardiac arrythmias _(Torsades, afib)_
hypercalc - cardiac arrythmias (_bradycardia_, AV block)
62
names types of Hyperparathyroidism
**Primary** - Parathyroid gland secretes ↑PTH regardless of Ca++ leve
* _Parathyroid adenoma_
* Hyperplasia
* _Carcinoma_
* FHH
**Secondary** - Parathyroid gland hyperplasia
* Prolonged CKD
* Vit D deficiency
**Tertiary** - 2/2 2o Hyperparathyroidism after many years, Parathyroid gland secretes ↑PTH regardless of Ca++ level even if original cause corrected
* ESRD
63
Hyperparathyroidism Dx: Ca PO4 PTH
Primary
Secondary
Tertiary
**Primary - ALL INC PTH**
* _INC Ca_
* _DEC PO4_
* INC PTH
**Secondary** - ONLY one to DEC Ca - (Ca and PO4 Oppisites)
* _DEC Ca_
* _INC PO4_
* INC PTH
**Tertiary**
* INC Ca
* INC PTH
64
dx imaging of Hyperparathyroidism
**DXA scan**- BMD
**Skull Xray**- “salt and pepper” --\> Cystic bone spaces
**Renal imaging** to evaluate for stones --\> XRay, CT, MRI
**Sestamibi pararthyroid scan** --\>Indicated if doing surgery
65
Tx Hyperparathyroidism
asymp
symp
acyte hypercalcemia
**Asymptomatic** : Observation +/- surgery
**Symptomatic**
* Parathyroidectomy
* Cinacalcet
**Acute hypercalcemia**
* IV Fluids
* Loop Diuretics
66
complications of Hyperparathyroidism
**Parathyroid adenoma**
* Profound hypocalcemia (_Hungry Bone Syndrome)_
**Parathyroid carcinoma**: Mets to bone & lung
67
2 associations of Parathyroid Adenoma
**Associated with MEN I** (parathyroid, pancreatic tumor, pituitary adenoma)
**Associated with MEN IIa** (medullary carcinoma of the thyroid, pheochromocytoma, hyperplasia of the parathyroid)
68
Parathyroid Adenoma most common location
**Right inferior gland** most common location--\> Hyperactivity of one gland --\> atrophy of remaining 3
69
Parathyroid Adenoma si/sx
Si/sx of hypercalcemia
**“Bones, Stones, Groans, & Psychiatric Moans”**
* Bone pain, Muscle weakness
* Nephrolithiasis
* Polyuria
* Fatigue/lethargy
* Confusion, hallucinations
* Anxiety/ Depression
* Constipation, Nausea
* **Slow / absent reflexes**
70
dx Parathyroid Adenoma
**↑Ca++**
**↓PO4**
**↑PTH**
**Sestamibi scan** – localizes the mass
71
complication of Parathyroid Adenoma
**Hungry Bone Syndrome** after excision
* Remove adenoma --\> Remove excess PTH
* _Rapid, profound, prolonged hypocalcemia_ (calcium taken up by bone
72
si/sx of Parathyroid Carcinoma
Symptoms of **hypercalcemia**
* More likely to have sx vs a parathyroid adenoma, more likely to have neck mass
**“Bones, Stones, Groans, & Psychiatric Moans”**
* Bone pain, Muscle weakness
* Nephrolithiasis
* Polyuria
* Fatigue/lethargy
* Confusion, hallucinations
* Anxiety/ Depression
* Constipation, Nausea
* **Slow / absent reflexes**
73
dx Parathyroid Carcinoma
↑Ca++
↓PO4
↑PTH (more likely to be abnormal vs parathyroid adenoma)
74
complication of Parathyroid Carcinoma
Can metastasize to bone and lung
75
Hypercalc - Hypo/er reflexia
hypocalc - Hypo/er rreflexia
Hypercalc - hyporeflexia
hypocalc - Hyperreflexia
76
hypercal ECG -
hypocal ECG -
hyp**_e_**rcal ECG - short**_e_**d QTc
hyp**_o_**cal ECG - _prolonged_ QTc
