Thyroid and Parathyroid Flashcards
function of thyroid gland
list hormones as well
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
biofeedback control of thyroid hormones
- 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
list common dz assoc w/ hyperthyroidism
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
si/sx of hyperthyroidism
- 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
dx hyperthyroidism
Graves?
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
imaging hyperthyroidism
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)
tx graves dz
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)
Tx of Toxic multinodular goiter
Sub-total thyroidectomy > Radioactive Iodine (131 Iodine)
tx of Toxic nodular goiter (Plummer’s disease)
Radioactive Iodine (131 Iodine) > unilateral lobectomy
Toxic multinodular goiter
VS
Toxic nodular goiter (Plummer’s disease)
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
on Nuclear scintigraphy w/ RAIU ( INC uptake) is a warm or cold nodule assoc w/ malignancy
Warm/hot “functioning nodule”
Cold “non-functioning nodule” (malignancy)
define thyroid storm
Untreated hyperthyroidism - SEVERE
•Can be brought on by stress (ex. trauma, MI, infection)
si/sx of thyroid storm
Exaggerated presentation of hyperthyroidism
- Tachycardiac (>140 bpm)
- HTN à CHF
- Fever (104-106°)
- AMS - Agitation, delirium, psychosis, stupor, or coma
- N/V / Abdominal pain
tx thyroid storm
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
define thyrotoxicosis & most commonc cause of it
define subacute thyroititis & common cause
thyroid scan - diffuse uptake or irregular/diminished upstake
Graves
Toxic multinod
Toxic goiter - plummers dz
diffuse uptake - Graves
irregular/diminished upstake
- Toxic multinod
- Toxic goiter - plummers dz
list types of Hypothyroidism
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
Most common inflammatory condition of thyroid gland
Most common cause of goiter
developing countries?
hashimotos hypothyroidism
Iodine Deficiency #1 cause in developing countries
si/sx of hypothyroidism
- 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
dx hypothyroid
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)
tx hypothyroidism
Levothyroxine (Synthroid) synthetic T4
Hyperthyroidism - ___TSH & ___ T3/T4
Hypothyroidism - ___TSH & ___ T3/T4
Hyperthyroidism - DEC TSH & INC T3/T4
Hypothyroidism - INC TSH & DEC T3/T4
define Myxedema coma
complciation opf hypothyroidism
Medication cessation
- Impaired cognition, confusion à coma (myxedema coma)
- Most often seen in elderly and those who have stopped taking meds
si/sx of Myxedema coma
- AMS
- Severe hypothermia
- Hypoventilation
- Hyponatremia
- Hypoglycemia
- Hypotension
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
Complication of hyperthyroid ___
Complication of hypothyroid ___
Complication of hyperthyroid: Thyroid storm
Complication of hypothyroid: Myxedema coma
2 classifications of Thyroiditis
Painful- Subacute granulomatous thyroiditis
Painless
- Med induced (ex. amiodarone, lithium)
- Hashimoto’s
list typea of thyroid nodules
Mostly Benign
- Cyst
- Follicular adenoma
- Colloid nodule
- Malignancy
malignnancy suspicition w/ thyroid nodule if..?
- History of head/neck radiation
- Young age
- Recent onset, rapid growth
- Family h/o medullary thyroid cancer
dx thyroid nodule
RAIU scan (hot vs. cold)
- The hotter the nodule on scan, the less likely lesion/nodule is cancerous
Tissue Bx
List types of thyroid cancer
Papillary 60%
Follicular 20%
Anaplastic 14%
Medullary 5%
si/sx of Thyroid cancer
•Painless, palpable, firm/fixed nodule
•Rapid growth
- Vocal cord paralysis
- Hoarseness
thyroid cancer dx of choice
US guided fine needle aspiration
type of thyroid cancer Linked to iodine deficiency
Follicular 20%
thyroid cancer w/
↑ serum calcitonin levels confirm diagnosis
Medullary 5%
tx of choice for what type of thyroid cancer:
Surgical isthmusectomy to Prevent tracheal compression
Anaplastic 14%
tx of thyroid cancers
Papillary 60%
Follicular 20%
Lobectomy on lesions < 1.5 cm
1.5 cm lesions = near-total thyroidectomy
Life-long levothyroxine after surgery
thyroid cancer seen in those >50 y/o
Anaplastic 14%
thyroid cancer seen families (AD)
Medullary 5%
dx thyroid cancer: reasons to use
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
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
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/ radioactive Iodine-131
- no uptake…levothyroxine to suppress TSH
PTH monitors & regulates blood Ca++
Low Ca++ …?
High Ca++….?
Low Ca++ –> Parathyroid glands secrete PTH –> ↑Ca++
High Ca++ –> Thyroid gland release calcitonin –> ↓Ca++
when do you need to correct serum Ca++
When hypo or hyperalbuminemia
Hypoalbuminemia can cause pseudohypocalcemia
Ca++ = Ca++ measured + (0.8 (4- measured albumin))
PTH monitors & regulate PO4 levels
Low PO4
High PO4
Low PO4 –> Parathyroid glands secrete PTH –> ↑PO4
High PO4--> Parathyroid glands secrete PTH –> ↓PO4
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
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
si/sx of hypocalc
Chvostek sign & Trousseaus sign
Hyperreflexia
Tetany
Muscle spasms
Seizures
Abd pain
Prolonged QTc
dx hypocalcemia
Chvostek sign & Trousseaus sign
ECG (prolonged QTc)
DEC Ca
Albumin (corrected Ca)
Dec PTH, Mg, 25-OH Vit D
INC PO4
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
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
most common cause of Hypoparathyroidism
↓PTH (cannot make PTH)
- Surgery (thyroid or parathyroid-ectomy,
- head/neck ca.)
- Neck radiation
- Autoimmune
- Genetics
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
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
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)
define Pseudo - hypoparathyroidism
Condition associated with resistance to PTH
dx Pseudo - hypoparathyroidism
↓Ca++
↑PO4
↑PTH (appropriately high due to low Ca++)
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
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
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
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
complciations
hypocalc
hypercalc
hypocalc - cardiac arrythmias (Torsades, afib)
hypercalc - cardiac arrythmias (bradycardia, AV block)
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
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
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
Tx Hyperparathyroidism
asymp
symp
acyte hypercalcemia
Asymptomatic : Observation +/- surgery
Symptomatic
- Parathyroidectomy
- Cinacalcet
Acute hypercalcemia
- IV Fluids
- Loop Diuretics
complications of Hyperparathyroidism
Parathyroid adenoma
- Profound hypocalcemia (Hungry Bone Syndrome)
Parathyroid carcinoma: Mets to bone & lung
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)
Parathyroid Adenoma most common location
Right inferior gland most common location–> Hyperactivity of one gland –> atrophy of remaining 3
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
dx Parathyroid Adenoma
↑Ca++
↓PO4
↑PTH
Sestamibi scan – localizes the mass
complication of Parathyroid Adenoma
Hungry Bone Syndrome after excision
- Remove adenoma –> Remove excess PTH
- Rapid, profound, prolonged hypocalcemia (calcium taken up by bone
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
dx Parathyroid Carcinoma
↑Ca++
↓PO4
↑PTH (more likely to be abnormal vs parathyroid adenoma)
complication of Parathyroid Carcinoma
Can metastasize to bone and lung
Hypercalc - Hypo/er reflexia
hypocalc - Hypo/er rreflexia
Hypercalc - hyporeflexia
hypocalc - Hyperreflexia
hypercal ECG -
hypocal ECG -
hypercal ECG - shorted QTc
hypocal ECG - prolonged QTc
