Endocrine Disorders Flashcards
Elevated TSH + Normal FT4
Subclinical hypothyroidism
Elevated TSH + High FT4
TSH-mediated hyperthyroidism (secondary or tertiary)
Low TSH + Low FT4
Secondary or tertiary hypothyroidism (rare). If present, it is usually pituitary
Low TSH + Normal FT4
Subclinical hyperthyroidism
Low TSH + High FT4
Primary hyperthyroidism or thyrotoxicosis (check RAIU to identify cause)
RAIU: DIFFUSE uptake
Grave’s disease or pituitary adenoma
RAIU: Decreased uptake
Thyroiditis
RAIU: hot nodule
Toxic adenoma
RAIU: Multiple nodules
toxic multinodular goiter
RAIU: cold nodules
Suspect malignancy
What is thyroiditis?
Transient hyperthyroidism due to thyroid inflammation/destruction causing leak of “preformed” thyroid hormones (NOT due to new hormone synthesis)
What is cretinism?
Congenital hypothyroidism due to maternal hypothyroidism or infant hypopituitarism
What is Riedel’s thyroiditis?
Normal thyroid stroma replaced by fibrotic tissue
Reidel’s thyroiditis: Clinical manifestations
Painless fixed nodular that may grow rapidly (resembles malignancy). *RARE*
Riedel’s thyroiditis: Management
Steroids, tamoxifen and levothyroxine
What is euthyroid sick syndrome?
Abnormal thyroid levels with normal thyroid gland function seen with illness (ex: surgery, malignancies, sepsis, cardiac disease)
Grave’s Disease: Management (4)
- Radioactive iodine: MC therapy used 2. Methimazole/propylthiouracil (PTU safe in pregnancy) 3. Beta blockers (propanolol) for symptomatic relief* 4. Thyroidectomy
Toxic multinodular goiter (plummer disease) and toxic adenoma treatment (4)
- Radioactive iodine: MC therapy 2. Surgery (subtotal thyroidectomy) if compressive symptoms are present 3. Antithyroid meds: Methimazole/PTU 4. Beta blockers for sx of thyrotoxicosis
Compressive symptoms of toxic multinodular goiter and toxic adenoma
Dyspnea, dysphagia, stridor, hoarseness
TSH secreting pituitary adenoma: Clinical manifestations (3)
- Diffuse enlarged thyroid 2. Bitemporal hemianopsia 3. Mental disturbances
TSH secreting pituitary adenoma: thyroid function tests
Increased FT4/T3 + Increased TSH (inappropriate TSH elevation in the setting of elevated FT4/T3 in the same direction)
TSH secreting pituitary adenoma: Management
Transsphenoidal surgery to remove pituitary tumor
Elevated TSH + Low FT4
Primary hypothyroidism
What is the MC cause of hypothyroidism in the US?
Hashimoto’s (chronic lymphocytic)
Hashimoto’s: Cause
Autoimmune (anti-thyroid ab)
Hashimoto’s: Diagnosis (4)
- Thyroid Ab present: thyroglobulin Ab, antimicrosomial and thyroid peroxidase Ab
- TFTs (us HypOthyroid)
- Decreased radioactive iodine uptake (usually not needed)
- Biopsy: Lymphocytes, germinal follicles, Hurthle
Silent (lymphocytic): cause
Autoimmune (anti-thyroid Ab)
Silent (lymphocytic): Clinical manifestations
- Painless enlarged thyroid
- Thyrotoxicosis → hypothyroid (depend on where they present)
Silent (lymphocytic): Diagnosis (3)
- thyroid Ab present (same as Hashimoto’s)
- TFT: (hyper/hypo) depend on where they present
- Decreased radioactive iodine uptake
Silent (lymphocytic): Duration/Management (3)
- Return to euthyroid state within 12-18 months w/o treatment. ASA
- No anti-thyroid meds**
- 20% possible permanent hypothyroidism
Post-partum thyroiditis: Cause
Autoimmune (anti-thryoid Ab)
Post-partum thyroiditis: clinical manifestations (2)
- Painless enlarged thyroid
- Thyrotoxicosis → hypothyroid (depend on where they present)
Post-partum thyroiditis: Diagnosis (3)
- Thyroid Ab present
- TFTs: (Hyper/hypo) depend on where they present
- Decreased radioactive iodine uptake
Post-partum thyroiditis: Duration (3)
- Monitor TFTs every 4-8 weeks
- If hyperthyroid symptoms are present: use propanolol or atenolol until levels are normal
- If hypothyroid symptoms are present, use levothyroxine
DeQuervain’s (Granulomatous) thyroiditis cause
MC post viral* or viral inflammatory reaction
DeQuervain’s (granulomatous) thyroiditis: Clinical manifestations (2)
- PAINFUL neck/thyroid
- Clinical hyperthyroidism
DeQuervain’s (granulomatous) thyroiditis: Diagnosis (4)
- Elevated ESR (hallmark)**
- No thyroid Ab
- TFTs (us hypERthyroid)
- Decreased radioactive iodine uptake
DeQuervain’s (granulomatous) thyroiditis: Duration (3)
- Return to euthyroid state within 12-18 months without treatment. ASA (for pain, inflammation, increases T4)
- No anti-thyroid meds
- 5% possible permanent hypothyroidism
Which medications are most responsible for causing medication induced thyroiditis?
Amiodarone, lithium, and alpha interferon
Acute thyroiditis: Diagnosis (2)
- Increased WBC count (left shift)
- Euthyroid
Acute thyroiditis: Duration
Antibiotics, drainage if abscess is present
Thyroid storm: Management (6)
- Anti-thyroid meds: Methimazole, PTU
- Beta-blockers for symptoms
- Supportive: IV fluids
- Glucocorticoids
- Oral/IV sodium iodide
- Antipyretics (avoid ASA as this increases T4)
What is the MC malignant thyroid tumor?
Papillary carcinoma
What is the MC type of thyroid nodule?
Colloid (50-60%)
On a radioactive iodine uptake scan, what type of nodule is highly suspicious for malignancy?
Cold nodule
Papillary carcinoma: Prognosis
Excellent (high cure rate)
Follicular carcinoma: METS (2)
- Local cervical lymph node invasion less common
- Distant METS comon (vascular invasion of lung, neck brain, bone, liver, skin)
Follicular carcinoma: Prognosis
Excellent
Medullary carcinoma: Risk factors (2)
- Not associated with radiation exposure
- MC associated with MEN 2*
Medullary carcinoma: Characteristics (3)
- More aggressive. Much lower cure rate.
- Arises from parafollicular cells → secrete calcitonin
- May cause diarrhea and flushing
Medullary carcinoma: METS (2)
- Local cervical LN occurs early in the disease
- Distant METS occur late (brain, bone, liver, adrenal medulla)
Medullary carcinoma: Prognosis
Poorer prognosis
Medullary carcinoma: Management (2)
- Total thyroidectomy
- Calcitonin levels used to monitor if residual disease present after treatment or detect recurrence
Anaplastic carcinoma: Age
MC in males >65 yo
Anaplastic carcinoma: Characteristics (2)
- Most aggressive*
- Rapid growth!! Often with compressive symptoms
Anaplastic carcinoma: METS (2)
- Local and distant METS
- May invade trachea (20% of patients need tracheostomy)
Anaplastic carcinoma: Prognosis
Poor prognosis*
Anaplastic carcinoma: Management (3)
- Most are not amenable to surgical resection
- External beam radiation
- Chemotherapy
What is the MC cause of primary hyperparathyroidism?
Parathyroid adenoma
MEN 1
- Hyperparathyroidism
- Pituitary Tumors
- Pancreatic Tumors
MEN 2a
- Hyperparathyroidism
- Pheochromocytoma
- Medullary thyroid carcinoma
Why does the PTH increase with secondary hyperparathyroidism?
It is a response to hypocalcemia or vitamin D deficiency
MC cause of secondary hyperparathyroidism
Chronic kidney failure
Clinical manifestations of hyperparathyroidism
Stones, bones, abdominal groans, psychic moans
Decreased DTR
Primary hyperparathyroidism: Diagnosis (4)
- Triad: Hypercalcemia + increased intact PTH + decreased phosphate
- Increased 24 hour urine calcium excretion
- Increased vitamin D
- Osteopenia on bone scan
Hypoparathryroidism: Clinical manifesetations
Signs of hypocalcemia: carpopedal spasm, Trousseau & Chvostek sign, perioral paresthesias, increased DTR
Hypoparathyroidism triad
- Hypocalcemia
- Decreased intact PTH
- Increased phosphate
Hypocalcemia: ECG findings
Prolonged QT interval
Hypocalcemia: GI findings
Diarrhea, abdominal cramps
Hypocalcemia: Management (severe or symptomatic)
Calcium gluconate IV* or calcium carbonate IV
Hypocalcemia: Management (mild) (2)
- PO calcium + Vitamin D (erogcalciferol, calcitriol)
- K and Mg repletion may be needed in some cases
Hypercalcemia: ECG findings
Shortened QT interval
Hypercalcemia: Management (4)
- IV saline → Fuorsemide* (Lasix) 1st line. Avoid HCTZ (causes increased calcium)
- No treatment needed for mild hypercalcemia
- Calcitonin, bisphosphonates added in severe cases
- Steroids (in vitamin D access, malignancies, granulomas)
Osteoporosis: Dexa scan results
Bone density T score ≤ -2.5
Osteopenia: Dexa scan results
T score ≤ 1.0 to -2.5
1st line treatment for osteoporosis
Bisphosphonates