Thyroid Disease Flashcards
Pt presents with headache, visual disturbances, palpitations, tremor, and enlarged thyroid.
↑/– TSH
↑ T3/T4
Diagnosis?
TSH-secreting pituitary adenoma
Fine-needle aspiration thyroid biopsy reveals large cells with ground glass cytoplasm, and pale nuclei containing inclusion bodies and central grooving consistent with ___. NBSIM?
papillary thyroid cancer
Thyroidectomy
(if high recurrence risk)
± radioiodine ablation + Levothyroxine
Pt presents with history of 1st Trimester miscarriages and non-tender thyroidmegaly.
↑ TSH
T4 wnl
Diagnosis? Treatment?
chronic lymphocytic/autoimmune thyroiditis
(Hashimoto thyroiditis)
(Subclinical)
–anti-TPO antibodies
–antithyroglobulin antibodies
Levothyroxine (even if subclinical) in pts with elevated anti-TPO antibodies.
Hypothyroidism can cause elevated levels of ____.
total cholesterol, LDL, & triglycerides
(↑ risk of CAD)
Levothyroxine can improve lipid levels, although normalization may take several months
Pt presents with anxiety, weight-loss, palpitations, tremor, and enlarged, non-tender thyroid.
↓ TSH
↑ T3/T4
↑ Radioactive iodine uptake at 24 hours and homogenously distributed.
Diagnosis? Treatment?
Graves disease
Propranolol
+
Propylthiouracil or Methimazole
Patients with mild Graves disease, small goiters, and low TSH receptor antibody titers can be managed with ___.
Propylthiouracil or Methimazole
alone with 50% of remission.
In patients with Graves disease who have significant symptoms and T3/T4 level >2-3x normal
Definitive treatment is ___.
Propranolol
+
Propylthiouracil or Methimazole
to stabilize the patient before
definitive treatment with RAI (adioactive iodine) or thyroidectomy.
Common post-surgical thyroidectomy complication
hypoparathyroidism → hypocalcemia
(presents with fatigue, anxiety, or depression; tetany of lips, face, and extremities; seizures)
ECG → QT-interval prolongation
Fever and sore throat in any patient taking antithyroid drugs (PTU or MMZ) suggests ____.
agranulocytosis
(d/c medication and get a CBC)
Pt presents with anxiety, palpitations, weight-loss, and enlarged, non-tender thyroid gland
↓ TSH
↑ T4
Radioactive iodine uptake is <5% (low)
+ anti-thyroid peroxidase antibodies (high titers)
Diagnosis & NBSIM?
painless (silent) thyroiditis
Tx: Propanolol
RAIU scan (normal: 8%-25%)
Pt presents with Hyperthyroid sxs
↓ TSH
↑ T4
+ Anti-TPO titers
+ Low RAIU
Diagnosis?
painless (silent) thyroiditis
(self-limited; can give propranolol for sxs)
This thyroiditis presents the same as postpartum thyroiditis but by definition excludes patients within a year of pregnancy.
painless (silent) thyroiditis
Primary hyperthyroidism can result from
↓ TSH
↑ T4
Overproduction of thyroid hormone (2)
Release of preformed hormone (2)
Overproduction → Graves disease, toxic nodular goiter
Preformed Released → painless thyroiditis, subacute (deQuervains) thyroiditis
Thyrotoxicosis (↑T4) with normal or ↑ RAIU
(3)
Graves disease
Toxic multinodular goiter
Toxic nodule
Thyrotoxicosis (↑T4) with ↓ RAIU
(3)
Painless (silent) thyroiditis
Subacute (de Quervain) thyroiditis
Excessive dose (or surreptitious intake) of levothyroxine
This thyroiditis is characterized by fever, neck pain, and a tender goiter following an upper respiratory illness.
Patients have a self-limited thyrotoxic phase followed by hypothyroidism and eventual recovery of thyroid function.
Diagnosis and Treatment?
Subacute (de Quervain) thyroiditis
Beta blockers (for sxs)
Levothyroxine requirements ____ during pregnancy.
increase
(Pts should increase their levothyroxine dose at the time pregnancy is detected)
Radioiodine therapy for Graves disease can acutely worsen Graves ____ due to increased titers of thyroid-stimulating autoantibodies.
ophthalmopathy
The initial evaluation of thyroid nodules includes (2).
serum TSH levels
thyroid ultrasound
Thyroid Nodule + ↓TSH →
radionuclide thyroid scan (scintigraphy)
Thyroid Nodule + ↑/– TSH →
Fine Needle Aspiration
A small, hyperfunctioning (“hot”) nodule (increased isotope uptake in the nodule with decreased surrounding uptake) → NBSIM?
No FNA
(associated with a low cancer risk)
A hypofunctioning (“cold”) nodule (decreased isotope uptake compared to surrounding tissue) → NBSIM?
FNA
(associated with a high risk of cancer)
Systolic hypertension in thyrotoxicosis is caused by hyperdynamic circulation resulting from increased ____ and heart rate.
myocardial contractility
Antithyroid Drugs adverse effects:
_____: 1st-trimester teratogen, cholestasis, agranulocytosis
______: Hepatic failure, agranulocytosis
Methimazole
Propylthiouracil
Postpartum woman with:
↓ TSH ↑ T3/T4
Thyroid peroxidase antibody positive
Thyrotropin receptor antibody negative
Diagnosis and NBSIM?
Post-Partum Thyroiditis
Tx:
Propanolol (hyperthyroid phase)
Levothyroxine (Hypothyroid phase)
___ is characterized by myalgias, proximal muscle weakness, and an ↑ creatine kinase level.
Hypothyroid myopathy
Pts have additional features of hypothyroidism (fatigue, delayed reflexes).
NBSIM: TSH and free T4 levels
Prominent fever & hyperthyroid features
hx of recent viral infection
Painful/tender goiter
↓ TSH ↑ T3/ T4
↓ radioiodine uptake (<5%)
↑ ESR & CRP
Subacute Granulomatous thyroiditis
(de Quervain’s thyroiditis)
Tx: Propanolol
Features of hyperthyroidism followed by features of hypothyroidism
Predominant hypothyroid features
Diffuse, non-tender goiter
↑ TSH ↓/– T3/T4
Radioiodine uptake (decreased, patchy, irregular)
(+) Anti- thyroglobulin
(+) Anti-TPO antibody
(+) anti-microsomal antibodies
Chronic autoimmune thyroiditis
(Hashimoto thyroiditis)
Tx: Levothyroxine
Predominant hyperthyroid features
hx of auto-immune disorder
Diffuse, non-tender goiter
↓ TSH ↑ T3/ T4
↓ radioiodine uptake (<5%)
(+) Anti-TPO antibody
Subacute lymphocytic thyroiditis
(Painless/Silent thyroiditis)
Tx: Propanolol
Features of hyperthyroidism followed by features of hypothyroidism
critically ill or post-op patient
↓ T3 TSH & T4 (wnl)
or
↓ TSH ↓ T4 ↓ T3
Diagnosis and Tx?
Euthyroid sick syndrome (low T3 syndrome)
No treatment indicated
s/t ↓ peripheral conversion of T4 to T3
(can be seen in pts on high dose IV glucocorticoids)
Reverse T3 is elevated in
Euthyroid sick syndrome (low T3 syndrome)
A high RAIU suggests de novo hormone synthesis due to Graves’ disease (diffusely increased uptake) or toxic nodular disease (nodular uptake). In contrast, a low RAIU suggests either release of preformed thyroid hormone (ie, thyroiditis) or exogenous thyroid hormone intake. In such cases, the serum thyroglobulin level can make the distinction: elevated thyroglobulin is consistent with endogenous thyroid hormone release whereas decreased thyroglobulin suggests exogenous or factitious thyrotoxicosis.
EDit
Secondary Hyperthyroidism
__ TSH
__ T3/T4
NBSIM?
↑ TSH
↑ T3/T4
MRI of Pituitary
Primary Hyperthyroidism
__ TSH
__ T3/T4
↓ TSH
↑ T3/T4
Primary Hyperthyroidism but not classic Graves Disease presentation.
NBSIM?
RAIU scintigraphy
↓ TSH
↑ T3/T4
(+) TSH receptor Antibodies
↑ RAIU scan (normal: 8%-25%)
Diffuse pattern
Diagnosis?
Graves disease
↓ TSH
↑ T3/T4
↑ RAIU scan (normal: 8%-25%)
Nodular pattern
Diagnosis? (2)
Multinodular Goiter
Toxic Adenoma
↓ TSH
↑ T3/T4
↓ RAIU scan (normal: 8%-25%)
↑ Thyroglobulin
Diagnosis? (2)
Thyroiditis
Excess Iodine
↓ TSH
↑ T3/T4
↓ RAIU scan (normal: 8%-25%)
↓ Thyroglobulin
Diagnosis?
Excessive dose (or surreptitious intake) of thyroid hormone meds
Post-partum woman presents with anxiety, fatigue, irritability, constipation, and weight-gain.
Vitals significant for HTN and Bradycardia. What is the NBSIM and why?
pt likely has Postpartum thyroiditis → get TSH/T4 labs
(brief hyperthyroid to hypothyroid phase)
we can rule out “psychological” etiology because pt has bradycardia which can’t be explained by depression.
Diagnosis:
Infants presents with apathy, weakness, hypotonia, large tongue, sluggish movement, abdominal bloating, and an umbilical hernia.
congenital hypothyroidism
Untreated hyperthyroidism in pts increases risk for ___ & atrial fibrillation.
osteoporosis (fragility fractures)
rapid bone loss s/t ↑ osteoclastic activity
Large _____ thyroid nodules carry an increased risk of malignancy and require fine needle aspiration biopsy.
hypofunctioning (“cold”)
Fetal hyperthyroidism can be seen in patients with active ______.
Graves disease
(b/c TSH receptor antibodies can cross the placenta)
(Nodular toxic adenoma pts do not have TSHR antibodies so this isn’t a problem in pregnancy for them)
proximal muscle weakness/atrophy in the setting of clinical features of hyperthyroidism. Diagnosis?
Chronic hyperthyroid myopathy
In evaluating thyroid nodules,
TSH levels and Thyroid Ultrasound need to be obtained 1st.
Thyroid Ultrasound helps determine nodule size and sonographic features.
High risk of Malignancy sonographic features include:
⬩microcalcifications
⬩ irregular borders
⬩internal vascularity
If nodule is >1cm and has the above features or is a _____ nodule
Do a fine-needle aspiration (FNA) biopsy.
> 2 cm, noncystic nodule
A radionuclide scan is indicated in evaluation of a thyroid nodule only for patients with ___.
low TSH
Hypothyroid Patient with Irregular menstruation:
__ TSH
__ FSH & LH
__ Prolactin
↑ TSH
↓ FSH & LH
↑ Prolactin
( ↓T3 ⇨ ↑TRH ⇨ ↑ TSH & Prolactin)
(↑Prolactin ━┫FSH, LH, & ovulation)
___ may represent a mild, transient central hypothyroid state that functions to minimize catabolism in severe illness (adaption to non-thyroidal illness).
Euthyroid sick syndrome (ESS)
___ stimulates/increases thyroxine-binding globulin (TGB), leading to increased total (but not free) T4.
High Estrogen
(Hormone replacement therapy, OCPs, Pregnancy)
Patients in a thyroid storm can develop fever, hemodynamic instability, AMS, cardiac arrhythmias, and ____.
Congestive heart failure
(Tx: Propanolol → PTU → Potassium → Prednisone to lower peripheral conversion of T4/T3)
___ directly stimulates TSH receptors, causing increased production of total T4 and suppressing TSH.
hCG
(seen in pregnancy)
(Recall: Estrogen stimulates TGB)
Estrogen stimulates/increases thyroxine-binding globulin (TGB), leading to increased ____.
total (but not free) T4
(suppresses TSH levels)
Neonatal Thyrotoxicosis is caused by ___ which bind to infant’s TSH receptors & cause excessive thyroid hormone release
Transplacental passage of maternal anti-TSH receptor antibodies
(Maternal Graves Disease)
In neonatal thyrotoxicosis, affected infants are warm/moist, irritable, tachycardic, and gain weight poorly.
___ & ___ are given to symptomatic patients until the condition self-resolves over a few weeks to months.
Methimazole + β blocker
what is the most common cause of congenital hypothyroidism worldwide?
Thyroid dysgenesis
Congenital Hypothyroidism presents weeks to months after ___ wanes
maternal thyroxine
