Thyroid

Question 1

A pt with fatigue myalgia proximal mm wkness sluggish reflexes elevated CK and normal ESR
LIKELY DX?

Answer 1

Hypothyroid myopathy

Question 2

pt having sxs of hypothyroidism but elevated T3, T4 with normal or mildly elevated TSH levels

Answer 2

Generalized resistance to thyroid hormones

Question 3

Additional metabolic abnormalities in hypothyroidism; name at least 4

Answer 3

Hyperlipidemia, hyponatremia, asymptomatic elevations of creatinine kinase, serum transaminases

Question 4

Autoantibodies in hashimoto’s

Answer 4

Antithyroperoxidase (>90% of pts) and antithyroglobulin antibodies

Question 5

Preferred Rx in graves and its side effects?

Answer 5

Radioiodine therapy

-side effects- hypothyroidism n exacerbation of ophthalmopathy.

Question 6

Euthyroid sick syndrome is?

Cause is?

Answer 6

Pts with an acute severe illness may have abnormal TFTs the most common pattern being low T3 with normal T4 n TSH ( low T3 syndrome)

• primarily due to impaired peripheral DEIODINATION( conversion of T4 to T3) which can b secondary to high endogenous cortisol, inflammatory cytokines, drugs like steroids, amiodarone
• late stage- May present with central hypothyroidism features.
• no Rx needed as it improves by itself when the pt recovers from the underlying illness

Question 7

Autoantibodies in Graves’ disease

Answer 7

Thyroid stimulating immunoglobulins.

Question 8

Pt taking herbal med for wt loss, presented with sxs of hyperthyroidism - diarrhea,…
What happens to her TFT including thyroglobulin?

Answer 8

Factitious thyrotoxicosis
Elevated thyroid hormones, low TSH
- the diagnostic test is low serum thyroglobulin due to suppression of native thyroid gland

Question 9

Methimazole Vs PTU

- which one is preferred? What r the 2 exceptions?

Answer 9

Methimazole Is preferred
PTU:-
- pregnancy- MMI is teratogenic
- thyroid storm

Question 10

Focal Vs diffuse radioactive iodine uptake

Answer 10

Focal- toxic nodule

Diffuse- graves

Question 11

A pt presenting with inability to comb her hair with difficulty holding her arms up and hyperthyroid sxs
Dx is ?

Answer 11

Myopathy

Question 12

Pathophysiology of graves ophthalmopathy

Answer 12

Stimulation of orbital fibroblasts by the anti-TSH receptor autoantibodies-> orbital tissue expansion

Question 13

Untreated Hyperthyroid pts r at increased risk for rapid bone loss
Mechanism is?

Answer 13

Increased osteoclastic activity

Question 14

Mechanism of hypertension in hypo Vs hyperthyroidism

Answer 14

Hypo- increase in systemic vascular resistance

Hyper- actually causes a decrease in SVR; htn is due to increased inotropic n cronotropic effect

Question 15

A pt with fatigue, myalgia, proximal mm wkness, sluggish reflexes, elevated CK and normal ESR. The likely Dx is?

Answer 15

Hypothyroid myopathy

Question 16

Thyroid lymphoma is 60times more common in pts with a preexisting thyroid hormonal disorder, which is?
Typical presentation?

Answer 16

Hashimoto’s thyroiditis

- rapid enlargement of the thyroid gland in pts with preexisting hashimoto’s

Question 17

In a hypothyroid pt taking levothyroxine, how would oral estrogen preparations affect the free thyroxine, TSH levels? Levothyroxine dose should b?

Answer 17

Estrogen causes increased production of thyroid binding globulin—> hypothyroid pts, as they can’t produce thyroxine, they r dependent on exogenous thyroxine to saturate TBG binding sites—> decreased free thyroxine n increased TSH
Therefore, higher dosing of levothyroxine may b neede

Question 18

Fever, neck pain, tender goiter following an upper respiratory tract infection is?
-inflammatory markers, radioiodine uptake?

Answer 18

Subacute thyroiditis( de Quervain thyroiditis) 
- elevated ESR, low radioiodine uptake