Thyroid disorders

Question 1

Hypothyroid clinical presentation

Answer 1

reduced systemic cellular energy release
* most often in women >50
* MOMS SO TIRED
* Memory loss
* Obesity
* Menorrhagia
* Slowness
* Skin and hair dryness
* Onset gradual
* Tiredness
* Intolerance to cold
* Raised BP
* Energy levels fall
* Depression/Delayed relaxation phase or reflexes

Question 2

Hypothyroidism Casues

Answer 2

Hashimoto thyroiditis
* most common cause
* autoimmune in origin
* discovered once thyroid is largely destryoed and non-functional

Post Radioactive iodine treatment
* status post Grave disease treatment
* status post thyroid cancer treatment with thyroid ablation

Select medication use
* lithium, amioderone, interferon

Question 3

Hyperthyroid Clincal presentation

Answer 3

Excessive cellular energy release
* most often found in women 30-50
* SWEATING
* Sweating
* Weigh loss
* Emotional lability, “mind racing”, memory alteration
* Appetite increased
* Tremor/tachycardia
* Intolerance of heat, Irregular menstration, Irritiability
* Nervousness
* Goiter, GI problems - frequent low volume loose stools

Question 4

Hyperthyroidism Causes

Answer 4

Graves’ Disease
* Most common cause
* Autoimmune in nature, seen with other autoimmune conditions like RA, lupus, vitiligo, celiac, T1DM
* Presentes as typical hyperthyroid plus exopthalmos, and goiter
* Atypical or apathetic hyperthyroidism presentation
* common in older adults
* often seen with new-onset tachydysrhythmia, A. fib, HF

Toxic adenoma
* benign metabolically active thyroid nodule
* typical hyperthyroid presentation with palpable unilateral thyroid mass

Thyroiditis
* usually transient, viral or autoimmune, postpartum, or drug induced
* Typically milder presentation with thyroid tenderness

Question 5

Lab tests for thyroid disorders

Answer 5

TSH - Thyroid stimulating hormone
* NL = 0.4 - 4
* Released by anterior pituitary, promotes release of T4 from thyroid
* Single most reliable test, if normal thyroid disease is ruled out

Free T4 (thyroxine)
* NL 10 - 27
* Unbound metabolically active portion of T4
* used to confirm/support the Dx of hyper/hypothyroid when TSH is abnormal

TPO Ab - Throid peroxidase antibody
* detects autoimmune thyroid disease
* measures antibody against peroxidase, an enzyme in the thyroid

Question 6

Hypothyroid treatment

TSH high
Free T4 low

Answer 6

Levothyroxine (synthroid, levoxyl)
* dose using ideal body weight in overweight or actual body weight if healthy or underweight
* 1.6 mcg/kg/day in adults
* 1.0 mcg/kg/day in elderly
* Check TSH after 8 weeks of therapy
* clincal improvement in 1 wk
* If TSH remains elevated ensure medication used properly - taken on empty stomach with water same time each day. Should not be taken within 2 hour of a cation (ca, iron, aluminum, mag) due to chelation effect and reduced absorbtion

T4/T3 porcine thyroid combination (Armor Thyroid)
* use not reccomended by AACE due to variable pharmacokinetics

Question 7

Hyperthyroidism Treatment

TSH low
T4 High

Answer 7

at time of Dx to treat tachycardia and tremor
* beta blocker (propranolol, nadolol) if not contraintdicated

Hyperthyroid
* PO methimazole (Tapazole) or PTU to reduce thyroxine production
* warning for acute hepatic failure even in the absence of liver disease risk factors

Once euthyroid from antithyroid med, radioactive iodine then treat with throid ablation with intetional hypothyroid to be threated with levothyroxine

Question 8

Subclinical Hypothyroidism

TSH high
T4 NL
TPO Ab high

Answer 8

Elevated TSH may be incidental finding, not symptomatic
* treatment reccomended with levothyroxine
1. when TSH >5 and presence of goiter or TPO Ab
2. Presence of symptoms compatible with hypothyroid, infertility, pregnancy, or imminent pregnancy

Question 9

Levothyroxine treatment

Answer 9

1. initiate treatment
2. TSH at 8 weeks
3. TSH 0.5-2.0 - continue dose, recheck TSH at 6 months, then annually or sooner if symtomatic
4. TSH >4 - (TSH remains high) - Increase dose by 12.5-25, recheck in 8 weeks
5. TSH <0.5 - (TSH too Low from over treatment) - decrease dose by 12.5-25, repeat test in 8 weeks.

Question 10

Thyroid nodule

Answer 10

• palpable thyroid mass, not specific to any dx, typically >1cm
• presentation of benign and malignant lesions are typically the same
• malignancy in 5%
• Malignancy presentation - hx of head/neck irradiation, >4cm, firm-nontender, fixed position, persistant nontender cervical lymphadenopathy, dysphonia, hemoptysis.
• work up: Check TSH and thyroid US, if TSH is normal refer for biopsy, if lesion is releaseing excessive TSH then radioablasion or surgery (benign)