Clinical Thyroid Disease Flashcards
What are the symptoms of hypothyroidism ?
Weight gain Lethargy Feeling cold Constipation Heavy periods Dry skin Hair fall out Bradcardia Slow reflexes Goitre
What are the TSH and FT4/FT3 levels in primary hypothyroidism?
Raised TSH
Low T3 and T4
What are the TSH and T3/T4 levels in subclincal hypothyroidism?
High TSH
Low or normal T3 T4
The TSH has managed to compensated for the reduced secretion of T3 T4
What are the TSH and T3/4 levels in secondary hypothyroidism?
Low TSH
Low T3/4
What is the commonest endocrine condition after DM?
Hypothyroidism
Are males or females more affected in hypothyroidism?
Females
How does risk of hypothyroidism change with age?
Increased risk with age
Why is everyone screened at birth for hypothyroidism?
Because if missed it can lead to inproper development
What are some causes of primary hypothyroidism?
Autoimmune thyroid disease (Hashmitos)
Iatrogenic
Chronic iodine deficiency
Drug induced
What are some causes of secondary hypothyroidism?
Pituitary/hypothalamic damage: Pituitary tumour Post PG surgery Sheehan's syndrome Isolated TRH deficiency
What are the investigations for hypothyroidism?
TSH
FT4/FT3
Autoantibodies (TPO)
What is the treatment for hypothyroidism?
Levothyroxine
Is there any benefit to combining FT3 and FT4 treatment?
No
What is the initial dose of levothyroxine?
50 mcg/day
For how long do you increase the dose of lvevothyroxine?
Until TSH is normal
After stabilisation how often is hypothyroidism checked?
Annual
When should levothyroxine be taken?
Same time everyday on an empty stomach
When would you be more cautious about levothyroxine dose?
IHD - angina
Pregnancy - increase dose by 25%
Potpartum thyroiditis
Myxedema coma
What is the treatment for myxedema coma?
IV T3 (steroid)
What is myxedema hypothyroidism?
Coma due to hypothyroidism
When should treatment of subclinical hypothyroidism be considered?
TSH>10
TSH>5 with positive thyroid antibodies
TSH elevated with symptoms
What is goitre?
Swelling of the neck resulting from enlargement of the TG
What causes goitre?
Puberty Pregnancy Grave's disease Hashmoto's disease Thyroiditis Iodine deficiency
What are the type of goitre?
Multinodular Diffuse Cysts tumours Miscellaneous
What tumours can cause goitre?
Adenomas
Carcinomas
Lymphomas
What are the investigations for a solitary nodule?
Thyroid function tests
Isotope scanning if low TSH
USS
FNA
What is the commonest type of thyroid cancer?
Papillary
What is the prognosis for follicular and papillary thyroid cancer?
Good prognosis
Who is papillary thyroid cancer common in?
younger females
Where does follicular thyroid carcinoma typically spread to?
Lungs
Bone
Rx for thyroid cancer?
Near total thyroidectomy
High does radioiodine
Long term suppressive doses of thyroxine
Follow up
What are other types of thyroid cancer?
Anaplastic
Lymphoma
Medullary
What is the prognosis for anaplastic thyroid cancer?
Very poor
Due to it being so aggressive and locally invasive
Where do medullary thyroid cancers arise from?
Parafollicular C cells
What are the signs of hyperthyroidism?
¥ Weight Loss ¥ Anxiety/Irritability ¥ Heat Intolerance ¥ Bowel frequency increases ¥ Light periods ¥ Sweaty palms ¥ Palpitations ¥ Hyperreflexia/Tremors ¥ Goitre ¥ Thyroid eye symptoms/signs
What are the causes of primary hyperthyroidism?
Grave’s disease
Toxic multinodular goitre
Toxic adenoma
What is the main cause of secondary thyrotoxicosis?
Pituitary adenoma secreting TSH
What causes thyrotoxicosis without hyperthyroidism?
Destructive thyroiditis
Excessive thyroxine administration
Who is more affected with Grave’s disease m or f?
F>M
What is a common goitre presentation of grave’s disease?
Diffuse goitre
Which antibodies drive grave’s disease?
Thyroid peroxidase antibodies
TSH receptor antibodies
What is the treatment for hyperthyroidism?
ATD - carbimazole
BB
Radioiodine
Thyroidectomy
What is the draw back to radioiodine treatment?
High chance of hypothyroidism
What are the anti thyroid drugs?
Carbimazole Propylthiouracil
Who cant radioiodine patients come into contact with for 4 weeks?
<18
Pregnant women
TSH: 15 (0.3-3.3)
FT4: 9 (10-25)
What is the diagnosis?
Primary hypothyroidism
TSH: 2 (0.3-3.3) - low end of normal
FT4: 9 (10-25)
What is the diagnosis?
Secondary hypothyroidism
TSH: 15 (0.3-3.3)
FT4: 12 (10-25)
What is the diagnosis?
Subclinical hypothyroidism
Why is FT4 normal and TSH elevated in subclinical hypothyroidism?
Because the PG rises TSH levels to compensate for the low FT4 levels
Why is TSH high but FT4 low in primary hypothyroidism?
TSH tried to produce more FT4 but the thyroid isn’t working so will not physically produce any more FT4
What are the investigations for hyper and hypothyroidism?
TSH
T4
T3
Thyroid antibodies
What are the draw backs to thyroidectomy in hyperparathyroidism?
Will need thyroid replacement therapy for life
Risk of hypoparathyroidism
Risk of damage to recurrent laryngeal n. – hoarseness
