Endocrine - High Flashcards
(453 cards)
Is thyroid stimulating hormone (TSH) elevated or decreased in hypothyroidism?
Elevated due to the loss of negative feedback from thyroxine (T4) on the pituitary
What are some signs and symptoms of hypothyroidism?
- fatigue
- weight gain
- constipation
- intolerance of the cold
- depression
- dry skin
- reduced body and scalp hair
- menstrual irregularities
What is meant by “Primary hypothyroidism”?
Primary hypothyroidism refers to when the condition arises from the thyroid gland and may be caused by iodine deficiency, autoimmune disease, radiotherapy, surgery or drugs, rather than due to a pituitary or hypothalamic disorder (secondary hypothyroidism)
Is hypothyroidism more common in males or females?
Females
What are the classifications of primary hypothyroidim, and how do they differ?
Primary hypothyrodism is characterised as either overt or subclinical, both of which may or may not symptomatic.
Overt is characterised as TSH levels being above the normal reference range and T4 levels being below the reference range.
Subclinical hypothyroidism is characterised as TSH levels above the reference range and T3 and T4 levels within the reference range.
How should secondary hypothyroidism be managed?
Th patient should be urgently referred to an Endocrinologist so the underlying cause of the issue can be assessed
How long can it take for patients who have had very high TSH levels before being initiated on levothyroxine treatment to see a return of levels to the reference range?
Up to 6 months
How is hypothyroidism defined in pregnancy?
In pregnancy hypothyroidism is always defined as overt using trimester specific reference ranges regardless of T4 levels
What is the first line treatment for overt hypothyroidism?
Levothyroxine
How often and in what form should thyroid function tests be measured in patients started on levothyroxine in both overt and subclinical hypothyroidism?
TSH levels should be measured every 3 months until stable levels within the reference range have been reached and then annually thereafter. T4 levls should also be measured in those who continue to be symptomatic.
When should levothyroxine be considered in a patient with subclinical hypothyroidism?
Patients with a TSH of 10mlU/L or higher on 2 separate occasions 3 months apart regardless of symptoms
When should a 6-month trial of levothyroxine be initiated for a patient with suspectd subclinical hypothyroidism?
In symptomatic patients under 65 years of age with a TSH above the reference range but less than 10mlU/L on 2 separate occasions within 3 months
What advice should be offered to a female patient with thyroid function tests outside of the reference range who is planning on getting pregnant?
Delay conception until established on levotyroxine and TFTs are stable within reference range
When is levothyroxine contra-indicated
Thyrotoxicosis
What drug class does thyrotropin alfa belong to?
Thyroid stimulating hormones
What is the primary cause of hyperthyroidism?
Graves Disease
What are the main symptoms of hyperthyroidism?
- hyperactivity
- disturbed sleep
- fatigue
- palpitations
- anxiety
- unintentional weight loss
- intolerance of heat
- increased appetite
What does “Primary hyperthyroidism” refer to?
The condition arises from the thyroid gland rather than due to a pituitary or hypothalmic disorder
What are the 2 classifications of hyperthyroidism and how are they defined?
Overt and subclinical
Overt - TSH levels are below he reference range and T4 and/or T3 are above the reference range
Subclinical - TSH levels are below the reference range but T4 and/or T3 levels are within the reference range
What is the first line recommendation for the treatment of hyperthyroidism?
Carbimazole
What is the alternative to carbimazole for the teatment of hyperthyroidism?
Propylthiouracil (where carbimazole is unsuitable)
What tests need to be performed before a patient is initiated on anti-thyroid medication such as carbimazole?
Full blood count and liver funcion tests
What is the first line treatment for Graves’ disease?
Radioactive iodine
How should carbimazole be prescribed for the treatment of Graves’ disease when the use of radioactive iodine has been deemed unnecessary?
Carbimazole should be offered as a 12-18 month course of block and replace regimen (with levothyroxine) OR as a titration regimen