Hypothyroid

Question 1

Definition

Answer 1

Inadequate thyroid hormone.

Question 2

Aetiology

Answer 2

Primary MOST COMMON-
Hashimoto- autoimmune for follicles or Ab blocks TSH R
Primary atrophic hypothyroid due to diffuse lymphocytic infiltration.
Idiopathic myoedema
Hyperthyroid tx
Subacute thyroiditis
Radiation to neck
Iodine deficiency or excess
Drugs eg lithium, sulphonamide, amiodarone.
Congenital
LT iodide tx, thyroidectomy, radioiodine, antithyroid drugs.
Secondary- lack TSH
Pituitary dysfunction, postpartum necrosis, neoplasm, infiltrative disease.
Tertiary-
Hypothalamic disease eg granuloma, neoplasm, radiation causing deficient TRH.
Rare- tissue resistance to thyroid hormone.

Question 3

Differentials

Answer 3

Depression
Dementia
Systemic eg nephrotic syndrome, CHF, amyloidosis.
Anaemia
Thyroid lymphoma
TBG deficiency 
Iodine deficiency

Question 4

Symptoms

Answer 4

Often subtle and non specific
Tired
Low mood
Cold
Weight gain
Constipation
Menorrhagia, infertility
Hoarse voice
Memory loss
Myalgia
Cramps
Muscle weakness.

Question 5

Signs

Answer 5

Brady
Reflexes slow to relax
Ataxia
Dry thin hair and skin, and slow growing. 
Drowsy
Cold hands
Ascites
Round face
Immobile ileus
Neuropathy
Myopathy
Goitre
Depression
CTS
Oedema (myxoedema= dry firm waxy swelling of skin and SC tissue)

Question 6

Management

Answer 6

Levothyroxine T4

Monitoring TSH and maybe T4.

Question 7

Diagnosis

Answer 7

Usually TSH high, T4 low.
TSH low too if pituitary problem.
High cholesterol and TG.
Macrocytosis.

Question 8

Complications

Answer 8

Risk heart disease as low thyroxine= increased cholesterol.
Pregnancy complications eg pre eclampsia, anaemia, premature labour, low birth weight, stillbirth, bleeding after birth.
Myxoedema coma rare.
Cretinism in neonate, now screened.

Question 9

General effects of thyroid hormones

Answer 9

Increased BMR
Stimulation of catabolic pathways
Normal tissue growth and development
Increased responsiveness of tissue to SNS

Question 10

Specific effects of thyroid hormone

Answer 10

NS development- myelination, reflexes, mental activity.
CVS- increase CO
Skin and SC tissue- increase t/o protein and gp.

Question 11

Explanation

Answer 11

• hypothyroid is where your thyroid gland isnt making enough thyroid hormone. It can be because of your immune system blocking its production, or other things. Thyroid hormone is important in general for how the body works. Its important in getting energy from the food we eat and generally speeds up processes in the body. So if you dont have enough, the body generally tends to slow down, so you get symtoms like weight gain, feeling cold, tired, constipation etc.
• it can be very well managed with medication but it can be dangerous if levels get too low, the body starts to shut down and can even cause a coma.
• lifestyle changes just include sticking to the medications, and keeping an eye out for any signs of symptoms coming back. Also it never hurts to eat healthily and stop smoking.
• the treatment is very simple in that we give you a tablet containing the thyroid hormone that you dont have enough of. We will need to monitor how your doing by taking blood tests, and might need to change the dose of your medication.