Causes of Thyrotoxicosis:
Graves' disease
Toxic nodule goiter
Subacute (de Quervain's) thyroiditis
Post-partum thyroiditis
Acute phase of Hashimoto's thyroiditis (later results in
hypothyroidism)
Toxic adenoma (Plummer's disease)
Amiodarone therapy
Clinical features of thyroid storm include:
Fever > 38.5ºc
Tachycardia
Confusion and agitation
Hypertension
Heart failure
Abnormal liver function test
Pregnancy and Thyroid:
In pregnancy there is increase in the levels of thyroxine-binding
globulin (TBG). This causes increase in the levels of total thyroxine but does
not affect the free thyroxine level
Graves' disease is the most common cause of thyrotoxicosis in
pregnancy
Glucocorticoid withdrawal can trigger immune
response ends with Graves’ disease
Ocular manifestations of thyrotoxicosis include: proptosis, diplopia,
conjunctival injection, corneal abrasions, periorbital puffiness, lid lag,
decreased visual acuity
Subacute Thyroiditis
Etiology is disruption of thyroid follicles by inflammatory process (painful:
viral, De Quervain’s or painless: postpartum, auto-immune) results in the
release of stored hormone rather than excessive production of new thyroid
hormone
Subclinical Hyperthyroidism defined as:
Normal T3 – T4
Decreased TSH (usually < 0.1 mu/)
Subclinical Hypothyroidism defined as:
Normal T3 – T4
Increased TSH
Hypothyroidism is the most common side effect of radioiodine
treatment
Skin Manifestations of Thyroid Diseases:
In hyperthyroidism:
Pretibial myxedema: erythematous, edematous lesions above the
lateral malleoli
Thyroid acropachy: clubbing
Scalp hair thinning
Increase sweating
In hypothyroidism:
Dry (anhydrosis), cold, yellowish skin
Non-pitting edema (e.g. Hands, face)
Dry, coarse scalp hair, loss of lateral aspect of eyebrows
Eczema
Xanthomata
Sick Euthyroid Syndrome:
(non-thyroidal illness), occur in patients with systemic illness,
everything (TSH, thyroxine and T3) is low usually.
There is initially low free T3 may be followed by low TSH and if
severe illness low free T4.
In some cases, the TSH level may be normal. Changes are reversible
after recovery from the systemic illness
Clinical features of myxedema coma:
Decreased mental status
Generalized edema
Hypothermia
Hyponatremia
Hypotension
Hypoglycemia
Hypoventilation
Thyroid cancer:
The most common type of thyroid
cancer is Papillary carcinoma with about 80% of cases then Follicular carcinoma
is the second most common type of thyroid cancer, about10% of cases, followed
by Medullary thyroid carcinoma with 4% of cases then Hürthle cell carcinoma
with 3% and the lest is Anaplastic carcinoma with 2% of cases
Papillary carcinoma: usually have good prognosis
Follicular carcinoma: more aggressive than papillary carcinoma, but
still have good prognosis.
Medullary thyroid carcinoma: it is more aggressive and less
differentiated than papillary or follicular cancers.
Anaplastic carcinoma: it is a very aggressive form of cancer
Papillary carcinoma: may spread to nearby lymph nodes in the neck,
Follicular carcinoma: do not usually spread to nearby lymph nodes,
but they are more likely than papillary cancers to spread to other organs, like
the lungs or the bones.
Medullary thyroid carcinoma: more likely to spread to lymph nodes
and other organs
Anaplastic carcinoma: quickly spreads to other parts of the neck
and body.
Papillary carcinoma can develop in one or both lobes of the thyroid
gland
Follicular carcinoma found more frequently in countries with an
inadequate dietary intake of iodine.
Hürthle cell carcinoma, also known as oxyphil cell carcinoma, is a
subtype of follicular carcinoma
Medullary thyroid carcinoma develops from C cells in the thyroid
gland, they release high levels calcitonin and carcinoembryonic antigen (CEA).
In primary hyperparathyroidism, the PTH level may be normal
Features of hyperparathyroidism:
Polydipsia, polyuria
Peptic ulceration/constipation/pancreatitis
Bone pain/fracture
Renal stones
Depression
Hypertension
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