Thyroid Gland Disorders 2 Flashcards
What are the 4 categories of thyroid disorders?
- Congenital anomalies
- Those associated with excessive release of thyroid hormone (Hyperthyroidism)
- Those associated with thyroid hormone deficiency (Hypothyroidism)
- Tumors of thyroid.
what are the congenital thyroid anomalities?
lingual thyroid
Thyroglossal duct cyst
what is Lingual thyroid?
what are the Clinical findings?
Failed descent of thyroid anlage from the base of the tongue
- Dysphagia for solids
- Mass lesion
- I 131 scan locates the lesion
what is Thyroglossal duct cyst?
how does it present?
what are the complications?
Occurs if the thyroglossal duct fails to atrophy.
May present as a cystic midline mass anterior to trachea.
- May get infected and lead to an abscess
- May give rise to carcinoma.
what are the diseases where thyroid hormone is made in excess?
Thyrotoxicosis
Hyperthyroidism
what is thyrotoxicosis?
Clinical, physiological and biochemical findings in response to elevated thyroid hormone levels regardless of cause
what is hyperthyroidism?
thyroid hormone excess due to hyperfunction of thyroid gland
Increased basal metabolic rate due to excess thyroid hormone will cause what changes in na/k atpase, O2, respiration, heat, cardiovascular?
Increased Na+/K+ ATPase activity
Increased oxygen consumption
Increased respiration
Heat generation
Increased cardiovascular activity
Increased beta adrenergic receptor synthesis will cause what changes?
Increased sympathetic activity
what is 1ry Hyperthyroidism?
- Hyperthyroidism due to intrinsic thyroid abnormality.
what are examples of 1ry hyperthyroidism?
Examples:
- Graves’ disease (most common cause)
- Toxic multinodular goiter
- Toxic thyroid adenoma
- Thyroiditis
what is 2ry hyperthyroidism?
give an example of a cause
Hyperthyroidism due to abnormality out side of thyroid.
TSH secreting pituitary tumor
what are Other causes of hyperthyroidism?
Struma ovarii – ovarian teratoma with ectopic thyroid
Exogenous administration of thyroid hormone.
General clinical features of hyperthyroidism are due to what?
- Hypermetabolic state
- Increased activity of sympathetic nervous system (due to increased expression of adrenergic receptors)
- Increased sensitivity to catecholamines
what are the CVS symptoms of hyperthyroidism?
what patients usually have CVS symptoms?
which symptom is mostly presented?
- Tachycardia, palpitations,Atrial fibrillation
- Elderly patients may have only CV symptoms, commonly new onset Atrial fibrillation
what are the neuromuscular symptoms of hyperthyroidism?
- Fine tremor of fingers & tongue
- Anxiety & restlessness, inability to sleep
- Brisk tendon reflex response
what are the gastrointestinal clinical features of hyperthyroidism?
- Diarrhea
- Weight loss despite increased appetite and polyphagia
what are the Dermatologic clinical features of hyperthyroidism?
- Warm and moist skin
- Fine hair
what are the eye clinical features of hyperthyroidism?
what are other clinical features of hyperthyroidism?
Wide staring gaze and lid lag
Due to overstimulation of levator palpebrae superioris
Heat intolerance and risk of Osteoporosis, hypocholesterolemia.
what is this feature, and what is it of?
wide-eyed staring gaze in hyperthyroidism
what are the lab findings for 1ry hyperthyroidism?
- Free T3 and T4 : increased
- TSH levels : decreased
what are the lab findings for 2ry hyperthyroidism?
TSH levels : raised
Increased free T3 and T4
what are the clinical features of grave’s disease?
Pretibial myxedema
Proptosis (Exophthalmos)
Acropachy
Thyromegaly
what is the most common cause of hyperthyroidism and Thyrotoxicosis?
graves disease
graves disease is genetically..
what locus is it related to?
female dominant autoimmune disease
HLA-DR3
what happens in graves disease?
TSH receptors are perceived as antigens
Thyroid stimulating (IgG) ab (TSI) synthesized against TSH receptorActivate TSH receptors causing excess thyroid hormone secretion resulting in
Hyperthyroidism and
Enlargement of thyroid = thyromegaly.
what clinical features will you see in grave’s disease?
clinical features of hyperthyroidism + those specific to the disease:
- Infiltrative Ophthalmopathy: Exophthalmos, Due to glycosaaminoglycans deposited in orbital tissue.
- Diplopia, conjunctival injection, chemosis, corneal abrasion
- Pretibial myxedema: raised and hyperpigmented pretibial areas, due to excess GAG in the dermis.
- Acropachy: separation of nail from nailbed
what are the gross findings of graves disease?
what are the micro findings in graves disease?
Diffuse, symmetrical, nontender thyromegaly (thyroid enlargement)
Hypertrophy and hyperplasia of follicular epithelium producing:
•Papillary infoldings in the glands
Scant colloid with scalloped margins.
what are the laboratory findings in graves disease?
Decreased serum TSH (single best test)
Increased free T3 and T4
Increased radioactive iodine uptake
Increased TSI
what is the treatment for graves disease?
- Beta blockers: block adrenergic effects of thyroid hormone (symptomatic treatment).
- Drugs that decrease hormone synthesis:
- Propylthiouracil (PTU) or methimazole
what is Toxic nodular goiter (Plummer’s disease)?
One or more nodule in MNG become TSH independent.
- Secretes excess T3 and T4 causing hyperthyroidism
in toxic goiter, if a radionactive scan is made, what will be the findings?
hot nodule
Patients with toxic goiter do not have signs of what?
Exophthalmos and pretibial myxedema.
what is a toxic adenoma?
what appears in a radioactive scan?
Single nodule in thyroid gland that autonomously release excessive amounts of thyroid hormone
hot nodule
what is Struma ovarii?
ovarian teratoma made up of thyroid tissue
how will hyperthyroidism present in the elderly?
Apathetic hyperthyroidism
Cardiac abnormalities - Atrial fibrillation, CHF
Thyromegaly
what is Thyrotoxic crisis / Thyroid storm?
Acute exacerbation of all the symptoms of thyrotoxicosis presenting in a life threatening state secondary to uncontrolled hyperthyroidism – medical emergency!!!
what are the clinical features of thryoid storm?
- Hyperthyroidism
- Extreme hyperthermia, tachycardia, vomiting, diarrhea, vascular collapse, hepatic failure, jaundice
- Tachy-arrythmia, congestive heart failure, shock
- Delirium to coma
what will appear in Lab investigations for thyroid storm?
- Increased free T3 and T4
- Undetectable TSH***
what is hypothyroidism?
Clinical syndrome caused by reduced secretion of thyroid hormone.
Normal T4, TSH mildly elevated
what causess 1ry hypothyroidism?
Hashimoto’s thyroiditis ********
Thyroid surgery and or irradiation
Iodine deficiency
Hereditary enzyme defects
what causes 2ry hypothyroidism?
TSH deficiency = hypopituitarism
what causes 3ry hypothyroidism?
Thyrotropin releasing hormone deficiency = hypothalamic disease
how does Hypothyroidism present in older children and adults?
and in infants and neonates?
- Myxedema in older children or adults
- Cretinism in neonates and infants
what is myxedema?
what can it lead to?
Refers to hypothyroidism developing in an adult.
Hashimotos thyroiditis**
what are the Clinical Features of early hypothyroidism?
Fatigue , constipation and cold intolerance, slowing of mental and physical performance.
what are the Clinical Features of late hypothyroidism?
- Weight gain: Due to hypometabolic state with retention of water and salt
- Mental slowness (forgetful)
- Dry and brittle hair, loss of lateral aspect of eye brow
- Deep and hoarse voice, large tongue (macroglossia)
- Periorbital puffiness ,
- Pretibial myxedema
- Slow deep tendon reflexes.
- Oligomenorrhea , hypercholesterolemia
what are the Laboratory findings in myxedema?
what is the treatment?
Increased TSH (single best test)
Decreased serum T4 and T3
Levothyroxine
what is Cretinism?
another name for this?
Hypothyroidism in infancy or early childhood.
congenital hypothyroidism
what are the causes for cretinism?
- Maternal hypothyroidism before development of fetal thyroid gland
- Iodine deficiency: during intrauterine and neonatal life.
- Maternal use of drugs that block thyroid hormone synthesis.
- Deficiency of enzyme necessary for thyroid hormone synthesis.
what are the clinical findings of cretinism?
- Severe mental retardation
- Increased weight &
- short stature (dwarfism),
- Coarse facial features,
- Protuberant abdomen (pot belly)
- Enlarged tongue
- Umblical hernia.
