Thyroid Gland Disorders 2

Question 1

What are the 4 categories of thyroid disorders?

Answer 1

1. Congenital anomalies
2. Those associated with excessive release of thyroid hormone (Hyperthyroidism)
3. Those associated with thyroid hormone deficiency (Hypothyroidism)
4. Tumors of thyroid.

Question 2

what are the congenital thyroid anomalities?

Answer 2

lingual thyroid

Thyroglossal duct cyst

Question 3

what is Lingual thyroid?

what are the Clinical findings?

Answer 3

Failed descent of thyroid anlage from the base of the tongue

• Dysphagia for solids
• Mass lesion
• I 131 scan locates the lesion

Question 4

what is Thyroglossal duct cyst?

how does it present?

what are the complications?

Answer 4

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.

Question 5

what are the diseases where thyroid hormone is made in excess?

Answer 5

Thyrotoxicosis

Hyperthyroidism

Question 6

what is thyrotoxicosis?

Answer 6

Clinical, physiological and biochemical findings in response to elevated thyroid hormone levels regardless of cause

Question 7

what is hyperthyroidism?

Answer 7

thyroid hormone excess due to hyperfunction of thyroid gland

Question 8

Increased basal metabolic rate due to excess thyroid hormone will cause what changes in na/k atpase, O2, respiration, heat, cardiovascular?

Answer 8

Increased Na+/K+ ATPase activity

Increased oxygen consumption

Increased respiration

Heat generation

Increased cardiovascular activity

Question 9

Increased beta adrenergic receptor synthesis will cause what changes?

Answer 9

Increased sympathetic activity

Question 10

what is 1ry Hyperthyroidism?

Answer 10

• Hyperthyroidism due to intrinsic thyroid abnormality.

Question 11

what are examples of 1ry hyperthyroidism?

Answer 11

Examples:

• Graves’ disease (most common cause)
• Toxic multinodular goiter
• Toxic thyroid adenoma
• Thyroiditis

Question 12

what is 2ry hyperthyroidism?

give an example of a cause

Answer 12

Hyperthyroidism due to abnormality out side of thyroid.

TSH secreting pituitary tumor

Question 13

what are Other causes of hyperthyroidism?

Answer 13

Struma ovarii – ovarian teratoma with ectopic thyroid

Exogenous administration of thyroid hormone.

Question 14

General clinical features of hyperthyroidism are due to what?

Answer 14

• Hypermetabolic state
• Increased activity of sympathetic nervous system (due to increased expression of adrenergic receptors)
• Increased sensitivity to catecholamines

Question 15

what are the CVS symptoms of hyperthyroidism?

what patients usually have CVS symptoms?

which symptom is mostly presented?

Answer 15

• Tachycardia, palpitations,Atrial fibrillation
• Elderly patients may have only CV symptoms, commonly new onset Atrial fibrillation

Question 16

what are the neuromuscular symptoms of hyperthyroidism?

Answer 16

• Fine tremor of fingers & tongue
• Anxiety & restlessness, inability to sleep
• Brisk tendon reflex response

Question 17

what are the gastrointestinal clinical features of hyperthyroidism?

Answer 17

• Diarrhea
• Weight loss despite increased appetite and polyphagia

Question 18

what are the Dermatologic clinical features of hyperthyroidism?

Answer 18

• Warm and moist skin
• Fine hair

Question 19

what are the eye clinical features of hyperthyroidism?

what are other clinical features of hyperthyroidism?

Answer 19

Wide staring gaze and lid lag

Due to overstimulation of levator palpebrae superioris

Heat intolerance and risk of Osteoporosis, hypocholesterolemia.

Question 20

what is this feature, and what is it of?

Answer 20

wide-eyed staring gaze in hyperthyroidism

Question 22

what are the lab findings for 1ry hyperthyroidism?

Answer 22

• Free T3 and T4 : increased
• TSH levels : decreased

Question 23

what are the lab findings for 2ry hyperthyroidism?

Answer 23

TSH levels : raised

Increased free T3 and T4

Question 24

what are the clinical features of grave’s disease?

Answer 24

Pretibial myxedema

Proptosis (Exophthalmos)

Acropachy

Thyromegaly

Question 25

what is the most common cause of hyperthyroidism and Thyrotoxicosis?

Answer 25

graves disease

Question 26

graves disease is genetically.. what locus is it related to?

Answer 26

female dominant autoimmune disease HLA-DR3

Question 27

what happens in graves disease?

Answer 27

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.

Question 28

what clinical features will you see in grave's disease?

Answer 28

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

Question 29

what are the gross findings of graves disease? what are the micro findings in graves disease?

Answer 29

Diffuse, symmetrical, nontender thyromegaly (thyroid enlargement) Hypertrophy and hyperplasia of follicular epithelium producing: •Papillary infoldings in the glands Scant colloid with scalloped margins.

Question 30

what are the laboratory findings in graves disease?

Answer 30

Decreased serum TSH (single best test) Increased free T3 and T4 Increased radioactive iodine uptake Increased TSI

Question 31

what is the treatment for graves disease?

Answer 31

* Beta blockers: block adrenergic effects of thyroid hormone (symptomatic treatment). * Drugs that decrease hormone synthesis: * Propylthiouracil (PTU) or methimazole

Question 32

what is Toxic nodular goiter (Plummer’s disease)?

Answer 32

One or more nodule in MNG become TSH independent. * Secretes excess T3 and T4 causing hyperthyroidism

Question 33

in toxic goiter, if a radionactive scan is made, what will be the findings?

Answer 33

hot nodule

Question 34

Patients with toxic goiter do not have signs of what?

Answer 34

Exophthalmos and pretibial myxedema.

Question 35

what is a toxic adenoma? what appears in a radioactive scan?

Answer 35

Single nodule in thyroid gland that autonomously release excessive amounts of thyroid hormone hot nodule

Question 36

what is Struma ovarii?

Answer 36

ovarian teratoma made up of thyroid tissue

Question 37

how will hyperthyroidism present in the elderly?

Answer 37

Apathetic hyperthyroidism Cardiac abnormalities - Atrial fibrillation, CHF Thyromegaly

Question 38

what is Thyrotoxic crisis / Thyroid storm?

Answer 38

Acute exacerbation of all the symptoms of thyrotoxicosis presenting in a life threatening state secondary to uncontrolled hyperthyroidism – medical emergency!!!

Question 39

what are the clinical features of thryoid storm?

Answer 39

* Hyperthyroidism * Extreme hyperthermia, tachycardia, vomiting, diarrhea, vascular collapse, hepatic failure, jaundice * Tachy-arrythmia, congestive heart failure, shock * Delirium to coma

Question 40

what will appear in Lab investigations for thyroid storm?

Answer 40

* Increased free T3 and T4 * Undetectable TSH\*\*\*

Question 41

what is hypothyroidism?

Answer 41

Clinical syndrome caused by reduced secretion of thyroid hormone. Normal T4, TSH mildly elevated

Question 42

what causess 1ry hypothyroidism?

Answer 42

Hashimoto’s thyroiditis \*\*\*\*\*\*\*\* Thyroid surgery and or irradiation Iodine deficiency Hereditary enzyme defects

Question 43

what causes 2ry hypothyroidism?

Answer 43

TSH deficiency = hypopituitarism

Question 44

what causes 3ry hypothyroidism?

Answer 44

Thyrotropin releasing hormone deficiency = hypothalamic disease

Question 45

how does Hypothyroidism present in older children and adults? and in infants and neonates?

Answer 45

* Myxedema in older children or adults * Cretinism in neonates and infants

Question 46

what is myxedema? what can it lead to?

Answer 46

Refers to hypothyroidism developing in an adult. Hashimotos thyroiditis\*\*

Question 47

what are the Clinical Features of early hypothyroidism?

Answer 47

Fatigue , constipation and cold intolerance, slowing of mental and physical performance.

Question 48

what are the Clinical Features of late hypothyroidism?

Answer 48

* 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

Question 49

what are the Laboratory findings in myxedema? what is the treatment?

Answer 49

Increased TSH (single best test) Decreased serum T4 and T3 Levothyroxine

Question 50

what is Cretinism? another name for this?

Answer 50

Hypothyroidism in infancy or early childhood. congenital hypothyroidism

Question 51

what are the causes for cretinism?

Answer 51

1. Maternal hypothyroidism before development of fetal thyroid gland 2. Iodine deficiency: during intrauterine and neonatal life. 3. Maternal use of drugs that block thyroid hormone synthesis. 4. Deficiency of enzyme necessary for thyroid hormone synthesis.

Question 52

what are the clinical findings of cretinism?

Answer 52

* Severe mental retardation * Increased weight & * short stature (dwarfism), * Coarse facial features, * Protuberant abdomen (pot belly) * Enlarged tongue * Umblical hernia.