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Thyroid Gland (nontoxic goiter & hyperthyroidism) (Simple (nontoxic)…
Thyroid Gland
(nontoxic goiter & hyperthyroidism)
Simple (nontoxic) goiter
every visible or palpable enlargement of thyroid or ectopic thyroid tissue like: ovarian & lingual goiter
WHO criteria: goiter occurs when each lobe of the thyroid gland is larger than distal phalanx of the thumbs.
WHO Classification:
0 stage: invisible & isn't palpable.
1 stage: palpable, visible only during leaning back head
2 stage: visible enlargement even in normal position of head
can any enlargement of thyroid gland that is not initially associated with thyrotoxicosis or myxoedema.
most common thyroid disease
commonly in women
aetiology:
-iodine deficiency is the most common cause of goiter.
-ingestion of goittogens: cabbage, cauliflower, babassu palm, nuts pignon
-external factors: industrial dirt, excess: lead, mercury, manganese, and deficit: selenium, magnesium, copper
-large doses iodine: inhibits of thyroid hormone synthesis and release; sea side goiter (eating of algae kelp)
-hypersecreation of HCG ( pregnancy), GH ( acromegaly) result in enlargement.
manifestations
commonly seen as cosmetic defect.
can cause oesophageal or tracheal compression ( dysphagia & dyspnea)
hoarseness is rare and may suggest neoplasm
pain is not typical, commonly due to thyroiditis.
prophylaxis
daily iodine: 90 microgram to 6 year old, 120 up to 10,
150 in > 10 in pregnancy and during lactation add 150.
in case of nuclear damage and fallout k+, iodine is recommended to stop radioactive iodine uptake.
treatment
conservative:
iodine: 9- 24 months: school children ( 200-300 micro pre day), adults to 40 yo. ( 200-500)
levothyroxine [L - T4]: 1,5 -2 mic pre KG pr day
iodine + L- T4: 1,5 -2 mic pre KG pr day + 150 -200 of iodine
surgery:
obstructive symptoms or malignancy.
subtotal thyroidectomy
postoperative care: L- T4 to inhibit regenerative hyperplasia
radioactive iodine:
for elderly with obstructive symptoms and high risk of surgical complication
recurrence goiter - after surgery
hypothyrosis: 3% pat. after 12 months
Hyperthyroidism
clinical syndrome result from elevation of circulation thyroid hormones.
manifestations due to direct physiologic effect of thyroid hormones as well as increased sensitivity to catecholamines
Focal enlargement of the thyroid can be associated with tumors (benign or malignant). Generalized enlargement can be associated with increased, normal, or decreased function of the gland depending on the underlying cause.
Always check free T4 to assess thyroid function.
suspicion of thyrotoxicosis:
TSH L, fT4 N, fT3 N: subclinical,
TSH L, fT4 H, OR TSH L, fT4 N, fT3 H: Hyperthyroidism, Graves disease's, toxic adenoma, thyroiditis, multuinodular goiter
TSH N OR
H
, fT4 H:
TSHoma
, thyroid hormone resistance
causes
autoimmune: Graves disease's (Grave-basedows), hashimoto's disease (Hashitoxicosis phase).
autonomic: toxic simple-nodular goiter ( goetsch's disease), toxic multi-nodular goiter (plummer's disease), diffuse toxic autonomy.
inflammation: postpartum thyroiditis,
subacute ( de Quervaine's thyroiditis)
, silent thyroiditis.
iatrogenic: iodine induced ; jod-basedow, amiodarone, lithium, interleukin 2, interferon a, after radio-iodine treatment.
secondary: TSH is elevated
-TSH secreting hormones: pituitary adenoma.
-hCG (chorionic gonadotrophin dependent): choriocarcinoma, molar hydatidiform, pregnancy hyperthyroidism.
-ectopic thyroid hormones secretion: metastases of follicular thyroid carcinoma, struma ovarii.
-pituitary thyroid hormones resistant.
in children:
95% graves disease
sometimes: de Quervaine's thyroiditis, toxic multi-nodular goiter (plummer's disease)
in adult:
not iodine deficiency: toxic multi-nodular goiter (plummer's disease) 9%,
graves 90%
iodine deficiency: toxic multi-nodular goiter (plummer's disease) 60% graves 39%
symptoms
feeling of heat, headache intolerance, tremor, palpitations, weight loss, sweating, muscle weakness, sleep disturbance
lab studies: total cholesterol , LDL
L
,
ALP, Ca, SHBG (sex hormones binding globulin), ACE (angiotensin converting enzyme), iron, ferritin
H
Physical Examination of the Hyperthyroid Patient
Painless & diffuse enlargement = Graves’
Painless & nodules = Plummer
Painful & diffuse enlargement = subacute thyroiditis
No thyroid enlargement or thyroid not palpated = factitious
Grave's disease (diffuse toxic goiter)
clinical manifestations
thyrotoxicosis
plummer's nail: separate of nail plate from the nail bed at its distal and lateral attachment.
brittle nails.
goiter
usually symmetrical, soft to smooth,
painless
, movable, NO lymphadenopathy, bruit over the gland, diffuse toxic goiter may be asymmetrical and lobular
thyroid acropachy
thyroid dermopathy - pretibial myxedma
thyroid eye disease - ophthalmolopathy
known as dysthyroid eye disease or graves' disease.
pathophysiology:
-immune response that cause retro-orbital inflammation.
-swelling and edam of extraocular mm. lead to limitation of eye movement and to proptosis which is usually bilateral, but can be unilateral.
characteristics:
can occur in pats. who may be: hyper-, eu, hypothyroid.
more common in smokers.
don't need for antithyroid treatment, but exacerbation of eye disease is more common after radio iodine therapy.
divided into:
spastic: the stare, lid lag & retraction - "frightened " face
mechanical: proptosis & congestive oculopathy characterised by chemises, conjunctivitis, periobital swelling, complications of corneal ulceration, optic neuritis & optic atrophy.
malignant exophthalmos:
unilateral that progress to bi..
strabismus with varying degrees of diplopia.
ocular m. weakness result in impaired upward gaze and convergence
diagnosis:
CT,
MRI of orbits will exclude other causes and show enlarged mm. and edema.
treatment:
hypothyroidism must be avoided, coz may exacerbate the eye problem.
stop smoking.
local or systemic.
methylcellulose or hypromellose eyedrops: aid lubrication and improve comfort .
sleeping upright may relief,
systemic steroid: reduce inflammation
irradiation of orbits: improve inflammation and motility, but little effect on proptosis
lid surgery: protect the cornea.
surgical decompression of orbit.
corrective eye m. surgery: improve diplopia.
plastic surgery around the eyes.
Diagnosis
TSH L, fT4 H, fT3 H and,
antibodies against thyroid TSH receptor ( tsab)- 80-90%,
anti thyroid peroxidase ( tbpa) - 70%,
anti thyroidgnobulin (tg)-50%
ultrasound
thyroid scintigraphy
treatment
characterised by cyclic phases of exacerbation and remission.
antithyroid drugs
beta adrenergic blocking drugs
radioiodine (131-i)
surgery
causes the production of antibodies (thyroid stimulating immunoglobulin [TSI]), which stimulate the thyroid to secrete T4 and T
toxic multi-nodular goiter (plummer's disease)
Simple (nontoxic) goiter --> nontoxic multi-nodular goiter --> toxic multi-nodular goiter
diagnosis:
-TSH L (atrophy due to decreased TSH), fT4 H, fT3 H and,
-ultrasound
-fine needle aspiration biopsy (FNA)
-thyroid scintigraphy
-to differentiate between graves'
antibodies against thyroid TSH receptor ( tsab)
anti thyroid peroxidase ( tbpa),
anti thyroidgnobulin (tg)
treatment:
-antithyroid drugs
-beta adrenergic blocking drugs
-radioiodine (131-i)
-surgery
antithyroid drugs
propylthiouracil (PTU).
carbimazole, metimazole, thiamazole.
effect:
block thyroid hormone synthesis by inhibiting thyroid peroxidase.
inhibit peripheral conversion of t4 to t3 ( only ptu).
immunosuppressive ( small effect)
doses:
propylthiouracil (PTU) 300 mg/d.
carbimazole 30 mg/d
every 6 or 8h
check up every month for TSH , fT4
side effects:
carbimazole, metimazole: rash & pruritus, nausea & vomiting, scholastic jaundice, acute arthralgia, rarely agranulocytosis
propylthiouracil (PTU):ash & pruritus, nausea & vomiting, rarely agranulocytosis.
for both
leukopenia
, treatment should be
stoped
when leucocyte below
1500
beta bockers
propranolol the best choice coz less side effects.
reduces adrenergic manifestations such as sweating , tremor , tachycardia .
in 40-120 mg/d may reduce the conversion of t4 to t3
hyperthyroidism in pregnancy
without primary thyroid disease ( 1% of pregnancy): thyrotoxicosis gravidarum
TREAT WITH: beta blockers & self limitation in 18 weeks.
hcg and beta hcg 3*H
fT3, fT4 H
TSH L
with primary thyroid disease (.2-.7%):
GRAVES DISEASE: antithyroid
TOXIC MULTINODULAR GOITER: antithyroid during all pregnancy
fT3, fT4 H
TSH L
Ma6ar