Thyroid gland disorders + Pics Flashcards
anatomical location of thyroid gland
,
Lies against and around front larynx and trachea
Below thyroid cartilage (Adam’s apple)
Isthmus extends from 2nd to 3rd rings of the trachea
butterfly 2 lobes joined by isthmus
•“Bow tie” shape and location
Describe what u see? describe causes
“Goitre”
is a swelling of the thyroid gland that causes a lump to form in the front of the neck. The lump will move up and down when you swallow.
It doesnt tell u anything about its function!
- May accompany either hypo- or hyperthyroidism (but not necessarily present in either)
• Develops when the thyroid gland is overstimulated
Describe this condition and its causes, treatments, symptoms
how long does it take for the hormones to NORMALIZE
- Most common cause of hyperthyrodism
- Autoimmune disease in which antibodies TSI (thyroid stimulating immunoglobin) is produced> stimulate TSH recepters on follicle cells>results in increase production and release of T3 & T4 hormones.
TSH levels decrease due to negative feedback of T3&T4 hormones.BUT this wont stop this crisis bc the stimulus for releasing the hormones in the first place was via TSI and not TSH
Findings:
Increased T3, Increased T4, VERY LOW TSH
TREATMENT:
Thionamides>> Carbimazole> inhibits Thyroid peroxidase
4-6wks
BEWARE
what is Hashimosto disease
describe the blood findings & treatments
what if no improvement despite treatment
-most common form of hypothyrodism
=• Most common disease of thyroid gland
-autoimmune disease that results from destruction of thryroid follicules or production of antibody that block TSH recepters on follicle cells.
Plasma
- LowT3
- LowT4
- HIGH TSH
TREATMENT
Oral thyroxine
typical starting dose is 50-100 Mg/day
elderly and IHD>> started on a lower dose
if not working>> not complient or malabsorption ex; celiac or medication like iron, calcium,PPI
Symptoms of thyrotoxicosis (hyperthyroidism is thyrotoxicosis due to over production of thyroxine by the thyroid gland)
what things can cause it?
Autoimmune Graves’ disease
Toxic multinodular goitre
Solitary toxic adenoma
Excessive T4 (or T3) therapy
Drugs - amiodarone
Thyroid carcinoma
Ectopic thyroid tissue
treatment
Carbimazole
Surgical excision of thyroid. Thyroidectomy
radioavctive iodine/
symptoms of hypothyroidism
what can cause it?
treatment?
Failure of thyroid gland
TSH or TRH deficiency
Severe iodine deficiency
Radioactiveiodine
Autoimmune destruction of the thyroid -hashimOto
Post surgical removal of thyroid
Congenital
Anti-thyroid drugs
TREATMENT?
Oral thyroxine>luckily not destroyed by gastric acid
and then we use the patients brain to see if weve got the right dose! by measuring TSH levels!
Low TSH>> means we gave them too much
and vise versa
why does she have periorbital edema?
what is this a manifestation of?
what caused this?
Hypothyroidism
Adults - myxedema“non pitting edema”
another way to refer to “hypothyrodism”
So if a doctor says “she has myxoedema”, this means that she has hypothroidism – a bit confusing!
this is due to the high TSH levels resulting from the hypoparathydoism stimulates TSH recepters in fibroblasts around the eyes, this increases deposition of substances like GAGS, mucopolysaccarides, hylornic acid and chondroitin sulfate! which draws in water resulting in osmotic edema and fluid retention!
why does the thyroid gland move up when swallowing?
the pre tracheal fascia INVESTS the thyroid and goes up to join the larynx!
when we swallow, the larynx is moving up against the epiglottis and closing off the entrance>> its a preotective mechanism
and the thyproid is attached to this, so mbtlsh wiyahum, it moves as well.
describe what u see
the CNS is very sensitive to thyroid hormones during development.
in the absence of these thyroid hormones from birth to puberty, child will remain physcially and mentally retarded CRETINISM
if this is not corrected within a few weeks of birht>> IRREVERSIBLE damage may occur.
SYMPTOMS:
- Dwarfed stature
- Mental deficiency
- Poor bone dev
- Slow pulse
- Muscle weakness
• GI disturbances
what r the tissue specicfic effects thyroid hormones have on speicifc tissues (2)
Regulation of thyroid
hormone secretion is via Negative feedback explain pathwyas
how to u test for functional thyroid?
we tend to give them IV technetium (wait 15 min, then scan) rather than iodine orally,
b if Iodine is taken orally,we have tp wait for it to be absorbed,and they have to come the next day.
Radioiodine scanning is rarely used
how do u perform thyroid examination?
stand behind patient, bc if u stand in front ur sensory ability of ur hands is reduces, so from behind is better.
BUT: It is not possible to feel a normal thyroid gland
Describe what u see in the image?
Radionuclide scan
Iodine131 scan showing enlarged/adenoma of right thyroid lobe,
Describe the thyroid gland development
Starts at the foramen cecum (cecum means blind ending)
moves down and goes behind the hyoid bone (lana malgoof)
then continues to come down and settles
IT IS THE FIRST ENDOCRINE GLAND TO DEVELOP!
just an image to help
ok babe
what is wring with this patient?
she has a lingual throid
part of her thyroid gland remained on the tongue! (see look it attached to the uvula) she was hypothryoid which mean her TSH went up, at that made it get large!
give her thyroixine>> TSH went down
how can u develop a thyroglossal duct cyst?
As it decends from the cecum, it can leave a bit of tissue behind and that gets stuck there causing a cyst
bc the thyroid descend in the midline.
near or within the body of the hyoid and forms a SWELLING
ITS ALWAYS EXACTLY IN THE MIDLINE
describe what is happening here and name the condition
A thyroglossal cyst that moves upwards and drawn in on tongue protrusion.
why?
bc its coming from the tongue
look alaa!
A thyroglossal cyst
define hyperthyrodism, hypothyroidism and thyrotoxicoisis
what treatments are used for thyrotoxicosis?
Long term treatment for thyrotoxicosis
describe how a Goitre may present?
- diffuse
- multinodular>> most common in UK women
- single nodule
in this xray, the trachea has been pushed to the right due to a goitre, what do u call this condition?
Retrosternal (behind sternum) mutinodular goitre
giote can enlarge into the superior mediastinum behind the sternum
what do u call this appearence?
when do u get it?
Peaches and cream facies
facies:appearence of face due to underlying pathology
HYPOthyrodism
when can u get lid lag and why?
in hyperthyrodism.
due to increased sympathetic actvity,
lookup and down, sinaaa 3ala bal ma il eyelid ytsakar!
a young woman with exopthalmos, diffuse goitre, hyperthyroidism and pretibial myxoedema
what is the most likely diagnosis
Graves’ disease
The TSI causes all of the classical signs and symptoms of thryotoxicosis, however the additional unique features of Graves’ disease are: (2)
– Exopthalmos (it is possible to have the exopthalmos alone)
– Pre-tibial myxoedema (confusing because nothing to do with
hypothyroidism/myxoedema!)
THESE both r symptoms of the autoimmune disease! itself! that why we use them to distinhuish btw graves and other (no autoimmune) causes of hyperthyrodism.
Summary of thyroid Abnormalities
ok
Which disease results from excess growth hormone secretion occuring after puberty after the epiphyseal plates have closed?
Acromagaly
is an extremely rare disease that results when the anterior pituitary gland produces excess growth hormone after epiphyseal plate closure at puberty
How do thyroid hormone bind to intracellular receptors ?
Binding of T3 to the hormone binding domain> conformational change in recepter> unmask DNA binding domain
when hormone recepter complex BINDS with DNA (nucleaur or mitochondrial)> increase transcription rate> translation> proteins
What is this called? When do u see it? What causes it and how?
Exopthalmos is casued by an infiltration of the orbital connective tissue by lymphocytes and other immune cell types in response to TSI recognising antigens in orbital fat and connective tissue.
The inflammation results in a deposition of collagen + GAGS in the muscles leading to subsequent enlargement and Fibrosis.
what is exopthalmus?
When do u get physiological goitre? (3)
Why do u get nonpitting edema in hypothyrodism?
Non pitting oedema – myxoedema
Due to deposition of
mucopolysaccharides, particularly around eyes, hands and feet
Symptoms og hyper wala hypo thyrodism?
Structures of T3 & T4
In pts with secondary hypothyroidism, why shoud t4 be replaced to the upper part of normal range?
Bc TSH cannot be relied upon as a measure of optimal replacment.
