Thyroid diseases Flashcards
(92 cards)
1
Q
What are the most important causes of hypothyroidism?
A
- IATROGENIC
- autoimmune thyroiditis (Hashimoto)
- congenital defect: agenesis, dyshormonogenesis
2
Q
What are the types according to age?
A
- Fetal or infantile: cretinism
- adulthood: hypothyroidism or myxedema
3
Q
inadequate thyroid hormone production during fetal & neonatal development causes what disease?
A
cretinism
4
Q
What are the types of cretinism?
A
- iatrogenic
- endemic: dietary iodine deficiency
- sporadic: agenesis or dyshormonogenesis
5
Q
What are the general clinical features of adult hypothyroidism?
A
tiredness weight gain cold intolerance cold extremities periorbital puffiness goiter hyperlipidemia
6
Q
What are the thyroid related congenital anomalies?
A
- ectopic thyroid
- dyshormonogenesis
- thyroglossal cyst
7
Q
What type of ectopic thyroid is present in the posterior third of the tongue?
A
Lingual thyroid
causing
- dysphagia
- speech impairment
- respiratory obstruction
- hemorrhage
8
Q
What is an ectopic thyroid?
A
- ectopic thyroid tissue may lie anywhere in the line of descent
- could be the whole thyroid or just residual thyroid tissue
- any disease that occurs in the thyroid could occur in ectopic goiter
9
Q
What methods of investigation are used to confirm ectopic thyroid tissue?
A
radioisotope scan: shows uptake of iodine
CT scan: intrathoracic thyroid
ultrasound should be done to see if the thyroid is absent from its normal location
10
Q
How should ectopic thyroid be treated?
A
surgical excision
L-thyroxine daily
radioisotope therapy for ablation
11
Q
which congenital thyroid disorder is an autosomal recessive condition where there is either a deficiency of thyroid enzyme or inability to bind or retain iodine?
A
dyshormonogenesis
12
Q
How should dyshormonogenesis be treated?
A
L-thyroxine
13
Q
What is Pendered’s syndrome?
A
type of dyshormonogenesis abnormal thyroxin synthesis - goiter - +/- hypothyroidism - hearing loss
14
Q
What is the cause of a thyroglossal cyst?
A
failure of obliteration of part of thyroglossal trunk
15
Q
What is the most common area for a thyroglossal cyst to occur?
A
subhyoid area
16
Q
What is the most specific diagnostic sign for a thyroglossal cyst?
A
MOVES UP WITH TONGUE PROTRUSION
moves up with deglutition
17
Q
Which thyroid congenital anomaly may be accompanied by infection & fistula formation?
A
thyroglossal cyst
fistula is always acquired
18
Q
What investigations should be used in assessment of thyroglossal cyst?
A
- NECK US
- radio-isotope scanning
19
Q
sistrunk operation is preformed to treat what?
A
thyroglossal cyst
- removal of cyst, tract & body of hyoid bone
20
Q
What is the classification of Goiter?
A
SIMPLE
- diffuse
- nodular
TOXIC
- Grave’s
- toxic nodule
- toxic nodular goiter
NEOPLASTIC
- Benign: follicular adenoma
- Malignant
INFLAMMATORY
- Autoimmune: Hashimoto
- Granuloma: De-Quervain’s
- Fibrosing: Riddle’s
- Infective: very rare
MYXEDEMATOUS
21
Q
What is most likely to be a malignancy in the thyroid?
A
solitary thyroid nodule
22
Q
What is a dominant thyroid nodule?
A
by palpation you feel one nodule but on examination there are many impalpable small nodules
- most likely benign
23
Q
What are the causes of simple goiter?
A
PRIMARY IODINE DEFICIENCY
- endemic areas (not enough iodine intake)
- increased demand (puberty, pergnancy, & lactation)
SECONDARY IODINE DEFICIENCY
- drugs
DYSHORMONOGENESIS
- like Pendred’s syndrome (abnormal peroxidase enzyme)
24
Q
which type of goiter is caused by an increased demand of T3 & T4 during pubertal age or pregnancy?
A
Physiological goiter (diffuse hyperplastic goiter)
its reversible if corrected early
25
What are the clinical signs of a physiological goiter?
- symmetrical
- diffuse
- soft
- smooth
- Euthyroid
26
How should a physiological goiter be managed?
- reassurance if Euthyroid
- iodized salt
- if there's an abnormal enlargement of the thyroid that looks cosmetically displeasing L-thyroxine could be used to inhibit TSH
27
Which type of goiter is specifically endemic?
- colloid goiter
| - longstanding iodine deficiency
28
Which type of goiter will cause hyperinvolution of most acini when treated with iodine replacement?
colloid goiter
there will be accumulation of colloid in the gland causing its enlargement (only reversible in early stage)
29
What is the clinical appearance of a colloid goiter?
- irregular enlarged soft gland
- sometimes firm & rubbery
- euthyroid
30
How should a colloid goiter be treated?
small gland: L-thyroxine to decrease TSH & colloid formation
large gland: subtotal thyroidectomy
31
What is the commonest disease of goiter & what is its cause?
Multinodular goiter
due to repeated episodes of stress ---> persistent TSH stimulation ---> diffuse hyperplasia of gland ---> fluctuation of TSH level ---> hyperinvolution ---> inactive nodules & internodular tissue is active ---> haemorrhage & necrosis ---> inactive nodule formation ---> MNG
32
MNG clinical picture?
- slowly progressive enlarging neck swelling causing disfigurement
- butterfly, globular or irregular shape
- nodular surface
33
What are the complications of MNG?
- secondary thyrotoxicosis (if there's abnormal hyperactive function of internodular tissue)
- follicular carcinoma
- tracheal obstruction by compression (dyspnea & stridor)
- cystic degeneration of nodule
- hemorrhage in cyst --> stridor
- retrosternal extension
- cosmetic issue
34
What investigation should be done for MNG?
- ULTRASOUND
| - isotope scanning to differentiate between toxic
35
How should any simple goiter be treated?
- in mild enlargement:
consercative & follow up US every 6 months
- large thyroid early in pathogenesis:
give L-troxin to control TSH
- late stage or complications:
thyriodectomy - subtotal has a risk of recurrence
- total no recurrence but life-long
supplementation
36
What are the types of retrosternal goiter?
- primary (intrathoracic): ectopic tissue in mediastinum
- secondary: extension from enlarged thyroid from neck
- plunging goitre: appear into neck by coughing or deglutition
37
What is the commonest type of a retrosternal goiter?
Secondary
(arises from lower pole of nodular goiter due to negative intrathoracic pressure it gets drawn into superior mediastinum)
38
What is the clinical picture of a retrosternal goiter?
- compression manifestation: on trachea, esophagus, carotid artery, IJN
- hoarseness of voice
- dilated veins over superior part of chest wall
- Pemberton's sign (RED FACE when hands are raised)
- lower border of gland is not seen or felt
- dull percussion over sternum
39
What is the most beneficial method of investigation in retrosternal goiter?
CT
40
What treatment should be done for a retrosternal goiter?
- TOTAL THYROIDECTOMY
41
What automimmune thyroid disease is caused by microsomal & thyroglobulin antibodies?
HASHIMOTO'S THYROIDITIS
42
What is the pathogenesis of Hashimoto thyroiditis?
hyperplasia ---> fibrosis
ASKANAZY CELLS are tyoical
43
What is the clinical picture of Hashimoto thyroiditis?
- HASHITOXICOSIS due to destruction of thyroid follicles THEN hypothyroidism
- associated with other autoimmune diseases & hepatosplenomegaly
44
What are the complication's of Hashimoto thyroiditis?
- Non-Hodgkin's lymohoma
| - hypothyroidism
45
What investigation is most diagnostic test for Hashimoto?
thyroid antibody assay
46
How should Hashimoto be treated?
- L-thyroxine therapy
| - if goitre is large and causing discomfort --> subtotal thyroidectomy
47
Which thyroid disease is caused by a viral infection?
- De-Quervain's thyroiditis (mumps or coxsackie)
- causes painful goiter
- treated by steroids to decrease pain
48
Which type of thyroiditis simulates malignancy?
Riedel's Thyroiditis
- collagen disorder
- stony hard
- FNA should be preformed to exclude malignancy
- treat with isthectomy
49
What are the types of toxic goiter?
- diffuse toxic goiter (Grave's disease, Primary
thyrotoxicosis)
- toxic multinodular goiter (secondary thyrotoxicosis)
(Plummer's disease)
- toxic nodules (autonomous nodule)
50
What disease is caused by an automimmune disorder with increased levels of TSI, Ts Ab, & LATS?
Grave's disease
51
what does the Exophthalmos producing substance cause?
Grave's opthalmopathy
52
What is the characteristic triad of Grave's disease?
- toxic manifestation
- diffuse vascular fleshy symmetrical goiter
- eye signs & pretibial myxoedema
53
long standing simple nodular goiter that is causing hyperthyroidism will lead to?
toxic nodular goiter
- nodules are inactive & internodular thyroid tissue is overactive
- usually in middle aged or elderly
54
a completely healthy thyroid gland with a single nodule that is over active is called?
autonomous nodule
| - autonomous hypertrophy & hyperplasia at nodule
55
What effects will an autonomous nodule have on TSH?
high levels of circulating thyroid hormone will SUPPRESS TSH secretion ---> normal thyroid tissue will be inactive
56
What is your diagnosis for a patient that is presenting with toxic & autoimmune manifestation?
Graves
57
What age group is Grave's disease more common in?
younger age group
58
What age group is secondary thyrotoxicosis more common in?
older age group
59
What are the metabolic changes that will occur in a patient developing a toxic goiter?
- sympathetic over activity
dyspnea, palpitation, tiredness, sweating, heat intolerance, nervousness, flushed face, warm moist extremities
- increased catabolism (increased appetite & decreased weight)
- fatigue & muscle weakness
- fine tremors
- exaggerated reflexes
60
What are the effects of toxic goiter on the cardiovascular system?
- palpitations even at rest
- shortness of breath at rest
- angina
- thyrotoxic arrhythmia stages
- multiple extrasystoles
- paroxysmal atrial tachycardia
- paroxysmal atrial fibrillations
- persistent atrial fibrillation not responsive to digoxin
61
What is the difference between true & false exophthalmos?
TRUE FALSE
- actual protrusion of - retraction of upper eyelid
eyeball (only in - hypercontraction of Muller's
autoimmune) muscle caused by sympathetic
hyperactivity
62
What other systemic effects could toxic goiter have on the patient?
- oligo- or amenorrhea
- urinary frequency
- hair loss
- pruritus & palmar erythema
- ostemyletia
- generalized bone aches due to osteoporosis
63
what is pretibial myxoedema?
- bilateral, symmetrical, shiny, yellowish thickened dry skin with coarse hair in feet & ankles
- due to deposition of myxomatous tissue in skin & subcutaneous plane under the effect of LATS
- only in Grave's disease (like acropathy (clubbing))
64
compare between primary & secondary thyrotoxicosis
GRAVE'S SECONDARY
- younger - older
- acute - gradual
- remission & exacerbation - progressive
- mainly toxic manifestations - neck swelling followed
by toxic manifestations
- neurological - cardiovascular
- true & false exophthalmos - only false
- may have other autoimmune - no
manifestations
- diffuse enlargement - NODULAR enlargement
- mild enlargement - large
- thrill & bruit - no
65
What investigations should be done in suspected toxic goiter?
THYROID FUNCTION TEST
- increased TH3 & TH4
- suppressed TSH
AUTOANTIBODY TITER
- only in Grave's
NECK US
ISOTOPE SCANNING
- differentiate between primary toxic & secondary
66
How should Grave's disease be treated?
MEDICAL TREATMENT
- antithyroid drugs
- beta blockers
- Lugol's iodine
- tranquilizers
IF MEDICAL TREATMENT DOESN'T WORK FOR 18 MONTHS
- if patient is <45 years old SURGERY
if patient is >45 years old RADIOACTIVE IODINE
67
How should secondary thyrotoxicosis be treated?
SURGERY
| prepare patient with medical treatment before surgery to avoid thyrotoxic crises
68
How should a toxic nodule be treated?
- if patient is <45 SURGERY
| - if patient is >45 RADIOIODINE
69
What are the contraindications for medical treatment?
- toxic autonomous nodule
- retrosternal goiter
- lactation & pregnancy
70
What is the commonest used antithyroid drug?
CARBIMAZOLE
- blocks oxidation of inorganic iodine with tyrosine
- suppresses autoimmune process in Grave's
- up to 60mg/day should be given initially
- taken for a maximum of 1 & a half year
71
Which antithyroid drug could be used in pregnancy?
Propyl thiouracil
- blocks peripheral conversion of T4 & T3
- decreases autoantibody levels
- could be used in children with hyperthyroidism as well
- could lead to neonatal goiter
- 100 - 200mb every 8hours till euthyroid then maintenance done of 50mg/day
72
What are the drugs used to prep patient for thyroidectomy?
PROPRANOLOL (inderal) + carbimazol until Euthyroid
- reduces cardiac problems
- blocks peripheral conversion of T3 & T4
LUGOL'S IODINE
- decreases vascularity of gland making it firm and easier to handle during surgery
- 10 days prior to surgery 10-30 drops/day
73
What are the disadvantages of medical treatment?
- prolonged course of treatment
- can't predict remission or relapse
- relapse rate is 40%
- size of swelling may not regress
74
What are the indications of surgical treatment?
- failure of drug treatment in primary thyrotoxicosis in young patients
- autonomous toxic nodule in <45 years
- nodular toxic goiter
- retrosternal toxic goiter
75
What are the disadvantages of surgical treatment?
- recurrent thyrotoxicosis: subtotal thyroidectomy
- thyroid insufficiency
- complications of surgery
76
What are the indications of radioiodine therapy?
- primary thyrotoxicosis after 45 years of age
- autonomous toxic nodule
- recurrent thyrotoxicosis
- refusal of surgery
77
What are the contraindications of radioiodine therapy?
- <45 years old
- pregnancy & lactation
- secondary thyrotoxicosis (extensive fibrosis)
- iodine allergy
78
What are the complications of radioiodine therapy?
- myxoedema (IN GRAVE'S cause all glands are hyperactive)
- genetic mutation, leukemia, carcinoma
- isolation
- takes 3 months to get full response then patient has to take antithyroid drugs
79
What is the first line of treatment in a toxic thyroid in pegnancy?
propyl thiouracil + inderal (propranolol)
ONLY IN 2nd trimester surgery is allowed
80
What is the first line treatment of toxic thyroid in children, and what is absolutely contraindicated?
First line = carbimazole + inderal until puberty if there's no regression then subtotal thyroidectomy
Contraindicated = radioiodine
81
secondary thyrotoxicosis causing thyrocardia should be treated with?
- control symptoms first & stabilize patient
| - subtotal thyroidectomy
82
how should recurrent thyrotoxicosis after surgery be treated?
- <45 yrs surgery
| - >45 yrs radioiodine
83
how should a thyrotoxicosis patient with recent onset of proptosis be treated?
AVOID early thyroidectomy cause it could lead to malignant exophthalmos
- medical treatment until exophthalmos is static for 6 months then total thyroidectomy
84
What is the difference between proptosis & exophthalmos?
PROPTOSIS: protrusion of eyeball due to any disease
EXOPHTHALMOS: protrusion of eyeball due to thyroid disease
85
What is malignant exophthalmos?
exophthalmos + complications
86
What is the pathogenesis of exophthalmous?
infiltration of retrobulbar tissues with fluid & round cells causing edema of retrobulbar contents mainly in GRAVES
87
How can we clinically differentiate between true & false exophthalmos?
- Nafziger's test: tilting patient's head while standing behind patient
- Frazer's test: look at patient from the side
88
What is the first eye sign to appear?
```
STELLWAG'S SIGN
starring look (infrequent blinking)
```
89
What is the second eye sign to appear?
DALRYMPLE'S SIGN
upper eye lid retraction
rim of upper sclera can be seen
90
What is the 3rd eye sign to appear?
VON GRAEFE'S SIGN lid lag
| inability of eyelid to keep pace with eyeball during examination
91
What is Joffroy's sign?
absence of wrinkling on forehead when patient looks up
only in true exophthalmous
92
Lack of convergence of eyeball is called?
Moebius sign: due to lymphocytic infiltration of inferior oblique & rectus muscles in primary toxicosis
