Toxic Goiter Flashcards
Types of toxic goiter?
In incidence order
- 1ry or diffuse toxic goiter
- Secondary or toxic nodular goiter
- Toxic nodule
1ry thyrotoxicosis occurs on top of?
Healthy thyroid
Type of antibody in 1ry toxicosis?
IgG
2ry thyrotoxicosis occurs on top of?
Diseased thyroid
Other rare causes of thyrotoxicosis?
- Neonatal thyrotoxicosis
- Inflammatory
- Drug induced
- Tumors
Most important 4 systems in checkin If patient is toxic?
Heart, CNS, metabolic and eye
Most important 4 signs in toxic pt?
Hands, legs, eyes and pulse
What is sick euthyroid syndrome?
T4 pseudotoxicosis seen in critically ill pt with increase in t4 but decrease level of t3 due to failure of conversion
What does adrenaline do?
Stimulate both a & b
A – VC (cold hand) and increase in peripheral resistance (diastole)
B – increase COP and systole
First eye sign of thyrotoxicosis is ?
Unfrequent blinking
What is thyrotoxicosis?
Clinicopathological condition due to excess thyroxin
This increase sensitivity of the tissue to circulating adrenaline and increase number of BETA receptors
Antibodies of 1ry thyrotoxicosis?
Thyroid stimulating antibodies (IgG)
Type of patient in 1ry and 2ry thyrotoxicosis?
1ry the pt is around 20 cause its AI (subjected to psychic trauma , infection, preg,labor) may give +ve family history
In 2ry pt around 40 cause it takes time for SNG to turn toxic
Some AI manifestations of 1ry thyrotoxicosis?
- Hemic murmur
- Clubbing
- Pretibial myxedema
- True exophthalmos
Pulse and 1ry thyrotoxicosis?
Very important
- tachycardia. Sleeping pulse >90/min (considered as an investigation)
- rhythm: maybe irregular (all sorts of arrhythmia except HB)
- volumn high
- special character water hammer pulse
why does water hammer pulse occur?
Increase in systolic pressure due to increase COP and decrease diastolic pressure due to decrease in PR
What is true exophthalmos?
Deposition of AB behind eye (dangerious) conjuntivity and cant close eyes
Eye signs are unilateral or bilateral in 1ry thyrotoxicosis?
It maybe unilateral
Pathology of 1ry thyrotoxicosis?
Follicular and thyroglobulin (sequestrated antigens) are surround by membrane protecting them from exposure to immune system. On STRESS (psychiatric trauma or infection) exposure to immune system – antibody formation TSA against TSH receptors which have TSH like action increasing thyroxin
Microscopic picture of 1ry thyrotoxicosis?
- Proliferation of epithelial cells
- Cella are columnar and full of granules
- Acini less voculated colloid or devoid
- Increased vascularity
- Extensive lymphocytic infiltration
Clinical picture of 1ry thyrotoxicosis?
Effects whole body but nervous metabolic and eye are more manifested than cardio
Abrupt onset with remission excercebation
Most frequent manifestations of 1ry thyrotoxicosis?
Symptoms ( fatigue, emotional liability, heat intolerance, weight loss, excessive appetite, and palpitation)
Signs (tachycardia, hot moist palms, exophthalmos, lid lag and agitation)
What is dalrymples sign?
Appearance of rim of sclera above the cornea
What is stellwag’s sign?
Staring look with infrequent blinking (lid retraction)
What is von graefe’s sign?
Lig lag on looking down without moving the head
What is mobius’s sign?
Failure of convergence or maintail convergance on looking at a near object
What is joffroy’s sign?
Lace of forehead wrinkling on looking up without moving the head
What is rosenbach’s sign?
Tremors on closure of eye
Pitting edema and 1ry thyrotoxicosis?
Usually its pretibial myxedema (non pitting) but if HF occurs pitting edema
Complications of 1ry thyrotoxicosis?
- High COP HF
- Thyrotoxic crisis
- Complications of exophthalmos
What is thyrotoxic crisis?
- Sever postoperative hyperthyroidism due to inadequate preoperative preparation
- CP hyperpyrexia, hypertension, delirium and convulsion
Ttt of thyrotoxic crisis?
Cooling + IV (indral, corticosteroid, propylthiouracil, antipyeretics)
Complications of exophthalmos?
- Keratitis
- Corneal ulceration
- Pan ophthalmitis ( is rapidy progressive)
- Retinal damage
Investigations of 1ry hyperparathyroidism?
- For diagnosis
a. Thyroid fx tests (free t3 t4 high TSH low)
b. US of the neck ( mild diffuse enlargement)
c. Thyroid scan (diffuse increase uptake and exclude retrosternal goiter)
d. Thyroid antibodies TSI - Investigations for exophthalmos
a. Exophthalmometer
b. Ruler - Preoperative preparations
a. CBC LFT KFT FBS CXR ECG
b. Indirect laryngoscope (medicolegal)
Why no biopsy in 1ry thyrotoxicosis?
Toxicity rules out malignancy plus increase vascularity may cause hematoma
Ttt of 1ry thyrotoxicosis?
- Graves
a. MAIN LINE medical
b. Surgical
c. Radio active iodine RAI - Special problems
a. Pregnancy
b. Children
c. Cardiac pts
d. True exophthalmos
Why medical ttt is the main line in graves disease?
Waiting for spontaneous remission in about 1 to 1 1/2 years ( some say 6 months)
What is the medical ttt in graves disease?
- Carbimazol or prophylthiouracil (decrease thyroxin)
- BB - Inderal (protects the heart till carbimazol gives effects)
Start with carbimazoel and Inderal together and after 3 weeks if t3 and t4 normal then stop Inderal - Diazepam (if severe CNS manifestation)
- K perchlorate
- Iodides (eg lugols iodine)
MOA of carbimazol (neomercazole) and prophylthiouracil?
Inhibits peroxidase enzyme & iodine binding to tyrosine
Why do we give Inderal with carbimazole in graves disease?
Because carbimazole stop the synthesis of new hormones but cannot effect the already present hormone (in blood and stored hormone) so it takes about 2 to 3 weeks to get rid of them. Till then the heart needs to be protected by Inderal. If ass with BA ( bb propranolol is CI) so give selective B1 blocker atenolol)
What is the aim of the medical ttt of graves disease?
To restore the pt to euthyroid state
MOA of K perchlorate in graves D medical ttt?
Compatitively inhibits iodine uptake by the thyroid
Use of iodides in ttt of graves disease?
- Reduce effect of TSH on thyroid
- Inhibit iodine binding
- Reduce VASCULARITY of thyroid gland
- Storage of colloid within the acini
- Effect is only temporary ( used as preoperative only)
Why lugols iodine is given pre operative only ?
Its temporary for max 2 weeks cause it causes rebound hypovascularity
What antithyroid drug is used in pregnancy ? and why?
Prophylthiouracil cause it doesn’t cross the placenta
Dose of carbimazole ( antithyroid ) in graves disease?
10mg * 3 / day till normal t3 t4 the n gradually reduce to 5mg*2 or 3 /day
SE of thiourea group drugs ?
- Agranulocytosis (most dangerous)
- Hepatotoxicity
- GIT upset
- Rashes
- arthralgia
So they should be followed up by CBC ( every 2 wks) and LFT
CI of thiourea group?
- Toxic nodular goiter
2. Retrostenal toxic goiter
What is the surgical ttt of 1ry thyrotoxicosis?
Subtotal thyroidectomy after preparation (to prevent crisis by decreasing vascularity). Some believe total thyroidectomy is better than subtotal to avoid progression of exophthalmos
Indication for surgery in 1ry thyrotoxicosis?
- Failure of medical ttt
- RSG
- Huge sized goiter
Indication for RAI in 1ry thyrotoxicosis?
Old patient >45 years with failure of medical ttt
Keep in mind RAI causes fibrosis around the neck area so surgery is difficult after that
Obstretics and toxic goiter?
- Thiouracil goiter (increase TSH- goiter in mom)
- Thiouracil transmitted goiter (TRH cross placentacause its smaller than TSH – baby goiter – cant flex head – obst labor) (prevented by small dose of Lthyroxin to suppress TRH ) before that thyroid of baby immature
- Surgery perfomed after 1st trimester to avoid abortion
- RAI CI
What is thiouracil goiter?
Ttt with anti thyroid drugs – decrease t3 t4 – increase TSH – goiter
Why is it not preferred to terminate the toxic status abruptly by surgery or RAI in 1ry thyrotoxicosis?
For fear of theoretical risk of progressing to malignant exophthalmos( increase in TSH with increase in EPF)
if subtotal thyroidectomy is indicated , exophthalmos should be stationary for how many months?
6 months
Medical ttt of true exophthalmos?
- Sleep with head up (decrease congestion)
- Protection of eye by day eyedrops
- Protection of eye by night ointment
- Dehydrating measures
- High doses of prednisone ( local administration is risky)
Surgical ttt of true exophthalmos?
Lateral tarsorrhaphy (doesn’t prevent progression) Orbital deroofing (naffziger operation)
What condition is prioritize in 1ry thyrotoxicosis with cardiac problem?
Cardiac problem is more important. Thyroidectomy done after control of cardiac condition
In 2ry thyrotoxicosis what are the active follicles?
Internodular tissue is active
Pathology of 2ry thyrotoxicosis is ?
On top of long standing simple nodular goiter
Type of patient in 2ry thyrotoxicosis?
Commonly female > 40 with past hx of thyroid swelling of long period followed by toxic manifestations
Most frequesnt manifestationsof 2ry thyrotoxicosis?
Just like graves disease but cardiac manifestations are more and its AGE related
Local manifestations of 2ry thyrotoxicosis?
NO AI MANIFESTATIONS
Gand is lage and nodular, firm, no pulsation and no thrill
DD of graves and toxic nodular goiter?
COCAMENT
- Course
- Onset
- Cardio manifestation
- Age
- Metabolic
- Eye signs
- Nervous
- Thyroid
Investigations of 2ry thyrotoxicosis?
- For diagnosis
a. Thyroid fx tests (free t3 t4 high TSH low)
b. US of the neck MULTIPLE NODES
c. Thyroid scan (internodular tissue overactive with cold nodules) - Preoperative preparations
a. CBC LFT KFT FBS CXR ECG
b. Indirect laryngoscope (medicolegal)
Ttt of 2ry thyrotoxicosis?
- Surgical MAIN LINE
- RAI ( in high risk pt like HF ) no effect as D is progressive
Why no RAI is main line of ttt in 2ry thyrotoxicosis?
Because it treats toxicity only cause nodules are fibrosed so no effect on the nodules so no decrease in size while surgery solves both size and toxicity
Surgical ttt of 2ry thyrotoxicosis?
Subtotal thyroidectomy after preparation
Most important dx and therapeutic procedure in toxic nodule?
RAI
What is a toxic nodule in summary?
Bening tumor turned malignant
Def of toxic nodule?
Excess secretion of thyroid hormone from autonomous hyperactive thyroid nodule
Ttt of toxic nodule ?
- Surgical
a. Ipsilateral total lobectomy
b. Indicated in pt <45 - RAI target therapy
a. Very effective used in pt >45 for fear of malignancy - Medical ttt
Thyrotoxicosis should be suspected in which ppl?
U CURE!!
- Unexplained diarrhea
- Children with growth spurt
- Unexplained loss of weight
- Refractory HF
- Elderly pp with unexplained tachy cardia or arrhythmia
Why diarrhea occurs in thyrotoxicosis?
Increased cAMP which increase permeability of cells of the mucous membrane
Why polyuria occurs in thyrotoxicosis?
- Increase COP which causes increase RBF
- Secondary DM glucosuria
- Increase metabolic water
- Increase intake 2ry to polyphagia
Why menorrhagia the amenorrhea in thyrotoxicosis?
Menorrhagia dt disturbance in estrogen metabolism – abnormal shedding
Amenorrhea dt drop os estrogen level
Why water hammer pulse occur in thyrotoxicosis?
Increase in systolic with decrease in diastolic
Increase COP and (accumulation of metabolites VD decrease PR)
Acral changes associated with thyrotoxicosis?
- Tremors
- Pretibial myxedema
- Nail changes
Thyrotoxicosis and bones?
Severe thyrotoxicosis causes osteoporosis. After operation osteoporotic bone will withdraw the ca from blood. BONE HUNGER. May cause post operative tetany
False exophthalmos is due to ?
Retraction of muller’s muscle (part of levator palpebrase superioris)
True exophthalmos ?
Actual protrusion of the eye balls
What is naffzigers method?
Examiner stand behind pt with head tilted backwards to see the level of supra and infra orbital ridges with the cornea
What is frazer’s method ?
The examiner stand on one side of pt with the eyes lightly closed and see obliteration of sulcus of orbital margin
What is ruler’s method?
See the level of supra and infra orbital magin with cornea by a ruer
What is medical thyroidectomy ?
L thyroxin 0.1mg/day decrease TSH decrease gland size
Indication for medical thyroidectomy ?
- Ectopid thyroid
- Physiological goiter ( venus neck)
- SNG ( if small young pt & post operative)
How to know the patient is ready for surgery?
- Symptomatic relief
- Gaining weight
- Sleeping pulse (not alone cause Inderal can cose normal pulse)
- Serum t3 t4 level
