L3: Toxic Goiter Flashcards
The term thyrotoxicosis is retained. Why?
Clinical Types of Thyrotoxicosis
- Diffuse toxic goiter (Gravesβ disease).
- Toxic nodular goiter.
- Toxic nodule.
- Hyperthyroidism due to rarer causes.
Compare between diffuse toxic goiter (Graveβs) & Toxic Nodular Goiter (Plummerβs) in tertms of:
- Name
- Time
- Eye Signs
- Age
- Pathology
Def of Toxic nodule
A toxic nodule is a solitary overactive nodule.
Types of Toxic nodule
- May be part of a generalized nodularity.
- OR a true toxic adenoma.
Characters of Toxic nodule
- It is autonomous (its hypertrophy and hyperplasia are not due to TSH-RAb).
- The normal thyroid tissue surrounding the nodule is itself suppressed and inactive.
Hyperthyroidism due to rarer causes
Thyrotoxicosis factitia (drug induced)
Intake of L-thyroxine more than normal.
Jod Basedow thyrotoxicosis
Large doses of iodides given to a hyperplastic endemic.
Autoimmune thyroiditis OR de Quervainβs thyroiditis
Inflammation/destruction of the thyroid cells β inapcropriate release of thyroid hormone.
Neonatal thyrotoxicosis
It subsides in 3-4 weeks β-> as TsAb titers fall in the babyβs serum.
Struma ovarii
- A type of ovarian tumors β Ectopic hormone procuction β symptoms of hyperthyroidism.
Drugs like amiodarone (antiarrhythmic agent)
- Rich in iodine.
- Having structural similarity to T4.
- Causing thyrotoxicosis.
Histology of Toxic Goiter
Which Sex is more affected by Thyrotoxicosis?
Thyrotoxicosis is 8 times rnore common in women than in men.
What age is more affected by Thyrotoxicosis?
Any age
Signs & Symptoms of Thyrotoxicosis
Cardiac Rhythm in Thyrotoxicosis
Myopathy in Thyrotoxicosis
Eye Signs in Thyrotoxicosis
- Some degree of exophthalmos is common.
- It may be unilateral.
- Forms: (true Exophthalmus & Weakness of the extraocular muscles)
True Exophthalmous in Thyrotoxicosis
Weaknes of extraoccular muscles in Thyrotoxicosis
particularly the elevators (inferior oblique) β diplopia.
what happens regarding eye signs in Severe Thyrotoxicosis?
In severe cases, papilledema & corneal ulceration occur. When severe & progressive:
- It is known as [Malignant exophthalmos].
- Eye may be destroyed.
TTT of Eye Signs in Thyrotoxicosis
- Spasm & retraction usually disappear when the hyperthyroidism is controlled.
- Beta-adrenergic blocking drugs can improve the condition.
- Exophthalmos tends to improve with time.
..
Thyroid Dermopathy in Thyrotoxicosis
Mechanism of Thyroid Dermopathy in Thyrotoxicosis
Deposition of hyaluronic acic in dermis & subcutis.
TTT of Thyroid Dermopathy in Thyrotoxicosis
- Treat the underlying thyroid disorder.
- Topical steroids.
Compare between 1ry (Graveβs disease)
& 2ry (Plummerβs disease) in terms of:
- Age
- Hx
- Manifestations (Meta, Nerv, Cardia, occul)
- Thyroid Enlargment
- Investigations
- TTT
- Recurrence after Surgery
Clinical Investigations of Thyrotoxicosis
Non-Specific Lab Investigations in Thyrotoxicosis
Specific Lab Investigations in Thyrotoxicosis
- Serum TSH
- Thyroxine (T4) & tri-iodothyronine (T3)
- Thyroid Autoantibodies
- Thyroglobulin Estimation
- Radioactive studies
Serum TSH in Thyrotoxicosis
T3 & T4 in Thyrotoxicosis
T3 toxicity (with a normal T4) is a distinct entity
- T3 toxicity (with a normal T4) is a distinct entity..
- It may only be diagnosed by measuring the serum T3.
- Although, a suppressed TSH level with a normal T4 may suggest the diagnosis.
Thyroid Autoantibodies in Thyrotoxicosis
Thyroglobulin Estimation in Thyrotoxicosis
Radioactive Studies in Thyrotoxicosis
Using I131, I123 or Tcm99
- Uptake by the gland (Rarely used nowadays)
- Thyroid Scanning.
Measuring Uptake by the gland
Radioactive studies in Thyrotoxicosis
What is the main value of Measuring Uptake by the gland?
Radioactive studies in Thyrotoxicosis
Differentiate between:
- Hyperthyroidism in Graveβs disease with high uptake.
- Hyperthyroidism in DeQuervain thyroiditis with low uptake.
Prinicipal Value of Measuring Uptake by the gland
Radioactive studies in Thyrotoxicosis
Localization of overactivity in the gland β will differentiate between:
- A toxic nodule: with suppression of the remainder of the gland.
- Toxic multinodular goiter: with several areas of increased uptake With important implications for therapy.
Whole body scanning
Used to demonstrate metastases, in patients have all normally functioning thyroid tissue ablated either by surgery or radioiodine.
- because metastatic thyroid cancer issue cannot compete with normal thyroid tissue in the uptake of iodine.
Measuring Uptake by the gland is inappropriate for β¦β¦
Radioactive studies in Thyrotoxicosis
Distinguishing benign from malignant iesions, Because:
- The majority (80 %) of βcoldβ swellings are benign.
- Some (5 %) functioning or βwarmβ swellings will be malignant.
Thyroid Scanning
Radioactive studies in Thyrotoxicosis
Findings in Thyroid Scanning
Radioactive studies in Thyrotoxicosis
Imaging Investigations in Thyrotoxicosis
- US
- Plain X-ray on neck & chest
- CT, MRI & PET-Scan on chest
- Bone survey (Bone Scan)
Advsntages of US in Thyrotoxicosis
Benign lesion VS Malignant lesion in US
Plain X-ray on neck & chest in Thyrotoxicosis
CT, MRI & PET-Scan on chest in Thyrotoxicosis
Bone survey (Bone Scan) in Thyrotoxicosis
In malignancy for bone metastasis.
Pathological Investigations in Toxic Goiter
what is The investigation of choice in most of thyroid diseases to conclude pathological diagnosis?
Uses of FNAC
- Suspicious solitary/multiple nodules/dominant nodules should be aspirated
- Aspiration is graded as β¦β¦
Diagnostic accuracy of FNAC
FNAC may be less reliable in a cyst
- If the cyst recurs after 3 aspirations β β¦..
Malignancy rate:
- In a simple cyst is β¦β¦
- In a complex cyst β¦β¦
FNAC is not reliable at present in follicular carcinoma of the thyroid, Why?
Characters of Tru-Cut Bx in Thyroid Gland
Open Bx in Thyroid Gland
Endoscopic Investigations in Toxic Goiter
Tumor Markers in Toxic Goiter
Read Medical TTT for Toxic Goiter in Notes
..
Indications of Surgical TTT in Toxic Goiter
CI of of Surgical TTT in Toxic Goiter
Advantages of of Surgical TTT in Toxic Goiter
- Goiter is removed.
- Cure is rapid.
- Cure rate is high if surgery is adequate
Disadvantages of of Surgical TTT in Toxic Goiter
Pre-Operative Preparation of Surgical TTT in Toxic Goiter
Potassium iodides (e.g., Lugolβs iodine)
Surgical TTT of Toxic Goiter
Mechanism of Potassium iodides (e.g., Lugolβs iodine)
Dose of Potassium iodides (e.g., Lugolβs iodine)
5 drops t.d.s. gradually increased to 15 drops t.d.s.
Effects of Potassium iodides (e.g., Lugolβs iodine)
Effect:
* Its effects appear within 24 hours.
* Maximum effect reached within 10-15 days.
* Its effect decreases afterwards (tolerance)
escape phenomena
βββ
So not used for long term therapy and used only in:
1. Preoperation preparation to I vascularity & toxicity
2. Treatment of thyroid crisis
SE of Potassium iodides (e.g., Lugolβs iodine)
- Allergy (Skin rash)
- Parotid swelling (Excessive salivation)
- Fibrosis around gland
Type of Operation in Solitary toxic nodule
Hemithyroldectomy
Types of Operation in Multiple toxic nodules
- Subtotal thyroldectomy
- Near total thyroldectomy
- Hartley- Dunhill procedure βBest choiceβ
- Total thyroldectomy
what is the best choice for Multiple toxic nodules?
Hartley-Dunhill procedure
Indications of Total thyroldectomy
a) Severe ophthalmopathy
b) Coexisting thyrold cancer
c) MEN Il syndrome
d) Patient refuses RAI therapy
e) Patient with life threatening reactions to antithyroid medications such as agranulocytosis or liver failure
..
Post-Operative Care after Thyroidectomy
Indications of Radio-Iodine Therapy of Toxic Goiter
CI of Radio-Iodine Therapy of Toxic Goiter
Advantages of Radio-Iodine Therapy of Toxic Goiter
- No surgery
- No prolonged drug therapy
Disadvantages of Radio-Iodine Therapy of Toxic Goiter
MOA of Radio-Iodine Therapy of Toxic Goiter
- Radioiodine destroys thyroid cells
- And, as in thyroidectomy, reduces the mass of functioning thyroid tissue to below a critical level.
When to use Radio-Iodine Therapy of Toxic Goiter? and when not to?
Today there is βno restriction of age and genderβ.
- However, this is preferred in children only after completion of growth and in adults only after family is complete.
- Conception must be avoided for a period of 4 months after radioiodine therapy
Managment of Toxic Goiter in pregnancy
Managment of Toxic Goiter in Thyro-Cardiac Cases
Managment of Toxic Goiter in Children
Done
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