FirstRanker Logo

FirstRanker.com - FirstRanker's Choice is a hub of Question Papers & Study Materials for B-Tech, B.E, M-Tech, MCA, M.Sc, MBBS, BDS, MBA, B.Sc, Degree, B.Sc Nursing, B-Pharmacy, D-Pharmacy, MD, Medical, Dental, Engineering students. All services of FirstRanker.com are FREE

📱

Get the MBBS Question Bank Android App

Access previous years' papers, solved question papers, notes, and more on the go!

Install From Play Store

Download MBBS General Surgery PPT 17 Thyrotoxicosis Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) General Surgery PPT 17 Thyrotoxicosis Lecture Notes

This post was last modified on 07 April 2022


THYROTOXICOSIS

Thyrotoxicosis Vs Hyperthyroidism
Thyrotoxicosis Vs Hyperthyroidism

--- Content provided by FirstRanker.com ---


.Thyrotoxicosis

Biochemical and physiological manifestation of Excessive thyroid hormone (irrespective of source).

--- Content provided by FirstRanker.com ---

Thyrotoxicosis need not be due to hyperthyroidism.

But hyperthyroidism mostly produce thyrotoxicosis.

.Hyperthyroidism

--- Content provided by FirstRanker.com ---


Disorder that result in over production of hormone by the thyroid gland.

In short, hyperthyroidism the pathology is in the thyroid gland itself.

--- Content provided by FirstRanker.com ---

Thyrotoxicosis Vs Hyperthyroidism
HYPERTHYROIDISM

TOXICOSIS WITHOUT HYPERTHYROIDISM

--- Content provided by FirstRanker.com ---

Subacute thyroiditis

Grave's disease

Ectopic functioning thyroid

--- Content provided by FirstRanker.com ---


Multi-nodular toxic goitre

Silent thyroiditis

--- Content provided by FirstRanker.com ---

Toxic adenoma

Struma ovarii

Jod ? Basedow's disease

--- Content provided by FirstRanker.com ---


Metastatic follicular carcinoma

Trophoblastic tumours

--- Content provided by FirstRanker.com ---

Postpartum thyroiditis

Thyrotoxicosis factitia
Diffuse toxic goitre....

--- Content provided by FirstRanker.com ---

.Also known as Graves' disease after Robert Graves, an Irish physician who described three patients in 1835.

.An autoimmune disease with a strong familial predisposition.

.Female preponderance (5:1).

--- Content provided by FirstRanker.com ---


.Peak incidence between the ages of 40 to 60 years.

.Characterized by:

--- Content provided by FirstRanker.com ---

Thyrotoxicosis

Diffuse goitre

Extrathyroidal conditions - Ophthalmopathy/ Dermopathy (Pretibial Myxoedema)/ Thyroid Acropachy/ Gynecomastia.

--- Content provided by FirstRanker.com ---


Diffuse toxic goitre....

.Etiology:

--- Content provided by FirstRanker.com ---

Exact etiology of the initiation of the autoimmune process is not known.

Possible triggering events:

o Postpartum state

--- Content provided by FirstRanker.com ---

o Iodine excess
o lithium therapy
o and bacterial and viral infections.

Genetic factors also play a role-HLA-B8, HLA-DR3 and HLADQA1*0501.

--- Content provided by FirstRanker.com ---

Diffuse toxic goitre....

.Pathogenesis:

Stimulate B lymphocytes, which produce antibodies directed against the TSH-receptor.

--- Content provided by FirstRanker.com ---


Thyroid stimulating Igs (TSIs) or antibodies that stimulate the TSH-R, as wel as TSH-binding inhibiting

immunoglobulins or antibodies have been described.

--- Content provided by FirstRanker.com ---

Thyroid-stimulating antibodies stimulate the thyrocytes to grow and synthesize excess thyroid hormone

(hal mark of Graves' disease).

Graves' disease also is associated with other autoimmune conditions such as-

--- Content provided by FirstRanker.com ---


o type I diabetes mel itus, Addison's disease, pernicious anaemia, and myasthenia gravis.

Diffuse toxic goitre....
Diffuse toxic goitre

--- Content provided by FirstRanker.com ---


.Pathology:

Macroscopical y:-

--- Content provided by FirstRanker.com ---

o Thyroid gland is diffusely and smoothly enlarged
o With a concomitant increase in vascularity.

Microscopical y:-

--- Content provided by FirstRanker.com ---

o Gland is hyperplastic
o Epithelium is columnar with minimal col oid present.
o Nuclei exhibit mitosis
o And papil ary projections of hyperplastic epithelium are common.

--- Content provided by FirstRanker.com ---

Diffuse toxic goitre....

.Clinical manifestation: Divided into-

Related to hyperthyroidism.

--- Content provided by FirstRanker.com ---


And specific to Graves' disease.
Diffuse toxic goitre....

.Hyperthyroid symptoms:

--- Content provided by FirstRanker.com ---


Heat intolerance.

Increased sweating and thirst.

--- Content provided by FirstRanker.com ---

Weight loss despite adequate caloric intake.

Symptoms of increased adrenergic stimulation- palpitations, nervousness, fatigue, emotional lability, hyperkinesia, and

tremors.

--- Content provided by FirstRanker.com ---


Most common GI symptoms include increased frequency of bowel movements and diarrhea.

Female patients- amenorrhea, decreased fertility, and an increased incidence of miscarriages.

--- Content provided by FirstRanker.com ---

Children- experience rapid growth with early bone maturation.

Older patients -cardiovascular complications such as atrial fibrillation and congestive heart failure.

Diffuse toxic goitre....

--- Content provided by FirstRanker.com ---


.Other manifestation of Grave's:

Approximately 50% of patients also develop clinical y evident ophthalmopathy.

--- Content provided by FirstRanker.com ---

Eye signs:(due to catecholamine excess)

o Lid lag (von Graefe's sign)
o Spasm of the upper eyelid revealing the sclera above the corneo-scleral limbus (Dalrymple's sign)
o And prominent stare.

--- Content provided by FirstRanker.com ---

Diffuse toxic goitre....

Diffuse toxic goitre

. True infiltrative eye disease results in:

--- Content provided by FirstRanker.com ---


Periorbital edema.

Conjunctival swelling and congestion (chemosis).

--- Content provided by FirstRanker.com ---

Proptosis.

Limitation of upward and lateral gaze (from involvement of the

inferior and medial rectus muscles, respectively).

--- Content provided by FirstRanker.com ---


Keratitis.

And even blindness due to optic nerve involvement.
Diffuse toxic goitre....

--- Content provided by FirstRanker.com ---


.Other manifestation of Grave's:

Dermopathy occurs in 1 to 2% of patients.

--- Content provided by FirstRanker.com ---

Rare bony involvement leads to subperiosteal

bone formation and swel ing in the
metacarpals (Thyroid Acropachy).

--- Content provided by FirstRanker.com ---

Onycholysis, or separation of fingernails from

their beds.

Diffuse toxic goitre

--- Content provided by FirstRanker.com ---


.Clinical signs:

Weight loss and facial flushing may be evident.

--- Content provided by FirstRanker.com ---

Skin- warm and moist and darkening of skin.

Cardiovascular:

o Tachycardia or atrial fibril ation.

--- Content provided by FirstRanker.com ---

o Cutaneous vasodilation leading to a widening of the pulse pressure and a rapid fal off in the transmitted pulse wave (col apsing pulse).
Diffuse toxic goitre

.Clinical signs:

--- Content provided by FirstRanker.com ---

Musculoskeletal:

o Fine tremor, muscle wasting.
o and proximal muscle group weakness with hyperactive tendon reflexes often are present.

--- Content provided by FirstRanker.com ---

Thyroid:

o Diffusely and symmetrical y enlarged, as evidenced by an enlarged pyramidal lobe.
o Overlying bruit or thril and loud venous hum in the supraclavicular space.

--- Content provided by FirstRanker.com ---

Diffuse toxic goitre....

.Diagnostic Tests:

Suppressed TSH with elevated free T4 or T3 level.

--- Content provided by FirstRanker.com ---


If eye signs are present- other tests are general y not needed.

In the absence of eye findings- an I-131 uptake and scan should be performed.

--- Content provided by FirstRanker.com ---

o An elevated uptake, with a diffusely enlarged gland- confirms the diagnosis.
o It helps to differentiate it from other causes of hyperthyroidism.

Anti-Tg and anti-TPO antibodies are elevated in up to 75% of patients.

--- Content provided by FirstRanker.com ---

Elevated TSH-R or thyroid-stimulating antibodies (TSAb) are diagnostic of Graves' disease (about 90% of

patients).
Diffuse toxic goitre....

--- Content provided by FirstRanker.com ---

.Management:

Treated by any of three treatment modalities-

o Anti-thyroid drugs.

--- Content provided by FirstRanker.com ---

o Thyroid ablation with radioactive I-131.
o Thyroidectomy.

Diffuse toxic goitre....

--- Content provided by FirstRanker.com ---

.Anti Thyroid Drugs:

General y are administered in preparation for RAI ablation or surgery.

Drugs commonly used are-

--- Content provided by FirstRanker.com ---


o Propylthiouracil (PTU, 100 to 300 mg three times daily)
o and methimazole (10 to 30 mg three times daily, then once daily).

Both drugs reduce thyroid hormone production by inhibiting the organic binding of iodine and the

--- Content provided by FirstRanker.com ---


coupling of iodo-tyrosines (mediated by TPO).

PTU also inhibits the peripheral conversion of T4 to T3, so useful for the treatment of thyroid storm.

--- Content provided by FirstRanker.com ---

PTU has a lower risk of transplacental transfer.
Diffuse toxic goitre

.Anti Thyroid Drugs:

--- Content provided by FirstRanker.com ---

Side effects of treatment include-

o Reversible granulocytopenia.
o Skin rashes, fever.
o Peripheral neuritis, polyarteritis, vasculitis.

--- Content provided by FirstRanker.com ---

o Rarely, agranulocytosis and aplastic anemia.

Catecholamine response of thyrotoxicosis can be al eviated by administering beta- blocking agents.

o Propranolol is the most commonly prescribed medication in doses of about 20 to 40 mg four times daily.

--- Content provided by FirstRanker.com ---


Diffuse toxic goitre....

.Radioactive Iodine Therapy (I-131):

--- Content provided by FirstRanker.com ---

RAI forms the mainstay of Graves' disease treatment in North America.

Major advantages- avoidance of a surgical procedure and its risks.

Dose - usual y consists of 8 to 12 mCi administered orally.

--- Content provided by FirstRanker.com ---


Most patients become euthyroid within 2 months.

About 50% of patients treated with RAI are euthyroid 6 months after treatment.

--- Content provided by FirstRanker.com ---

And remaining are stil hyperthyroid or already hypothyroid.
Diffuse toxic goitre....

.Radioactive Iodine Therapy (I-131):

--- Content provided by FirstRanker.com ---

RAI therapy is most often used in-

Older patients with small or moderate-sized goiters

Those who have relapsed after medical or surgical therapy.

--- Content provided by FirstRanker.com ---


Contraindication:

Absolute : Women who are pregnant or breastfeeding.

--- Content provided by FirstRanker.com ---

Relative : Young patients (i.e., especially children and adolescents), those with thyroid nodules, and those with

ophthalmopathy.

Diffuse toxic goitre....

--- Content provided by FirstRanker.com ---


.Surgical Treatment:

Recommended when RAI is contraindicated:

--- Content provided by FirstRanker.com ---

Have confirmed cancer or suspicious thyroid nodules.

Young and Pregnant or desire to conceive soon after treatment.

Severe reactions to anti-thyroid medications

--- Content provided by FirstRanker.com ---


Large goitres causing compressive symptoms.

Reluctant to undergo RAI therapy.

--- Content provided by FirstRanker.com ---

What surgical Procedure ?-(Solely based on discretion of surgeon and their experience.)

Near total thyroidectomy

Subtotal thyroidectomy

--- Content provided by FirstRanker.com ---


Total thyroidectomy
Toxic MNG....

.Usual y occur in older individuals, who often have a prior history of a nontoxic multinodular goitre.

--- Content provided by FirstRanker.com ---


.Over several years, thyroid nodules become autonomous to cause hyperthyroidism.

.Hyperthyroidism also can be precipitated by iodide-containing drugs such as contrast media and the anti-

--- Content provided by FirstRanker.com ---

arrhythmic agent amiodarone (jod-basedow hyperthyroidism).

.Symptoms and signs of hyperthyroidism are similar to Graves' disease, but extra-thyroidal manifestations

are absent.

--- Content provided by FirstRanker.com ---


Toxic MNG....

.Blood tests- similar to Graves' disease with a suppressed TSH level and elevated free T4 or T3 levels.

--- Content provided by FirstRanker.com ---

.RAI uptake also is increased, showing multiple nodules with increased uptake and suppression of the

remaining gland.

.Treatment ? After adequately controlling hyperthyroid state Total Thyroidectomy is treatment of choice.

--- Content provided by FirstRanker.com ---

Toxic Adenoma (Plummer's Disease)

.Hyperthyroidism from a single hyper-functioning nodule.

.Typical y occurs in younger patients who note recent growth of a long-standing nodule along with

--- Content provided by FirstRanker.com ---


the symptoms of hyperthyroidism.

.Most hyper-functioning or autonomous thyroid nodules have attained a size of at least 3 cm before

--- Content provided by FirstRanker.com ---

hyperthyroidism occurs.

Toxic Adenoma (Plummer's Disease)

.Physical examination- usually reveals a solitary thyroid nodule without palpable thyroid tissue

--- Content provided by FirstRanker.com ---


on the contralateral side.

.RAI scanning shows a "hot" nodule with suppression the rest of the thyroid gland.

--- Content provided by FirstRanker.com ---

.Surgery (lobectomy and isthmusectomy) is preferred.
Thyroid Storm

.A condition of hyperthyroidism accompanied by-

--- Content provided by FirstRanker.com ---

Fever, central nervous system agitation or depression, cardiovascular dysfunction.

.May be precipitated by infection, surgery or trauma.

Thyroid Storm

--- Content provided by FirstRanker.com ---


.Management:

Beta blockers- given to reduce peripheral T4 to T3 conversion and decrease the hyperthyroid symptoms.

--- Content provided by FirstRanker.com ---

Oxygen supplementation and hemodynamic support should be instituted.

Non-aspirin compounds can be used to treat pyrexia.

Lugol's iodine or sodium ipodate (intravenously) should be administered to decrease iodine uptake and thyroid hormone

--- Content provided by FirstRanker.com ---


secretion.

PTU therapy blocks the formation of new thyroid hormone and reduces peripheral conversion of T4 to T3.

--- Content provided by FirstRanker.com ---

Corticosteroids often are helpful to prevent adrenal exhaustion and block hepatic thyroid hormone conversion.