HYPERTHYROIDISM

 Hyperthyroidism is the condition that occur due to excessive production of thyroid hormones by the thyroid gland.

CAUSES :

A) PRIMARY HYPERTHYROIDISM

Most common cause of PRIMARY HYPERTHYROIDISM is  GRAVE'S DISEASE

GRAVE'S DISEASE

↓

Have L.A.T.S - Ab (Long acting thyroid stimulating antibody)

identical to TSH

↓

Resulting in INCREASE T4 , INCREASE T3 , DECREASE TSH

B) SECONDARY HYPERTHYROIDISM

Due to Pituitary adenoma ⇢ INCREASED TSH , INCREASED T3 , INCREASED T4

C) TOXIC NODULAR GOITER

Frequent in areas of iodine deficiency

Diagnosed by Thyroid scan using I - 123/I - 132

Warm nodule ⇒ Normal uptake

Cold nodule ⇒ suggestive of malignancy

Hot nodule ⇒ over active tissue

D) JOD BASEDOW EFFECT :

Seen with intake of iodized salt for long duration in iodine replete population.

Has upgrade of [iodine trapping leading to increase production of T4/T3.

E) THYROTOXICOSIS FACTITIA :

It is Thyrotoxicosis occurring  due to any other cause other than high salt intake.

example: seen in patient consuming poor quality beef containing thyroid gland of animals

F) STRUMA OVARI :

Ovarian tumor synthesizing hormones

G) GESTATIONAL TROPHOBLASTIC NEOPLASIA ;

HCG ∝ TSH

Thus, HCG can bind to TSH receptors and stimulate them

CLINICAL FEATURES :

1. Sympathomimetics (+) : Palpitations, fine tremors, sweaty palms/soles ,hypertension

2. BMR  Increased resulting in weight loss

3. Calorigenesis Increased causes HEAT INTOLERANCE

4.Females⇾ oligomenorrhea /infertility

5. Proptosis ( due to retrobulbar fat deposition )⇢ blinking action inadequate ⇢ results in drying of cornea ⇢ EXPOSURE  KERATITIS 

ON EXAMINATION

1. Sleeping pulse rate increased (most reliable sign)

2. Resting Tachycardia

3. Fine tremors

4. Pretibial Myxedema

5. Pemberton sign : On rising arms, there will be facial congestion due to compression of SVC by retrosternal goiter

WORKUP:

= Thyroid function test - total T4 and T3 increased , free T4,T3 increased

= TSH

- If TSH   LOW - Primary hyperthyroidism (most common GRAVE'S) - further investigations are 

- LATS titer

- Thyroid scan

- USG abdomen (females pt to rule out ovarian or uterine tumor)

-If  TSH   HIGH - Secondary hyperthyroidism - pituitary adenoma - diagnosis MRI head

TREATMENT :

1. Anti Thyroid Drugs : PROPYLTHIOURACIL (PTU)

propranolol for symptomatic management

Total thyroidectomy in case of poor response to medical therapy

2. Ablation of thyroid gland using  Radioiodine I - 131

Secondary Hyperthyroidism due to pituitary adenoma - Trans-sphenoidal surgery