Congenital anomalies of the thyroid gland are a relatively common problem affecting approximately 1-3% of the general population. These anomalies can lead to a range of thyroid disorders, including hypothyroidism, hyperthyroidism, and goiters, and may require surgical intervention.
Surgical management of congenital anomalies of the thyroid gland can be complex and requires a good understanding of anatomy, surgical techniques, and postoperative care.
From the perspective of the NEET PG exam, congenital anomalies of the thyroid gland are an important topic that is commonly tested in the exams. Having a good understanding of this topic is essential in order to perform well.
A neck lump called a thyroglossal duct cyst can develop after the thyroid gland forms during fetal development. Typically, it is discovered in preschoolers or in the middle of adolescents.
Clinical features of thyroglossal cyst:
Midline swelling in the anterior part of neck. Which moves with deglutition and moves up on protrusion of tongue
DIAGNOSIS OF THYROGLOSSAL CYST:
There are a variety of possible diagnostic procedures for thyroglossal duct cysts, including:
X-rays taken with a tiny needle and a contrast agent
Infection of thyroglossal cyst leads to abscess formation; managed with Incision and drainage. Thyroglossal Fistula occurs as a complication of I/D. Therefore, it is an acquired condition. Thyroglossal cyst is congenital conditions. Thyroglossal cyst increases the risk for papillary Carcinoma Thyroid.
Treatment of Thyroglossal Cyst
Treatment of choice: Sistrunk Operation (En Bloc removal of central part or body of Hyoid bone with cyst)
5% people in population have goiter
It is also known as Substernal / Mediastinal goiter. More than 50% of Thyroid Tissue is located below the opening of thoracic cage. Mostly asymptomatic and diagnosed incidentally on radiological investigation
Hoarseness of voice
Dilated veins over Anterior Chest wall
Pemberton Sign is positive
Treatment of Retrosternal Goiter:
Thyroidectomy by cervical incision
Commonly used radioisotopes in thyroid disorders:
l123 (Iodine 123)- its Half-life is 13 hours . it is Used for Diagnostic purpose only in RAI (Radioactive Iodine) Scan
l131- its Half-life is 8 days.It is Used for Diagnostic and Therapeutic purpose in RAI scan and Ablation
l131- it Emits β Rays (90%) and Y - Rays (10%)
Emits β Rays (90%)
Emits Y - Rays (10%)
β Rays mainly responsible for therapeutic effects
Depth of penetration of β Rays - 0.5 min
Y- Rays- Used in Tracer studies and responsible for side effects.
Absolute Contraindications for Radioactive Iodine Ablation
Radioactive iodine scan aka thyroid scan
Hot nodule: Increased uptake as compared to surrounding tissue- Risk of malignancy 1-3%
Cold Nodule: Decreased uptake as compared to surrounding tissue- Risk of malignancy 17-20%
In Graves’ Disease: In whole thyroid there is relatively increased RAI uptake
In Toxic MultiNodular Goiter: Certain nodules having increased uptake and certain nodules having decreased uptake i.e. both hot and cold nodules are present
In Thyroiditis: There is inflammation of thyroid. Therefore, decreased uptake of RAI i.e. <5% uptake of RAI
Types of thyroidectomy
Total thyroidectomy: Removal of all visible thyroid tissue
Hemithyroidectomy: Removal of one lobe with isthmus
Subtotal Thyroidectomy: Only 3-4 gm of thyroid tissue left in each lobe superiorly
Hartley Dunhill procedure: Modification of Subtotal Thyroidectomy 4-6 gm of tissue left in Single Lobe
Near Total thyroidectomy: Total less than 1 gm of tissue is left near/ adjacent to Recurrent Laryngeal Nerve at Ligament of Berry
HemiThyroidectomy: Performed in Benign disorder involving one lobe
Total Thyroidectomy: Performed in Thyroid Malignancy and benign disorders involving both lobes
Subtotal Thyroidectomy: Performed in Multinodular Goiter in Elderly
Solitary Thyroid Nodule
It Most common STN: Colloid Goiter > Follicular Adenoma. 1st Investigation done in STN: TFT (TSH, T3, T4) investigation of choice for Solitary thyroid nodule is FNAC.
Limitations of FNAC in Solitary Thyroid Nodule
Follicular neoplasms: It cannot differentiate Follicular Adenoma from follicular Carcinoma. (Capsular/Follicular invasion not seen on FNAC). Riedel’s Thyroiditis: Whole thyroid is replaced by fibrous tissue
Thyroid Lymphoma: Any lymphoma Investigation of choice is biopsy. In All of the above limitations of FNAC: Investigation of choice is Biopsy
Most common Cause of Hypothyroidism worldwide: Hashimoto's Thyroiditis. Most common Cause of Hyperthyroidism worldwide: Grave's Disease
Aka Diffuse Toxic Goiter.Associated with HLA-B8/DR-3. It is an Autoimmune disorder (autoimmune disorder are most commonly seen in females)
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