Thyroid Gland Embryology and Anatomy Quiz
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Questions and Answers

Which of the following is NOT a common symptom of goiter?

  • Intolerance to heat
  • Palpitations
  • Difficulty swallowing
  • Weight loss (correct)

    • Goiter primarily causes swelling in the neck and has no effect on breathing.

    False

    What anatomical structure allows the goiter to move up with deglutition?

    Thyroid cartilage

    In a case of goiter, the thyroid gland is often described as having a __________ shaped swelling.

    <p>butterfly</p> Signup and view all the answers

    Match the following goiter symptoms with their descriptions:

    <p>Intolerance to heat = Increased metabolism leading to discomfort in high temperatures Swelling in the neck = Enlargement of the thyroid gland that is visible externally Fast heart rate = Increased heart rate often observed in hyperthyroid conditions Respiratory difficulty = Potential obstruction of airways due to swelling</p> Signup and view all the answers

    What is the embryological origin of the thyroid gland?

    <p>Median bud of the pharynx</p> Signup and view all the answers

    The inferior parathyroid glands develop from the 4th pharyngeal pouch.

    <p>False</p> Signup and view all the answers

    Name the arteries that supply blood to the thyroid gland.

    <p>Superior thyroid artery and inferior thyroid artery</p> Signup and view all the answers

    The thyroid gland is situated opposite to the _____ cervical vertebrae.

    <p>5th, 6th, &amp; 7th</p> Signup and view all the answers

    Which of the following is a component of the venous drainage of the thyroid gland?

    <p>Superior thyroid vein</p> Signup and view all the answers

    Match the following components of the thyroid with their relevant anatomy:

    <p>Superior thyroid artery = 1st branch of the external carotid artery Inferior thyroid artery = Branches from the thyrocervical trunk Thyroid ima = Present only in 1-3% Lateral lymphatic drainage = To upper &amp; lower deep cervical lymph nodes</p> Signup and view all the answers

    The thyroid gland is covered by true capsule and false capsule from the pretracheal fascia.

    <p>True</p> Signup and view all the answers

    What type of cells develop from the neural crest in the thyroid gland?

    <p>Para follicular C cells</p> Signup and view all the answers

    What is the consequence of an injury to the external laryngeal nerve?

    <p>Loss of high pitched voice and voice fatigue</p> Signup and view all the answers

    A thyroglossal cyst is commonly found in the lateral aspect of the neck.

    <p>False</p> Signup and view all the answers

    What is the primary treatment for a symptomatic lingual thyroid?

    <p>Excision</p> Signup and view all the answers

    The condition of enlargement of the thyroid gland is called __________.

    <p>goitre</p> Signup and view all the answers

    What investigation is used to exclude the presence of the only thyroid tissue in case of ectopic thyroid?

    <p>Thyroid Scan</p> Signup and view all the answers

    Match the following functions or conditions with their corresponding terms:

    <p>TRH = Stimulates TSH secretion TSH = Stimulates thyroid hormone production Lingual thyroid = Ectopic thyroid tissue at the base of the tongue Goitre = Enlargement of the thyroid gland</p> Signup and view all the answers

    Colloid goitre occurs when there is persistent stimulation by TSH.

    <p>True</p> Signup and view all the answers

    Where is the commonest site for a thyroglossal cyst?

    <p>Subhyoid in midline</p> Signup and view all the answers

    What is the primary cause of primary toxic goitre?

    <p>Thyroid stimulating antibodies</p> Signup and view all the answers

    Thyrotoxicosis is defined as having elevated levels of free T3 and free T4 in the body.

    <p>True</p> Signup and view all the answers

    Name two treatments used in managing thyrotoxicosis.

    <p>Antithyroid drugs and radioiodine therapy</p> Signup and view all the answers

    Toxic goitre can either be _______ or _______.

    <p>diffuse toxic goitre, toxic nodular goitre</p> Signup and view all the answers

    Match the following types of thyroiditis with their characteristics:

    <p>Hashimoto thyroiditis = Autoimmune destruction of thyroid tissue De Quervain thyroiditis = Painful inflammation often following viral infection</p> Signup and view all the answers

    In which age group is primary toxic goitre most common?

    <p>Young females aged 20-30 years</p> Signup and view all the answers

    Secondary toxic goitre typically presents with exophthalmos.

    <p>False</p> Signup and view all the answers

    List one indication for total thyroidectomy in thyrotoxicosis.

    <p>Failure of medical treatment</p> Signup and view all the answers

    What is a common treatment option for a toxic nodule in a patient over the age of 45?

    <p>Radio iodine</p> Signup and view all the answers

    Hashimoto’s thyroiditis is primarily caused by anti-thyroglobulin antibodies.

    <p>True</p> Signup and view all the answers

    What imaging technique is primarily used to assess a solitary thyroid nodule?

    <p>Ultrasound</p> Signup and view all the answers

    Patients with a large goiter, compression manifestations, or suspicion of malignancy should be considered for __________ treatment.

    <p>surgical</p> Signup and view all the answers

    Match each type of goiter or condition with the appropriate treatment:

    <p>Primary toxic goiter &gt; 45yr = Radio iodine Secondary toxic goiter = Surgery Toxic nodule &lt; 45yr = Surgery Recurrence after adequate surgery &gt; 45yr = Ablation by radio iodine</p> Signup and view all the answers

    The majority of cases of Hashimoto’s thyroiditis occur in which demographic?

    <p>Middle-aged females</p> Signup and view all the answers

    Ultrasound is not important in the investigation of a solitary thyroid nodule.

    <p>False</p> Signup and view all the answers

    What may predispose a patient to Papillary thyroid carcinoma?

    <p>Hashimoto’s thyroiditis</p> Signup and view all the answers

    What symptom is commonly associated with goiter that affects breathing when the patient lies down?

    <p>Difficulty in swallowing</p> Signup and view all the answers

    Which vital sign abnormality is observed in the patient with goiter symptoms?

    <p>High respiratory rate</p> Signup and view all the answers

    What underlying pathophysiology typically leads to the enlargement of the thyroid gland in goiter?

    <p>Increased stimulation by thyroid-stimulating hormone (TSH)</p> Signup and view all the answers

    What is a common complication of long-standing goiter?

    <p>Tracheal compression</p> Signup and view all the answers

    Which examination finding is most indicative of the presence of a multinodular goiter?

    <p>Bilateral nodular enlargement with mobility</p> Signup and view all the answers

    What is a characteristic finding in primary toxic goitre?

    <p>True exophthalmos</p> Signup and view all the answers

    What treatment is indicated if medical treatment fails for thyrotoxicosis?

    <p>Subtotal thyroidectomy</p> Signup and view all the answers

    Which of the following conditions may lead to a thyrotoxic crisis?

    <p>Inadequate preoperative preparation</p> Signup and view all the answers

    What is the common treatment for secondary toxic goitre?

    <p>Surgery after preoperative preparation</p> Signup and view all the answers

    Which age group is most commonly affected by primary toxic goitre?

    <p>Young females aged 20-30</p> Signup and view all the answers

    Which enzyme is safe to use during pregnancy for managing thyrotoxicosis?

    <p>Propylthiouracil</p> Signup and view all the answers

    What is a common cause of thyrotoxicosis due to excess hormone secretion?

    <p>Functioning thyroid carcinoma</p> Signup and view all the answers

    What symptom is commonly associated with thyrotoxic crisis?

    <p>Delirium</p> Signup and view all the answers

    What may result from an injury to the external laryngeal nerve?

    <p>Loss of high pitched voice and voice fatigue</p> Signup and view all the answers

    Which investigation is most appropriate to exclude the presence of only thyroid tissue in the case of a lingual thyroid?

    <p>Thyroid scan</p> Signup and view all the answers

    What is the commonest site for a thyroglossal cyst?

    <p>Subhyoid region in midline</p> Signup and view all the answers

    What is the hallmark characteristic of a thyroglossal cyst during examination?

    <p>It moves with tongue protrusion and deglutition</p> Signup and view all the answers

    What occurs when there is a sudden drop in TSH due to factors like shock dose of iodine?

    <p>Thyroid follicles become inactive and distended with colloid</p> Signup and view all the answers

    Which of the following conditions is defined by the presence of painless midline neck swelling?

    <p>Thyroglossal cyst</p> Signup and view all the answers

    What is a potential complication of a thyroglossal cyst if inadequately managed?

    <p>Development of a fistula</p> Signup and view all the answers

    What is the physiological response of the thyroid gland under persistent TSH stimulation?

    <p>Diffuse hyperplasia and hypertrophy</p> Signup and view all the answers

    What is the primary cause of simple diffuse goitre?

    <p>Increased body demands for thyroid hormones leading to elevated TSH</p> Signup and view all the answers

    Which complication is associated with a simple nodular goitre?

    <p>Compression manifestations affecting nearby structures</p> Signup and view all the answers

    What is the usual treatment option for colloid goitre when symptoms are minimal?

    <p>Regular monitoring with assurance unless symptoms worsen</p> Signup and view all the answers

    Which diagnostic technique is recommended for assessing thyroid nodules?

    <p>Ultrasound to evaluate size and characteristics of nodules</p> Signup and view all the answers

    In which demographic is simple nodular goitre most commonly observed?

    <p>Females aged 30-50 years</p> Signup and view all the answers

    What indicates the need for surgical intervention in cases of thyroid disease?

    <p>Suspicion of malignancy or significant compression manifestations</p> Signup and view all the answers

    Which statement about the late stage of diffuse hyperplasia is true?

    <p>It occurs when TSH stimulation has fallen and follicles become inactive</p> Signup and view all the answers

    Which type of surgery is indicated for localized nodular goitre?

    <p>Hemithyroidectomy when localized to one lobe</p> Signup and view all the answers

    In the treatment of a primary toxic goiter for a patient over the age of 45, which of the following treatment options is preferred?

    <p>Radio iodine</p> Signup and view all the answers

    What is the primary method for diagnosing Hashimoto’s thyroiditis?

    <p>FNAC</p> Signup and view all the answers

    In the case of a solitary thyroid nodule, which imaging technique is crucial for its investigation?

    <p>Ultrasound</p> Signup and view all the answers

    What indicates the presence of a hot nodule on a thyroid scan?

    <p>Suppression of surrounding tissue uptake</p> Signup and view all the answers

    If a patient younger than 45 years has a toxic nodule, what is the recommended treatment?

    <p>Surgery (lobectomy or hemithyroidectomy)</p> Signup and view all the answers

    What role does FNAC play in the management of thyroid conditions?

    <p>It is used to determine the presence of malignancy.</p> Signup and view all the answers

    What is a common condition associated with adult females that may lead to myxedema manifestations?

    <p>Hashimoto’s thyroiditis</p> Signup and view all the answers

    In which situation would a patient be recommended for surgical intervention despite prior treatment with antithyroid drugs?

    <p>Failure of treatment with antithyroid drugs</p> Signup and view all the answers

    What is the main function of Broca's area located in the left frontal lobe?

    <p>Controlling expressive language function</p> Signup and view all the answers

    Which artery is primarily responsible for supplying the posterior part of the brain?

    <p>Vertebral artery</p> Signup and view all the answers

    What is the function of the Wernicke area located in the temporal lobe?

    <p>Interpreting sensory information related to speech</p> Signup and view all the answers

    Which lobes of the cerebrum are primarily responsible for processing somatic sensations?

    <p>Parietal and temporal lobes</p> Signup and view all the answers

    Which of the following best describes the Circle of Willis?

    <p>A fusion of anterior and posterior circulation supplying the brain</p> Signup and view all the answers

    What is a common treatment option for a patient experiencing symptoms of a stroke?

    <p>Tissue plasminogen activator (tPA)</p> Signup and view all the answers

    In which brain lobe is the awareness and processing of visual stimuli primarily handled?

    <p>Occipital lobe</p> Signup and view all the answers

    What condition is indicated by sudden onset aphasia and weakness in lower limbs?

    <p>Ischemic stroke</p> Signup and view all the answers

    What function is associated with the Broca's area located in the left frontal lobe?

    <p>Expressive language function</p> Signup and view all the answers

    Which artery is part of the anterior circulation supplying the brain?

    <p>Middle cerebral artery</p> Signup and view all the answers

    What role does the temporalis lobe play in brain function?

    <p>Interpreting speech</p> Signup and view all the answers

    How does the Circle of Willis contribute to brain blood supply?

    <p>Ensures collateral circulation</p> Signup and view all the answers

    Which symptom might indicate a compromise in the blood supply from the anterior cerebral artery?

    <p>Weakness in the arms</p> Signup and view all the answers

    What is the primary responsibility of the cerebellum?

    <p>Coordination and balance</p> Signup and view all the answers

    What condition is indicated by sudden onset aphasia and weakness in lower limbs?

    <p>Ischemic stroke</p> Signup and view all the answers

    What characteristic is linked to the awareness of visual stimuli?

    <p>Occipital lobe function</p> Signup and view all the answers

    Study Notes

    Thyroid gland Embryology

    • Develops from the median bud of the pharynx at the foramen cecum (junction between anterior two-thirds and posterior third of the tongue)
    • Descends in the neck passing close to or through the hyoid bone
    • The remaining part of the lobes develop from ultimobranchial body (4th pharyngeal pouch) which gives rise to the superior parathyroid glands
    • The inferior parathyroid glands develop from the (3rd pharyngeal pouch)

    Thyroid gland Anatomy

    • Situated in the neck opposite to the 5th, 6th, & 7th cervical vertebrae. Made up of 2 lobes joined by a thin band of tissues; the isthmus.
    • Its apex lies below the oblique line of the thyroid cartilage while the base is at the level of 6th tracheal cartilage
    • Covered by true capsule and false capsule from the pretracheal fascia

    Thyroid gland Arterial supply

    • Superior thyroid artery: The 1st branch of the external carotid artery. Related to the external laryngeal nerve
    • Inferior thyroid artery: branch from thyrocervical trunk of subclavian artery. Related to recurrent laryngeal nerve
    • Accessory esophageal and tracheal branches
    • Thyroid ima (from aortic arch-only in 1-3%)

    Thyroid gland Venous drainage

    • Superior thyroid vein: into Internal jugular vein
    • Middle thyroid vein: into Internal jugular vein
    • Inferior thyroid vein: into the left innominate vein

    Thyroid gland Lymphatic drainage

    • Lateral part: To the upper & lower deep cervical lymph nodes (Levels: II,III,IV,Vb).
    • Medial parts of both lobes: 1) Pre-laryngeal LNs over cricothyroid membrane. 2) Pre-tracheal LNs (Delphi). 3) Para-tracheal LNs (mediastinal).
    • External laryngeal nerve: from sup.Laryngeal from vagus. Supplies cricothyroid + inferior constrictor. Injury: loss of high pitched voice + voice fatigue
    • Recurrent laryngeal nerve: from Vagus nerve

    Goiter

    • Enlargement of the thyroid gland

    Goiter Pathophysiology

    • Deficiency of Thyroid hormones, either relative or absolute, stimulates the hypothalamus to produce TRH, which in turn stimulate TSH secretion.
    • Persistent TSH stimulation leads to diffuse hyperplasia & hypertrophy of the thyroid gland
    • If the stress is over, Involution of the gland occurs, and the gland may return to its normal size
    • If the stress is persistent, hyperplasia persists → Physiological Goiter
    • Sudden fall of TSH, will lead to inactivation of most of the follicles, and the acini become distended with colloid → Colloid goiter
    • Fluctuation of TSH levels will lead to cycles of hyperplasia and involution

    Thyrotoxicosis

    • Is a clinical syndrome in which free T3 or free T4 or both are elevated and peripheral tissues are hypermetabolic, irrespective of the source of the excess hormones
    • Etiology: Thyrotoxic goitre, Thyroiditis (Hashimoto thyroiditis/ De Queirvan thyroiditis), Thyrotoxic facticia ( intake of Eltroxin), Functioning thyroid carcinoma, TSH secreting pituitary adenoma, Struma ovarii (ovarian cancer secreting tumor)

    Toxic Goiter

    • Goitre with increased thyroid hormones
    • Either: Diffuse toxic goitre (1ry/Grave’s disease), Toxic nodular goitre (2ry/Plummer’s disease), Toxic adenoma

    Primary Toxic Goiter

    • Autoimmune disease due to thyroid stimulating antibodies (TSAb). Common in young females (20-30 years)
    • Disease has abrupt onset with remission and exacerbation
    • 50% of patients have a family hx of autoimmune endocrine disorders
    • True exophthalmos is characteristic
    • May be complicated by heart failure
    • Diffuse thyroid swelling without nodules
    • Toxic thyroid profile with high thyroid autoantibodies
    • Treatment is mainly medical if failed Surgery or RAI

    Primary Toxic Goiter Treatment

    • Medical treatment: Antithyroid drugs (Neomercazol/propyl thiouracil), B-blockers, Diazepam
    • Surgical treatment: Subtotal thyroidectomy or total thyroidectomy
    • RAI: (teratogenic/carcinogenic): Used in old patients (˃ 45 years) after failure of medical treatment or recurrence after thyroidectomy

    Thyrotoxic crisis

    • Severe postoperative hyperthyroidism due to inadequate preoperative preparation
    • Clinical picture: Hyperpyrexia, Hypertension, Delirium & Convulsions.
    • Treatment: Cooling + lV (lndral, Corticosteroid, Propylthiouracil, Antipyretics )

    Secondary Toxic Goiter

    • Occurs in older females (30-50 years)
    • On top of long standing nodular goitre. No exophthalmos.
    • Thyroid gland is enlarged and nodular. Thyroid hormones are elevated but antibodies are within normal
    • Treatment: Surgery after preoperative preparation. RAI might have a role.

    Toxic Nodule

    • Excess secretion of thyroid hormone from autonomous hyperactive thyroid nodule
    • Manifested by thyrotoxic manifestations
    • Elevated thyroid hormones, no elevated autoantibodies.
    • By U/S: solitary thyroid nodule with increased vascularity
    • Thyroid scan : hot nodule with suppression of the uptake of surrounding thyroid tissue.
    • Treatment : Surgery & RAI might have a role in elderly

    Treatment Based on Patient Age and Goiter Type

    • 1ry toxic goiter: > 45yr → Radio iodine. < 45yr → small goiter → Antithyroid drugs. → Large goiter → Surgery.
    • 2ry toxic goiter: Surgery
    • Toxic nodule: > 45yr → Radio iodine. < 45yr → Surgery (lobectomy or hemithyroidectomy).
    • Recurrence after adequate surgery: > 45yr → Ablation by radio iodine. < 45yr → Antithyroid drugs.
    • Failure of treatment with antithyroid drugs: Surgery or Radio-iodine

    Thyroiditis

    • Hashimoto’s thyroiditis: Most common form of thyroiditis, Autoimmune thyroiditis due to anti-thyroglobulin antibodies & thyroid peroxidase antibodies (TPO). Common in middle aged females. Initial manifestations of thyrotoxicosis. Later on →manifestations of myxedema. FNAC is diagnostic. May predispose to Papillary thyroid carcinoma or thyroid lymphoma. Treatment : Medical. Surgical treatment in large goitre, compression manifestations or suspicion of malignancy.

    Retrosternal Goitre

    • More common in males (tough neck muscles)
    • Manifestations is mainly compression manifestations
    • Mediastinal syndrome?!
    • CT is important
    • Treatment is mainly surgical (sternotomy may be required)

    Solitary Thyroid Nodule

    • May be clinically STN but by U/S reveals MNG (Multinodular goiter)

    Solitary Thyroid Nodule Investigation

    • Ultrasound
    • FNAC
    • TFT
    • Thyroid scan

    Thyroid Gland Disorders

    • A 30-year-old female patient presents with neck swelling, intolerance to heat, fast heart rate, sweaty palms, difficulty swallowing and breathing, especially when lying down.
    • The swelling in her neck is described as butterfly-shaped, multinodular, and extending to the retrosternal area.
    • The swelling moves up with deglutition (swallowing), indicating involvement of the thyroid gland.

    Goiter

    • Definition: Enlargement of the thyroid gland.

    Pathophysiology of Goiter

    • Iodine Deficiency: Deficiency of thyroid hormones, either relative or absolute, triggers the hypothalamus to produce TRH, which stimulates TSH secretion.
    • Persistent TSH Stimulation: Persistent TSH stimulation leads to diffuse hyperplasia and hypertrophy of the thyroid gland, potentially resulting in:
      • Physiological Goiter: Hyperplasia persists due to continuous stress.
      • Colloid Goiter: Sudden decrease in TSH leads to inactivation of follicles and distension of acini with colloid.
      • Nodular Goiter: Fluctuation of TSH levels causes cycles of hyperplasia and involution, resulting in a mixed pattern with areas of both.

    Types of Goiter

    • Simple Diffuse Goiter (Physiological Goiter): Common in females, often due to increased body demands (puberty, pregnancy, lactation). Characterized by diffuse, smooth, symmetrical enlargement of the thyroid gland ("Venus Neck").
    • Colloid Goiter: Late stage of diffuse hyperplasia with inactive follicles filled with colloid.
    • Simple Nodular Goiter: Most common thyroid disease. Occurs due to fluctuations in TSH levels, leading to mixed patterns of active and inactive thyroid follicles. Often presents as a painless neck swelling.

    Clinical Features of Goiter

    • Common Presentations:
      • Neck swelling
      • Dysphagia (difficulty swallowing)
      • Dyspnea (difficulty breathing)
      • Compression of the trachea or esophagus
      • Hoarseness (due to recurrent laryngeal nerve compression)
      • Symptoms exacerbated when lying down

    Investigations for Goiter

    • Ultrasound:
      • Assessment of thyroid nodule size and characteristics (TIRADS classification).
      • Assessment of lymph node status.
      • Guidance for fine-needle aspiration cytology (FNAC) for impalpable or small nodules.
    • FNAC: Performed if suspicious nodules are identified (based on TIRADS).
    • Indirect Laryngoscopy: To evaluate for asymptomatic vocal cord paralysis (occurs in 4% of cases).

    Treatment of Goiter

    • Indications for Surgery:

      • Suspicion of malignancy
      • Compression symptoms
      • Cosmetic concerns

    • Types of Surgery:

      • Hemithyroidectomy: Removal of one lobe of the thyroid gland (for unilateral or localized disease).
      • Subtotal Thyroidectomy: Removal of a significant portion of the thyroid gland (often used for diffuse disease).
      • Near Total Thyroidectomy: Removal of most of the thyroid gland with a small portion left behind.
      • Total Thyroidectomy: Complete removal of the thyroid gland.

    • Surgical Approach:

      • Open: Traditional surgical approach with an incision in the neck.
      • Endoscopic: Minimally invasive approach using a small camera and instruments inserted through the mouth.

    Thyrotoxicosis

    • Definition: A clinical syndrome characterized by elevated free T3 or free T4 levels, leading to hypermetabolism in peripheral tissues.

    Causes of Thyrotoxicosis

    • Thyrotoxic Goiter: Excess thyroid hormone production due to an enlarged thyroid gland.
    • Other Causes:
      • Thyroiditis: Inflammation of the thyroid gland (Hashimoto or De Quervain thyroiditis).
      • Thyrotoxic Facticia: Ingestion of thyroid hormone medication.
      • Functioning Thyroid Carcinoma: Malignant tumor of the thyroid gland producing excess thyroid hormone.
      • TSH-Secreting Pituitary Adenoma: Tumor in the pituitary gland producing excess TSH.
      • Struma Ovarii: Ovarian cancer secreting thyroid hormone.

    Types of Thyrotoxic Goiter

    • Diffuse Toxic Goiter (Graves' Disease): Autoimmune disease caused by thyroid-stimulating antibodies (TSAb).
    • Toxic Nodular Goiter (Plummer's Disease): Occurs in long-standing nodular goiter (due to autonomous nodules).

    Clinical Features of Thyrotoxic Goiter

    • Primary Toxic Goiter (Graves’ Disease):

      • Common in young females.
      • Abrupt onset with remissions and exacerbations.
      • May be complicated by heart failure.
      • Diffuse thyroid swelling without nodules.
      • Elevated thyroid hormones with high thyroid autoantibodies.
      • Characteristic exophthalmos (bulging eyes).

    • Secondary Toxic Goiter (Plummer's Disease):

      • Occurs in older females.
      • Enlarged and nodular thyroid gland.
      • Elevated thyroid hormones but normal thyroid autoantibodies.
      • No exophthalmos.

    • Toxic Nodule:

      • Excess thyroid hormone production from an autonomous hyperactive thyroid nodule.
      • Presents with thyrotoxic symptoms and elevated thyroid hormones without elevated autoantibodies.
      • Identified on ultrasound as a solitary nodule with increased vascularity.
      • Thyroid scan shows a "hot" nodule with suppression of uptake in the surrounding thyroid tissue.

    Treatment of Thyrotoxic Goiter

    • Medical Treatment:
      • Antithyroid drugs: Neomercazol or propylthiouracil (safe during pregnancy).
      • Beta-blockers: To manage tachycardia.
      • Diazepam: For aggressive central nervous system manifestations.
      • Medical treatment can last up to 2 years.
    • Surgical Treatment:
      • Subtotal thyroidectomy: Removal of a significant portion of the thyroid gland (often used in patients with Graves' disease).
      • Total thyroidectomy: Complete removal of the thyroid gland (may be necessary for large goiters or recurrent disease).
      • Indications: Failure of medical treatment, recurrent symptoms, compression manifestations.
      • Requires careful preoperative preparation to minimize risk of thyrotoxic crisis.
    • Radioactive Iodine (RAI):
      • Used in older patients (>45 years) with failure of medical treatment or recurrent disease after thyroidectomy.
      • Teratogenic and carcinogenic, so use should be carefully considered.

    Thyrotoxic Crisis

    • Definition: Severe postoperative hyperthyroidism due to inadequate preoperative preparation.
    • Clinical Features: High fever, hypertension, delirium, and seizures.
    • Treatment: Cooling measures, intravenous administration of medications (Inderal, corticosteroids, propylthiouracil, antipyretics).

    Treatment Summary

    • Primary Toxic Goiter:
      • >45 years: Radioactive iodine.
      • <45 years:
        • Small goiter: Antithyroid drugs.
        • Large goiter: Surgery.
    • Secondary Toxic Goiter: Surgery.
    • Toxic Nodule:
      • >45 years: Radioactive iodine.
      • <45 years: Surgery (lobectomy or hemithyroidectomy).
    • Recurrence after adequate surgery:
      • >45 years: Ablation with radioactive iodine.
      • <45 years: Antithyroid drugs.
    • Failure of treatment with antithyroid drugs: Surgery or radioactive iodine.

    Thyroiditis

    • Hashimoto's Thyroiditis:
      • Most common form of thyroiditis.
      • Autoimmune thyroiditis with antibodies against thyroglobulin and thyroid peroxidase.
      • Common in middle-aged females.
      • Initial presentation of thyrotoxicosis followed by hypothyroidism (myxedema).
      • Diagnosed by fine-needle aspiration cytology (FNAC).
      • May increase risk of papillary thyroid carcinoma or thyroid lymphoma.
      • Treatment: Medical management, surgery may be considered for large goiters, compression manifestations, or suspicion of malignancy.

    Retrosternal Goiter

    • More common in males.
    • Primarily presents with compression symptoms.
    • May cause mediastinal syndrome.
    • Important to utilize CT imaging.
    • Treatment: Surgical (may require sternotomy).

    Solitary Thyroid Nodule

    • Key Considerations:
      • Solitary thyroid nodule versus dominant nodule within a multinodular goiter.
      • Clinical assessment may suggest a solitary thyroid nodule, but ultrasound may reveal a multinodular goiter.

    Investigation of Solitary Thyroid Nodule

    • Ultrasound
    • Fine-Needle Aspiration Cytology (FNAC)
    • Thyroid Function Tests (TFT)
    • Thyroid Scan

    Lobes of the Cerebrum

    • Frontal Lobe: Controls motor function, responsible for expressive language (Broca's area).
    • Temporal Lobe: Processes auditory information and is involved in the interpretation of speech (Wernicke's area).
    • Parietal Lobe: Responsible for awareness and processing of somatic sensations like touch, pain, and temperature.
    • Occipital Lobe: Processes and analyzes visual stimuli, recognizing and memorizing visual information.

    Surgical Anatomy

    • Limbic System: Involved in emotions, memory, and behavior.
    • Brain Stem: Controls essential functions like breathing, heart rate, and blood pressure.
    • Cerebellum: Coordinates movement, balance, and posture.

    Blood Supply of the Brain

    • Main Arteries: The brain is supplied by the carotid and vertebral arteries.
    • Two Brain Supply Systems: Anterior Circulation (carotid arteries) and Posterior Circulation (vertebral arteries).
    • Circle of Willis: A critical arterial structure that connects the anterior and posterior circulations, providing alternative pathways for blood flow in case of an obstruction.
    • Case Examples:
      • Patient 1: A 71-year-old man with sudden aphasia and lower limb weakness, suggestive of a stroke. Investigated with CT and MRI to identify the location and cause of the stroke, managed conservatively.
      • Patient 2: A 37-year-old man with sudden right hemiparesis likely due to a stroke, diagnosed with CT/CT Angio and MRI. Treated surgically to alleviate pressure and improve blood flow.
      • Patient 3: A 40-year-old man with right-sided paralysis and aphasia, treated within a therapeutic time window with tissue plasminogen activator (tPA) and digital subtraction angiography to identify the location of the blockage.

    External Carotid Artery

    • Supplies the face, neck, and scalp.
    • Branches include: superior thyroid artery, lingual artery, facial artery, and internal maxillary artery.

    Venus Drainage

    • Venous drainage of brain is through dural sinuses:
      • Superior sagittal sinus: Drains blood from superior portion of brain.
      • Inferior sagittal sinus: Drains blood from inferior portion of brain.
      • Straight sinus: Connects superior and inferior sagittal sinuses.
      • Transverse sinus: Drains blood from lateral portion of brain.
      • Sigmoid sinus: Continues from transverse sinus and drains into internal jugular vein.

    Lobes of the Cerebrum

    • Frontal Lobe: Contains the motor strip, responsible for voluntary movement.
    • Broca's Area: Located in the left frontal lobe, controls expressive language.
    • Temporal Lobe: Houses Wernicke's area, responsible for speech comprehension.
    • Parietal Lobe: Processes somatic sensation, including touch, pain, and temperature.
    • Occipital Lobe: Processes visual stimuli, analyzing, recognizing, and memorizing visual information.

    Surgical Anatomy

    • Limbic System: Responsible for emotions, memory, and motivation.
    • Brain Stem: Controls vital functions like breathing, heart rate, and blood pressure.
    • Cerebellum: Coordinates movement, balance, and posture.

    Blood Supply of the Brain

    • Main Arteries: Carotid and vertebral arteries supply the brain.
    • Two Brain Supply Systems: Anterior and posterior circulation systems.
    • Circle of Willis: Fusion point of anterior and posterior circulation, ensuring constant blood flow to the brain.

    Case Examples

    • Case 1: A 71-year-old man experienced sudden aphasia and lower limb weakness. This could be caused by a stroke affecting areas like the middle cerebral artery.
    • Case 2: A 37-year-old man had sudden right hemiparesis. CT scans and MRI were used to identify potential causes (like a stroke).
    • Case 3: A 40-year-old man had right-sided paralysis and aphasia. CT angiography identified a blocked P2 segment of the left middle cerebral artery.

    External Carotid Artery

    • Areas of Supply: This artery supplies various areas of the head and face, not primarily the brain.

    Venus Drainage

    • Blood Drainage: The venous drainage system carries deoxygenated blood from the brain back to the heart.

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    Description

    Test your knowledge on the embryology and anatomy of the thyroid gland. This quiz covers its development, structure, and arterial supply. Ideal for students studying human anatomy or endocrinology.

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