๐ฎ๐๐๐๐๐ & ๐ป๐๐๐๐๐๐๐๐๐๐๐๐๐ Flashcards
Describe the complete feedback mechanism of thyroid hormone regulation
Hypothalamus releases TRH (+) โ Anterior pituitary releases TSH (+) โ Thyroid releases T3/T4 โ T3/T4 provide negative feedback to both hypothalamus and anterior pituitary
What is the clinical significance of RLN damage during thyroid surgery and its symptoms?
Critical during thyroid surgery due to nerveโs close anatomical relationship
RLN damage causes:
1) Hoarseness
2) Difficulty breathing
3) Difficulty swallowing
4) Loss of voice.
Differentiate between toxic and non-toxic goitre
Non-toxic goitre: Enlarged but produces normal thyroid hormone levels.
Toxic goitre: Enlarged and produces excess hormone causing hyperthyroidism
List the complete venous drainage pathway of the thyroid gland
Superior thyroid vein โ Internal jugular vein
Middle thyroid vein โ Internal jugular vein
Inferior thyroid vein โ Brachiocephalic veins
Compare and contrast Gravesโ disease and Hashimotoโs thyroiditis
Both are autoimmune conditions.
Gravesโ causes hyperthyroidism through stimulating antibodies
Hashimotoโs causes hypothyroidism through destructive antibodies
What are the three types of thyroid carcinoma cells and their origins?
1) Papillary - from follicular cells
2) Medullary - from parafollicular cells
3) Follicular - from follicular cells
Why is papillary thyroid cancer considered most significant clinically?
Most common type and more malignant, characteristically spreads to lungs, bones, and brain
Explain the mechanism of goitre formation in iodine deficiency
Iodine deficiency โ Hypothyroidism โ Increased TSH โ Thyroid cells undergo hypertrophy & hyperplasia to compensate โ Goitre formation
What are the key components of thyroid function assessment?
1) Serum T3
2) Serum T4
3) Serum TSH
4) Thyroid autoantibody level
5) Serum thyroglobulin
6) Fine needle aspiration
7) Thyroid imaging
8) Thyroid scintigraphy
Describe the complete surgical anatomy of thyroid gland
Located in anterior neck (C5-T1)
Weighs 20-25g
Anterior to tracheal rings 2,3,4
Two lobes connected by isthmus
Pyramidal lobe may be present
Attached to hyoid bone by levator glandulae thyroideae
What is the clinical significance of goitrogens and list examples
Goitrogens interfere with iodine uptake leading to hypothyroidism. Examples: cabbage, broccoli, kale, cassava. Important dietary consideration in iodine-deficient regions
Explain De Quervainโs thyroiditis: cause, pathology, and significance
Granulomatous/ Giant cell thyroiditis usually caused by viral infection.
Important cause of transient thyroid dysfunction
Compare different types of simple/non-toxic goitre and their clinical significance
Types: 1) Diffuse 2) Multi-nodular 3) Recurrent 4) Nodule. Important for surgical planning and malignancy risk assessment
What is the embryological development of thyroid and its clinical relevance?
Develops from thyroglossal duct, first endocrine gland to develop. Clinical relevance: thyroglossal duct cysts, ectopic thyroid tissue
List all physiological causes of goitre and their mechanism
Pregnancy
Puberty
Breast feeding
Describe the complete blood supply of thyroid gland
Superior thyroid artery (external carotid), Inferior thyroid artery (thyrocervical trunk), Thyroid ima artery (occasionally present)
What is Riedelโs thyroiditis and its clinical significance?
Chronic form of thyroiditis characterized by fibrosis and infiltration by IgG & secretory plasma cells. Can cause compressive symptoms
Explain the transport mechanism of thyroid hormones in blood
T3 & T4 bound to: 1) Albumin 2) Globulin 3) Pre-albumin. Understanding important for interpreting thyroid function tests
What are the histological features of thyroid follicles?
Thyroid folliclesโ Lined by Cuboidal cells
Follicular cellsโ Produce T3 & T4 and have basophilic cytoplasm
Para-follicular (C) cellsโ Secretes Calcitonin
List risk factors for thyroid disease with clinical significance
1) Post partum state
2) Smoking
3) Stress
4) Lithium therapy
5) Iodine excess
6) Radiation exposure
7) Family history
Describe the complete nerve supply of thyroid gland
Sympathetic: superior, middle & inferior cervical ganglia; Parasympathetic: vagus nerve (superior laryngeal & recurrent laryngeal)
Compare the 3 inflammatory types of thyroiditis
Riedelโs: Fibrosis & infiltration by IgG & secretory plasma cells
De Quervainโs: Caused by viral infection
Hashimotoโs: autoimmune destruction of thyroid cells
How do drugs like amiodarone and lithium affect thyroid function?
Amiodarone: contains iodine, can cause both hyper/hypothyroidism;
Lithium: inhibits hormone release, causes hypothyroidism
What are the anatomical relations of thyroid gland?
Anterior: strap muscles; Lateral: carotid sheath; Posterior: trachea, esophagus, parathyroids; Superior: cricoid cartilage
What is the significance of thyroid autoantibodies?
Indicate autoimmune thyroid disease, help diagnose Gravesโ disease and Hashimotoโs thyroiditis, monitor treatment response
Explain the role of TSH in thyroid physiology
Stimulates: 1) Thyroid growth 2) Iodine uptake 3) Hormone synthesis 4) Hormone release. Key in diagnosis and monitoring
What is a total thyroidectomy?
The entire gland is removed.
In which conditions is total thyroidectomy performed?
It is done in follicular and medullary carcinoma.
What is a Hartley-Dunhill operation?
It involves the removal of one entire lateral lobe along with the isthmus and subtotal removal of the opposite lobe.
When is a Hartley-Dunhill operation performed?
It is done in non-toxic multinodular goitre.
What are some complications of thyroidectomy?
Bleeding
Laryngeal edema
Infection
Wound dehiscence
Hoarseness/voice changes
Respiratory obstruction
Parathyroid insufficiency
Thyroid crisis
Thyroid insufficiency.
What complication of thyroidectomy can cause breathing difficulties?
Laryngeal edema and respiratory obstruction.
Which complication of thyroidectomy affects calcium levels?
Parathyroid insufficiency.
What is thyroid crisis?
A life-threatening condition caused by excessive thyroid hormone release post-thyroidectomy.
What is wound dehiscence?
The reopening of a surgical wound after thyroidectomy.
How can thyroidectomy affect the voice?
It can cause hoarseness or voice changes due to nerve damage.
List and explain the WHO grading system for goiter
Grade 0: No visible/palpable goiter
Grade 1: Palpable but not visible in normal neck position
Grade 2: Visible goiter
What are the three key characteristics in thyroid swelling history that suggest malignancy?
1) Short duration with rapid growthโ Malignancy
2) Sudden increase in size with pain โ Haemorrhage
3) Long-standing swelling โ Benign Condition
Compare and contrast the consistency findings in different thyroid conditions
Soft โ Gravesโ disease & colloid goiter
Firm โ Adenoma & MNG
Hard โ Cancer
List all CNS symptoms of hyperthyroidism
Tremors, Preference to cold, Excitability, Irritability, Insomnia
What are the complete CVS manifestations of hyperthyroidism?
Palpitations, Precordial chest pain, Dyspnea on exertion
Describe the metabolic manifestations of hyperthyroidism
Weight loss with hyperphagia, Diarrhea, Amenorrhea
List and explain all eye signs in thyroid eye disease
1) Stellwagโs: Absence of normal blinking
2) Von Graefeโs: Upper lid lag
3) Joffreyโs: Absence of forehead wrinkling
4) Mรถbius: Lack of convergence
5) Gifford: Difficulty everting upper lid
6) Naffzigerโs: Protruded eyes visible from behind
What are the key aspects to examine in thyroid inspection?
Site, Size & Shape (bilobar or butterfly), Surface (smooth/irregular/nodular), Skin over swelling, Surrounding skin, Movement with swallowing
Describe the proper technique for examining thyroid from behind the patient
1) Place hand on swelling & ask patient to swallow 2) Palpate each thyroid lobe for surface & consistency 3) Check mobility 4) Palpate each carotid pulse one after another
What are the three grades of thyroid eye disease and their features?
Mild: Lid retraction & widening of palpebral fissure; Moderate: Orbital fat deposition causing bulging & Joffreyโs sign; Severe: Intra-orbital edema, raised IOP, diplopia, ophthalmoplegias
List all investigations required for thyroid swelling evaluation
1) Thyroid function test 2) X-ray 3) Ultrasound 4) CT scan 5) Fine needle aspiration cytology 6) Radioactive iodine scan
What are the complete indications for thyroidectomy?
1) Thyrotoxicosis therapy 2) Benign/malignant tumors 3) Cosmetic purpose 4) Establish definitive diagnosis 5) Pressure symptoms (dysphagia/respiratory distress)
Compare and contrast different types of thyroidectomy and their indications
Hemi-thyroidectomy: One lobe removed, for benign diseases; Sub-total: 8gm tissue retained, for toxic/non-toxic MNG; Near-total: Both lobes except small portion, for papillary carcinoma
What is the complete approach to examining upper and lower limb in thyroid disease?
Check: 1) Static hand tremor 2) Fine tremors 3) Pre-tibial myxedema 4) Ankle reflex
List the key features in thyroid swelling history that suggest benign condition
1) Long-standing swelling 2) Slow growth 3) No associated pain or compression symptoms
What are the causes of dyspnea in thyroid disease?
1) Malignant or retrosternal goiter 2) Thyrotoxicosis 3) Tracheal compression
Describe the ocular manifestations of hyperthyroidism
1) Double vision 2) Protruding eyeball 3) Eye muscle weakness 4) Lid retraction
What are the integumentary changes in hyperthyroidism?
Hair loss, Pruritus, Palmar erythema
List the symptoms of toxic goiter
Weight gain, Cold intolerance, Constipation, Slow thought & speech, Muscle fatigue, Hoarseness of voice
What is exophthalmos and its pathophysiology in Gravesโ disease?
Immune system mistakenly attacks muscles & fatty tissues around eyes causing them to swell, leading to eye protrusion
Compare the different types of goiter based on surface characteristics
Smooth: Adenoma, Puberty goiter, Gravesโ disease; Irregular: Thyroid Ca; Nodular: Multi-nodular goiter
What are the differential diagnoses for anterior neck swelling?
Thyroid mass, Thyroglossal cyst, Laryngocele, Dermoid cyst, Lymph nodes
List all preventive measures for thyroid disease
1) Prevent iodine deficiency 2) Avoid goitrogens (cabbage) 3) Avoid triggering drugs
What complications necessitate immediate thyroidectomy?
1) Tracheal obstruction 2) Hemorrhage in nodule 3) Severe compression symptoms
Describe the complete genito-urinary symptoms in thyroid disease
Oligomenorrhea/Amenorrhea, Occasional urinary frequency changes
What are the key points to note in skin examination over thyroid swelling?
Temperature, Tenderness, Surface characteristics, Skin attachment
List all treatments available for hyperthyroidism
Surgery, Radio-active iodine, Anti-thyroid medication, Beta-blockers
What are the characteristic features of movement with swallowing in thyroid swelling?
Movement restricted in malignancy, retrosternal goiter & large goiter; Free movement in benign conditions
Compare the different causes of thyroid enlargement based on consistency
Soft: Early Gravesโ; Firm: Established Gravesโ/MNG; Hard: Malignancy/Hashimotoโs
What are the complete GI manifestations of thyroid disease?
Diarrhea in hyperthyroidism, Constipation in hypothyroidism, Weight changes, Appetite changes
What is the weight of the thyroid gland?
20-25g
What is the location of the thyroid?
Located in anterior neck (C5-T1)
Classify Goitre
- Non-toxic goitre
- Toxic goitre
*Neoplastic goitre
*Inflammatory goitre
*Rare
What are the types of neoplastic goitre?
*Papillary
*Medullary
*Follicular
*Anaplastic
List 10 features of hyperthyroidism
CNSโ Tremors, Heat intolerance, Sweating, Irritability
CVSโ Palpitations, Chest pain, Dyspnoea
Metabolicโ Weight loss with hyperphagia, Diarrhoea
Eyeโ Double vision, protruding Eyeball
Othersโ Amenorrhoea, Hair loss
