RCSI: Endocrine Disorders Flashcards
What is the anatomical structure of the thyroid gland?
Formed from two triangular lobes connected by a central isthmus overlying the 2nd and 3rd tracheal rings.
Where is the thyroid gland located?
Between the levels of C5-T1, invested within the pretracheal fascia.
What are the arterial supplies to the thyroid gland?
- Inferior thyroid artery
- Superior thyroid artery
What is the venous drainage of the thyroid gland?
- Superior thyroid vein
- Middle thyroid vein
- Inferior thyroid vein
What are the lymphatic drainage nodes for the thyroid gland?
- Prelaryngeal nodes
- Pretracheal nodes
- Paratracheal nodes
How many pairs of parathyroid glands are generally found?
Two pairs.
What is the function of the external laryngeal nerve?
Innervates the cricothyroid muscle.
What is the significance of the recurrent laryngeal nerve?
It supplies all other intrinsic laryngeal muscles and is vulnerable during thyroid and parathyroid surgery.
What hormones are involved in the central control of thyroid hormones?
- TRH (Thyrotropin-releasing hormone)
- TSH (Thyroid-stimulating hormone)
- T3 (Triiodothyronine)
- T4 (Thyroxine)
What are the thyroid function test results for hyperthyroidism?
TSH: ↓, T4: ↑
What are the clinical presentations of hyperthyroidism?
- Hyperactivity
- Tachycardia
- Mood swings
- Protruded eyes
- Insomnia
- Irregular menstruation
What are the symptoms of hypothyroidism?
- Fatigue
- Sluggishness
- Bradycardia
- Irregular uterine bleeding
What is Graves’ disease?
Hyperthyroidism, goitre, eye disease, and pretibial/localised myxoedema.
What characterizes Hashimoto’s thyroiditis?
Chronic autoimmune thyroiditis with high TPO and thyroglobulin antibodies, typically resulting in hypothyroidism.
What is the effect of iodine deficiency on the thyroid?
May present with a diffuse goitre, usually painless and slow growing.
What is a cystic thyroid nodule?
Also known as a ‘simple cyst’, may lead to thyroid pain and dysphagia.
What is the Sistrunk procedure?
Surgical excision technique used for thyroglossal cysts.
What is the primary imaging method for thyroid pathology?
Ultrasound (US) is non-invasive and does not expose the patient to radiation.
What defines thyrotoxicosis?
A hypermetabolic syndrome due to elevated thyroid hormone levels.
What are the clinical signs of thyrotoxicosis?
- Sweats
- Tremors
- Weight loss despite increased appetite
- Anxiety
- Heat intolerance
What is the management for Graves’ disease?
Carbimazole for 18 months, consider radioiodine treatment or surgery if refractory.
What are the indications for thyroidectomy?
- Cancer
- Compression of adjacent structures
- Cosmesis
- Carbimazole failure
Which antibodies are associated with Graves’ disease?
- TSH receptor antibodies
- TPO antibodies
What is the relationship between TSH and thyroid disease severity?
TSH correlates well with the severity of the disease.
What are the causes of thyrotoxicosis?
- Graves’ disease
- Toxic multinodular goitre
- Solitary toxic nodule
- Thyroiditis
What is the typical age range for Graves’ disease onset?
Commonly occurs in women aged 20–40 years old.
What is the main complication associated with hyperthyroidism?
Increased risk of atrial fibrillation.
What are the common symptoms of thyroiditis?
- Pain
- Fever
- Fatigue
What does a fine needle aspiration cytology (FNAC) help determine?
It is used for evaluating thyroid nodules for malignancy.
True or False: Amiodarone can cause both hyperthyroidism and hypothyroidism.
True
What is Ophthalmoplegia?
A condition where eye movement is impaired due to muscle or nerve issues.
Look up to stretch inferior rectus to provoke as the inferior rectus muscle becomes fibrous and tight.
What are the key findings in TFTs for Graves’ disease?
High fT4, low TSH.
TSH correlates well with the severity of disease.
Which autoantibodies are positive in Graves’ disease?
- TSH receptor antibodies
- TPO antibodies (up to 80%)
- Thyroglobulin antibodies (up to 70%)
What does scintigraphy demonstrate in Graves’ disease?
Increased uptake.
What is the first-line medical treatment for Graves’ disease?
Beta blocker for symptom relief.
What is the mechanism of action for Carbimazole?
Blocks the action of TPO, preventing the formation of thyroid hormone.
What is the typical duration of Carbimazole treatment for Graves’ disease?
18 months.
What is the less potent alternative to Carbimazole?
Propylthiouracil (PTU).
What are the risks associated with radioactive iodine treatment?
- Hypothyroidism
- Transient thyroiditis
- Transient worsening of Graves’ ophthalmopathy
What are the indications for surgical intervention in Graves’ disease?
- Cancer
- Compression of adjacent structures
- Carbimazole failure
- Cosmesis/severe ophthalmopathy
What is the most common type of thyroid cancer?
Papillary carcinoma (80%).
What are the epidemiological risk factors for papillary thyroid cancer?
- Incidence of 12.5 per 100,000
- Female:male ratio of 2.5:1
- Most common in ages 30–50
What are the pathological features of papillary thyroid cancer?
- Not encapsulated
- May be partially cystic
- Papillae consist of tumour cells surrounding a fibro-vascular core
What percentage of patients with papillary thyroid cancer have metastatic disease at presentation?
2–10%.
What are the negative prognostic factors for medullary thyroid cancer?
- Soft tissue invasion
- Distant metastases
What characterizes anaplastic thyroid cancer?
Undifferentiated tumours with aggressive behavior and near 100% disease-specific mortality.
What is the mainstay of treatment for thyroid cancer?
Thyroidectomy.
What is the incidence of primary hyperparathyroidism?
3/1000 in the general population; 21/1000 in women aged 55–75.
What are the diagnostic criteria for primary hyperparathyroidism?
- High corrected calcium
- High PTH
- Increased 24-hour urinary calcium excretion
What is the most common presentation of primary hyperparathyroidism?
Mostly asymptomatic; often found incidentally.
What are the symptoms associated with primary hyperparathyroidism?
- Renal stones
- Psychiatric symptoms (MOANS)
- Bone pain
- Gastrointestinal issues (GIT GROANS)
- Generalized fatigue (OVERTONES)
What is the classic triad of symptoms for pheochromocytoma?
- Episodic headache
- Sweating
- Tachycardia
What is the mainstay treatment for pheochromocytoma?
Total adrenalectomy.
What is the Rule of 10s in pheochromocytoma?
- 10% bilateral
- 10% extra-adrenal
- 10% malignant
- 10% recur
- 10% normotensive
- 10% calcify
- 10% children
- 10% familial
What are the common imaging techniques used to investigate pheochromocytoma?
- CT
- MRI
- MIBG scan for metastatic disease
What is the primary purpose of alpha-adrenergic blockade before surgery?
To control hypertension and encourage volume expansion.
When should beta-adrenergic blockade be initiated before surgery?
2–3 days prior to surgery, once sufficient alpha-blockade is achieved.
What percentage of patients can undergo laparoscopic resection?
Approximately 90%.
How can malignant tumors be identified?
By their metastatic activity, commonly involving local organs.
What is a notable risk following resection of malignant tumors?
Distant metastases may occur up to 20 years following resection.
What are common clinical features of Cushing’s disease?
- Weight gain (buffalo hump; truncal obesity)
- Muscle wasting (lemon on a stick)
- Striae
- Facial plethora (moon facies)
- Thinning of the skin, easy bruising
- Mood changes: lethargy, depression, suicidal ideation, psychosis
- Menstrual irregularities
- Hirsutism in women, hair loss in men
- Glucose intolerance, diabetes
List the causes of Cushing’s disease.
- Iatrogenic
- Primary adrenal disease
- Secondary adrenal disease
- Ectopic ACTH secretion
What is the significance of high cortisol levels in Cushing’s disease?
Morning peak and midnight nadir pattern is lost; 24-hour urinary cortisol is elevated.
What does the overnight dexamethasone suppression test measure?
If morning cortisol will be low in normal patients after administration of 1 mg dexamethasone.
What distinguishes pituitary from ectopic sources of ACTH in high-dose dexamethasone suppression test?
Pituitary will still show some inhibition; ectopic will not.
What are the ACTH levels in different types of Cushing’s disease?
- High in patients with pituitary adenomas and ectopic production
- Low in primary adrenal disease.
What is the initial treatment for iatrogenic Cushing’s disease?
Taper and stop exogenous glucocorticoids.
What is the surgical treatment for adrenal adenoma?
Surgical excision, unilateral adrenalectomy.
What is the required post-operative management after adrenal gland resection?
Patients will require cortisol replacement.
What lifelong treatment is required after bilateral adrenalectomy for Conn’s syndrome?
Lifelong cortisol and mineralocorticoid replacement.
Define Conn’s syndrome.
Usually autonomous aldosterone secretion by adrenocortical tissue (zona glomerulosa).
What are common clinical features of Conn’s syndrome?
- Hypertension
- Hypokalemia (not always)
- Hypernatremia (not always)
- Metabolic alkalosis (not always)
- Fluid retention
- Reduced plasma renin activity (PRA)
List the complications associated with Conn’s syndrome.
- Hypertension
- Cardiac arrhythmias
- Cardiac fibrosis
- Increased cardiac mortality
What biochemical tests are used to investigate Conn’s syndrome?
- Failure of aldosterone suppression with sodium load or fludrocortisone suppression test
- Plasma aldosterone: Renin ratio.
What is the surgical treatment for classic Conn’s syndrome with a solitary adenoma?
Laparoscopic or retroperitoneoscopic adrenalectomy.
True or False: Aldosterone-secreting cancer is common in Conn’s syndrome.
False.
