Internal Medicine Quiz
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Case Summary (Brief)
A 42-year-old man presents with 2 months history of generalized weakness, palpitations, weight loss, and a skin rash on both legs. Chest X-ray shows widening of the superior mediastinum with tracheal deviation to the right. Examination reveals raised pink-purplish plaques on the anterior aspect of both legs.
History
- Weight loss for 2 months
- Palpitations
- Generalized weakness
- Skin rash on both legs
Examination
- Raised pink-purplish plaques on anterior legs
- Possible signs of thyrotoxicosis (tachycardia, tremor)
Investigations
- Chest X-ray: widened superior mediastinum, tracheal deviation
- Thyroid function tests (TFTs)
- TSH receptor antibodies (TRAb)
- Thyroid ultrasound / uptake scan
MCQ 1
What is the MOST likely diagnosis?
Explanation: Clinical features + skin lesion (pretibial myxoedema) + mediastinal goitre suggest Graves’ disease.
Why not others: Hashimoto causes hypothyroidism, De Quervain is painful thyroiditis, toxic multinodular goitre lacks dermopathy.
No autoimmune dermopathy or TRAb positivity expected.
Painful thyroid, post-viral, no dermopathy.
MCQ 2
The skin lesion on both legs is BEST described as:
Tender nodules, not plaques.
Seen in diabetes, yellow atrophic plaques.
Classic Graves’ dermopathy due to glycosaminoglycan deposition.
Palpable purpura, not plaques.
MCQ 3
CXR widening of superior mediastinum is MOST likely due to:
No thyroid symptoms linked.
Usually systemic B symptoms + mass.
Associated with myasthenia gravis.
Extension of thyroid causing mediastinal widening + tracheal deviation.
MCQ 4
Most specific test for confirming diagnosis?
Confirms thyrotoxicosis, not cause.
Suppressed in all thyrotoxicosis.
Specific for Graves’ disease.
Shows structure, not autoimmune cause.
MCQ 5
Which of the following is NOT a recognised physical finding in this condition?
Seen in hyperthyroidism due to increased circulation.
Plummer’s nails commonly seen in Graves’ disease.
Classic Graves dermopathy feature.
AF is a complication, not a physical examination finding.
MCQ 6
Which drug is FIRST-LINE antithyroid therapy?
Used for hypothyroidism.
First-line antithyroid drug in Graves’ disease.
Definitive therapy, not first-line in acute management.
Used in thyroid eye disease, not routine first-line.
MCQ 7
Atrial fibrillation in hyperthyroidism is BEST managed initially by:
Not first-line unless unstable.
Controls rate + addresses cause.
May worsen thyroid dysfunction.
5 Brief Case Scenarios
- Young adult with weight loss, tremor, and goitre → Graves’ disease
- Post-viral painful thyroid enlargement → De Quervain thyroiditis
- Elderly patient with irregular pulse → Thyrotoxic atrial fibrillation
- Neck swelling + mediastinal widening → Retrosternal goitre
- Eye bulging + lid lag → Graves ophthalmopathy
Pathophysiology (Simplified)
Autoimmune activation of TSH receptor antibodies → continuous thyroid stimulation → excess T3/T4 → hypermetabolic state, increased adrenergic sensitivity, and glycosaminoglycan deposition in skin (pretibial myxoedema).
Physical Examination Pearls
- Fine tremor
- Warm moist skin
- Proptosis / lid lag
- Diffuse goitre with bruit
- Pretibial myxoedema
Investigation Findings
- Low TSH
- High Free T4 / T3
- Positive TRAb
- Increased uptake in thyroid scan
Complications
- Atrial fibrillation
- Thyroid storm
- Heart failure
- Osteoporosis
Clinical Pearls
- Graves disease = autoimmune hyperthyroidism
- Dermopathy strongly suggests Graves
- Beta-blockers relieve symptoms quickly
Clinical Pitfalls
- Misdiagnosing AF cause
- Ignoring thyroid eye disease
- Using amiodarone without caution
Management
- Start Carbimazole as first-line antithyroid therapy.
- Use a beta-blocker (e.g., propranolol) for symptom control.
- Consider radioactive iodine for definitive treatment in suitable patients.
- Thyroidectomy for large goitre, retrosternal extension, compressive symptoms, or suspected malignancy.
- Treat Graves' ophthalmopathy appropriately.
- Manage atrial fibrillation according to current guidelines.
- Educate regarding medication adherence and adverse effects.
Differential Diagnosis
- Toxic multinodular goitre
- Toxic thyroid adenoma
- Hashimoto thyroiditis (thyrotoxic phase)
- Subacute (De Quervain) thyroiditis
- Factitious thyrotoxicosis
- TSH-secreting pituitary adenoma
Clinical Pearls
- Pretibial myxoedema is highly suggestive of Graves' disease.
- Diffuse goitre with bruit strongly supports Graves' disease.
- TRAb is the most specific diagnostic test.
- Always assess for thyroid eye disease.
- Beta-blockers improve symptoms rapidly but do not treat the underlying disease.
Clinical Pitfalls
- Missing retrosternal goitre on chest X-ray.
- Confusing pretibial myxoedema with erythema nodosum.
- Using amiodarone without considering thyroid status.
- Failing to monitor blood counts during carbimazole therapy.
- Ignoring persistent atrial fibrillation after euthyroidism.
Monitoring & Follow-up
- Repeat TFT every 4–6 weeks initially.
- Monitor TSH, Free T4 and Free T3.
- Review pulse rate and blood pressure.
- Monitor for carbimazole adverse effects.
- Advise immediate review if sore throat or fever develops.
- Assess eye symptoms at follow-up.
- Long-term follow-up for relapse after treatment.
Prognosis
Most patients respond well to antithyroid medication. Relapse may occur after stopping treatment. Radioiodine or surgery provides definitive treatment in selected patients. Early diagnosis reduces the risk of atrial fibrillation, heart failure and thyroid storm.
Frequently Asked Questions (FAQ)
1. What is Graves' disease?
An autoimmune disorder causing hyperthyroidism.
2. What causes Graves' disease?
TSH receptor antibodies stimulate excessive thyroid hormone production.
3. What is pretibial myxoedema?
Localized skin thickening caused by glycosaminoglycan deposition.
4. Why is TSH low?
Negative feedback from elevated thyroid hormones suppresses pituitary TSH.
5. Which investigation confirms Graves' disease?
Positive TSH receptor antibodies (TRAb).
6. Why does atrial fibrillation occur?
Excess thyroid hormone increases sympathetic activity.
7. What is the first-line medicine?
Carbimazole.
8. Why are beta-blockers used?
They rapidly control adrenergic symptoms.
9. When is surgery indicated?
Large goitre, retrosternal extension, compression or suspected malignancy.
10. What is thyroid storm?
A life-threatening complication of severe thyrotoxicosis.
11. Can Graves' disease recur?
Yes. Relapse may occur after stopping antithyroid medication.
12. What eye disease is associated?
Graves' orbitopathy.
13. What ECG abnormality is common?
Atrial fibrillation.
14. Which chest X-ray finding suggests retrosternal goitre?
Mediastinal widening with tracheal deviation.
15. What follow-up is required?
Regular thyroid function tests and clinical review.
References
- Harrison's Principles of Internal Medicine, 22nd Edition.
- Davidson's Principles and Practice of Medicine, 25th Edition.
- Oxford Handbook of Clinical Medicine.
- American Thyroid Association Guidelines.
- European Thyroid Association Guidelines.
Keywords
Graves disease, Hyperthyroidism, Pretibial myxoedema, TRAb, Carbimazole, Retrosternal goitre, Atrial fibrillation, Diffuse goitre, Thyrotoxicosis, Thyroid eye disease, Thyroid function test, Beta blocker, Autoimmune thyroid disease, Thyroid storm, Internal Medicine Quiz