New onset atrial fibrillation, prominent chest wall veins, and dyspnoeaBMJ 2018; 363 doi: https://doi.org/10.1136/bmj.k3779 (Published 11 October 2018) Cite this as: BMJ 2018;363:k3779
- Correspondence to
A 74 year old man presented with palpitations concurrent with new onset atrial fibrillation. He also complained of increasingly visible markings on his chest and occasional breathlessness on waking.
His comorbidities included chronic obstructive pulmonary disease and hypertension with left ventricular hypertrophy.
On examination, he had prominent vessels over his chest wall but nothing else of note. He underwent chest radiography (fig 1)
What is the most likely diagnosis?
A large retrosternal goitre causing venous and tracheal compression, with atrial fibrillation secondary to hyperthyroidism.
Retrosternal goitres are anterior mediastinal masses (anterior to the pericardium and great vessels), and can usually be distinguished on plain film from posterior mediastinal masses (posterior to the trachea and pericardium) by the presence of the hilum overlay sign and preservation of paraspinal lines.1
The hilum overlay sign is visible when normal hilar structures project through a mass, and indicate that the mass is not in the middle mediastinum (consisting of the heart and major vessels).1 Paraspinal lines mark the interface between the lung and pleural reflections over the vertebral bodies and are obliterated by the presence of paravertebral masses, thus if they are visible the mass is anterior.1 In this case, the thyroid gland had extended retrosternally into the anterior mediastinum (fig 2); however the hilum overlay sign is not present as the mass does not extend inferiorly enough to reach the hilum. The paraspinal lines are also not visible; however, this is not unusual as the left paraspinal line, which is more commonly seen, is only reported in about 41% of chest radiographs.2
Retrosternal enlargement of the thyroid can cause compression of adjacent mediastinal structures including
-The trachea, causing unproductive cough and dyspnoea
-The oesophagus, causing dysphagia.
-The superior vena cava, causing superior vena cava syndrome and venous thrombosis.3
More rarely, retrosternal goitre enlargement can compress the following structures:
- The recurrent laryngeal nerve, causing vocal cord palsy and hoarseness
- The cervical sympathetic nerve, causing Horner’s syndrome
- The arterial system, causing cerebrohypoperfusion and stroke.3
The formation of collateral veins over the chest wall may occur if there is occlusion of the right brachiocephalic vein.
If there is thyroid dysfunction, the patient may present with clinical signs suggestive of hyperthyroidism or hypothyroidism. The most common cause of thyroid disorder worldwide is iodine deficiency, which causes goitre and hypothyroidism; however, this is rare in the developed world.4 The most common cause of hyperthyroidism and goitre is toxic multinodular goitre.4
Atrial fibrillation is a recognised manifestation of the hyperthyroid state.5
A goitre is an anterior mediastinal mass, and can usually be distinguished from other mediastinal masses on plain radiography by the preservation of the hilum overlay sign and paraspinal lines.
A goitre can present with symptoms of either obstruction or thyroid dysfunction, or asymptomatically as a palpable goitre or an incidental finding on imaging.
The patient was found to be biochemically hyperthyroid. Computed tomography showed occlusion of the right brachiocephalic vein, which may explain the formation of collateral veins over the chest wall.
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Patient consent obtained.
Provenance and peer review: not commissioned, externally peer reviewed.