Teaching Case

A 22-year-old male patient came to the emergency with complaints of palpitations, quadriplegia and aphasia for the last 1 year. Vitally he was stable with modified Rankin Scale of 4. On examination, power was 1/5 in all four limbs, no verbal response, bilateral pupils showed sluggish response to light, pendular nystagmus was seen on both sides. Abdominal examination and blood profile was unremarkable.

Patient underwent a chest radiograph as a part of routine workup, which was notable for an abnormal well defined bulging left cardiac border. Lung fields were otherwise normal (Fig 1). A transthoracic echocardiogram was subsequently performed which showed a large cystic lesion around the heart with spontaneous echo contrast inside it (not shown) and was reported as a pericardial cyst.

MRI was performed next for the evaluation of neurological symptoms which showed encephalomalacic changes in the right temporal and frontal lobes (Fig 2a ,b) along with complete occlusion of the Right Internal Carotid Artery seen on MRA and MIP images.  (Fig 2e, f) Further, there was central pontine encephalomalacia and hemosiderosis as well. (Fig 2c, d) Rest of the brain showed normal grey and white matter differentiation.

On CT chest, a well-circumscribed hyper-enhancing outpouching was identified in the left hemithorax, measuring approximately 8 x 8 cm, showing its communication with the left atrial appendage. (Fig 3 and 4) The classic appearance of compression of the lateral wall of the left ventricle was also appreciated. These findings were suggestive of left atrial appendage aneurysm.

Patient was discharged on conservative treatment.

Left atrial appendage aneurysm (LAAA) is regarded as localized or diffuse dilatation of the left atrial appendage. The mean age of presentation is 23.5 years however, it may vary widely from 1 month to 66 years. (1) It is a very rare entity with less than a hundred cases reported in literature. (2) It may be congenital or acquired. Similar to our case, if seen as a primary pathology with an otherwise normal atrial chamber, it is considered congenital. However, should be considered acquired if it has developed secondary to raised left atrial pressure. (3) This condition is caused by dysplasia of the atrial muscle bands and can also occur as sequelae of mitral valve disease or left ventricular myocardial disease (4) which can be due to increased pressure in the left atrium or weakening of the atrial wall (5).

Suspicion of left atrial aneurysm should be raised on a chest X-ray showing prominent left cardiac border. A very useful non-invasive diagnostic modality is a 2-D echocardiography imaging with colour and pulsed-wave Doppler which typically shows the cyst-like structure, as depicted in our case, connected to the left atrium. (3)

Where majority of the patients remain asymptomatic, there is a propensity for embolic events and supraventricular arrhythmias likely secondary to the stasis of blood within the aneurysm. (5) Chest pain is another presentation, due to tension over the pericardium or by temporary compression on the coronary arteries. Due to aneurysmal compression, there may be reduced left ventricular compliance leading to raised ventricular filling pressures and diastolic dysfunction, as seen in our case, which might result in dyspnoea and heart failure. (1) Neonates and infants are more prone to congestive heart failure and respiratory distress with large aneurysms because the condition may be associated with physical compression of the pulmonary veins and airway obstruction, respectively. (6) These potentially lethal complications necessitate quick diagnosis and treatment.

Mild symptoms may be treated with conservative management while in cases of compressive symptoms surgical intervention is needed to be performed. (6) Most of the authors have proposed surgical resection as the standard treatment regardless of the presence or absence of symptoms in order to prevent the occurrence of atrial fibrillation, thromboembolic events or myocardial dysfunction. (3)

This case report demonstrates that a large LAAA has probably led to the propensity of thromboembolic events that resulted in stroke. There were no signs of heart failure.