Abstract

A 73 year old man with a past medical history of hypertension, osteoathritis and asthma presented to the local district general hospital with recurrent episodes of spontaneously resolving encephalopathy.

The initial presentation was characterised by acute confusion and visual hallucinations followed by a generalised tonic–clonic seizure. On examination his blood pressure was 215/115 mmHg. Neurological examination did not reveal any lateralising signs but the patient was found to be encephalopathic with a Montreal Cognitive Assessment (MOCA) score of 9/30.

Routine blood tests were unremarkable. A CT brain scan showed features suggestive of acute infarct in the right temporal lobe. The working diagnosis of the attending physicians was acute stroke with secondary seizure. Treatment with aspirin and sodium valproate was commenced. The patient improved substantially during the 4 days of admission. His blood pressure stabilised to around 150/80 mmHg and a MOCA score on the day of discharge was 22/30.

One month after initial presentation, the patient was admitted again with a recurrence of encephalopathy. The blood pressure was again raised at 210/100 mmHg, Examination showed right sided weakness in combination with a predominantly receptive aphasia. Routine bloods were again normal. A further CT brain scan showed oedema in the right temporal lobe. An MRI brain scan showed significant white matter hyperintensity changes consistent with oedema in both temporal lobes with sparing of the medial portions bilaterally and a small established watershed infarction in the left parieto–occipital region. Multiple petechial haemorrhages were noted within the temporal lobe lesions best demonstrated on T2* sequences. No abnormal enhancement was seen after administration of Gadolinium. A lumbar puncture showed CSF with normal constituents and no oligoclonal bands.

Within 5 days the patient's symptoms spontaneously improved and he returned to his baseline cognitive function. Delayed repeat MRI scan showed radiological resolution of the temporal lobe white matter lesions with persistence of the haemorrhagic areas.

The unifying diagnosis was thought to be reversible Cerebral Amyloid Angiopathy (CAA) leukoencephalopathy syndrome. This is a rare condition which has been described in a limited number of case reports in which accompanying histology from brain biopsy has also been available. This is characterised by features of CAA with or without associated inflammation.¹ This case, given the spontaneous resolution without immunosuppression, is likely to represent the non–inflammatory form of the syndrome. It is hypothesised that in this form, CAA causes altered vascular autoregulation and impaired blood–brain barrier integrity in the face of precipitating factors such as hypertension.² This pathological process is similar to that proposed for the Posterior Reversible Encephalopathy Syndrome (PRES) and it is likely that in this patient the CAA predisposed the patient to developing a PRES like syndrome.