Antiphospholipid syndrome and reversible posterior leukoencephalopathy syndrome.

We commend Arnson and coworkers for their review, which opportunely highlights the relevance of antiphospholipid syndrome (APS) as a neurological disease (1). We read with interest all the central nervous system manifestations associated with antiphospholipid antibodies described in the article, such as stroke, headache, migraine, epilepsy, movement and psychiatric disorders, ocular syndromes, cognitive dysfunction, dementia, and neurologic symptoms possibly associated with or possibly mimicked by APS. As described by the authors, acute encephalopathy is a rare clinical diagnosis in APS, but we want to underscore the importance of this condition because of its potential reversibility in some cases. In particular, the occurrence of reversible posterior leukoencephalopathy syndrome (RPLS) in APS has been recently reported in 1 patient with a history of systemic lupus erythematosus and secondary APS who developed bilateral blindness with brain computed tomography findings of white matter hypodensity mostly in the posterior cerebral region (2). RPLS is a condition first described by Hinchey and coworkers as neurological abnormalities resulting from an acute encephalopathy caused by white matter edema predominantly in the posterior cerebral region (3). Typical clinical features are headache, decreased alertness, altered mental functioning, seizures, and visual loss. Associated causes are connective tissue diseases, thrombotic thrombocytopenic purpura, human immunodeficiency virus infection, porphyria, and organ transplantation, while precipitating factors are hypertensive encephalopathy, preeclampsia, eclampsia, cytotoxic chemotherapies, and immunosuppressive agents (4). We recently observed a case of RPLS due to severe hypertension and renal failure in a patient with primary APS. This 33-year-old man with deep venous thrombosis of the right lower limb and seizures was hospitalized in the Department of Internal Medicine where laboratory examination showed a reduced platelet count, prolonged activated partial thromboplastin time, and persistently high titers of anticardiolipin IgG and IgM antibodies. The diagnosis of primary APS was made and he was treated with acenocumarol with a good clinical outcome. At the age of 45 years, he was again hospitalized because of edema of the legs and laboratory examination showed anemia, reduced platelet counts, signs of acute renal failure, and an autoimmune panel compatible with seroconversion to systemic lupus erythematosus. Eleven days after admission, he developed malignant hypertension (220/130 mm Hg) associated with seizures and bilateral amaurosis. An electroencephalogram recorded in the interictal period showed generalized slowing of activity with bilateral temporal theta waves and the cerebral computed tomography scan demonstrated posterior white matter hypodensity. A posterior leukoencephalopathy was suspected and therefore the patient underwent aggressive antihypertensive treatment with intravenous labetalol with dramatic improvement of both clinical and neuroradiological signs. As soon as he overcame the acute phase, he was then treated with immunosuppressive drugs with clinical and laboratory improvement. Early recognition and treatment of RPLS is essential because of its potential reversibility with appropriate management. The distinction between other neurological disorders reported by Arnson and coworkers, such as stroke or transient ischemic attack, is crucial to properly manage patients, since an aggressive reduction of the blood pressure minimizes the vasogenic edema in RPLS, while maintaining a relatively high mean arterial pressure allows for cerebral perfusion in acute stroke (5). In our case, multisystem involvement associated with visual loss and seizures also required the exclusion of central nervous system vasculitis, a condition that can be seen in patients with underlying autoimmune diseases. The differential diagnosis between these entities is important, since vasculitis requires immunosuppressive therapy, which should be avoided in the management of RPLS (6). In conclusion, we agree with Arnson and coworkers that neurological symptoms are significant manifestations of APS. We suggest that the possibility of RPLS in APS patients with neurological signs compatible with acute encephalopathy should be considered because of its potential reversibility with appropriate management even in those cases with severe manifestations on presentation.