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DESCRIPTIONPosterior reversible encephalopathy (PRES) is a clinicalradiological syndrome characterised by brain symmetric lesions of vasogenic oedema, in white matter, basal ganglia or cerebral cortex, preferentially in posterior topography. 1 Typical manifestations are headache and altered mental status. Epileptic seizures are also frequent, although status epilepticus (SE) is a rare occurrence. 2 Chemotherapy may trigger PRES. Nevertheless, no single chemotherapy agent was consistently implicated. 2 Two cases are presented: a young man (patient 1) with a Hodgkin lymphoma, under ABVD chemotherapy (adriamicin, vinblastine, bleomicine, dacarbazin), and an adult woman (patient 2), under docetaxel and gemcitabine treatment due to a femoral sarcoma. Both patients were admitted with a non-convulsive SE. Brain resonance MRI depicted bilateral, predominantly parietal-occipital lesions, hyperintense on T2/ fl uid attenuated inversion recovery and with no water restriction on diffusion-weighted MRI/apparent diffusion coeffi cient maps, consistent with vasogenic oedema ( fi gure 1 ); patient 2 also presented intracranial vasospasm on magnetic resonance angiography. Both patients were successfully treated for the SE with antiepileptic drugs plus blood pressure control and nimodipine. The fi rst patient repeated ABVD afterwards without recurrence of PRES. In the second patient, no further chemotherapy regimens were performed due to neoplasm refractoriness. Furthermore, both patients showed complete resolution of cytotoxic oedema on repeated MRI.The association between PRES and platinum, taxanes, vinca alkaloids, biological agents and combination chemotherapy, is increasingly recognised. The exact mechanism of toxicity remains unknown. Vasospasm and loss of cerebrovascular auto-regulation, with the development of vasogenic oedema is a hypothesis. If PRES is left untreated, cytotoxic oedema and permanent neurological defi cit may occur, 2 hence the need for an early recognition is required.

Psychogenic non epileptic seizures (PNES) are clinical events of psychological nature. Videoelectroencephalography monitoring (V-EEGM) is a valuable method for the diagnosis of PNES and may be combined with provocative tests to induce seizures. The use of placebo in provocative tests for the diagnosis of PNES is controversial because of associated deception, and contrasts with the use of truly decreasing epileptogenic threshold techniques such as hyperventilation and photo stimulation. We present a clinical case of a pregnant woman with a past history of refractory epilepsy, admitted in the obstetric department due to unremitting seizures. In this clinical context, non-deceiving provocative tests such as hyperventilation and photo stimulation could be potentially harmful, nevertheless, the use of intravenous saline injection presented as a safer alternative to diagnose PNES and hence obviate an urgent caesarean. This case illustrates a disproportionate risk of causing harm when telling the truth, in comparison with the benefit of avoiding such risk, although deceiving the patient. This is a clinical example of how considerations concerning the use of placebo must be evaluated in an individual basis.