Brian GWeinshenker, Mayo Clinic, 200 First St SW Rochester MN 55905[email protected]
Setty M. Magana, Marcelo Matiello, Alejandro A. Rabinstein
Submitted May 21, 2009
We appreciate Dr. Ito’s interest in our article describing five patients with acute reversible encephalopathy in the setting of neuromyelitis optica spectrum disorders. We understand his concern about the indiscriminate use of the term posterior reversible encephalopathy (PRES) particularly for patients 4 and 5. We also felt that patient 4, who had persistent T2 signal abnormality, and patient 5, who had evidence of destructive changes, were different than patients 1,2 and 3. These patients had symmetrical, rapidly improving MRI lesions characteristic of vasogenic edema and “pure PRES.”
We comment on the distinction between these two groups of patients in the last paragraph of our Discussion. Nonetheless, the dramatic improvement in the encephalopathy in patient 4 within 1 week and in patient 5 within an undefined period suggests a reversible component of cerebral edema. However, we had much less convincing MRI data in those patients to support a major role of vasogenic edema.
As we discussed, the contrast between these cases may highlight the duality of the pathogenesis of acute, encephalopathy-producing brain lesions in neuromyelitis optica. Pure vasogenic edema due to blockade of aquaporin-4 water channels may cause rapidly reversible, symmetrical, cerebral edema (cases 1-3), whereas a combination of aquaporin-4 blockade and complement-mediated aquaporin-4-directed cellular necrosis may cause both reversible edema and (MRI-evident) irreversible encephalopathy (cases 4 and 5).
While the limits of PRES are not precisely defined, its apparent association with NMO may yield a clue to the underlying pathobiology of PRES.
Disclosures: Dr. Matiello was supported by a postdoctoral fellowship from the National Multiple Sclerosis Society.
Ms. Magana is a NIH-CTSA funded Mayo Graduate Student and is funded by Grant Number 1 TL1 RR024152-0.
Dr. Weinshenker has received personal compensation or consulting fees from Novartis, Viral Logic and Caridian BCT, has received honoraria from Innovia CME, has received research support from Genzyme, the National MS Society and Guthy Jackson Charitable Foundation, has received royalty payments from a patent related to NMO antibody that has been licensed to RSRLtd.
We appreciate Dr. Ito’s interest in our article describing five patients with acute reversible encephalopathy in the setting of neuromyelitis optica spectrum disorders. We understand his concern about the indiscriminate use of the term posterior reversible encephalopathy (PRES) particularly for patients 4 and 5. We also felt that patient 4, who had persistent T2 signal abnormality, and patient 5, who had evidence of destructive changes, were different than patients 1,2 and 3. These patients had symmetrical, rapidly improving MRI lesions characteristic of vasogenic edema and “pure PRES.”
We comment on the distinction between these two groups of patients in the last paragraph of our Discussion. Nonetheless, the dramatic improvement in the encephalopathy in patient 4 within 1 week and in patient 5 within an undefined period suggests a reversible component of cerebral edema. However, we had much less convincing MRI data in those patients to support a major role of vasogenic edema. As we discussed, the contrast between these cases may highlight the duality of the pathogenesis of acute, encephalopathy-producing brain lesions in neuromyelitis optica. Pure vasogenic edema due to blockade of aquaporin-4 water channels may cause rapidly reversible, symmetrical, cerebral edema (cases 1-3), whereas a combination of aquaporin-4 blockade and complement-mediated aquaporin-4-directed cellular necrosis may cause both reversible edema and (MRI-evident) irreversible encephalopathy (cases 4 and 5).
While the limits of PRES are not precisely defined, its apparent association with NMO may yield a clue to the underlying pathobiology of PRES.
Disclosures: Dr. Matiello was supported by a postdoctoral fellowship from the National Multiple Sclerosis Society.
Ms. Magana is a NIH-CTSA funded Mayo Graduate Student and is funded by Grant Number 1 TL1 RR024152-0.
Dr. Weinshenker has received personal compensation or consulting fees from Novartis, Viral Logic and Caridian BCT, has received honoraria from Innovia CME, has received research support from Genzyme, the National MS Society and Guthy Jackson Charitable Foundation, has received royalty payments from a patent related to NMO antibody that has been licensed to RSRLtd.
Dr. Rabinstein reports no disclosures.