Brain MRI Findings and Neuro-Psychiatric Involvement in Paroxysmal Nocturnal Hemoglobinuria (PNH)

PNH is a rare disorder characterized by hemolytic anemia, marrow failure and thrombosis, due to a deficiency in GPI-anchored proteins. Thrombotic events in PNH are commonly described in hepatic, portal, mesenteric, splenic, and renal veins, along with anecdotic case reports of cerebral venous sinus thrombosis and arterial ischemic strokes. This study was aimed at investigate brain involvement in 19 asymptomatic PNH patients by non-enhanced cerebral magnetic resonance imaging (MRI), and by intracranial arterial and venous angio-MRI. Neuroradiological findings were completed with a neuro-psychiatric evaluation, and correlated with clinical/hematologic features and therapy. Seventeen out of 19 patients were classical hemolytic (63% transfusion dependent before treatment with eculizumab and 1 patient also after), and 2 PNH in the context of aplastic anemia (all transfusion-dependent until treatment with ATG-CyA). Median age at diagnosis was 44 years (range 17-80); asthenia and dyspnea on exertion were present in all patients, abdominal pain in 8, and a thrombotic event in 4. Median Hb was 9.6 g/dL (range 6.7-12.9), LDH 3.7-fold (range 1.2-16.3) over upper limit of normal (ULN), and 73% of patients displayed a clone size greater than 50% GPI negative cells; 10/19 of patients were on eculizumab at the moment of the study. On MRI, 11 subjects showed pathological findings: 9 cases displayed white matter (WM) abnormalities related to chronic ischemic small vessel disease, of whom 6 periventricular WM vascular degeneration, and 8 deep WM focal chronic ischemic lesions (5 cases have both sites involved). Moreover, 1 subject showed a focal abnormality >5 mm and 5 subjects a score > 4 as evaluated in WM and basal ganglia by the age related white matter changes (ARWMC) scale. No subject displayed active or previous bleeding, nor were focal alterations of the basal nuclei by the ARWMC scale found. Two patients (80 and 81 yrs) showed atrophy of the cerebral hemispheres. Regarding vascular abnormalities, one subject had hypoplastic left transverse sinus with irregularities in the sinus wall, suspected for prior partial venous thrombosis. Three further cases displayed hypoplastic transverse sinus associated with collateral draining cortical veins, indistinguishable from anatomical variants. Intracranial artery stenosis or aneurysm, and Moya-Moya like alterations were not observed. Finally, cerebral MRI was unremarkable in 8/19 subjects. By comparing patients with or without any MRI abnormality (WM and vascular alterations), mean age was significantly higher in the former (60+17 vs 43+8 yrs, mean+SD, p<0.05), whereas blood counts, hemolytic markers and clone size showed no remarkable differences. Hemoglobin at diagnosis was slightly lower (9.5+1.5 vs 9.9+1.6 g/dL, mean+SD), and LDH greater (5.8+4.4 vs 4.1+2.9 over ULN, mean+SD) in subjects who displayed MRI abnormalities. Moreover, individual hemoglobin levels negatively correlated with the ARWMC score (r=-0.45, p<0.05). No relationship was found between history of abdominal pain/thrombosis and MRI pathological findings. Likewise, MRI abnormalities were not correlated with disease duration. As regards therapy with eculizumab, a pathological MRI was found in 6/10 subjects under treatment and in 5/9 without; the sole significant vascular alteration was detected in a patient under treatment. Neurological examination was unremarkable in all patients but one, who complained of progressive rest tremor in his left arm and leg (twelve years after PNH diagnosis), and was diagnosed with possible Parkinson disease. Previous history of neurological disorders was observed in 3 patients: one typical transient global amnesia (at the age of 60), one seizures (at 5 years), and one headache before the diagnosis of PNH. Regarding psychiatric evaluation, 3/18 patients had a psychiatric disorder according to structured clinical interview for axis I DSM-IV-TR disorders (1 generalized anxiety disorder, 1 bipolar disorder type 2, and 1 adjustment disorder as a consequence of PNH diagnosis). No relationship was observed between MRI findings and neuro-psychiatric assessment. In conclusion, brain MRI revealed chronic ischemic and vascular lesions in 58% of asymptomatic PNH patients. Brain MRI is advisable at diagnosis and during the course of the disease, and WM lesion burden may be useful in the decision to start therapy.