Multifocal motor neuropathy as a mimic of amyotrophic lateral sclerosis: Serum neurofilament light chain as a reliable diagnostic biomarker.

INTRODUCTION/AIMS: The clinical presentation of multifocal motor neuropathy (MMN) may mimic early amyotrophic lateral sclerosis (ALS) with predominant lower motor neuron (LMN) involvement, posing a diagnostic challenge. Both diseases have specific treatments and prognoses, highlighting the importance of early diagnosis. The aim of this study was to assess the diagnostic value of serum neurofilament light chain (NfL) in differentiating MMN from LMN dominant ALS. METHODS: NfL was measured in serum in n = 37 patients with MMN and n = 37 age- and sex-matched patients with LMN dominant ALS, to determine the diagnostic accuracy. Clinical and demographic data were obtained at the time of NfL sampling. RESULTS: Serum NfL concentration was significantly lower in MMN patients compared to ALS patients (mean 20.7 pg/mL vs. 59.4 pg/mL, p < .01). NfL demonstrated good diagnostic value in discriminating the two groups (AUC 0.985 [95% CI 0.963-1.000], sensitivity 94.6%, specificity 100%, cut-off 44.00 pg/mL). DISCUSSION: NfL could be a helpful tool in differentiating MMN from LMN dominant ALS in those patients in whom electrophysiological and clinical examinations remain inconclusive early in the diagnostic process.

Lyme neuroborreliosis: Progressive cerebral vasculitis responsive to cyclophosphamide. A case report and review of the literature.

OBJECTIVES: Less than 1 % of patients with Lyme Neuroborreliosis (LNB) present with a cerebrovascular event. Ischaemic strokes occur more commonly than parenchymal or subarachnoid haemorrhages. If cerebral vasculitis due to LNB is suspected, antibiotic treatment should be started immediately, which will normally lead to remission. Very rarely progression and recurrent strokes are observed despite sufficient antibiotic therapy, even if steroids are added. Currently there are no guidelines on the adequate treatment of cerebral vasculitis due to LNB which is not responsive to antibiotics and steroids, but in very few reported cases cyclophosphamide led to disease stabilisation. We reviewed the literature regarding cyclophosphamide treatment in these patients and want to share our experience of cyclophosphamide therapy in progressive cerebral vasculitis due to LNB. RESULTS: We report a 71-year-old female patient with cerebral vasculitis and multiple strokes as a complication of LNB. Progression could only be halted by additional immunosuppressive treatment using cyclophosphamide. However, at that point the patient had already suffered severe ischaemic brain damage. Similarly, in existing case reports cyclophosphamide had been administered only at a time when patients already showed serious neurological deficits. CONCLUSION: Cerebral vasculitis in patients with LNB is very rare and normally responds to antibiotic treatment. A minority of patients show disease progression despite antibiotics and steroids. Our case report strengthens the recommendation that in those patients - even if signs of progressive vasculitis are only detectable on imaging and not clinically - cyclophosphamide should be considered without delay to prevent further cerebrovascular events.

Month-of-birth-effect in multiple sclerosis in Austria.

BACKGROUND: The month-of-birth-effect (MoBE) describes the finding that multiple sclerosis (MS) patients seem to have been born significantly more frequently in spring, with a rise in May, and significantly less often in autumn and winter with the fewest births in November. OBJECTIVES: To analyse if the MoBE can also be found in the Austrian MS population, and if so, whether the pattern is similar to the reported pattern in Canada, United Kingdom, and some Scandinavian countries. METHODS: The data of 7886 MS patients in Austria were compared to all live births in Austria from 1940 to 2010, that is, 7.256545 data entries of the Austrian birth registry and analysed in detail. RESULTS: Patterns observed in our MS cohort were not different from patterns in the general population, even when stratifying for gender. However, the noticeable and partly significant ups and downs over the examined years did not follow the distinct specific pattern with highest birth rates in spring and lowest birth rates in autumn that has been described previously for countries above the 49th latitude. CONCLUSION: After correcting for month-of-birth patterns in the general Austrian population, there is no evidence for the previously described MoBE in Austrian MS patients.

Differences in T cell cytotoxicity and cell death mechanisms between progressive multifocal leukoencephalopathy, herpes simplex virus encephalitis and cytomegalovirus encephalitis.

During the appearance of human immunodeficiency virus infection in the 1980 and the 1990s, progressive multifocal leukoencephalopathy (PML), a viral encephalitis induced by the JC virus, was the leading opportunistic brain infection. As a result of the use of modern immunomodulatory compounds such as Natalizumab and Rituximab, the number of patients with PML is once again increasing. Despite the presence of PML over decades, little is known regarding the mechanisms leading to death of infected cells and the role the immune system plays in this process. Here we compared the presence of inflammatory T cells and the targeting of infected cells by cytotoxic T cells in PML, herpes simplex virus encephalitis (HSVE) and cytomegalovirus encephalitis (CMVE). In addition, we analyzed cell death mechanisms in infected cells in these encephalitides. Our results show that large numbers of inflammatory cytotoxic T cells are present in PML lesions. Whereas in HSVE and CMVE, single or multiple appositions of CD8+ or granzyme-B+ T cells to infected cells are found, in PML such appositions are significantly less apparent. Analysis of apoptotic pathways by markers such as activated caspase-3, caspase-6, poly(ADP-ribose) polymerase-1 (PARP-1) and apoptosis-inducing factor (AIF) showed upregulation of caspase-3 and loss of caspase-6 from mitochondria in CMVE and HSVE infected cells. Infected oligodendrocytes in PML did not upregulate activated caspase-3 but instead showed translocation of PARP-1 from nucleus to cytoplasm and AIF from mitochondria to nucleus. These findings suggest that in HSVE and CMVE, cells die by caspase-mediated apoptosis induced by cytotoxic T cells. In PML, on the other hand, infected cells are not eliminated by the immune system but seem to die by virus-induced PARP and AIF translocation in a type of cell death defined as parthanatos.

Susac's syndrome: clinical course and epidemiology in a Central European population.

OBJECTIVE: Susac's syndrome is characterized by inflammation and occlusion of pre-capillary arterioles with the clinical triad of branch retinal artery occlusion (BRAO), encephalopathy and hearing loss. No epidemiological data are available for the disease. METHODS: All neurology departments in Austria were addressed to report adult patients who were on immunosuppressive treatment for a diagnosis of Susac's syndrome between 1 August 2010 and 1 August 2015. Clinical course, treatment regimens, period and point prevalence rates, and annual incidence of Susac's syndrome in Austria in people over 19 years of age are reported. RESULTS: Ten patients with Susac's syndrome were identified, and eight of them were newly diagnosed within the five-year timeframe. Minimum five-year period prevalence of the disease is 0.148/100,000 (95% confidence interval (CI) 0.071-0.272), annual incidence is 0.024/100,000 (95% CI 0.010-0.047). Minimum point prevalence rates varied from 0.030/100,000 (95% CI 0.004-0.108) to 0.088/100,000 (95% CI 0.032-0.192). Of all 10 patients, 8 showed typical callosal or internal capsule magnetic resonance imaging lesions at first presentation, 7 presented with BRAO and 5 had hearing loss or tinnitus at the beginning of the disease. Four patients developed the complete clinical triad of Susac's syndrome during the observation period. CONCLUSIONS: We provide for the first time population-based data about the clinical course, prevalence and incidence of Susac's syndrome.

Ultrasound-Guided Blockade of the Lateral Cutaneous Branch of the Iliohypogastric Nerve to Differentiate Neuropathy From Greater Trochanteric Pain Syndrome: Cadaver Study and Initial Case Series.

OBJECTIVE: Neuropathy of the lateral cutaneous branch of the iliohypogastric nerve (LCBIN) may represent a differential diagnosis for greater trochanteric pain syndrome (GTPS). Ultrasound-guided neural blockade of the LCBIN may lead to diagnosis of this neuropathy. The aim of this study was to evaluate the accuracy of ultrasound-guided nerve block in cadavers and to present a first clinical case series of patients with neuropathy of the LCBIN where the workup for GTPS remained unremarkable. Ultrasound-guided nerve block led to pain relief in these patients, indicating LCBIN neuropathy. METHODS: First, ultrasound-guided injections at the LCBIN were performed bilaterally in 24 fresh, non-frozen, non-embalmed body donors. Accuracy and nerve localization were validated by anatomic dissection. Second, a clinical case series of nine patients with suspected GTPS who underwent ultrasound-guided diagnostic LCBIN blockade was retrospectively analyzed. RESULTS: Ultrasound-guided injections at the LCBIN yielded 91.7% accuracy (95% confidence interval: 0.80-0.98). On the right side the nerve was found within a range of 3-14 cm from the anterior superior iliac spine, and within a range of 7-15 cm on the left side. This clinical case series indicates that ultrasound-guided blockade at the LCBIN provides temporary pain relief and indicates the presence of LCBIN neuropathy. CONCLUSION: Ultrasound has demonstrated high accuracy for localization and injection guidance in the examination of LCBIN. Ultrasound-guided injection of local anesthetics may help to identify LCBIN neuropathy as a differential diagnosis in patients with suspected GTPS.

Multiple sclerosis in the elderly: a retrospective cohort study.

BACKGROUND: There is a lack of knowledge of disease course, prognosis, comorbidities and potential treatments of elderly MS patients. OBJECTIVE: To characterize the disease course including disability progression and relapses, to quantify the use of DMTs and to identify comorbidities and risk factors for progression in elderly multiple sclerosis (MS) patients. METHODS: This is a retrospective study of 1200 Austrian MS patients older than 55 years as of May 1st, 2017 representing roughly one-third of all the MS patients of this age in Austria. Data were collected from 15 MS centers including demographics, first symptom at onset, number of relapses, evolvement of disability, medication, and comorbidities. RESULTS: Median observation time was 17.1 years with 957 (80%) relapsing and 243 (20%) progressive onsets. Average age at diagnosis was 45 years with a female predominance of 71%. Three-hundred and twenty-six (27%) patients were never treated with a DMT, while most treated patients received interferons (496; 41%) at some point. At last follow-up, 420 (35%) patients were still treated with a DMT. No difference was found between treated and never-treated patients in terms of clinical outcome; however, patients with worse disability progression had significantly more DMT switches. Pyramidal onset, number of comorbidities, dementia, epilepsy, and psychiatric conditions as well as a higher number of relapses were associated with worse outcome. The risk of reaching EDSS 6 rose with every additional comorbidity by 22%. In late and very-late-onset MS (LOMS, VLOMS) time to diagnosis took nearly twice the time compared to adult and early onset (AEOMS). The overall annualized relapse rate (ARR) decreased over time and patients with AEOMS had significantly higher ARR compared to LOMS and VLOMS. Four percent of MS patients had five medications or more fulfilling criteria of polypharmacy and 20% of psychiatric drugs were administered without a matching diagnosis. CONCLUSIONS: In this study, we identified number of comorbidities, pyramidal and cerebellar signs, and a higher number of relapses as unfavorable prognostic factors in elderly MS patients filling gaps of knowledge in patients usually underrepresented in clinical trials and may guide future therapeutic studies.

Rituximab versus mitoxantrone: comparing effectiveness and safety in advanced relapsing multiple sclerosis.

BACKGROUND: Rituximab (RTX), a CD20 depleting agent, is a frequently used off-label treatment for multiple sclerosis (MS), while mitoxantrone (MTX) is approved, albeit rarely used for active relapsing MS (RMS). However, observational data comparing RTX and MTX effectiveness and safety are scarce. OBJECTIVE: We aimed to compare effectiveness and safety of MTX and RTX in patients with active RMS. METHODS: From combined retrospective clinical data of three MS centers, we selected patients who had received at least one infusion of RTX or MTX and had at least a 6-month clinical follow-up available. Treatment groups were compared by propensity score (PS)-adjusted regression and inverse PS-weighted generalized estimated equation models regarding disability progression, relapse activity, and adverse events (AEs). RESULTS: We included 292 RMS patients (mean age 41.8 years, 71.6% female) who received RTX (119 patients, mean age 36.8 years, 74.8% female) or MTX (173 patients mean age 45.3 years, 69.4% female). Using both PS methods, we did not find a significant effect favoring RTX or MTX treatment regarding the probability of disability worsening or relapse occurrence. However, RTX treatment was associated with a significantly lower probability of severe AEs and AEs. CONCLUSIONS: RTX shows comparable effectiveness but a favorable safety profile compared with MTX in active RMS.

Functional Recovery in Autoimmune Encephalitis: A Prospective Observational Study.

Background: Prospective observations of functional recovery are lacking in patients with autoimmune encephalitis defined by antibodies against synaptic proteins and neuronal cell surface receptors. Methods: Adult patients with a diagnosis of autoimmune encephalitis were included into a prospective registry. At 3, 6 and 12 months of follow-up, the patients' modified Rankin Scale (mRS) was obtained. Results: Patients were stratified into three groups according to their antibody (Ab) status: anti-NMDAR-Ab (n=12; group I), anti-LGI1/CASPR2-Ab (n=35; group II), and other antibodies (n=24; group III). A comparably higher proportion of patients in group I received plasma exchange/immunoadsorption and second line immunosuppressive treatments at baseline. A higher proportion of patients in group II presented with seizures. Group III mainly included patients with anti-GABABR-, anti-GAD65- and anti-GlyR-Ab. At baseline, one third of them had cancer. Patients in groups I and III had much higher median mRS scores at 3 months compared to patients in group II. A median mRS of 1 was found at all follow-up time points in group II. Conclusions: The different dynamics in the recovery of patients with certain autoimmune encephalitides have important implications for clinical trials. The high proportion of patients with significant disability at 3 months after diagnosis in groups I and III points to the need for improving treatment options. More distinct scores rather than the mRS are necessary to differentiate potential neurological improvements in patients with anti-LGI1-/CASPR2-encephalitis.

The relation between inflammation and neurodegeneration in multiple sclerosis brains.

Some recent studies suggest that in progressive multiple sclerosis, neurodegeneration may occur independently from inflammation. The aim of our study was to analyse the interdependence of inflammation, neurodegeneration and disease progression in various multiple sclerosis stages in relation to lesional activity and clinical course, with a particular focus on progressive multiple sclerosis. The study is based on detailed quantification of different inflammatory cells in relation to axonal injury in 67 multiple sclerosis autopsies from different disease stages and 28 controls without neurological disease or brain lesions. We found that pronounced inflammation in the brain is not only present in acute and relapsing multiple sclerosis but also in the secondary and primary progressive disease. T- and B-cell infiltrates correlated with the activity of demyelinating lesions, while plasma cell infiltrates were most pronounced in patients with secondary progressive multiple sclerosis (SPMS) and primary progressive multiple sclerosis (PPMS) and even persisted, when T- and B-cell infiltrates declined to levels seen in age matched controls. A highly significant association between inflammation and axonal injury was seen in the global multiple sclerosis population as well as in progressive multiple sclerosis alone. In older patients (median 76 years) with long-disease duration (median 372 months), inflammatory infiltrates declined to levels similar to those found in age-matched controls and the extent of axonal injury, too, was comparable with that in age-matched controls. Ongoing neurodegeneration in these patients, which exceeded the extent found in normal controls, could be attributed to confounding pathologies such as Alzheimer's or vascular disease. Our study suggests a close association between inflammation and neurodegeneration in all lesions and disease stages of multiple sclerosis. It further indicates that the disease processes of multiple sclerosis may die out in aged patients with long-standing disease.

Correction to: Routine diagnostics for neural antibodies, clinical correlates, treatment and functional outcome.

The original version of this article unfortunately contained a mistake.

Routine diagnostics for neural antibodies, clinical correlates, treatment and functional outcome.

OBJECTIVE: To determine frequencies, interlaboratory reproducibility, clinical ratings, and prognostic implications of neural antibodies in a routine laboratory setting in patients with suspected neuropsychiatric autoimmune conditions. METHODS: Earliest available samples from 10,919 patients were tested for a broad panel of neural antibodies. Sera that reacted with leucine-rich glioma-inactivated protein 1 (LGI1), contactin-associated protein-2 (CASPR2), or the voltage-gated potassium channel (VGKC) complex were retested for LGI1 and CASPR2 antibodies by another laboratory. Physicians in charge of patients with positive antibody results retrospectively reported on clinical, treatment, and outcome parameters. RESULTS: Positive results were obtained for 576 patients (5.3%). Median disease duration was 6 months (interquartile range 0.6-46 months). In most patients, antibodies were detected both in CSF and serum. However, in 16 (28%) patients with N-methyl-D-aspartate receptor (NMDAR) antibodies, this diagnosis could be made only in cerebrospinal fluid (CSF). The two laboratories agreed largely on LGI1 and CASPR2 antibody diagnoses (κ = 0.95). The clinicians (413 responses, 71.7%) rated two-thirds of the antibody-positive patients as autoimmune. Antibodies against the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), NMDAR (CSF or high serum titer), γ-aminobutyric acid-B receptor (GABABR), and LGI1 had ≥ 90% positive ratings, whereas antibodies against the glycine receptor, VGKC complex, or otherwise unspecified neuropil had ≤ 40% positive ratings. Of the patients with surface antibodies, 64% improved after ≥ 3 months, mostly with ≥ 1 immunotherapy intervention. CONCLUSIONS: This novel approach starting from routine diagnostics in a dedicated laboratory provides reliable and useful results with therapeutic implications. Counseling should consider clinical presentation, demographic features, and antibody titers of the individual patient.

Hereditary ATTR Amyloidosis in Austria: Prevalence and Epidemiological Hot Spots.

BACKGROUND: Hereditary transthyretin amyloidosis (hATTR) is an autosomal dominantly inherited disorder caused by an accumulation of amyloid fibrils in tissues due to mutations in the transthyretin (TTR) gene. The prevalence of hATTR is still unclear and likely underestimated in many countries. In order to apply new therapies in a targeted manner, early diagnosis and knowledge of phenotype-genotype correlations are mandatory. This study aimed to assess the prevalence and phenotypic spectrum of hATTR in Austria. METHODS: Within the period of 2014-2019, patients with ATTR-associated cardiomyopathy and/or unexplained progressive polyneuropathies were screened for mutations in the TTR gene. RESULTS: We identified 43 cases from 22 families carrying 10 different TTR missense mutations and confirmed two mutational hot spots at c.323A>G (p.His108Arg) and c.337G>C (p.Val113Leu). Two further patients with late onset ATTR carried TTR variants of unknown significance. The majority of patients initially presented with heart failure symptoms that were subsequently accompanied by progressive polyneuropathy in most cases. A total of 55% had a history of carpal tunnel syndrome before the onset of other organ manifestations. CONCLUSIONS: Our study underlined the relevance of hATTR in the pathogenesis of amyloid-driven cardiomyopathy and axonal polyneuropathy and indicated considerable genetic heterogeneity of this disease in the Austrian population. The estimated prevalence of hATTR in Austria based on this study is 1:200,000 but a potentially higher number of unknown cases must be taken into account. With respect to new therapeutic approaches, we strongly propose genetic testing of the TTR gene in an extended cohort of patients with unexplained heart failure and progressive polyneuropathy.

Coronary ectasia in amyloid cardiomyopathy and neuropathy due to the transthyretin mutation c.323A>G.

BACKGROUND: atrial fibrillation(AF) is a frequent manifestation of cardiac involvement in genetic and wild-type transthyretin-related familial amyloidosis(TTR-FA). However, ectasia of coronary arteries and ablation for AF have not been reported in TTR-FA. METHODS AND RESULTS: A 65yo male developed progressive sensori-motor polyneuropathy since age 59y. At age 60y bifascicular block and myocardial thickening were recognised. At age 62y heart failure developed and work-up with cardiac MRI suggested amyloidosis but biopsy was non-informative. Coronary angiography revealed ectasias of the coronary arteries. At age 65y AF developed, neither responding to electrical cardioversion nor ablation. Work-up for polyneuropathy revealed the point mutation c.323A>G (p.His108Arg) in the TTR-gene. Tafamidis was started but did not exhibit a beneficial effect after 7 months. CONCLUSIONS: TTR-FA may manifest in the coronary arteries with ectasia. Ablation for AF in TTR-FA may be unsuccessful. Tafamidis has been unsuccessful for cardiac or nerve involvement after the first seven months.

Secondary dementia due to Lyme neuroborreliosis.

Dementia-like syndromes are rare manifestations of Lyme neuroborreliosis. The clinical patterns are summarized using our own cases and case reports from the literature, which were diagnosed as definite Lyme neuroborreliosis according to the European guidelines. The cases disclose signs of subcortical dementia that occur more rapidly than in patients suffering from primary dementia. Gait disturbances early in the disease course is another frequently observed characteristic feature. The response to 2-4 weeks of antibiotic treatment with ceftriaxone was excellent. There were no indications for a prolonged antibiotic treatment. It is essential to be aware of this manifestation of Lyme neuroborreliosis, because early antibiotic treatment will prevent permanent sequelae that may occur throughout the further course of the untreated disease.

Widespread demyelination in the cerebellar cortex in multiple sclerosis.

Neocortical demyelination in the forebrain has recently been identified as an important pathological feature of multiple sclerosis (MS). Here we describe that the cerebellar cortex is a major predilection site for demyelination, in particular in patients with primary and secondary progressive MS. In these patients, on average, 38.7% of cerebellar cortical area is affected, reaching in extreme examples up to 92%. Cerebellar cortical demyelination occurs mainly in a band-like manner, affecting multiple folia. The lesions are characterized by primary demyelination with relative axonal and neuronal preservation, although some axonal spheroids and a moderate reduction of Purkinje cells are present. Although cortical demyelination sometimes occurs together with demyelination in the adjacent white matter (leukocortical lesions), in most instances, the cortex was affected independently from white matter lesions. We found no correlation between demyelination in the cortex and the white matter, and in some cases, extensive cortical demyelination was present in the near absence of white matter lesions. Our data identify cortical demyelination as a potential substrate of cerebellar dysfunction in MS.

Acute cerebral white matter damage in lethal salicylate intoxication.

A 34-year-old oligophrenic woman was admitted in comatose state with marked tachypnea. History revealed the oral ingestion of a large amount of acetylsalicylate to attenuate ear pain within the preceding 3 days. Laboratory investigations showed a toxic concentration of serum salicylate (668 mg/l, toxic range above 200 mg/l) and metabolic acidosis. Oxygenation, blood pressure, electrocardiography, echocardiography and CT of thorax and brain were normal. The patient was intubated, fluid and bicarbonate was given intravenously. Six hours after admission asystolia refractory to resuscitation led to death. Autopsy showed venous congestion of the brain, cardiac dilatation and pulmonary edema. Brain histopathology showed myelin disintegration and caspase-3 activation in glial cells, whereas, grey matter changes were sparse. Acute white matter damage is suggested to be the substrate of cerebral dysfunction in salicylate intoxication and possible mechanisms are discussed.

Remyelination is extensive in a subset of multiple sclerosis patients.

Although spontaneous remyelination does occur in multiple sclerosis lesions, its extent within the global population with this disease is presently unknown. We have systematically analysed the incidence and distribution of completely remyelinated lesions (so-called shadow plaques) or partially remyelinated lesions (shadow plaque areas) in 51 autopsies of patients with different clinical courses and disease durations. The extent of remyelination was variable between cases. In 20% of the patients, the extent of remyelination was extensive with 60-96% of the global lesion area remyelinated. Extensive remyelination was found not only in patients with relapsing multiple sclerosis, but also in a subset of patients with progressive disease. Older age at death and longer disease duration were associated with significantly more remyelinated lesions or lesion areas. No correlation was found between the extent of remyelination and either gender or age at disease onset. These results suggest that the variable and patient-dependent extent of remyelination must be considered in the design of future clinical trials aimed at promoting CNS repair.

Affection of the Respiratory Muscles in Combined Complex I and IV Deficiency.

OBJECTIVES: Combined complex I+IV deficiency has rarely been reported to manifest with the involvement of the respiratory muscles. CASE REPORT: A 45y male was admitted for hypercapnia due to muscular respiratory insufficiency. He required intubation and mechanical ventilation. He had a previous history of ophthalmoparesis since age 6y, ptosis since age 23y, and anterocollis since at least age 40y. Muscle biopsy from the right deltoid muscle at age 41y was indicative of mitochondrial myopathy. Biochemical investigations revealed a combined complex I+IV defect. Respiratory insufficiency was attributed to mitochondrial myopathy affecting not only the extra-ocular and the axial muscles but also the shoulder girdle and respiratory muscles. In addition to myopathy, he had mitochondrial neuropathy, abnormal EEG, and elevated CSF-protein. Possibly, this is why a single cycle of immunoglobulins was somehow beneficial. For muscular respiratory insufficiency he required tracheostomy and was scheduled for long-term intermittent positive pressure ventilation. CONCLUSION: Mitochondrial myopathy due to a combined complex I+IV defect with predominant affection of the extra-ocular muscles may progress to involvement of the limb-girdle, axial and respiratory muscles resulting in muscular respiratory insufficiency. In patients with mitochondrial myopathy, neuropathy and elevated cerebrospinal fluid protein, immunoglobulins may be beneficial even for respiratory functions.

Cortical demyelination and diffuse white matter injury in multiple sclerosis.

Focal demyelinated plaques in white matter, which are the hallmark of multiple sclerosis pathology, only partially explain the patient's clinical deficits. We thus analysed global brain pathology in multiple sclerosis, focusing on the normal-appearing white matter (NAWM) and the cortex. Autopsy tissue from 52 multiple sclerosis patients (acute, relapsing-remitting, primary and secondary progressive multiple sclerosis) and from 30 controls was analysed using quantitative morphological techniques. New and active focal inflammatory demyelinating lesions in the white matter were mainly present in patients with acute and relapsing multiple sclerosis, while diffuse injury of the NAWM and cortical demyelination were characteristic hallmarks of primary and secondary progressive multiple sclerosis. Cortical demyelination and injury of the NAWM, reflected by diffuse axonal injury with profound microglia activation, occurred on the background of a global inflammatory response in the whole brain and meninges. There was only a marginal correlation between focal lesion load in the white matter and diffuse white matter injury, or cortical pathology, respectively. Our data suggest that multiple sclerosis starts as a focal inflammatory disease of the CNS, which gives rise to circumscribed demyelinated plaques in the white matter. With chronicity, diffuse inflammation accumulates throughout the whole brain, and is associated with slowly progressive axonal injury in the NAWM and cortical demyelination.