Immune checkpoint inhibitor-related myositis and myocarditis: diagnostic pitfalls and imaging contribution in a real-world, institutional case series

BACKGROUND

Immune checkpoint inhibitors (ICIs) are reshaping the prognosis of many cancers, but often cause immune-related adverse events (irAEs). Among neurological irAEs, myositis is the most frequently reported. Our aim is to describe clinical and non-clinical characteristics, treatment and outcome of all irMyositis (skeletal limb-girdle and/or ocular myositis) and irMyocarditis cases in our reference center.

METHODS

We retrospectively enrolled all irMyositis/irMyocarditis patients seen between 2018 and 2022. We reviewed demographics, clinical characteristics, biological, neurophysiological, imaging workup, treatment and outcome.

RESULTS

We included 14 consecutive patients. The most frequent treatments were pembrolizumab (35%) or ipilimumab-nivolumab combination (35%). Limb-girdle, ocular (non-fluctuating palpebral ptosis and/or diplopia with or without ophthalmoparesis) and cardiac phenotypes were equally distributed, overlapping in 40% of cases. Ocular involvement was frequently misdiagnosed; review of brain MRIs disclosed initially missed signs of skeletal myositis in one patient and ocular myositis in 3. Seven patients had other co-existing irAEs. When performed, myography showed a myogenic pattern. CK was elevated in 8/15 patients, troponin-T in 12/12 and troponin-I in 7/9 tested patients. ICI were discontinued in all cases, with further immunosuppressive treatment in nine patients. In most cases, neurological and cardiological outcome was good at last follow-up.

CONCLUSION

Myositis is a potentially severe irAE. Despite its heterogeneous presentation, some highly suggestive clinical symptoms, such as ocular involvement, or radiological signs should raise physicians' attention to avoid misdiagnosis. We thus recommend a multidisciplinary assessment (including complete neuromuscular evaluation) even in case of isolated myocarditis. Our series underlines the importance of an early diagnosis, since suspension of ICI and adequate treatment are usually associated with good functional outcome.

Neuropathies related to hepatitis E virus infection: A prospective, matched case-control study

BACKGROUND

Acute hepatitis E virus (HEV) infection has recently emerged as a potential trigger for acute dysimmune neuropathies, but prospective controlled studies are lacking.

AIMS

To compare the frequency of concomitant acute HEV infection in patients with neuralgic amyotrophy (NA), Guillain-Barré syndrome (GBS), and Bell's palsy with a matched control population.

METHODS

Swiss multicenter, prospective, observational, matched case-control study over 3 years (September 2019-October 2022). Neurological cases with NA, GBS, or Bell's palsy were recruited within 1 month of disease onset. Healthy controls were matched for age, sex, geographical location, and timing of blood collection. Diagnostic criteria for acute hepatitis E were reactive serum anti-HEV IgM and IgG assays (ELISA test) and/or HEV RNA detection in serum by real-time polymerase chain reaction (RT-PCR). RT-PCR was performed on sera to confirm IgM positivity.

RESULTS

We included 180 patients (59 GBS, 51 NA, 70 Bell's palsy cases) and corresponding matched controls (blood donors) with median age 51 years for both groups and equal gender distribution. Six IgM+ cases were detected in the NA, two in the GBS, and none in the Bell's palsy group. Two controls were anti-HEV IgM-positive. At disease onset, most cases with acute HEV infection had increased liver enzymes. A moderate association (p = 0.027, Fisher's exact test; Cramér's V = -0.25) was observed only between acute HEV infection and NA.

CONCLUSION

This prospective observational study suggests an association between concomitant acute HEV infection and NA, but not with GBS or Bell's palsy.

Respiratory function in a large cohort of treatment-naïve adult spinal muscular atrophy patients: a cross-sectional study

Due to poor data in literature, we aimed to investigate the respiratory function in a large cohort of naïve Italian adult (≥18 years) SMA patients in a multi-centric cross-sectional study. The following respiratory parameters were considered: forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and need for non-invasive ventilation (NIV). We included 145 treatment-naïve adult patients (SMA2=18, SMA3=125; SMA4=2), 58 females (40 %), with median age at evaluation of 37 years (range 18-72). Fifty-six (37 %) and 41 (31 %) patients had abnormal (<80 %) values of FVC and FEV1, respectively. Fourteen (14 %) patients needed NIV, started at median age of 21 (range 4-68). Motor function, measured by Hammersmith Functional Motor Scale Expanded and Revised Upper Limb Module as well as SMA2, loss of walking ability, surgery for scoliosis, use of NIV, and cough assisting device (CAD) were all significantly associated to lower FVC and FEV1 values, while no association with age at baseline, disease duration, gender or 6 min walking test was observed, except for a correlation between FVC and age in SMA3 walkers (p < 0.05). In conclusion, respiratory function in adult SMA patients is relatively frequently impaired, substantially stable, and significantly correlated with motor function and disease severity.

Diagnostics in skeletal muscle channelopathies

INTRODUCTION

Skeletal muscle channelopathies (SMCs) are a heterogenous group of disorders, caused by mutations in skeletal ion channels leading to abnormal muscle excitability, resulting in either delayed muscle relaxation (myotonia) which characterizes non-dystrophic myotonias (NDMs), or membrane transient inactivation, causing episodic weakness, typical of periodic paralyses (PPs).

AREAS COVERED

SMCs include myotonia congenita, paramyotonia congenita, and sodium-channel myotonia among NDMs, and hyper-normokalemic, hypokalemic, or late-onset periodic paralyses among PPs. When suspecting an SMC, a structured diagnostic approach is required. Detailed personal and family history and clinical examination are essential, while neurophysiological tests should confirm myotonia and rule out alternative diagnosis. Moreover, specific electrodiagnostic studies are important to further define the phenotype of de novo cases and drive molecular analyses together with clinical data. Definite diagnosis is achieved through genetic testing, either with Sanger sequencing or multigene next-generation sequencing panel. In still unsolved patients, more advanced techniques, as exome-variant sequencing or whole-genome sequencing, may be considered in expert centers.

EXPERT OPINION

The diagnostic approach to SMC is still mainly based on clinical data; moreover, definite diagnosis is sometimes complicated by the difficulty to establish a proper genotype-phenotype correlation. Lastly, further studies are needed to allow the genetic characterization of unsolved patients.

A severe case of neuroleukemiosis caused by B cell chronic lymphocytic leukemia, presenting as mononeuritis multiplex

AIMS

To report an exceptional case of nerve infiltration by an otherwise benign chronic B cell leukemia, inducing severe mononeuritis multiplex.

METHODS

The patient underwent extensive evaluation, including nerve conduction study and myography, brain and plexus MRI and nerve biopsy.

RESULTS

The clinical and electrophysiological diagnosis was a mononeuritis multiplex with severe motor and sensory involvement; only the nerve biopsy allowed definite diagnosis and introduction of chemotherapy, leading to resolution of sensory deficit and progressive motor improvement.

DISCUSSION

Neuroleukemiosis caused by chronic lymphoid leukemia is an exceptional diagnosis. The presence of other possible causes like cryoglobulinemia could induce avoidance of nerve biopsy thus undertreating patient, since steroid treatment is not expected to be efficient on lymphocytic proliferation. Our case stretches the importance of nerve biopsy and raises neuromuscular specialist's awareness of this rare entity.

Serum neurofilament light chain as a reliable biomarker of hereditary transthyretin-related amyloidosis-A Swiss reference center experience

Hereditary transthyretin-related (hATTR) amyloidosis is a rare disease, causing a disabling and life-threatening axonal length-dependent polyneuropathy. Monitoring of disease progression and treatment response is difficult. We aimed to determine if serum neurofilament light chain (sNfL) is a reliable and early biomarker of peripheral neuropathy in hATTR amyloidosis. We prospectively included 20 hATTR patients, 14 symptomatic and 6 asymptomatic. Patients were assessed at baseline and 1 year, including a full clinical examination with disease severity and functional scores, electrochemical skin conductance measurement with Sudoscan and nerve conduction studies, and sNfL level. hATTR patient sNfL were also compared with sNfL of 4532 healthy controls of a reference database by calculating age and BMI-adjusted Z scores. At baseline, median sNfL concentration was 3.6-fold higher in symptomatic than asymptomatic hATTR patients (P = .003), and this difference was also found in our under 60-years-old patients (P = .003). There was no significant difference of sNfL concentration between asymptomatic patients and healthy controls (Z-score of -0.29), but a significant difference between symptomatic patients and healthy controls (Z-score of 2.52). We found a significant correlation between sNfL levels and most clinical and electrophysiological disease severity scores, the strongest correlation being with the NIS score. sNfL seems to be a reliable biomarker of peripheral neuropathy severity in hATTR amyloidosis and can distinguish between asymptomatic and symptomatic patients. sNfL could also become a reliable biomarker to establish disease onset and treatment response.

Clinical Reasoning: A 39-Year-Old Man With Asymmetric Distal Weakness and Loss of Sensitivity

A 39-year-old man presented with an asymmetric distal weakness and loss of sensitivity sequentially affecting both lower extremities and the left upper limb. Nerve conduction studies showed a multifocal sensory and motor axonal neuropathy, and a pseudo-conduction block of the right fibular nerve, the whole being consistent with a mononeuropathy multiplex. An uncommon etiology was found after an extensive workup. Axonal loss was severe, with only partial response to treatment with corticosteroids and IV immunoglobulins.

[Small fiber neuropathy diagnosis]

Small fiber neuropathies affect small, poorly myelinated sensory Aδ and amyelinated C autonomic fibers. Neuropathic pain is often the main symptom. Positive diagnosis is based on the presence of deficient thermo-algesic sensory signs and/or dysautonomic signs with normal neurography. Several tests help to confirm the involvement of small fibers, ranging from simple tests such as the sympathetic skin response to skin biopsy, which measures the density of intraepidermal nerve fibers. The availability of these different tests varies greatly from one center to another. There are multiple etiologies, from rare genetic causes to the more frequent acquired dysimmune or metabolic causes. However, in more than half of the cases, no etiology is identified.

[Muscle disease in the adults: when to suspect it?]

Muscle diseases or myopathies have heterogeneous clinical presentations and etiologies. The principal sign is muscular weakness, whose distribution can help diagnostic orientation. Exercise intolerance, even without weakness at rest, can indicate an underlying myopathy. An isolated CK elevation can have multiple causes, but its persistence after a period of rest can point towards a subclinical myopathy. Isolated myalgia, especially at rest, are usually not associated with muscle disease. If the suspicion of myopathy is high, the patient will be assessed by a neurologist trained in muscle disorders, with correlation of clinical and neurophysiological findings, muscle imaging and, if indicated, muscle biopsy and genetic analysis. Cardiac and respiratory assessments are mandatory if a myopathy is suspected.

[Treating hereditary neuropathies : a dream come true?]

Hereditary neuropathies have been the subject of recent major therapeutic advances. Treatments based on antisense oligonucleotides (ASO) and small interfering RNA (siRNA) have been developed and are now commercially available to treat hereditary transthyretin amyloidosis (hTTR) and porphyria. More recently, a CRISPR-Cas9 genomic editing treatment targeting the TTR gene has been developed and is being tested in patients with hTTR. Based on their success in hTTR and porphyria, innovative treatments targeting mRNA and DNA are being evaluated in other hereditary neuropathies, including Charcot-Marie-Tooth disease (CMT).

[Neurological shoulder pain and weakness : practical attitudes]

Shoulder pain or paresis should be assessed carefully, as there are many possible causes, which can be osteoarticular, degenerative, inflammatory, or neurological. Weakness or pain can be related to cervicobrachialgia, plexitis, or focal mononeuropathy. The clinical picture should identify any muscular or mechanical origin of paresis responsible for pseudo-paretic functional limitation. Neurogenic scapulalgia with functional deficit implies the compression or entrapment of a nerve trunk including the axillary, long thoracic, accessory, suprascapular, or dorsal scapular nerves. Nerve conduction study and myography together with medical imaging help to identify the relevant etiology. Treatment mostly includes pain relief and physiotherapy, but surgery is rarely necessary.

[What have we learned about chronic inflammatory demyelinating polyradiculoneuropathyin the last twenty years ?]

chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) has been widely described during the last quarter of the twentieth century. The last 20 years have seen decisive progress in its understanding. The diagnostic criteria have been simplified and the steps of the diagnostic process have been clarified. The phenotypic contours of the disease are now well known, as are the diagnostic pitfalls. From a pathophysiological point of view, the discovery of autoantibodies directed against nodal and paranodal proteins has been a major advance, although it concerns only a minority of patients. These discoveries have a major impact on the therapeutic management of these patients, often suffering from a very active form of the disease. The next 20 years will surely see a further deepening of knowledge about this fascinating disease.

[Cramps and fasciculations: is it amyotrophic lateral sclerosis?]

Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease of the adult age. It is an aggressive condition with a mean disease duration of only 3 to 5 years, characterized by progressive weakness and atrophy of limb, bulbar, and respiratory muscles. In general, death is caused by chronic hypoventilation due to respiratory insufficiency. No causal treatment is known today, but the two therapeutic agents authorized in Switzerland for the treatment of ALS can slow disease progression significantly. Other important therapeutic strategies include invasive/non-invasive ventilation, pain therapy, as well as physio-, ergo- and speech therapy on a regular basis.

[Muscle cramps]

Muscle cramps are very common and can reduce quality of life. There are multiple causes, including some physiological conditions, metabolic, endocrine, vascular disorders or neuromuscular diseases. Adequate management first requires differentiating cramps from other muscular phenomena. In most cases, the investigations are limited to a comprehensive history and clinical examination, but a biological, radiological and/or electrophysiological work-up may be useful. Treatment, when needed, is most often symptomatic and is unfortunately based on little evidence.

[Neurology : what's new in 2021]

In 2021, we assisted to the publication of new diagnostic criteria, classifications, and guidelines (CIDP, brain tumors, auto-immune encephalitis). Several studies helped to define the pharmacological management of focal and generalized epileptic seizures and epilepsy in pregnant women. The availability of biomarkers and the approval of immunotherapies are modifying the landscape of dementia management. Endovascular interventions without previous thrombolysis seems to be effective in anterior circulation acute ischemic stroke (AIS) and severe posterior circulation AIS. Neurologic complications of Sars-CoV-2 infection were further studied, as well as the efficacy of vaccines in immunosuppressed patients. New molecules and techniques show promising results for the treatment of migraine and cluster headache.

Guillain-Barré syndrome after SARS-CoV-2 infection in an international prospective cohort study

In the wake of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, an increasing number of patients with neurological disorders, including Guillain-Barré syndrome (GBS), have been reported following this infection. It remains unclear, however, if these cases are coincidental or not, as most publications were case reports or small regional retrospective cohort studies. The International GBS Outcome Study is an ongoing prospective observational cohort study enrolling patients with GBS within 2 weeks from onset of weakness. Data from patients included in this study, between 30 January 2020 and 30 May 2020, were used to investigate clinical and laboratory signs of a preceding or concurrent SARS-CoV-2 infection and to describe the associated clinical phenotype and disease course. Patients were classified according to the SARS-CoV-2 case definitions of the European Centre for Disease Prevention and Control and laboratory recommendations of the World Health Organization. Forty-nine patients with GBS were included, of whom eight (16%) had a confirmed and three (6%) a probable SARS-CoV-2 infection. Nine of these 11 patients had no serological evidence of other recent preceding infections associated with GBS, whereas two had serological evidence of a recent Campylobacter jejuni infection. Patients with a confirmed or probable SARS-CoV-2 infection frequently had a sensorimotor variant 8/11 (73%) and facial palsy 7/11 (64%). The eight patients who underwent electrophysiological examination all had a demyelinating subtype, which was more prevalent than the other patients included in the same time window [14/30 (47%), P = 0.012] as well as historical region and age-matched control subjects included in the International GBS Outcome Study before the pandemic [23/44 (52%), P = 0.016]. The median time from the onset of infection to neurological symptoms was 16 days (interquartile range 12-22). Patients with SARS-CoV-2 infection shared uniform neurological features, similar to those previously described in other post-viral GBS patients. The frequency (22%) of a preceding SARS-CoV-2 infection in our study population was higher than estimates of the contemporaneous background prevalence of SARS-CoV-2, which may be a result of recruitment bias during the pandemic, but could also indicate that GBS may rarely follow a recent SARS-CoV-2 infection. Consistent with previous studies, we found no increase in patient recruitment during the pandemic for our ongoing International GBS Outcome Study compared to previous years, making a strong relationship of GBS with SARS-CoV-2 unlikely. A case-control study is required to determine if there is a causative link or not.

Home-based subcutaneous immunoglobulin for chronic inflammatory demyelinating polyneuropathy patients: A Swiss cost-minimization analysis

PURPOSE

To compare the cost of two patient management strategies with similar efficacies for chronic inflammatory demyelinating polyneuropathy (CIDP) patients in the chronic phase: hospital-based IV immunoglobulin G (IVIg) and home-based subcutaneous immunoglobulin G (SCIg) associated with an interprofessional drug therapy management programme (initial training and follow-up).

METHODS

A 48-week model-based cost-minimization analysis from a societal perspective was performed. Resources included immunoglobulin (IVIg: 1 g/kg/3 weeks; SCIg: 0.4 g/kg/week initially and 0.2 g/kg/week in the maintenance phase), hospital charges, time of professionals, infusion material, transport and losses of productivity for patients. Costs were expressed in Swiss francs (CHF) (1 CHF = 0.93€ = US$1.10, www.xe.com, 2020/10/28).

RESULTS

The total costs of IVIg were higher than those of SCIg for health insurance and other payers: 114,747 CHF versus 86,558 CHF and 8,762 CHF versus 2,401 CHF, respectively. The results were sensitive to the immunoglobulin doses, as this was the main cost driver. The SCIg daily cost in the initial phase was higher for health insurance than hospital-based IVIg was, but the additional costs were compensated during the maintenance phase (from week 28). The professional costs associated with the switch were not fully covered by the insurance and were borne by the pharmacist and the nurse.

CONCLUSIONS

SCIg for CIDP patients reinforced by an interprofessional drug therapy management programme may be a cost-effective and sustainable alternative to IVIg in the Swiss system context. From an economic perspective, this therapy alternative should be more widely supported by healthcare systems and proposed to eligible patients by professionals.

Motor unit number index as an individual biomarker: Reference limits of intra-individual variability over time in healthy subjects

OBJECTIVE

Motor unit number index (MUNIX) is proposed to monitor neuromuscular disorders. Our objective is to determine the intra-individual variability over time of the MUNIX.

METHODS

In 11 different hospital centres, MUNIX was assessed twice, at least 3 months apart (range 90-360 days), in tibialis anterior (TA), abductor pollicis brevis (APB), abductor digiti minimi (ADM) and deltoid muscles in 118 healthy subjects. MUNIX sum score 2, 3 and 4 were respectively the sum of the MUNIX of the TA and ADM, of the TA, APB and ADM and of the TA, APB, ADM and deltoid muscles.

RESULTS

The repeatability of the MUNIX was better for sum scores than for single muscle recordings. The variability of the MUNIX was independent of sex, age, interval between measurements and was lower for experienced than non-experienced operators. The 95th percentile of the coefficient of variability of the MUNIX sum score 2, 3 and 4 were respectively 22%, 18% and 15% for experienced operators.

CONCLUSIONS

The MUNIX technique must be performed by experienced operators on several muscles to reduce its variability and improve its reliability.

SIGNIFICANCE

A variation of the MUNIX sum score ≥20% can be interpreted as a significant change of muscle innervation.

A severe case of neuro-Sjögren's syndrome induced by pembrolizumab

BACKGROUND

The prevalence of connective tissue disease (CTD) induced by immune checkpoint inhibitors (CPIs) in the absence of pre-existing autoimmunity is unknown.

CASE PRESENTATION

We report the case of a melanoma patient treated for 8 months with pembrolizumab who developed a subacute ataxic sensory neuronopathy (SNN), including a right trigeminal neuropathy. Salivary gland biopsy showed inflammatory changes suggestive of Sjögren's syndrome, while brain MRI revealed enhancement of the right trigeminal ganglia. A high level of protein and pleocytosis was found in the cerebrospinal fluid, with negative cultures. Nerve conduction studies revealed the absence of sensory nerve action potentials in the upper and lower limbs and reduced motor responses in the upper limbs, fulfilling criteria for SNN. Blood tests revealed an important inflammatory syndrome, hemolytic anemia, elevation of total IgG levels and the presence of ANA autoantibodies specific to anti-SSA (52 and 60 kd). All these elements were absent before the initiation of the treatment with pembrolizumab. Initially, there was a clinical response following intravenous frontline methylprednisone, but the subacute relapse required the introduction of second-line treatment with intravenous immunoglobulins and then rituximab, which led to a quick clinical improvement.

CONCLUSIONS

Herein, we describe the first case of a patient who developed a typical SNN as a complication of severe neuro-Sjögren's syndrome induced by pembrolizumab treatment.

The FeTouch project: an application of haptic technologies to obstetrics and gynaecology

Ultrasound technologies have been widely used in gynecology and obstetrics. Modern ultrasound systems allow the reconstruction of a 3D model of the subject being scanned, but even though visual interfaces have reached very high standards, the problem of representing a 3D image on a 2D computer screen still exists. Moreover no physical interaction is possible with such a model. The FeTouch system, developed at Siena University in the last two years, partially solves such issues by using stereo visual feedback and haptic devices. While the system can be used with any 3D model obtained from ultrasound scans, its current prime use is to allow mothers to interact with a model of the fetus they are carrying. The system is freely available on the project web page.

Virtual fetal touch through a haptic interface decreases maternal anxiety and salivary cortisol

OBJECTIVE

To evaluate whether a virtual reality workstation (Fetouch system) offering three-dimensional (3D) fetal visual and kinesthetic interaction may affect maternal stress.

METHODS

Maternal-fetal visual and kinesthetic interaction was obtained through a haptic interface based on 3D reconstruction of sequencial bi-dimensional ultrasound images of the fetus. Maternal stress was assessed before and after visual/kinesthetic interaction with the fetus: 1) by using the State Trait Anxiety Inventory-Form Y (STAI) test, and 2) by measuring salivary cortisol levels. Statistical analysis was performed by paired t test and analysis of variance for repeated measures.

RESULTS

After the fetal visual and kinesthetic experiences, a significant reduction was observed in anxiety (low state anxiety group, P < .0034; high state anxiety group, P < .0108), as well as in salivary cortisol concentration (P < .0004).

CONCLUSION

Physical interaction with the fetus through a 3D model may reduce maternal stress.

Video-based eye tracking: our experience with Advanced Stimuli Design for Eye Tracking software

We present an independent, flexible, and easily programmable software program for generating a wide set of visual stimuli paradigms in eye-movement studies. The software, called ASTIDET (Advanced Stimuli Design for Eye Tracking), has been interfaced in real time with a high speed video-based eye tracking system in order to obtain a reliable measurement of saccades. Two saccadic paradigms have been tested (gap and memory guided tasks) in 10 normal subjects. The preliminary results confirm that ASTIDET is a user-friendly software and can be interfaced with a video-based eye-tracking device in order to obtain reliable measurement of saccades.