Early diagnosis of amyotrophic lateral sclerosis mimic syndromes: pros and cons of current clinical diagnostic criteria

Diagnosis and differential diagnosis of MND/ALS: IFCN handbook chapter

•Accurate and rapid diagnosis of amyotrophic lateral sclerosis (ALS) is important to prevent erroneous interventions. •The recent Gold Coast criteria are easily applicable and have high sensitivity and specificity. •Future developments will help to distinguish ALS as a specific clinical-pathologic entity.

Accurate and rapid diagnosis of amyotrophic lateral sclerosis (ALS) is essential in order to provide accurate information for patient and family, to avoid time-consuming investigations and to permit an appropriate management plan. ALS is variable regarding presentation, disease progression, genetic profile and patient reaction to the diagnosis. It is obviously important to exclude treatable conditions but, in most patients, for experienced neurologists the diagnosis is clear-cut, depending on the presence of progressive upper and lower motor neuron signs. Patients with signs of restricted lower motor neuron (LMN) or upper motor neuron (UMN) dysfunction may present diagnostic difficulty, but electromyography (EMG) is often a determinant diagnostic test since it may exclude other disorders. Transcranial magnetic stimulation may aid detection of UMN dysfunction, and brain and spinal cord MRI, ultrasound and blood neurofilament measurements, have begun to have clinical impact, although none are themselves diagnostic tests. Several sets of diagnostic criteria have been proposed in the past; all rely on clinical LMN and UMN signs in different anatomic territories, EMG changes, exclusion of other disorders, and disease progression, in particular evidence of spreading to other anatomic territories. Fasciculations are a characteristic clinical feature and increased importance is now attached to fasciculation potentials detected by EMG, when associated with classical signs of denervation and reinnervation. The Gold Coast diagnostic criteria rely on the presence of UMN and LMN signs in one (or more) anatomic territory, or LMN signs in two (or more) anatomic territories, recognizing the fundamental clinical requirements of disease progression and exclusion of other diseases. Recent studies confirm a high sensitivity without loss of specificity using these Gold Coast criteria. In considering the diagnosis of ALS a critical question for future understanding is whether ALS should be considered a syndrome or a specific clinico-pathologic entity; this can only be addressed in the light of more complete knowledge.

Progressive Course of Chronic Tick-Borne Encephalitis Manifesting as Amyotrophic Lateral Sclerosis-like Syndrome 35 Years after the Acute Disease

The chronic form of tick-borne encephalitis (TBE) is understudied and seems to be linked exclusively to Siberian and Far Eastern TBE virus (TBEV) subtypes. There are limited clinical descriptions demonstrating that chronic TBE can resemble an amyotrophic lateral sclerosis (ALS)-like disease. Here, we present a description of a clinical case of progressive chronic TBEV infection with a relapse 35 years after the initial acute infection following a tick bite. The disease manifested as an ALS-like syndrome with bulbar signs, progressive muscle weakness and atrophy, decreased reflexes, and eventual respiratory failure and death. There is no clear differentiation between chronic TBE and postencephalitic syndrome described in European sources. The reactivation of TBEV infection was supported by the presence of anti-TBEV antibodies in serum and antibodies to E protein and to the nonstructural protein NS1 in the CSF. These findings support the diagnosis of a relapse of chronic TBE in this patient.

A Descriptive Review of Global Real World Evidence Efforts to Advance Drug Discovery and Clinical Development in Amyotrophic Lateral Sclerosis

Understanding patient clinical progression is a key gateway to planning effective clinical trials and ultimately enabling bringing treatments to patients in need. In a rare disease like amyotrophic lateral sclerosis (ALS), studies of disease natural history critically depend on collaboration between clinical centers, regions, and countries to enable creation of platforms to allow patients, caregivers, clinicians, and researchers to come together and more fully understand the condition. Rare disease registries and collaborative platforms such as those developed in ALS collect real-world data (RWD) in standardized formats, including clinical and biological specimen data used to evaluate risk factors and natural history of disease, treatment patterns and clinical (ClinROs) and patient- reported outcomes (PROs) and validate novel endpoints. Importantly, these data support the development of new therapeutics by supporting the evaluation of feasibility and design of clinical trials and offer valuable information on real-world disease trajectory and outcomes outside of the clinical trial setting for comparative purposes. RWD may help to accelerate therapy development by identifying and validating outcome measures and disease subpopulations. RWD can also make potential contributions to the evaluation of the safety and effectiveness of new indications for approved products and to satisfy post-approval regulatory and market access requirements. There is a lack of amalgamated information on available registries, databases, and other sources of real-world data on ALS; thus, a global review of all available resources was warranted. This targeted review identifies and describes ALS registries, biobanks and collaborative research networks that are collecting and synthesizing RWD for the purposes of increasing patient awareness and advancing scientific knowledge with the hope of expediting future development of new therapies.

Severe cervical compressive polydiscopathic myelopathy with features of motor neuron disease: A case report

Cervical myelopathy is part of ALS mimic syndrome and should be considered in patients with clinical signs of motor neuron disease.

Amyotrophic Lateral Sclerosis-like Syndrome after Chikungunya

Amyotrophic lateral sclerosis (ALS)-like syndrome refers to a group of conditions whose outcome is similar to that of amyotrophic lateral sclerosis, but with different characteristics in the initial phase and response to therapy. The involvement of an earlier age group, the subacute course, and the stabilization or improvement of the clinical condition during the treatment are most important. There is still no evidence of an association between amyotrophic lateral sclerosis-like syndrome and chikungunya (CHK) infection in the literature. This report was intended to review this syndrome and present a case that occurred after the epidemic of CHK in Pernambuco in 2016. CHK is a fast-onset febrile illness characterized by intense asthenia, arthralgia, myalgia, headache, and skin rash. Reports range from encephalitis, optic neuritis, myeloradiculitis to Guillain-Barré syndrome, generating drastic sequelae such as mental deficiency, blindness, and persistent paralysis. This is the first case report of a possible association of ALS-like syndrome and chikungunya infection. CHK infection may cause ALS-like syndrome. There is a need for further research in this field to develop therapies for neurological complications such as that of CHK.

Predictors of amyotrophic lateral sclerosis mimic syndrome

The term amyotrophic lateral sclerosis mimic syndrome (ALSms) includes pathologies that present signs or symptoms similar to those caused by amyotrophic lateral sclerosis (ALS), which can lead to misdiagnosis. In general, any kind of misdiagnosis can result in negative clinical, psychological and economic consequences as well diagnostic and treatment delay. The objectives were to determine the frequency and to compare the demographic and clinical characteristics of patients with ALS and ALSms in our ALS clinic. We retrospectively studied all patients evaluated from 2007 to 2017 including only patients with a definite final diagnosis. Out of 368 patients with motor neuron disease symptomatology, 43 (11.7%) had an ALSms. The most frequent etiology was compressive myelopathy (32.6%). Multivariate analysis considering positive associations was statistically significant for patients having only upper or lower motor neuron signs in the physical examination, a non-compatible electromyogram (EMG), as well as atypical first symptoms. ALS misdiagnosis is an ongoing and not infrequent problem. From our series of patients, atypical symptoms, absence of EMG pathological findings or isolated upper or lower motor neuron disease should prompt suspicion of a differential diagnosis.

Distinct Clinical Features and Outcomes in Motor Neuron Disease Associated with Behavioural Variant Frontotemporal Dementia

AIM

To determine the motor phenotype and outcome in a clinically ascertained group of patients with motor neuron disease (MND) and frontotemporal dementia (FTD).

METHODS

This is an observational retrospective clinical study of patients fulfilling the clinical criteria for MND-FTD. A contemporary series of patients with amyotrophic lateral sclerosis (ALS) without dementia were included for comparison. Demographic, clinical, genetic, and neuropathological data were collected. A descriptive and comparative data analysis was performed.

RESULTS

We identified 22 patients with MND-FTD. Selective distal upper limb muscle weakness and atrophy with non-significant lower limb weakness during follow-up was the most frequent motor pattern, present in 18 patients - in 15 of them associated with severe dysphagia. Aspiration pneumonia was the most common cause of death (12/19; 63%) despite gastrostomy. One-third of the patients did not develop upper motor neuron dysfunction. When compared to classic ALS without dementia (n = 162), these features were significantly different. A neuro-pathological examination was performed on 7 patients, and it confirmed the presence of MND with TDP43 protein aggregates in all patients.

CONCLUSIONS

The MND-FTD patients frequently displayed a distinctive motor pattern characterized by weakness and atrophy in distal upper limb muscles and dysphagia, with no or little spreading to other regions. These features may help to define specific subgroups of patients, which is important with regard to clinical management, outcome, and research.

What is in the Literature?

This edition of "What is in the Literature?" will focus on motor neuron disease (MND), including adult forms [amyotrophic lateral sclerosis (ALS), progressive muscular atrophy (PMA), primary lateral sclerosis (PLS), progressive bulbar palsy (PBA), and monomelic mononeuropathy (MMND)], and childhood forms [spinal muscle atrophy (SMA)].