Can clinical signs identify newborns with neuromuscular disorders?

doi:10.1016/j.jpeds.2004.08.047

The Journal of Pediatrics

Volume 146, Issue 1, January 2005, Pages 73-79

https://doi.org/10.1016/j.jpeds.2004.08.047 Get rights and content

Objective

To evaluate retrospectively the prevalence of neuromuscular disorders in 83 newborns referred to a tertiary care center because of hypotonia and weakness and/or contractures, with a possible diagnosis of neuromuscular disorder. We also aimed to establish whether clinical signs could help to identify infants with neuromuscular disorders.

Study design

Sixty-six of the 83 infants who fulfilled the inclusion criteria (79.5%) had an identifiable disorder, which was a neuromuscular disorder in 39 (46.9%).

Results

Absent or extremely reduced antigravity movements were mainly found in infants with neuromuscular disorders (sensitivity and specificity 97.4% and 75%), whereas partial range antigravity movements were more frequent in infants with other diagnosis. Contractures were mainly found in infants with peripheral nerve or muscle involvement but also were relatively frequent in infants with genetic or metabolic syndromes (sensitivity 69.2%, specificity 61.3%). Reduced fetal movements and abnormal liquor were frequent but not present consistently in infants with neuromuscular disorders (sensitivity 46.1% and 38.4%) and were found rarely in infants with other disorders (specificity 88.6% and 75.0%).

Conclusions

Severe muscle weakness and contractures are the most reliable indicators of a neuromuscular disorder and should be carefully assessed in an infant with neonatal hypotonia.

Section snippets

Subjects and methods

This was a retrospective study of infants born at or referred to a tertiary care center for neuromuscular disorders (Hammersmith and Queen Charlotte's Hospital, London) in the first weeks after birth between January 1998 and May 2003. Infants were enrolled only if they had hypotonia associated with muscle weakness (revealed by absent or reduced antigravity movements spontaneously or on stimulation) and/or contractures that suggested a neuromuscular disorder. Infants with hypotonia and clear

Results

A total of 83 infants fulfilled the inclusion criteria. Of those 83 infants, 49 (59.0%) were male. The mean gestational age at birth was 37⁺⁴ weeks (range 23-42⁺³) Of those 83 infants, 38 (45.7%) presented with hypotonia and weakness, 6 (7.2%) with hypotonia and contractures, and 39 (46.9%) with a combination of the three. In all, diagnosis at presentation was that of neonatal hypotonia and of a possible neuromuscular disorder.

Sixty-six of the 83 infants (79.5%) had an identifiable disorder,

Discussion

The aim of this study was to establish the relative accuracy of clinical examination in the diagnosis of infants referred to a tertiary care center because of a suspected neuromuscular disorder. The main reason for referral was that these infants were not only hypotonic, but they also had contractures and/or weakness that suggested a neuromuscular disorder. It is well known that weakness in neonates can be assessed by looking for a reduction of antigravity movements, and that poor antigravity

References (8)

L.P. Richer et al.
Diagnostic Profile of Neonatal Hypotonia: an 11-year study
Pediatr Neurol
(2001)
A.N. Prasad et al.
The floppy infant: contribution of genetic and metabolic disorders
Brain Develop
(2003)
H.M. Johnston
The floppy weak infant revisited
Brain Develop
(2003)
L. Dubowitz et al.
An optimality score for the neurologic examination of the term newborn
J Pediatr
(1998)

There are more references available in the full text version of this article.

Cited by (43)

Neonatal and infantile hypotonia
2023, Handbook of Clinical Neurology
The underlying etiology of neonatal and infantile hypotonia can be divided into primary peripheral and central nervous system and acquired or genetic disorders. The approach to identifying the likeliest cause of hypotonia begins with a bedside assessment followed by a careful review of the birth history and early development and family pedigree and obtaining available genetic studies and age- and disease-appropriate laboratory investigations. Until about a decade ago, the main goal was to identify the clinical signs and a battery of basic investigations including electrophysiology to confirm or exclude a given neuromuscular disorder, however the availability of whole-exome sequencing and next generation sequencing and transcriptome sequencing has simplified the identification of specific underlying genetic defect and improved the accuracy of diagnosis in many related Mendelian disorders.
Hypotonia: Is It a Clear Term and an Objective Diagnosis? An Exploratory Systematic Review
2023, Pediatric Neurology
Citation Excerpt :
Responding to the objective of knowing what characteristics are described as associated with hypotonia in children and what methods are used for its diagnosis, a variety of attributes have been found, some of them controversial, especially on strength, differentiation with hypermobility, and the ability to maintain postures against gravity. When referring to muscle strength, several authors accept it as a differential characteristic between central and peripheral hypotonia,26,28,32,37,43 considering that it is maintained at values close to normal in the case of central origin,43 and weakness would be observed in the case of peripheral involvement. With the aim of finding out the relationship between strength and hypotonia, research was carried out measuring strength in children affected by syndromes described with the presence of central hypotonia.
Hypotonia is considered a determinant factor in multiple developmental disorders and is associated with various characteristics and morbidities. It is necessary to perform a systematic review to know which characteristics are described as associated with hypotonia in children and which methods are used for its diagnosis.
Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used to develop the systematic review protocol. A search of databases (Pubmed, Cochrane, Web of Knowledge, among others) was performed in May 2021 to identify relevant studies. Those describing characteristics or tests of hypotonia assessment were included, excluding those that exclusively addressed peripheral hypotonia. Two reviewers evaluated the articles and collected the data in a table, noting the authors, date of publication, type of study, and characteristics or tests described in relation to hypotonia. The quality of the studies was also assessed, and data were extracted.
A total of 8778 studies were identified and analyzed, of which 45 met the inclusion criteria. Fifty-three characteristics associated with hypotonia and tests used for its evaluation were located, with pull to sit and vertical suspension being the most frequently referenced.
The characteristics associated with hypotonia, more highly debated by authors are muscle strength, hypermobility, or the maintenance of antigravity postures. The most used test in the diagnosis of hypotonia is observation, followed by the pull-to-sit test, and adoption of frog posture. A unanimous understanding of the term hypotonia would favor further research.
Utility of Hypotonia Diagnostic Investigations: A 12-year Single Center Study
2020, Molecular Genetics and Metabolism Reports
Citation Excerpt :
The occurrence of peripheral hypotonia was significantly lower in our study, at only 17% compared to other studies, which can be attributed to the fact that comparable studies investigated specific patient categories, e.g., neonatal hypotonia or patients admitted to ICUs. In our cohort, we tried to minimize the selection bias that had been reported by previous studies, by including patients of all age groups from multiple hospital areas (ED, ICU, Wards, and clinics) and further classified patients into central hypotonia, peripheral and mixed hypotonia [5,9]. The age of the presentation was significantly correlated with hypotonia type in our study.
Hypotonia is a common presentation that child neurologists encounter daily. The hypotonic neonate represents a diagnostic challenge as a lesion at any level in the neuro-axis may cause hypotonia. In this paper, we study the diagnostic yield of investigations commonly used as part of a hypotonia work-up.
A 12-year retrospective cohort study was conducted at a tertiary care center in Saudi Arabia from 2007 to 2018. Final diagnoses, clinical presentations, laboratory tests, imaging and genetic studies were reviewed from the patient's electronic health records.
164 patients were identified as fitting the inclusion criteria of the study. 50% had central hypotonia, 18% peripheral hypotonia and 32% mixed hypotonia. Molecular testing was performed for 82% (74) of patients. 65 Microarray studies were done; 27% abnormal and 9% diagnostic. 55 gene panels were done; 58% abnormal and 30% diagnostic. 53 single-gene tests were done; 57% abnormal and 40% diagnostic. 61 whole exome sequences were done; 72% positive and 59% diagnostic. 126 MRIs were reviewed; 56% abnormal and 33% contributed to the diagnosis.
Molecular genetic testing is our recommended next step in the diagnosis of patients with hypotonia after careful phenotyping. Neuroimaging is helpful to guide further costly workup of patients with hypotonia.
Neonatal hypotonia and neuromuscular conditions
2019, Handbook of Clinical Neurology
Citation Excerpt :
A neuromuscular disorder should be suspected when the infant has a generalized hypotonia and additional clinical features, such as weakness or contractures (Dubowitz, 1968; Vasta et al., 2005).
The differential diagnosis of neonatal hypotonia is a complex task, as in newborns hypotonia can be the presenting sign of different underlying causes, including peripheral and central nervous system involvement and genetic and metabolic diseases. This chapter describes how a combined approach, based on the combination of clinical signs and new genetic techniques, can help not only to establish when the hypotonia is related to peripheral involvement but also to achieve an accurate and early diagnosis of the specific neuromuscular diseases with neonatal onset. The early identification of such disorders is important, as this allows early intervention with disease-specific standards of care and, more importantly, because of the possibility to treat some of them, such as spinal muscular atrophy, with therapeutic approaches that have recently become available.
Hypotonic syndrome manifestation of neuromuscular hereditary disease in infants
2018, Revista Medica Clinica Las Condes
La hipotonía es un signo no específico definido como una disminución de la resistencia al movimiento pasivo de las articulaciones, la cual comprende un grupo amplio y heterogéneo de condiciones que afectan tanto al sistema nervioso central como periférico. En la orientación clínica sigue siendo crucial distinguir pacientes con o sin debilidad asociada y la diferenciación entre hipotonía central, periférica y mixta. A través de la historia clínica y examen físico es posible lograr esta distinción en cerca de la mitad de los casos, siendo las centrales las más frecuentes. Este artículo tiene como objetivo realizar una puesta al día en síndrome hipotónico del recién nacido y lactante menor (<2 años), con énfasis en las causas de origen neuromuscular hereditario, fundamentalmente en la evaluación clínica y enfoque diagnóstico.
Hypotonia is a non-specific sign defined as decrease resistence to passive joint's movement, wich comprises a broad and heterogeneous group of conditions that affect the central or peripheral nervous system. in the first clinical orientation it is still crucial to distinguish patients with oy without associated weakness and the differentiation between central, peripheral and mixed hypotonia. Through clinical history and physical examination it is possible to achieve this distinction in about half of the cases, with central causes being the most frequent. The objetive of this article is to make an update hypotonic syndrome in newborns and infants (less than 2 years), with emphasis on hereditary neuromuscular causes, focused on clinical evaluation and diagnosis approach.
Features of Pena-Shokeir Syndrome
2018, Volpe's Neurology of the Newborn

View all citing articles on Scopus

View full text

Article preview

The Journal of Pediatrics

Objective

Study design

Results

Conclusions

Section snippets

Subjects and methods

Results

Discussion

References (8)

Diagnostic Profile of Neonatal Hypotonia: an 11-year study

Pediatr Neurol

The floppy infant: contribution of genetic and metabolic disorders

Brain Develop

The floppy weak infant revisited

Brain Develop

An optimality score for the neurologic examination of the term newborn

J Pediatr

Cited by (43)

Neonatal and infantile hypotonia

Hypotonia: Is It a Clear Term and an Objective Diagnosis? An Exploratory Systematic Review

Utility of Hypotonia Diagnostic Investigations: A 12-year Single Center Study

Neonatal hypotonia and neuromuscular conditions

Hypotonic syndrome manifestation of neuromuscular hereditary disease in infants

Features of Pena-Shokeir Syndrome

Original ArticleCan clinical signs identify newborns with neuromuscular disorders?

Objective

Study design

Results

Conclusions

Section snippets

Subjects and methods

Results

Discussion

Pediatr Neurol

Brain Develop

Brain Develop

J Pediatr

Original Article
Can clinical signs identify newborns with neuromuscular disorders?