What is the diagnosis and treatment for Split Hand Split Foot Malformation (SHFM) associated with Amyotrophic Lateral Sclerosis (ALS)?

From the Guidelines

Split Hand Split Foot Malformation (SHFM) associated with Amyotrophic Lateral Sclerosis (ALS) is a complex condition that requires a multidisciplinary approach to management, focusing on symptom control, slowing disease progression, and improving quality of life, as emphasized in the 2024 National Academies of Sciences, Engineering, and Medicine report 1.

Diagnosis

The diagnosis of SHFM associated with ALS involves a comprehensive clinical evaluation, including physical examination, electromyography, and genetic testing to identify underlying genetic mutations. It is essential to distinguish SHFM from other motor neuron diseases, considering the specific presentation of split hand and foot malformations.

Treatment

The treatment of SHFM associated with ALS should prioritize symptom management, with a focus on maintaining mobility, preventing complications, and improving quality of life, as recommended by the National Academies of Sciences, Engineering, and Medicine report 1. Key aspects of treatment include:

• FDA-approved medications, such as riluzole (50 mg twice daily) and edaravone (60 mg daily for 14 days, followed by 14-day drug-free periods), to slow disease progression and improve survival
• Supportive care, including physical therapy, occupational therapy, respiratory support, and nutritional management, to maintain mobility and prevent complications
• Early intervention with a multidisciplinary ALS team to provide comprehensive care and address the complex needs of patients with SHFM associated with ALS
• Regular evaluation and management of dysphagia, using clinical severity scales, such as the ALS Functional Rating Scale-Revised (ALSFRS-R) or ALS Swallowing Severity Scale (ALSSS), and instrumental assessments, like videofluoroscopy (VFS) or fiberoptic endoscopic evaluation of swallowing (FEES) 1
• Nutritional management, considering the importance of nutritional status in ALS patients, with a focus on preventing malnutrition, maintaining optimal body weight, and monitoring body composition, as highlighted in the ESPEN guideline on clinical nutrition in neurology 1

Quality of Life

Improving quality of life is a critical aspect of managing SHFM associated with ALS, and healthcare providers should prioritize patient-centered care, addressing the physical, emotional, and social needs of patients and their families, as emphasized in the 2024 National Academies of Sciences, Engineering, and Medicine report 1. This includes:

• Providing access to multidisciplinary care, including physical therapy, occupational therapy, respiratory support, and nutritional management
• Addressing the emotional and psychological needs of patients and their families, through counseling and support services
• Facilitating communication and collaboration between healthcare providers, patients, and families to ensure comprehensive and coordinated care
• Promoting patient autonomy and dignity, respecting the values and preferences of patients and their families in care decisions, as highlighted in the review of palliative care in ALS 1

From the Research

Diagnosis of Split Hand Split Foot Malformation (SHFM) associated with Amyotrophic Lateral Sclerosis (ALS)

• The split-hand index (SI) can be used as a diagnostic marker for ALS, with a reduced SI indicating a higher likelihood of ALS 2, 3, 4.
• The SI is calculated by dividing the product of the compound muscle action potential (CMAP) amplitude recorded over the first dorsal interosseous and abductor pollicis brevis by the CMAP amplitude recorded over the abductor digiti minimi 2.
• A study found that an SI cutoff of 5.2 exhibited a sensitivity of 74% and specificity of 80% for differentiating ALS from other neuromuscular disorders 2.
• Another study found that an SIFP cutoff of 73.3 showed 85.7% sensitivity and 80.7% specificity for differentiating ALS from non-ALS 3.

Treatment of SHFM associated with ALS

• There is no specific treatment mentioned in the studies for SHFM associated with ALS, but the studies focus on the diagnosis and diagnostic markers of ALS 3, 2, 5, 4.
• A study highlights the importance of accurate diagnosis to prevent unnecessary morbidities, such as nerve decompression surgery, which can result in poor outcomes 6.
• The study recommends neurodiagnostic testing and prompt referral to a neurologist for further work-up and treatment if "red flag" symptoms are present, such as weakness without sensory symptoms, profound weakness and atrophy in multiple nerve distributions, and bulbar symptoms 6.

Prognosis of SHFM associated with ALS

• The split-hand index (SI) may have potential utility as a prognostic marker in ALS, with a longitudinal study finding that the rate of SI decline correlated with the decline in ALSFRS-R 4.
• The study suggests that the SI could be used as an outcome biomarker in a clinical trial setting, although further multicenter studies are required to confirm this 4.