What is the management approach for frontal parietal atrophy with motor symptoms, such as amyotrophic lateral sclerosis (ALS)?

Management of Frontal Parietal Atrophy with Motor Symptoms in ALS

MRI brain without contrast is the optimal initial imaging for suspected ALS with frontal parietal atrophy, followed by a multidisciplinary approach focused on nutritional support, riluzole therapy, and palliative care. 1, 2

Diagnostic Approach

• MRI head without IV contrast is the preferred initial imaging modality for suspected ALS with frontal parietal atrophy to identify characteristic findings and exclude other conditions 1
• Common MRI findings in ALS include abnormal T2/FLAIR signal in the corticospinal tracts (most frequently seen in the posterior limb of the internal capsule and cerebral peduncles) and abnormal hypointensity in the precentral gyrus on T2*/susceptibility-weighted imaging 1
• MRI spine without IV contrast may be appropriate in certain patients to exclude structural, infectious, or neoplastic etiologies that can mimic motor neuron disease 1
• Up to 20-50% of ALS patients may have cognitive dysfunction, primarily frontotemporal dementia, which can be detected through neuropsychological testing 1, 3

Pharmacological Management

• Riluzole (50 mg twice daily, taken at least 1 hour before or 2 hours after meals) is FDA-approved for ALS treatment 2
• Monitor serum aminotransferases before and during riluzole treatment due to risk of hepatic injury 2
• Discontinue riluzole if there is evidence of liver dysfunction or if interstitial lung disease develops 2
• Caution is advised when co-administering riluzole with strong to moderate CYP1A2 inhibitors or inducers, as they may increase adverse reactions or decrease efficacy, respectively 2

Nutritional Management

• Regular nutritional status assessment (BMI, weight loss) is essential to detect early malnutrition and plan appropriate interventions 1, 4
• Body composition analysis using DEXA or BIA with validated formula should be performed if available 1
• For patients with dysphagia, adapt food texture to facilitate swallowing, implement postural maneuvers, and use thicker liquids and semisolid foods with high water content instead of thin liquids 4
• Consider enteral nutrition via feeding tubes (preferably gastrostomy) when oral intake becomes insufficient, with PEG placement recommended before respiratory function significantly deteriorates 4

Management of Cognitive and Behavioral Symptoms

• ALS patients with frontal parietal atrophy often exhibit cognitive flexibility impairment, which can be assessed using tests with minimal motor demands 5
• Cognitive and behavioral symptoms in ALS with frontal parietal involvement may include executive dysfunction, depression, apathy, compulsiveness, and loss of empathy 3, 6
• Patients with ALS and cognitive impairment (ALS-ci/bi) show distinct functional connectivity patterns compared to those with only motor symptoms, suggesting they may represent a phenotypic variant of ALS rather than disease progression 3

Multidisciplinary Care

• A palliative care approach should be adopted from the time of diagnosis, with early referral to palliative services 4
• Regular follow-up with a multidisciplinary team including neurologists, pulmonologists, nutritionists, speech therapists, and palliative care specialists is recommended 4
• Address respiratory symptoms, which often become the primary cause of death along with malnutrition and dehydration 1

Prognosis

• Mean survival of typical ALS is 3-5 years after symptom onset, with only 5-10% living longer than 10 years 1, 7
• Patients with bulbar onset and older age have the shortest life expectancy 1
• The presence of frontal parietal atrophy and cognitive impairment may indicate a more complex phenotype with potentially different progression patterns 3

Common Pitfalls and Caveats

• CT of the head or spine is not useful in diagnosing ALS due to limited soft-tissue characterization 1
• There is insufficient evidence to support the use of FDG-PET/CT, MR spectroscopy, or functional MRI in the initial evaluation of suspected ALS 1
• Macroscopic atrophy on MRI is uncommon in early ALS, despite the presence of clinical symptoms 1
• Riluzole-treated patients taking other hepatotoxic drugs may be at increased risk for hepatotoxicity 2