From the Guidelines
Cortical knob syndrome is not explicitly defined in the provided evidence, but based on the context of malformations of cortical development (MCD), it can be inferred that it may refer to a specific type of MCD characterized by abnormal cortical structure or heterotopic grey matter, potentially causing significant morbidity, including epilepsy, developmental delay, intellectual disability, or cerebral palsy 1.
Definition and Classification
The provided evidence discusses the definitions and classification of MCD, highlighting the complexity and heterogeneity of these disorders, which can cause significant morbidity at any age 1. MCD are characterized by abnormal cortical structure or presence of heterotopic grey matter, sometimes associated with abnormal brain size, and may cause epilepsy, developmental delay, intellectual disability, or cerebral palsy 1.
Diagnostic Approach
The definitive diagnosis of MCD is based on neuropathological findings, but for most practical purposes, diagnosis begins with neuroimaging features, and associated clinical phenotyping and genetic findings aid in subclassification 1. A multidisciplinary approach, including substantial expertise in pattern recognition using brain MRI with high-quality age-specific protocols, is required for accurate diagnosis 1.
Clinical Implications
While the provided evidence does not specifically mention cortical knob syndrome, it emphasizes the importance of accurate diagnosis and classification of MCD to improve genotype-phenotype correlations and communication among radiologists, clinicians, pathologists, and laboratory geneticists 1. Novel digital pathology methods for computer-aided analysis of images may be helpful in improving detection rates and reducing the human factor in making correct diagnoses of MCD 1.
Key Points
- MCD comprise a large, heterogeneous group of disorders of disrupted cerebral cortex formation caused by various genetic, infectious, vascular, or metabolic aetiologies 1.
- Accurate diagnosis and classification of MCD are crucial for improving genotype-phenotype correlations and communication among healthcare professionals 1.
- A multidisciplinary approach, including substantial expertise in pattern recognition using brain MRI, is required for accurate diagnosis of MCD 1.
From the Research
Definition and Characteristics
- Cortical knob syndrome, also known as cortical hand knob stroke, is a rare form of stroke that affects the motor cortex responsible for controlling fine hand movements 2.
- This condition is most commonly caused by ischemia in the "hand knob" region of the precentral gyrus, and can present with isolated hand weakness, often mimicking peripheral neuropathies and leading to diagnostic delays 3, 2.
Clinical Presentation
- Patients with cortical hand knob stroke may experience sudden onset of hand weakness, which can be accompanied by other symptoms such as slurred speech and facial droop 2.
- The condition can be easily misdiagnosed as peripheral lesions, and correct diagnosis is vital to enable initiation of secondary prevention 3.
Diagnosis and Treatment
- Magnetic resonance imaging (MRI) of the brain can reveal a focal ischemic lesion in the precentral gyrus, specifically involving the cortical hand knob region 2.
- Treatment for cortical hand knob stroke may include antiplatelet therapy, high-dose statins, and lifestyle modifications, such as smoking cessation 2.
- Recognition of this rare stroke subtype is essential for timely management and improved patient outcomes 2.
Related Conditions
- Malformations of cortical development (MCD) can also affect the motor cortex and lead to neurological impairments, including epilepsy and developmental disabilities 4, 5.
- Conditions such as lissencephaly, periventricular nodular heterotopia, and double cortex syndrome can cause intractable epilepsy and mental retardation, but are not necessarily amenable to surgical treatment 5.