Diagnostic Approach to Progressive Ascending Weakness with Mixed Reflex Pattern

Clinical Recognition and Differential Diagnosis

The American Academy of Neurology suggests that progressive bilateral weakness starting in legs and ascending to arms is characteristic of classic sensorimotor Guillain-Barré syndrome (GBS) 1
Reflexes are typically decreased or absent in most patients at presentation and almost all at nadir, according to the American Academy of Neurology 1
The presence of normal reflexes in lower limbs represents an atypical feature that warrants careful consideration, as stated by the American Academy of Neurology 1
The reduced upper limb reflexes combined with weakness supports a peripheral nerve process, as indicated by the American Academy of Neurology 2
Transverse myelitis is a critical red flag requiring immediate attention, characterized by acute/subacute weakness with sensory changes, often bilateral with increased deep tendon reflexes, according to the American Society of Clinical Oncology 3
Spinal cord compression is another critical red flag, requiring urgent imaging to exclude progressive neurologic deficits, as recommended by the American College of Radiology 4

The American College of Radiology recommends MRI spine without contrast as the critical initial imaging study to evaluate for spinal cord pathology or nerve root enhancement 3, 4
MRI of the entire spine (cervical, thoracic, lumbar) with thin axial cuts through regions of suspected abnormality is essential, as stated by the American College of Radiology 3, 4
CSF analysis is essential for diagnosis, including cell count, protein, glucose, and oligoclonal bands, according to the American Academy of Neurology 2
Electrodiagnostic studies, such as nerve conduction studies and EMG, should be performed to reveal sensorimotor polyradiculoneuropathy or polyneuropathy in GBS, as recommended by the American Academy of Neurology 2

The American Academy of Neurology suggests that treatment should be initiated urgently once GBS diagnosis is established, with IVIG 2 g/kg over 5 days or plasmapheresis as first-line treatments 1, 3
Respiratory monitoring, including vital capacity and negative inspiratory force, is crucial, as stated by the American Thoracic Society 3
Dysautonomia monitoring, including blood pressure and heart rate instability, is common, according to the American Academy of Neurology 1
Pain management, including muscular, radicular, or neuropathic pain, is frequently reported, as indicated by the American Academy of Neurology 1