What is the appropriate management and diagnosis for a patient presenting with increased brachial deep tendon reflex (DTR)?

Increased Brachial Deep Tendon Reflex: Diagnostic Approach and Management

Primary Diagnostic Consideration

Increased brachial DTR is a hallmark sign of upper motor neuron (UMN) dysfunction and specifically indicates cervical spinal cord compression, particularly at the C3-4 and/or C2-3 levels. 1

Clinical Significance and Localization

• Hyperactive brachial reflexes (including biceps, brachioradialis, and triceps) indicate upper motor neuron lesions affecting the cervical spinal cord 2
• The presence of a hyperactive pectoralis reflex is highly specific for upper cervical spinal cord compression at C2-3 and/or C3-4 levels (p < 0.004), and this finding should prompt immediate investigation of these specific levels 1
• Hyperreflexia at C3-4 or higher levels may also produce hyperactive deltoid reflexes, though this is less specific than the pectoralis reflex 1

Associated Upper Motor Neuron Signs to Assess

When evaluating increased brachial DTR, systematically examine for other UMN signs that confirm the diagnosis:

• Abnormal plantar reflex (extensor response/Babinski sign) indicating corticospinal tract involvement 2, 3
• Clonus at the wrist or ankle 3
• Velocity-dependent increased muscle tone (spasticity) rather than rigidity 3
• Clasp-knife response during passive movement 3
• Loss of fine motor control and selective muscle activation 3
• Absence of muscle atrophy (distinguishes from lower motor neuron lesions) 2

Differential Diagnosis Framework

Upper Motor Neuron Causes (Most Likely)

• Cervical spondylotic myelopathy - most common cause in adults, particularly with multilevel disease 1
• Cervical spinal cord compression from disc herniation, tumor, or trauma 1
• Multiple sclerosis or other demyelinating diseases
• Stroke affecting motor cortex or internal capsule

Lower Motor Neuron Causes (Would Show DECREASED Reflexes)

• Peripheral neuropathy - presents with diminished or absent DTRs 2
• Guillain-Barré syndrome - characterized by absent or decreased reflexes in affected limbs 2
• Radiculopathy - may show focal reflex loss at specific nerve root levels

Diagnostic Workup Algorithm

Step 1: Detailed Neurological Examination

• Document the specific pattern of hyperreflexia: Test biceps (C5-6), brachioradialis (C5-6), triceps (C7-8), pectoralis (C5-T1), and deltoid reflexes 1, 4
• Assess for sensory level: Sharp sensory level indicates spinal cord injury 2
• Evaluate lower extremity reflexes: Hyperreflexia in legs suggests myelopathy above the lumbar enlargement 2
• Test for pathological reflexes: Hoffman sign, Babinski sign 2
• Assess proprioception and vibratory sense: Posterior column involvement suggests myelopathy 2

Step 2: Imaging Studies

• MRI of the cervical spine is the gold standard for evaluating suspected cervical myelopathy and spinal cord compression 1
• If hyperactive pectoralis reflex is present, specifically evaluate C2-3 and C3-4 levels as these are the responsible compression sites 1
• MRI should include T1-weighted and T2-weighted sequences in sagittal and axial planes to delineate cord compression and signal changes 2

Step 3: Electrodiagnostic Studies (When Indicated)

• Nerve conduction studies and EMG help differentiate UMN from lower motor neuron pathology 2
• In UMN lesions, nerve conduction studies are typically normal, distinguishing from peripheral neuropathy 2
• Quantitative reflex testing can objectively measure reflex hyperactivity when clinical assessment is equivocal 5, 6

Management Approach

Immediate Actions

• Urgent neurosurgical consultation if cervical myelopathy is suspected, as progressive cord compression can lead to permanent neurological deficit 1
• Avoid neck manipulation until structural pathology is excluded
• Assess for red flags: Rapidly progressive weakness, bowel/bladder dysfunction, or severe pain requiring emergent intervention 2

Definitive Treatment

• Surgical decompression at the appropriate levels (guided by imaging and clinical localization) is indicated for symptomatic cervical myelopathy 1
• The presence of hyperactive pectoralis reflex helps identify C2-3/C3-4 as critical levels requiring decompression in multilevel disease 1

Common Pitfalls to Avoid

• Do not dismiss hyperreflexia as "normal variation" - it always indicates pathology requiring investigation 3, 1
• Do not confuse increased tone from spasticity (UMN) with rigidity (extrapyramidal) - spasticity is velocity-dependent and shows clasp-knife phenomenon 3
• Do not rely solely on lower cervical imaging (C5-7) when hyperactive pectoralis reflex is present, as the pathology is likely at C2-4 1
• Do not attribute hyperreflexia to anxiety or examiner technique - true pathological hyperreflexia persists across multiple examinations 6
• Do not delay imaging in patients with progressive symptoms - cervical myelopathy can cause irreversible cord damage if untreated 1