What is the appropriate workup for a positive Romberg sign?

Workup for Positive Romberg Sign

A positive Romberg sign indicates proprioceptive pathway dysfunction in the dorsal columns of the spinal cord, and the workup should prioritize MRI of the brain and cervical/thoracic spine without contrast to identify structural lesions, followed by targeted laboratory testing for metabolic and infectious causes. 1, 2

Initial Clinical Assessment

Confirm the test was performed correctly:

• Patient stood with feet together, arms at sides, for at least 20-30 seconds with eyes closed 2
• Significant worsening of balance or fall occurred specifically when eyes were closed (not present with eyes open) 2, 3
• Test was performed in a safe environment with the examiner positioned to catch the patient 2

Distinguish the type of ataxia present:

• Sensory ataxia (positive Romberg): Marked instability only with eyes closed, indicating dorsal column dysfunction 1, 2, 3
• Cerebellar ataxia (negative Romberg): Instability present with eyes both open and closed, often with dysmetria, dysarthria, and nystagmus 1, 3
• Vestibular ataxia: Instability with nystagmus and vertigo, may worsen on compliant surfaces 1, 4

Neuroimaging (First Priority)

MRI brain and cervical/thoracic spine without IV contrast is the initial imaging of choice 1:

• Evaluates for structural lesions affecting the dorsal columns (spinal cord compression, demyelination, infarction, tumors) 1
• Identifies posterior fossa pathology if cerebellar involvement is suspected 1
• Detects brainstem lesions that may affect proprioceptive pathways 1

Add IV contrast if:

• Inflammatory or infectious etiology suspected (transverse myelitis, abscess) 1
• Concern for neoplastic process 1

Laboratory Workup

Essential initial laboratory tests:

• Vitamin B12 level and methylmalonic acid: Subacute combined degeneration is a reversible cause of dorsal column dysfunction 1
• Hemoglobin A1c and fasting glucose: Diabetic neuropathy commonly affects proprioception 1
• TSH: Hypothyroidism can cause peripheral neuropathy 1
• RPR/VDRL: Neurosyphilis (tabes dorsalis) was the original disease associated with positive Romberg 5, 6
• Complete blood count: Anemia, infection, or hematologic malignancy 1

Additional testing based on clinical context:

• Copper and ceruloplasmin: Copper deficiency myelopathy mimics B12 deficiency 1
• HIV testing: HIV-associated myelopathy 1
• Lyme serology: If endemic area exposure 1
• Paraneoplastic antibody panel: If concern for paraneoplastic syndrome 1
• Heavy metal screening: If occupational or environmental exposure 1

Electrodiagnostic Studies

Nerve conduction studies and EMG should be performed if peripheral neuropathy is suspected 1, 7:

• Distinguishes between peripheral nerve (sensory neuropathy) versus central (spinal cord) pathology 4, 7
• Identifies pure sensory neuropathies affecting large fiber proprioceptive function 4, 7
• Quantifies severity of peripheral nerve dysfunction 7

Specialized Testing

Consider lumbar puncture if:

• MRI shows demyelinating lesions (evaluate for multiple sclerosis with oligoclonal bands, IgG index) 1
• Concern for Guillain-Barré syndrome or chronic inflammatory demyelinating polyneuropathy (elevated protein with albuminocytologic dissociation) 1
• Infectious etiology suspected (neurosyphilis, Lyme disease) 1

Vestibular function testing may be needed if:

• Clinical distinction between sensory and vestibular ataxia is unclear 1, 8
• Head impulse testing, vestibular evoked myogenic potentials can assess semicircular canal and otolith function 8

Common Pitfalls to Avoid

• Do not assume cerebellar pathology: A positive Romberg specifically indicates sensory pathway dysfunction, not cerebellar disease 1, 2, 3
• Do not order CT instead of MRI: CT has insufficient sensitivity for spinal cord and posterior fossa pathology 1
• Do not delay B12 testing: Subacute combined degeneration can progress rapidly and is reversible if caught early 1
• Do not forget copper deficiency: Increasingly recognized cause that mimics B12 deficiency but requires different treatment 1
• Do not overlook medication history: Certain drugs (chemotherapy agents, metronidazole, isoniazid) cause sensory neuropathy 1

Clinical Context Considerations

Acute onset (hours to days):

• Prioritize MRI to exclude stroke, transverse myelitis, or spinal cord compression 1
• Consider Guillain-Barré syndrome if areflexia present 1

Subacute onset (weeks to months):

• Focus on nutritional deficiencies (B12, copper), inflammatory conditions, and infections 1

Chronic progressive:

• Consider hereditary sensory neuropathies, paraneoplastic syndromes, or degenerative conditions 1, 9