What are the differential diagnoses for a patient with a history of neurological conditions presenting with worsening spinal spasticity, especially in the evening?

Differential Diagnoses for Worsening Spinal Spasticity with Evening Predominance

Immediate Life-Threatening Conditions to Exclude

Urgent neuroimaging with brain and spinal cord MRI must be obtained immediately to exclude acute stroke, spinal cord compression, hemorrhage, hydrocephalus, or new structural lesions, as any sudden neurological deterioration in a patient with established neurological conditions is inconsistent with the natural history of static conditions and demands investigation for new pathology. 1

Critical Acute Pathologies

• Spinal cord compression or injury - Can present with rapidly evolving symptoms and increased spasticity, requires immediate MRI 2, 1
• Acute transverse myelitis - Presents with rapidly evolving symptoms; patients may show upper motor neuron dysfunction with spasticity and hyperreflexia 2
• Spinal cord ischemia/thrombotic myelopathy - Can cause acute worsening of spasticity, particularly in patients with antiphospholipid antibodies 2
• Acute stroke or hemorrhage - Must be excluded with brain imaging 1
• Hydrocephalus - Can cause acute neurological deterioration 1

Infectious and Inflammatory Triggers

Urinary tract infection should be assessed immediately with urinalysis and urine culture, as UTIs occur in 15-60% of patients with neurological conditions and commonly cause acute changes in consciousness and neurological deterioration, including increased spasticity. 1

Common Precipitants

• Urinary tract infection - Most common trigger; causes 15-60% of acute deteriorations in neurological patients 1
• Infectious myelitis - Requires microbiological CSF studies to exclude 2
• Systemic infections - Can trigger increased spasticity through reflex hyperexcitability 3

Mechanical and Structural Causes

• Urinary retention with overflow - New incontinence warrants evaluation; can trigger spasticity 1
• Constipation/fecal impaction - Recognized trigger for excessive spasticity in spinal cord patients 1, 3
• Pressure ulcers - Normally painful conditions set off hyper-sensitive reflexes causing increased spasticity 3
• Renal calculi - Can trigger spasticity as substitute for pain in spinal cord patients 3

Neuromuscular and Demyelinating Conditions

• Neuromyelitis optica (NMO) - Associated with longitudinal myelopathy involving more than three spinal segments; upper motor neuron dysfunction with spasticity and hyperreflexia; should check serum NMO IgG (aquaporin) antibodies 2
• Multiple sclerosis - Can present with spasticity; requires brain MRI when other neuropsychiatric symptoms coexist 2
• Systemic lupus erythematosus with myelitis - Presents with upper motor neuron signs including spasticity; contrast-enhanced spinal cord MRI recommended 2

Vascular and Thrombotic Etiologies

• Antiphospholipid-associated myelopathy - More commonly associated with upper motor neuron dysfunction and spasticity; may require anticoagulation 2
• Vertebrobasilar insufficiency - Can cause transient neurological symptoms, though typically lasting less than 30 minutes 2

Medication-Related Causes

• Medication side effects - Antihypertensive medications, cardiovascular medications, Mysoline, carbamazepine, and phenytoin can produce dizziness and neurological symptoms 2
• Baclofen withdrawal - Abrupt discontinuation can cause severe rebound spasticity 4

Critical Diagnostic Pitfalls to Avoid

Never assume new symptoms represent progression of an established static neurological condition; cerebral palsy and other congenital conditions are non-progressive by definition, and any sudden neurological deterioration demands urgent investigation for alternative pathology. 1

• Do not delay neuroimaging - Acute stroke or spinal cord pathology requires time-sensitive intervention 1
• Excessive spasticity is not a normal state - In spinal cord injured patients, it should be recognized as a substitute for pain; infections, calculi, pressure ulcers, and other normally painful conditions trigger hyper-sensitive reflexes 3
• Evening worsening suggests underlying trigger - Circadian patterns may indicate accumulating irritants (full bladder, constipation) or fatigue-related factors 1, 3

Diagnostic Algorithm

1. Obtain urgent brain and spinal cord MRI to exclude acute stroke, hemorrhage, compression, or new lesions 1
2. Obtain urinalysis and urine culture immediately to assess for UTI 1
3. Assess for urinary retention with post-void residual if new incontinence present 1
4. Evaluate for constipation/fecal impaction through history and examination 1, 3
5. Perform complete skin examination for pressure ulcers 1, 3
6. If imaging and initial workup negative, treat underlying triggers first (UTI, constipation, pressure ulcers) before attributing symptoms to baseline condition 1
7. Consider specialized testing if initial workup unrevealing: NMO antibodies if longitudinal myelopathy present, antiphospholipid antibodies if thrombotic mechanism suspected 2