What imaging or investigations are recommended for a patient with a history of chronic pain who self-removed their Spinal Cord Stimulator (SCS) while delirious?

Imaging and Investigations for Self-Removed Spinal Cord Stimulator During Delirium

Immediate non-contrast CT of the spine at the level of the removed electrode is the essential first imaging study to evaluate for epidural hematoma, lead fragments, or other acute complications, followed by comprehensive laboratory workup to identify the underlying cause of delirium. 1, 2

Immediate Imaging Studies

Spinal Imaging (Priority)

• Non-contrast CT of the spine at the electrode implantation level should be obtained urgently to assess for:

  • Epidural hematoma (a known complication of SCS removal occurring in approximately 2.94% of cases) 3
  • Retained lead fragments or hardware 4, 3
  • Cerebrospinal fluid leak (occurs in approximately 1.2% of SCS procedures) 5, 6
  • Spinal cord compression or injury 4

• MRI of the spine with and without contrast should be considered if CT is non-diagnostic and neurological deficits are present, though this requires careful risk-benefit assessment given the patient's delirium and potential retained hardware 7

  • MRI is superior for detecting subtle spinal cord injury, infection, or mass lesions 7
  • The presence of SCS components does not absolutely contraindicate MRI, but requires careful evaluation of device specifications 7

Brain Imaging

• Non-contrast CT head is usually appropriate as initial imaging when evaluating new-onset delirium, particularly with: 1, 2, 8

  • Focal neurological deficits
  • History of recent trauma (including self-inflicted during device removal)
  • Altered mental status without clear precipitant
  • Signs of increased intracranial pressure

• The diagnostic yield of neuroimaging in undifferentiated delirium is only 5-11%, so selective use based on clinical indicators is appropriate 1, 8, 9

Essential Laboratory Investigations

Immediate Laboratory Testing

• Point-of-care glucose to rule out hypoglycemia as a reversible cause 8, 9
• Complete blood count with differential to evaluate for infection and blood loss from device removal 2, 9
• Comprehensive metabolic panel including electrolytes, renal function, liver function, and calcium 2, 9
• Urinalysis and urine culture given urinary tract infection is the most common infectious precipitant in delirium 8, 9

Additional Targeted Testing

• Thyroid function tests to exclude thyroid disorders presenting with altered mental status 2, 8
• Medication levels for any psychotropic medications or pain medications the patient is taking 2
• Toxicology screen to assess for substance intoxication or withdrawal 2, 9
• Blood cultures if fever is present or infection is suspected from the device removal 9

Specialized Investigations When Indicated

Cardiac Evaluation

• Electrocardiogram to assess for myocardial ischemia or arrhythmias that may precipitate delirium 2
• Chest radiography to evaluate for pneumonia or other pulmonary processes 2

Neurological Studies

• Electroencephalography (EEG) if seizure activity is suspected as a cause of altered mental status 2
• Lumbar puncture should be performed when: 2, 9
  • Fever is present without clear source
  • Meningeal signs are present
  • Patient is immunocompromised
  • Central nervous system infection is suspected

Critical Clinical Assessment Components

Neurological Examination Focus

• Assess for focal neurological deficits that may indicate spinal cord injury from device removal 1, 2
• Evaluate for progressive lower extremity weakness or new sensory deficits 7
• Document baseline cognitive function through collateral history to distinguish delirium from dementia 9

Delirium Screening

• Use the Confusion Assessment Method (CAM) to formally assess for delirium features 2, 9
• Screen systematically at least once per nursing shift using validated tools 9

Common Pitfalls to Avoid

• Failing to image the spine when a patient self-removes hardware can miss life-threatening epidural hematoma, which occurred in 2.94% of planned SCS removals 3
• Attributing all symptoms to delirium without investigating for acute spinal complications from the device removal 2, 8
• Overlooking medication side effects as the precipitant of delirium, particularly anticholinergics, sedatives, and opioids used for chronic pain 8, 9
• Mistaking hypoactive delirium for primary psychiatric disorder leading to delayed diagnosis 2
• Inadequate assessment for infection at the device site, which occurs in 4.2-13% of SCS cases 4, 6

Risk Stratification for Complications

Hardware-related complications from self-removal may include:

• Lead migration or fracture (most common SCS complication at approximately 11%) 4, 5
• Infection (occurs in 1.2-13% of cases) 4, 5, 6
• Epidural hematoma (major complication in 2.94% of removals) 3
• CSF leak (occurs in 0.9-1.2% of cases) 5, 6
• Neurological deficit (rare but reported in 0.9% of cases) 6

Patients who lost more than 20 mL of blood during planned removal had higher complication rates, suggesting traumatic self-removal carries significant risk 3