Catheter tip-associated granuloma: inflammatory mass with intrathecal drug delivery

Use of the intrathecal route to deliver drugs has become an acceptable treatment method for difficult pain syndromes. The primary advantage of intrathecal administration is the ability to deliver adequate relief at substantially lower doses of medication compared with other routes. This reduction of drug dosing leads to fewer side effects and improved efficacy. Morphine sulfate has been the most commonly used drug although other opioids and nonopioids have been prescribed. Over the past decade, the complication of an inflammatory mass at the catheter tip has been described. The prevalence of this problem appears to be much lower than 1%; however, because of the potential hazards, diagnostic vigilance is critical. Patient evaluation and reevaluation are the most important part aspect of the diagnosis. Loss of clinical efficacy, dermatomal pain in the distribution of the catheter tip, proprioceptive change, and sensory loss are early warnings. Motor loss, bladder and bowel dysfunction, and paralysis are late findings and occur with progression. When suspicion of the complication arises, a plain film should be obtained to identify the catheter tip, and then a T₁-weighted image should be performed at the tip. When magnetic resonance imaging (MRI) is not possible, a computerized tomography (CT) myelogram is an acceptable alternative. Treatment of this lesion involves discontinuing the infusion, then revising or removing the catheter. If spinal cord compression occurs, the treatment is direct surgical decompression. Many patients have continued with treatment after an inflammatory mass is diagnosed, once the catheter is revised or replaced. Prevention includes change of medications, avoidance of high-concentration morphine and hydromorphone, change of catheter tip location, and use of multiorifice catheters.