Symptomatic Intrathecal Catheter Tip Granuloma Formation With Ultralow-Dose and Low-Concentration Morphine Infusion: A Case Report and Review of Literature

ObjectivesThis study aimed to describe catheter tip granuloma (CTG) formation in a patient on ultralow-dose, low-concentration morphine via intrathecal (IT) drug delivery system (IDDS) and to review literature for reports of IT granuloma formation and association with drug type, drug dose, and drug concentration.Materials and MethodsThis review describes diagnosis and management of a patient with CTG on ultralow-dose, low-concentration morphine. PubMed data base search was conducted from January 1990 to July 2021 for original articles on CTG formation in humans getting intrathecal analgesics. Data were extracted on indications for IDDS, time to detect CTG, and type of drug/s with drug doses and concentrations. Percentages and average with range for age, sex, duration of infusion, drug doses, and drug concentrations were calculated.ResultsWe describe CTG formation and spinal cord compression with worsening of sensorimotor deficits in a patient receiving intrathecal morphine at ultralow dose (0.6 mg/d) and low concentration (1.2 mg/mL), which is the lowest reported morphine dose associated with CTG in the literature. Our literature review shows all IT drugs have the potential for granuloma formation, and there is no drug with granuloma-inhibiting effect.ConclusionsThere is no drug, dose, or concentration that has granuloma-sparing effect. It is imperative to maintain vigilance for potential CTG in all patients with IDDS. Routine monitoring and prompt evaluation for any unexplained symptoms or change in neurologic status from baseline is critical in early detection and treatment of CTG.