The Journal of the Arkansas Medical Society Med Journal June 2020 | Page 14

Case Study by Greg Cox; Rani H. Lindberg, MD 1 1 Associate Professor, Department of Physical Medicine and Rehabilitation, UAMS, Little Rock, Ark. Unrecognized Baclofen Withdrawal Secondary to Inaccurate Medication Reconciliation in a Spinal Cord Injury Patient with an Intrathecal Baclofen Pump Abstract Baclofen therapy is often utilized to treat spasticity in patients that have suffered neurologic insult. In this case, a 39-year-old man with spastic quadriplegia presented with fever, abdominal pain, nausea, and hematemesis 24 hours after intrathecal baclofen (ITB) pump replacement. Initial work-up was negative, and ITB pump was confirmed to be functioning properly. Later, it was discovered that the patient had been taking oral and intrathecal baclofen, and was in acute baclofen withdrawal. Baclofen withdrawal has a non-specific array of symptoms and can easily be misdiagnosed. Review of dosing habits can prevent adverse drug events and prolonged hospitalizations. Case Diagnosis A 39-year-old man with spastic quadriplegia secondary to complete spinal cord injury presented to the emergency department (ED) 24 hours after intrathecal baclofen (ITB) pump replacement with complaints of fever, abdominal pain, nausea, and coffee ground emesis. Routine work up for infection and abdominal pain was notable for a urinary tract infection (UTI) and bowel impaction. Due to the severity of symptoms, he was admitted and started on empiric antibiotics. Despite treatment with antibiotics, his fever, hypertension, and tachycardia did not improve. The surgical site was evaluated, and no wound infection or surgical complication was found. The patient then underwent bowel disimpaction for suspected autonomic dysreflexia, but this also failed to alleviate his symptoms. Within 24 hours of admission, he had developed mental status changes with hallucinations. The Physical Medicine and Rehabilitation team was consulted to interrogate the ITB pump for possible pump malfunction, and it was found to be functioning appropriately. On review of the patient’s medication list, it was noted that he had an outpatient prescription for oral baclofen as needed (PRN). The outpatient ITB pump clinic notes were then reviewed, and it was discovered the patient had been taking oral baclofen scheduled rather than intermittently. Because his outpatient prescription for oral baclofen had been documented as PRN, oral baclofen was not scheduled during his admission for ITB pump replacement, nor had it been administered during this readmission. Oral baclofen therapy was reinitiated, and within 12 hours patient had resolution of cognitive impairments and significant improvement in spasticity, blood pressures, and heart rate Figure 1. Baclofen pump catheter entering the spinal canal at L3- 4 level and terminating at the T6-7 level without discontinuity or kinking. confirming that a significant contribution to his presenting symptoms was baclofen withdrawal. Discussion We present a case of unrecognized baclofen withdrawal resulting in a complicated post-operative course and prolonged hospital stay. Baclofen is commonly used for the treatment of spasticity. It is a GABA-B receptor agonist in the central nervous system, and achieves its therapeutic effect via prevention of calcium influx in presynaptic neurons, which reduces presynaptic neurotransmitter release.4 It has been shown to improve spasticity in 70-96% of patients. 4 Baclofen is administered either orally or intrathecally. Administration of baclofen intrathecally has been found to be effective for patients with spasticity that is not well-controlled with the maximum dose of oral baclofen therapy. Intrathecal baclofen therapy allows for higher concentrations of drug in the cerebrospinal fluid than can be achieved with oral baclofen therapy. 6 Withdrawal from baclofen can be a life-threatening condition and has a wide variety of signs and symptoms such as high fever, pruritis, sedation, weakness, altered mental status, rebound spasticity, and muscle rigidity. 2 Baclofen withdrawal may be treated with IV hydration, administration of oral or intrathecal baclofen, or even dantrolene and IV benzodiazepines. 7 The consequences of untreated baclofen withdrawal are severe and have been seen to progress to rhabdomyolysis, neuroleptic malignant syndrome, disseminated intravascular coagulation, 3 multi-organ system failure, and death. 8 Due to the non-specific sequelae associated with baclofen withdrawal, work-up for a different cause is often sought. There are case reports of baclofen withdrawal initially being misinterpreted as sepsis, myocardial infarction, and pulmonary embolism due to the often-complicated presentation of acute baclofen withdrawal. 8,9 278 • The Journal of the Arkansas Medical Society www.ArkMed.org