Multiple myeloma and malignant lesions: a potential risk factor for local anesthetic systemic toxicity.

BACKGROUND: Multiple myeloma is a cancer of plasma cells that often leads to complications including osteolytic bone lesions, nephropathy and neuropathy. Multiple myeloma is only one etiology of many cancer pain conditions that may necessitate interventional pain treatment when refractory to multimodal medications. Notably, local anesthetic systemic toxicity is a rare but life-threatening complication of local anesthetic administered for these interventions. CASE PRESENTATION: A 50-60-year-old woman presented with multiple myeloma complicated by chronic bone pain and in an acute pain crisis. A fluoroscopic-guided L4-5 epidural catheter was placed with clinical doses of bupivacaine for comfort to undergo MRI of the spine. Soon after, she became tachycardic, tachypneic and hypoxic requiring non-invasive positive pressure airway support. As this respiratory distress was attributed to a large pleural effusion, a pigtail catheter was inserted in the intensive care unit with submaximally dosed lidocaine infiltration. She then developed a left bundle branch block followed by cardiovascular collapse minimally responsive to high-dose inotrope and vasopressor support. Lipid emulsion was started with dramatic therapeutic response and recovery to baseline. A CT of the thoracolumbar spine showed worsening extensive lytic lesions throughout all vertebral bodies and ribs from diffuse myeloma. CONCLUSIONS: Patients with oncologic lesions focal to the thoracolumbar spine may be at higher risk for local anesthetic systemic toxicity from palliative epidurals due to increased cancer-related angiogenesis. Likewise, local anesthetic infiltration for procedures near any malignant sites could have a similar risk and may require lower initial fractionated dosages with increased vigilance.

Prevalence of house dust mite allergens in low-income homes with evaporative coolers in a semiarid climate.

House dust mites are typically absent in homes in arid and semiarid climates due to low humidity. Evaporative "swamp" cooling significantly increases indoor humidity in dry climates and is suspected of promoting dust mite survival in these regions. We investigated the prevalence and concentration of mite allergens in dust from low-income homes (N = 22) with evaporative coolers in Utah County, Utah. Overall, 15 homes (68.2%) were positive for either Der p 1 or Der f 1 in at least 1 location. Geometric mean allergen levels in mattresses were 0.107 and 0.087 ug/g dust for Der p 1 and Der f 1, respectively. In furniture, levels were 0.143 and 0.165 ug/g dust for Der p1 and Der f 1, respectively. The percentage of positive homes in this study was much higher than previously reported in larger homes with swamp coolers in the same community. These results suggest socioeconomic factors may play a role in dust mite allergen prevalence in homes with evaporative coolers in dry climates.