Acute and chronic neuropathic pain in the hospital setting: use of screening tools.

OBJECTIVES: Chronic neuropathic pain (NP) is a well-known phenomenon, whereas acute neuropathic pain is increasingly recognized. Both are potentially difficult for a nonspecialist to diagnose. The Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) and DN4 scales are screening tools developed to identify chronic NP. We aimed to evaluate and compare their performance in 2 different populations: outpatients with chronic pain, and inpatients with acute postoperative pain.
METHODS: Consecutive outpatients attending the Lothian Chronic Pain Service completed the LANSS and DN4. Experienced clinicians independently classified each patient's pain as NP, mixed, or non-NP. In the acute setting, patients undergoing elective general or orthopedic surgery were assessed postoperatively using the LANSS and DN4.
RESULTS: Of 67 patients with chronic pain, consultants identified 17 (25.4%) patients with NP, 17 (25.4%) with mixed pain, and 33 (49%) with non-NP. The LANSS performed better than the DN4 in identification (positive predictive value 0.87 compared with 0.57). In the acute setting, the LANSS identified 5 of 165 patients (3%) as experiencing NP and the DN4 identified 7 of 165 (4.2%). DISCUSSION: Although the LANSS performed better than the DN4 in the chronic population, both tools performed less well than published literature, demonstrating the importance of evaluating screening tools in the proposed patient population. There may be potential for using these questionnaires to identify acute NP.