Background & Aims
Background: Herpetic (HN) and Post- Herpetic (PHN) neuralgia are painful conditions that affects up to 30% of Herpes Zoster patients, reducing quality of life and promoting severe mechanical and thermal allodynia and burning pain for years. HN and PHN patients may develop varied pain and exteroceptive responses, including sensory loss due to peripheral deafferentation of small unmyelinated fibers or abnormal sensations associated to irritable nociceptors. Pharmacological treatments are partially effective and brings together many adverse effects. Photobiomodulation, such as the low-level laser (LLL) demonstrates effectiveness as an adjuvant analgesic therapy and has been successfully used to reduced pain scores in PHN cases.
Aims: To characterize the painful responses and sensory exteroceptive profile of a sample of volunteers with HN and PHN pre and post PBM treatment with LLL, using pain and quality of life screening questionnaires and the Quantitative Sensory Test (QST).
Methods
Interventional study, with a sample of 33 volunteers with HN and /or PHN evaluated, until this date, including men and women (18 to 99 yo), who confirmed participation through the informed consent form. Patients were asked to answer the Brief Pain Inventory (IBD), Brief McGill, Neuropathic Pain Symptons Inventory (NPSI), Neuropathic Pain-4 (NP-4) questionnaires, and the Hospitalar Anxiety and Depression Scale (HADS). Exteroceptive responses of detection and pain thresholds and suprathreshold for mechanical and thermal stimuli ipsi and contralateral to the affected area were evaluated withby QST. 12 patients were included and concluded PBM treatment (continuous, 660nm, 4J, 142,85 J/cm2, 100 MW, 40’, 0,28 cm2), applied punctually, covering all the affected area, with 1 cm of distance between dots, in a total of 8 sessions, once a week. Pain scores and QST were re-evaluated at the end of treatment.
Results
Up to 81% patients presented PHN, mostly (87%) older then 50 years old, that had the thoracic dermatomes (51%) affected. 75% of patients used pharmacological analgesics with 48% of pain relief. IBD and McGill questionnaires showed moderate to severe pain in 88%, with DN-4 suggesting neuropathic pain (81%), in which 48% had frequent neuropathic symptoms according to NPSI. 66% presented anxiety-like symptoms and 42% also showed depression factors. QST responses for mechanical and thermal thresholds were similar between ipsi and contralateral areas and controls. PBM decreased pain score in BPI and NPSI however most still presented severe neuropathic pain according to McGill and DN-4 questionnaires. No changes on HADS scores were observed. After PBM, 58% of patients kept using pharmacological treatments, now with 71% of pain relief. QST pre and post PBM did not showed significant alterations.
Conclusions
Our data suggested a beneficial effect of PBM as an adjuvant therapy to conventional used pharmacology, together with greater quality of life, anxiety and depression scores.
References
FASHNER, J.; BELL, A. L. American family physician, v. 83, n. 12, p. 1432–7, 15 jun. 2011;
MALLICK-SEARLE, T.; SNODGRASS, B.; BRANT, J. M. Journal of Multidisciplinary Healthcare, v. 9, p. 447–454, 2016;
MUKHTAR, R et al. Lasers in Medical Science, v. 35, p. 1759-1764, 2020.
Presenting Author
Heloisa Alonso Matielo
Poster Authors
Camila Squarzoni Dale
Associate Professor
Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo
Lead Author
Topics
- Specific Pain Conditions/Pain in Specific Populations: Pain in Infectious Diseases