Early insights into the neurobiology of pain in sickle cell disease: A systematic review of the literature.

Novel insights into the neurobiology of sickle cell disease (SCD) pain have recently been discovered. We systematically reviewed the literature focusing on original research that examined the biology of pain in SCD and/or addressed assessment or treatment of neuropathic pain in SCD. This review of 15 articles that met inclusion criteria provides epidemiological, basic, and clinical data that support central and/or peripheral nervous system abnormalities likely contribute to sickle cell pain. Continued basic and clinical investigation into pain neurobiology is imperative to translate these discoveries into novel ways to assess and treat neuropathic pain and decrease patient suffering.

The use of neuropathic pain drugs in children with sickle cell disease is associated with older age, female sex, and longer length of hospital stay.

Although neuropathic pain is increasingly recognized in sickle cell disease (SCD), it is unknown how neuropathic pain drugs are used in children with SCD. Thus, we investigated use of these drugs and hypothesized older age and female sex are associated with increased neuropathic drug use and the use of these drugs is associated with longer length of stay. We analyzed the Pediatric Health Information System (2004 to 2009) including all inpatient visits aged 0 to 18 years with any SCD-related (all genotypes) discharge diagnosis. To limit confounding we excluded psychiatric and seizure visits. Antiepileptics, tricyclic antidepressants, and selective serotonin reuptake inhibitors were drugs of interest. Generalized Estimating Equations determined the impact of age and sex on neuropathic drug use and the impact of neuropathic drug use on length of stay. We analyzed 53,557 visits; 2.9% received≥1 neuropathic drugs. The odds of receiving a neuropathic drug increased significantly with age (reference group, 0 to 4 y: 5 to 10, odds ratio [OR], 5.7; 11 to 14: OR, 12.5; 15 to 18: OR, 22.8; all P<0.0001] and female sex (OR, 1.5; P=0.001). Neuropathic drug use was associated with longer length of stay (risk ratio, 8.3; P<0.0001). Neuropathic drug use in children with SCD was associated with older age, female sex, and longer length of stay.

Neuropathic pain in patients with sickle cell disease.

BACKGROUND: Despite the suggestion of a neuropathic component to sickle cell disease (SCD) pain, there are minimal data on the systematic assessment of neuropathic pain in patients with SCD. Neuropathic pain is defined as pain primarily initiated by dysfunction of the peripheral or central nervous system. PROCEDURE: In a cross-sectional study, we used the painDETECT questionnaire, a one-page validated neuropathic pain screening tool, to determine the presence of neuropathic pain in patients with SCD and to evaluate the relationship between neuropathic pain, age, and gender. We hypothesized that 20% of patients with SCD will experience neuropathic pain and that neuropathic pain will be associated with older age and female gender. The completed painDETECT questionnaire yields a total score between 0 and 38 (≥ 19 = definite neuropathic pain, 13-18 = probable neuropathic pain, ≤ 12 = no neuropathic pain). Scores ≥ 13 were designated as having evidence of neuropathic pain. RESULTS: A total of 56 patients participated. Median age was 20.3 years and 77% were female. We found 37% of patients had evidence of neuropathic pain. Age was positively correlated with total score (r = 0.43; P = 0.001) suggesting older patients experience more neuropathic pain. Females had higher mean total scores (13 vs. 8.4; P = 0.04). Significantly more patients with neuropathic pain were taking hydroxyurea (90% vs. 59%; P = 0.015). Despite 37% of patients experiencing neuropathic pain, only 5% were taking a neuropathic pain drug. CONCLUSIONS: Neuropathic pain exists in SCD. Valid screening tools can identify patients that would benefit from existing and future neuropathic pain therapies and could determine the impact of these therapies.