Quantitative sensory testing in children with sickle cell disease: additional insights and future possibilities

Abstract

Summary Quantitative sensory testing (QST) is used in a variety of pain disorders to characterize pain and predict prognosis and response to specific therapies. In this study, we aimed to confirm results in the literature documenting altered QST thresholds in sickle cell disease (SCD) and assess the test–retest reliability of results over time. Fifty‐seven SCD and 60 control subjects aged 8–20 years underwent heat and cold detection and pain threshold testing using a Medoc TSAII. Participants were tested at baseline and 3 months; SCD subjects were additionally tested at 6 months. An important facet of our study was the development and use of a novel QST modelling approach, allowing us to model all data together across modalities. We have not demonstrated significant differences in thermal thresholds between subjects with SCD and controls. Thermal thresholds were consistent over a 3‐ to 6‐month period. Subjects on whom hydroxycarbamide (HC) was initiated shortly before or after baseline testing (new HC users) exhibited progressive decreases in thermal sensitivity from baseline to 6 months, suggesting that thermal testing may be sensitive to effective therapy to prevent vasoocclusive pain. These findings inform the use of QST as an endpoint in the evaluation of preventative pain therapies.

Multimodal phenotyping and correlates of pain following hematopoietic cell transplant in children with sickle cell disease

“…The experimental pain sensitivity reported here was generally comparable to previously published data in children with SCD 13,32,39 . Due to a small sample size and missing follow‐up QST measurements post‐HCT, we were limited in the conclusions that can be drawn.…”

“…40 Experimental pain sensitivity in SCD may also vary with age, 32 sex, 13 psychological factors, 13,41 pain frequency, 13 and may also change in response to interventions such as hydroxyurea. 39 Future studies should consider these confounding factors in studying…”

“…The experimental pain sensitivity reported here was generally comparable to previously published data in children with SCD. 13,32,39 Due to a small sample size and missing follow-up QST measurements post-HCT, we were limited in the conclusions that can be drawn. Both somatosensory deficits and pain sensitization have been described in patients who have undergone stem-cell transplantation for acute lymphoblastic leukemia.…”

Assessing neuropathic pain in sickle cell disease: How useful is quantitative sensory testing?

“…We also found that females were more sensitive to all modalities at the thenar eminence and dorsolateral foot, and that older subjects less sensitive to all at those sites except HPT and PPT at the thenar eminence and PPT at the dorsolateral foot. Sex differences are not commonly seen in QST in SCD studies (17,18). However, Brandow et al (13) have reported that both older SCD subjects and older non-SCD controls were more sensitive to heat and mechanical stimuli and that although there were no overall significant sex differences between groups, females with SCD had higher mechanical pain thresholds compared to males.…”

Sickle cell disease chronic joint pain: Clinical assessment based on maladaptive central nervous system plasticity

“…In SCD, the thermal pain threshold (TPT) to cold <17.01°C and heat <43.91°C are indicative of impaired nerve sensitivity, and pressure pain threshold (PPT) <4.42 g is indicative of the existence of altered sensory function ( 68 ). Thermal pain threshold (TPT) assessment with temperature in 32°C baselines and an increasing/decreasing temperature at a rate of 1.5°C/s is used in clinical settings (ICC >0.55) ( 69 ). In cases of non-SCD pain, specifically osteoarthritis of the knee, the PPT increasing pressure at a rate of 0.5 kgf/s has a good diagnostic reliability value varying according to the evaluated joint site (ICC: 0.64–0.73) ( 70 ).…”