Sickle cell pain: a critical reappraisal

Pain measurement as part of primary healthcare of adult patients with sickle cell disease

Objective

The aim of this exploratory, cross-sectional study was to evaluate pain in sickle cell disease patients and aspects related to primary healthcare.

Methods

Data were obtained through home interviews. The assessment instruments (body diagram, Numerical Pain Scale, McGill Pain Questionnaire) collected information on the underlying disease and on pain. Data were analyzed using the Statistical Package for Social Sciences program for Windows. Associations between the subgroups of sickle cell disease patients (hemoglobin SS, hemoglobin SC, sickle β-thalassemia and others) and pain were analyzed using contingency tables and non-parametric tests of association (classic chi-square, Fisher's and Kruskal-Wallis) with a level of 5% (p-value < 0.05) being set for the rejection of the null hypothesis.

Results

Forty-seven over 18-year-old patients with sickle cell disease were evaluated. Most were black (78.7%) and female (59.6%) and the mean age was 30.1 years. The average number of bouts of pain annually was 7.02; pain was predominantly reported by individuals with sickle cell anemia (hemoglobin SS). The intensity of pain (Numeric Pain Scale) was 5.5 and the quantitative index (McGill) was 35.9. This study also shows that patients presented a high frequency of moderately painful crises in their own homes.

Conclusion

According to these facts, it is essential that pain related to sickle cell disease is properly identified, quantified, characterized and treated at the three levels of healthcare. In primary healthcare, accurate measurement of pain combined with better care may decrease acute painful episodes and consequently minimize tissue damage, thus improving the patient's overall health.

Sickle cell disease related mortality in the United States (1999-2009)

BACKGROUND

Little is known about the national outcome of children and adults with sickle cell disease (SCD) given contemporary care.

PROCEDURE

We investigated the number of deaths, standardized crude and age-adjusted mortality rates, and causes of death among individuals with SCD across the United States during 1999-2009 according to death certificates by using a publicly available website (http://wonder.cdc.gov/). Data were compared to mortality during 1979-1998.

RESULTS

When compared to 1979-1998, mortality significantly decreased by 61% in infants <1 year of age, by 67% in children aged 1-4 years, and by 22-35% in children aged 5-19 years. After 19 years of age, mortality rates increased from 0.6 in the 15-19 year group to 1.4/100,000 in the 20-24 year group, corresponding to the transition period from pediatric to adult medical care, and this increase was similar during 1979-1998. Although the age groups with the highest mortality were 35-44 years for males and 45-54 years for females, there was a tendency for longer survival because there were more deaths among those individuals 55-74 years of age compared to previous years. For all individuals, the causes of deaths were cardiac disease (31.6%), respiratory (28.1%), renal (16.4%), infectious (14.4%), neurologic (11.9%), and gastrointestinal and hepatobiliary (9.2%) in nature. Cancer was the cause of death in <1%.

CONCLUSION

Mortality during childhood has decreased significantly. However, the transition period from pediatric to adult care is critical. Risk-reduction, monitoring, and early treatment intervention of cardiovascular disease in adults is warranted.

Morphine stimulates platelet-derived growth factor receptor-β signalling in mesangial cells in vitro and transgenic sickle mouse kidney in vivo

BACKGROUND

Pain and renal dysfunction occur in sickle cell disease. Morphine used to treat pain also co-activates platelet-derived growth factor receptor-β (PDGFR-β), which can adversely affect renal disease. We examined the influence of morphine in mesangial cells in vitro and in mouse kidneys in vivo.

METHODS

> Mouse mesangial cells treated with 1 μM morphine in vitro or kidneys of transgenic homozygous or hemizygous sickle or control mice (n=3 for each), treated with morphine (0.75, 1.4, 2.14, 2.8, 3.6, and 4.3 mg kg(-1) day(-1) in two divided doses during the first, second, third, fourth, fifth, and sixth weeks, respectively), were used. Western blotting, bromylated deoxy uridine incorporation-based cell proliferation assay, reverse transcriptase-polymerase chain reaction, immunofluorescent microscopy, and blood/urine chemistry were used to analyse signalling, cell proliferation, opioid receptor (OP) expression, and renal function.

RESULTS

Morphine stimulated phosphorylation of PDGFR-β and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) to the same extent as induced by platelet-derived growth factor-BB (PDGF-BB) and promoted a two-fold increase in mesangial cell proliferation. The PDGFR-β inhibitor, AG1296, OP antagonists, and silencing of μ- and κ-OP abrogated morphine-induced MAPK/ERK phosphorylation and proliferation by ~100%. Morphine treatment of transgenic mice resulted in phosphorylation of PDGFR-β, MAPK/ERK, and signal transducer and activator of transcription 3 (Stat3) in the kidneys. Morphine inhibited micturition and blood urea nitrogen (BUN) clearance and increased BUN and urinary protein in sickle mice.

CONCLUSION

Morphine stimulates mitogenic signalling leading to mesangial cell proliferation and promotes renal dysfunction in sickle mice.

Mast cell activation contributes to sickle cell pathobiology and pain in mice

Sickle cell anemia (SCA) is an inherited disorder associated with severe lifelong pain and significant morbidity. The mechanisms of pain in SCA remain poorly understood. We show that mast cell activation/degranulation contributes to sickle pain pathophysiology by promoting neurogenic inflammation and nociceptor activation via the release of substance P in the skin and dorsal root ganglion. Mast cell inhibition with imatinib ameliorated cytokine release from skin biopsies and led to a correlative decrease in granulocyte-macrophage colony-stimulating factor and white blood cells in transgenic sickle mice. Targeting mast cells by genetic mutation or pharmacologic inhibition with imatinib ameliorates tonic hyperalgesia and prevents hypoxia/reoxygenation-induced hyperalgesia in sickle mice. Pretreatment with the mast cell stabilizer cromolyn sodium improved analgesia following low doses of morphine that were otherwise ineffective. Mast cell activation therefore underlies sickle pathophysiology leading to inflammation, vascular dysfunction, pain, and requirement for high doses of morphine. Pharmacological targeting of mast cells with imatinib may be a suitable approach to address pain and perhaps treat SCA.

Male gender, increased blood viscosity, body mass index and triglyceride levels are independently associated with systemic relative hypertension in sickle cell anemia

Patients with sickle cell anemia (SCA) have usually lower diastolic, systolic and mean blood pressure (BP) than the general population. However, BP values ≥120/70 mmHg considerably increase the risk for acute and chronic complications in SCA. The aim of this study was to identify biological factors associated with relative hypertension in adults with SCA. We compared the hematological, lipid and hemolytic profiles, as well as blood viscosity, between SCA patients with normal BP (<120/70 mmHg, n = 54) and those with relative hypertension (BP≥120/70 mmHg, n = 43). Our results demonstrated that male gender (OR: 3.49; 95%CI 1.20 to 10.16, p<0.05), triglycerides (OR: 9.19; 95% CI 2.29 to 36.95, p<0.01), blood viscosity (OR: 1.35; 95% CI 1.01 to 1.81, p<0.05) and body mass index (OR: 1.37; 95% CI 1.14 to 1.64, p<0.01) were independent risks factors for relative hypertension in SCA. No association was found between the BP status and the positive history of painful vaso-occlusive crisis or acute chest syndrome. An association between triglycerides level and the occurrence of these two major acute complications was detected. Our study suggests that male gender, increased triglycerides level, BMI and blood viscosity could increase the risk for developing relative hypertension in SCA. In addition, our results support a role of moderately elevated triglycerides in the pathophysiology of vaso-occlusive events.

Oral ketamine for sickle cell crisis pain refractory to opioids

There is literature demonstrating that the N-methyl-d-aspartate (NMDA) receptor antagonist ketamine has analgesic properties that can be used as an adjuvant to opiates for pain relief in multiple various conditions and pain states. However, there is a lack of published information on ketamine used in persons with sickle cell disease in acute pain crises. The Virginia Commonwealth University Palliative Care team was consulted on a 38-year-old African American female with sickle cell thalassemia in severe acute pain crisis overlying chronic pain related to her disease. Pain control was unable to be achieved with escalating doses of opiates and other adjuvant medications. The patient responded well to an intravenous test dose of ketamine and was subsequently placed on an oral regimen of ketamine in addition to opiates. In the 24-hour period following ketamine initiation, the patient's pain was able to be controlled on decreased amounts of opiates. She was eventually transitioned to an oral opiate and ketamine regimen, which allowed her to be discharged home with pain levels close to her baseline and the ability to function and perform all activities of daily living.

Nature and nurture of human pain

Humans are very different when it comes to pain. Some get painful piercings and tattoos; others can not stand even a flu shot. Interindividual variability is one of the main characteristics of human pain on every level including the processing of nociceptive impulses at the periphery, modification of pain signal in the central nervous system, perception of pain, and response to analgesic strategies. As for many other complex behaviors, the sources of this variability come from both nurture (environment) and nature (genes). Here, I will discuss how these factors contribute to human pain separately and via interplay and how epigenetic mechanisms add to the complexity of their effects.

Sudden death in a case of sickle cell anemia: post-mortem computed tomography and autopsy correlation from a radiologist's perspective

Sickle cell anemia (SCA) is a hemolytic disease characterized by the production of abnormal hemoglobin chains and distorted red blood cell morphology or sickling. "Sickle cell crisis" includes vaso-occlusive crisis, a plastic crisis, sequestration crisis, haemolytic crisis and often culminating in serious complications, organ damage and even sudden death. Post-mortem computed tomography (PMCT) findings of sickle cell disease have never been reported in literature. This case of sudden death from acute hemolytic crisis in SCA where post-mortem computed tomography (PMCT) and autopsy findings complemented each other, both revealing findings invisible to the other and both crucial to the case.