Evaluating Causes of Back Pain in Patients with Sickle Cell Disease
Authors: Whitfield Andrea R , Kanter Julie 
Published: October 2019

Abstract
Background: Low back pain is a very common and costly problem that results in significant morbidity. When patients with sickle cell disease (SCD) present with back pain, physicians often assume that their pain is related to an acute painful crisis or to chronic pain caused by bone infarcts in the spinal column resulting in "H" shaped vertebral bodies. The occurrence of vertebral osteonecrosis in SCD patients is a well-documented cause of back pain and is noted on radiographs and often confirmed on magnetic resonance imaging (MRI). However, as with all presentations of pain in persons with SCD, the etiology can also be non-SCD related and should be fully evaluated. This case series profiles six patients with SCD who presented with back pain and underwent further assessment.
Methods: We conducted a retrospective chart review of six patients with SCD (mean age of 30.8 years) who presented with back pain during 2014. Institutional review board (IRB) approval was obtained from the Medical University of South Carolina for retrospective chart review. All of the patients were seen in the Comprehensive Lifespan Sickle Cell Clinic for regular evaluation. These patients underwent further evaluation due to presenting symptoms of increased pain, change in quality or character of pain, or associated neuropathic complaints.
Results: Three of the patients who presented with neuropathic symptoms were noted to have other (non-SCD) etiologies of back pain (facet cyst, vertebral disc protrusion) as outlined in Table 2. The etiology of the other three patients who presented with increased frequency of baseline pain was secondary to complications of SCD (Table 1).
Table 1. Patients with back pain secondary to SCD complications Patient #1 Patient #2 Patient #3 Age 15yo 25yo 31yo Sex Male Female Female Genotype Hgb SS Hgb SS Hgb SS Body Mass Index (BMI) 27 20 27 Presentation Chronic low back pain (increased symptom for patient on chronic transfusion therapy) Increased frequency of low back pain Increased frequency of back pain MRI findings Diffuse decreased signal intensity of the vertebral bodies, related to iron deposition. Osseous sequelae of SCD with Lincoln log morphology. No evidence of significant degenerative changes. Remodeling of the vertebral bodies consistent with patient's known history of sickle cell disease (hyperplastic marrow). Treatment Ferriprox (on study) Opiates, Cymbalta Opiates
Table 2. Patients with back pain secondary to other etiologies Patient #4 Patient #5 Patient #6 Age 32yo 36yo 46yo Sex Female Female Female Genotype Hgb SS Hgb SC Hgb SB+ Body Mass Index (BMI) 30 40 Not recorded Presentation New, atypical low back pain, worse with ambulation and upright position Chronic back pain with numbness and tingling in left leg Chronic low back pain and lower extremity tingling MRI findings Mild facet arthropathy at L3-L4 and L4-S1 with small juxta-articular/facet cysts at L3-4 without neuroforaminal or canal narrowing. Right central disc protrusion at L5-S1 with moderate central canal stenosis contacting the right transiting S1 nerve root. Slight interval increase in posterior disc bulge with bilateral paracentral protrusions and mild bilateral facet hypertrophy at L5-S1 causing mild narrowing of left neural foramen. Treatment Facet block and steroid administration with relief Neuropathic pain medication, physical therapy Neuropathic pain medication, referral for steroid injections
Discussion: This case series reveals the importance of full evaluation of pain in patients with SCD, especially in those individuals who present with neuropathic or neurologic causes. These cases demonstrate that other etiologies of back pain can be seen and should be treated in patients with SCD. In addition, there is substantial evidence linking obesity (increased BMI) and incidence of low back pain (as also seen in several of these patients). Thus, enhanced primary care, including attention to obesity and diet, is also imperative in this patient population.

Disclosures
No relevant conflicts of interest to declare.