Diabetes Care Volume 44, March 2021 e53

Vertebral Ischemic Necrosis in Diabetic Ari Breiner,1,2 Thanh B. Nguyen,3 Bibianna Purgina,4 and Lumbosacral Radiculoplexus Neuropathy Pierre R. Bourque1,2 Diabetes Care 2021;44:e53–e54 | https://doi.org/10.2337/dc20-2787

Diabetic lumbosacral radiculoplexus neu- level of L1–L4 myotomes. The clinical and ropathy (DLRPN), or diabetic amyotrophy, electrodiagnostic findings were in keep- is an infrequent neurovascular complica- ing with DLRPN. tion of diabetes thought to result from MRI studies of the lumbosacral spine immune-mediated infarction of periph- (Fig. 1a and b) demonstrated serpigi- eral nerve branches (1). DLRPN has not nous, heterogenous T1 and T2 signal previously been reported in association with contrast enhancement in the pos- with infarction of the vertebral bone, terior and left aspects of the L4 vertebral which itself is a rare occurrence, typically body. This was felt to be most in keeping in the setting of aortic surgery and spinal with infarction. There was soft tissue cord infarction (2). We report a case of edema and enhancement surrounding simultaneous DLRPN and vertebral bony the left L4 nerve root exiting the neural infarction in a patient with type 2 di- foramen, as well as the left lumbosacral Figure 1—a: Axial T1-weighted image shows abetes, highlighting the unifying vascular plexus. Mild edema and mild abnormal a serpiginous line with low T1 signal within etiology responsible for both these un- enhancement were noted in the left the vertebral body. There is a decrease in size common pathologies. psoas, left iliacus, and left L4/L5 para- of the left psoas musclewith a subtleincrease in T1 signal compared with right. b: Axial T1- A 47-year-old man of Nepalese ori- spinal muscles. Although the suspected weighted image post-contrast shows serpig- gin presented to hospital with a 2-week diagnosis was multiple infarcts (affecting inous enhancement within the vertebral body, history of relatively acute-onset left lum- vertebral bone and peripheral nerves) in keeping with a vertebral infarct. There is bar pain, numbness and paresthesia in and acute denervation muscle atrophy, enhancement of the left proximallumbosacral the left obturator and saphenous nerve biopsy was pursued to exclude a malig- plexus (arrow), in keeping with an acute lum- bosacralplexitis.Thereisdiffuseenhancement distributions, and marked proximal left nant or infectious cause (including spi- of the left psoas and iliac muscles, which is

leg weakness. His past health was nota- nal tuberculosis, given recent travel to suggestive of acute denervation atrophy. c:At e-LETTERS ble for a 4-year history of type 2 diabetes, Nepal). Biopsy of the L4 vertebral body low power, the core biopsy shows viable and well controlled with sitagliptin, canagli- (Fig. 1c and d) demonstrated viable and nonviable bony spicules with focal marrow fat flozin, and metformin. On examination, nonviable bony spicules consistent with necrosis and occasional hematopoietic ele- ments (magnification 32, hematoxylin and – there was Medical Research Council (MRC) bone infarction, without any evidence eosin [H&E] stain). d: At higher power, there OBSERVATIONS grade 2/5 paresis of the left hip flexor and of neoplasia or inflammation. Tissue are nonviable fragments of lamellar bone with hip adductor muscles, with grade 1/5 and cerebrospinal fluid mycobacterial empty lacunae (lacking osteocytes). Along one power of knee extension. The left patel- cultures were negative. With conserva- edge (superior aspect), there is immature wo- fl ven bone being laid down on top of the non- lar re ex was absent. Electrodiagnostic tive management, there was marked im- viable bone (an “osteoid seam”)byosteoblasts, studies showed a reduced left femoral provement of pain within 2 weeks. At representing bone remodeling in the setting of motor potential and denervation at the 1-year follow-up there was only minimal osteonecrosis (magnification 320, H&E stain).

1Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, Ontario, Canada 2Ottawa Hospital Research Institute, Ottawa, Ontario, Canada 3Division of Neuroradiology, Department of Radiology, The Ottawa Hospital, Ottawa, Ontario, Canada 4Department of Pathology and Laboratory Medicine, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada Corresponding author: Ari Breiner, [email protected] Received 14 November 2020 and accepted 11 December 2020 © 2021 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at https://www.diabetesjournals.org/content/license. e54 Vertebral Ischemic Necrosis in DLRPN Diabetes Care Volume 44, March 2021

residual weakness in proximal left leg in autopsy studies showing infarcts of the Duality of Interest. No potential conflicts of muscles. lumbosacral plexus and proximal nerve interest relevant to this article were reported. Author Contributions. A.B. conceived the DLRPN is an uncommon, proximal, trunks (4). Moreover, biopsy studies of study and wrote the initial manuscript draft. asymmetrical form of diabetic neu- distal sensory nerves have shown regions T.B.N., B.P., and P.R.B. made significant contri- ropathy with significant morbidity. The of patchy inflammation surrounding small- butions to drafting subsequent iterations of the clinical presentation is typically one of caliber blood vessels, causing nerve ische- manuscript and made critical revisions for im- excruciating unilateral pain in the hip mia and subsequent axonal loss and focal portantintellectual content. A.B. is the guarantor of this work and, as such, had full access to all the girdle, proximal thigh, or lumbar region. demyelination (1,5). Similarly, numerous data in this study and takes responsibility for This is followed within days or weeks by cases of painful focal muscle infarction the integrity of the data and the accuracy of the significant, predominantly proximal, lower- (diabetic myonecrosis) have been re- data analysis. extremity weakness. In some cases, spread ported in the medical literature, and al- to the contralateral lower extremity oc- though the mechanism is not entirely References curs within weeks to months. There may clear, immune-mediated ischemia is felt 1. Dyck PJ, Norell JE, Dyck PJ. Microvasculitis and be prominent associated weight loss and to play an important role. ischemia in diabetic lumbosacral radiculoplexus neuropathy. Neurology 1999;53:2113–2121 dysautonomia. In many cases, there is This unique case, supported by both 2. Cheng MY, Lyu RK, Chang YJ, et al. Concom- incomplete recovery resulting in lasting radiological and pathological data, high- itant spinal cord and vertebral body infarction is neurologic disability. lights the occurrence of ischemic verte- highly associated with aortic pathology: a clinical Initial descriptions of DLPRN empha- bral osteonecrosis concurrent with DLRPN, and magnetic resonance imaging study. J Neurol 2009;256:1418–1426 sized the possibility of vasculopathy re- broadening the spectrum of complications 3. AsburyAK.Proximaldiabeticneuropathy.Ann lating to diabetic metabolic factors (3). of diabetes. It also lends further support Neurol 1977;2:179–180 More recent literature, however, favors to the role of ischemia in DLRPN. Finally, 4. Raff MC, Sangalang V, Asbury AK. Ischemic immune-mediated nerve ischemia re- this case also draws attention to the pos- mononeuropathy multiplex associated with – sulting from microvasculitis of vasa nerv- sibility of diabetic osteonecrosis in the diabetes mellitus. Arch Neurol 1968;18:487 499 osa at the level of very proximal nerve differential diagnosis of suspected malig- 5. Llewelyn JG, Thomas PK, King RH. Epineurial trunks. The presence of ischemic periph- nant or infectious disease of the spine. microvasculitis in proximal diabetic neuropathy. eral nerve damage has been documented J Neurol 1998;245:159–165