Spinal Artery Thrombosis: An Unrecognized Severe Complication in Thalassemia and Sickle Disorders
Authors: Marzolini Maria , Poggiali Erika , Badat Mohsin , Cassinerio Elena , Cappellini Maria D , Porter John B. 
Published: October 2019

Abstract
Abstract 1155

Introduction.
Anterior spinal artery thrombosis (AST) results in sudden, often irreversible sensory and motor loss, with partial or complete paraplegia. This is recognized as a complication of: prothrombotic states; right to left shunting; trauma and spinal surgery. Both venous and arterial thrombosis, including the central nervous system, are well-recognized risks in sickle cell disease (SCD) but AST has not been described. In thalassemia disorders (Thal), cerebral infarction, often silent, is increasingly recognized (Mussalam et al, Thromb Res, Aug 2012). However AST is not a recognized complication. Here we describe four cases of acute onset AST in adults (3 Thal major, 1 SCD), leading to severe neurological irreversible or partially reversible deficits.

Patients and Methods.
Patients described were attending outpatients for monitoring drawn from two large adults clinics in the UK (UCLH, Whittington, over 1500 hemoglobinopathy patients) and Italy (Ospedale Maggiore Policlinico, Milan, 400 patients). All events occurred within a 3 year period.

Results.
Presenting symptoms and Magnetic Resonance Imaging (MRI) findings are shown in the Table. All cases presented acutely with a sensory level on examination and with bladder dysfunction. Three presented with motor weakness of both lower limbs (1 case initially in one limb). Case 3 presented with a sensory deficit affecting the sacral region but no motor deficit. Partial reversibility occurred in cases 1 and 3. In Thal cases, no prodromal syndrome and no prior history of thrombosis were seen. MRI showed changes consistent with acute cord ischemia (delayed in case 4 until 5 days). Extra-medullary hematopoiesis was demonstrated by MRI only in case 2, but was not sufficient to cause cord compression. Cerebrospinal fluid analysis was normal in all cases. Concomitant risk factors such as autoimmune markers, active hepatitis, trauma, or demonstrable prothrombotic markers other than those expected in SCD or Thal were not detected. In none of the Thal cases was a thrombotic history elicited but the SCD patient had a history of retinal artery and renal artery thrombosis (1 year previously).

Discussion.
A case series of this serious complication has not been previously reported. The known prothrombotic tendency in SCD and Thal is the most likely risk factor as other risk factors were absent. Thal cases were transfusion dependent, where thrombosis risk is generally about a quarter of that in non transfusion dependent Thal (Cappellini, Blood Reviews, 265, 2012, S20–23). In the SCD case, the prior history of arterial thrombosis, consistent with an embolic etiology, led us to examine whether a patent foramen ovale (PFO) was present, which was confirmed by bubble jet studies. This was subsequently closed. In patients with a history of embolic thrombosis, the presence of PFO should be sought and closure considered. Two cases were treated with Methylprednisolone soon after presentation. Two cases were commenced on Aspirin 75mg once a day to limit extension and as secondary prevention. The use of thrombolytic agents such as tissue thromboplastin activator have not been described in AST. In conclusion, spinal cord ischemia should be considered when facing a Thal or SCD patient with acute neurological symptoms affecting legs or bladder. This may be more common in hemoglobin disorders than is apparent from the literature.

Disclosures:
Cappellini: Novartis Pharmaceuticals: Research Funding.