Pearls & oy-sters: clues for spinal dural arteriovenous fistulae

Delayed Diagnosis of Spinal Dural Arteriovenous Fistula: A Case Report and Scoping Review

Spinal dural arteriovenous fistula (SDAVF) is among the most common arterial shunt diseases typically found in middle aged or older men. Herein, we aimed to clarify the reasons for misdiagnoses and delayed diagnoses of SDAVF, determine how these affect prognoses, and establish how they can be prevented. We conducted a PubMed/MEDLINE literature search using "spinal dural arteriovenous fistula", "delayed diagnosis", "late diagnosis", and "misdiagnosis" terms. We identified 18 articles, including 965 SDAVF cases. Patients were predominantly males (71.8-100.0%) (mean age: 53.5-71.0 years). Misdiagnoses rates varied (17.5-100.0%) and encompassed many conditions. The mean time between early manifestations and confirmed diagnosis was approximately 10-15 months and from the first radiologic image revealing dural arteriovenous fistula (DAVF) features to diagnosis was 9.2-20.7 months. Posttreatment outcomes showed a significant improvement in motor functions, gait, and micturition, particularly in patients exhibiting preoperative symptoms over a short period. SDAVF is frequently misdiagnosed or subject to delayed diagnosis, causing poor clinical outcomes. SDAVF symptoms including progressive lower-limb weakness, paresthesia, and vesicorectal dysfunction are indications for spinal magnetic resonance imaging with subsequent spinal angiography, wherein DAVF is evidenced by extensive T2 hyperintensity and flow-void abnormalities. We reported a representative case with delayed diagnosis.

Early diagnosis of thoracic spinal dural arteriovenous fistula using lumbar magnetic resonance imaging: A case report

In middle-aged and older men, clinicians often suspect lumbar spine disease when gait is impaired with intermittent claudication, but spinal dural arteriovenous fistula (SDAVF) may be the etiology. An understanding of the key magnetic resonance imaging findings of SDAVF is necessary for early diagnosis, appropriate treatment, and minimization of complications.

Factors Associated with Rapidly Deteriorating Myelopathy in Patients with Spinal Arteriovenous Shunts

Spinal arteriovenous (AV) shunts are rare conditions that sometimes present with myelopathy symptoms. The progression of the symptoms is usually gradual; however, some cases show rapid deterioration. We retrospectively investigated the factors that induced the rapid deterioration of myelopathy symptoms in patients with spinal AV shunts. We treated 33 patients with myelopathy with spinal AV shunts at our institutions, eight of whom experienced rapid deterioration (within 24 hours: 24.2%). Of these, three were related to the body movement or particular postures associated with playing golf, 30 minutes of Japanese straight sitting, and massage care. One patient showed deterioration after embolization for a tracheal aneurysm. The remaining four patients received steroid pulse therapy (high-dose steroid infusion) shortly before the rapid deterioration. These symptoms stopped progressing after cessation of steroid use. While positional or physical factors contributing to myelopathy deterioration might exist, we could not identify specific factors in this study. Nevertheless, rapid deterioration was frequently observed after high-dose steroid use. We must take care not to administer high-dose steroids for myelopathy caused by spinal AV shunt disease.

Vascular Spinal Cord Disorders

Vascular disorders of the spinal cord are uncommon yet under-recognized causes of myelopathy. Etiologies can be predominantly categorized into clinical and radiographic presentations of arterial ischemia, venous congestion/ischemia, hematomyelia, and extraparenchymal hemorrhage. While vascular myelopathies often produce significant morbidity, recent advances in the understanding and recognition of these disorders should continue to expedite diagnosis and proper management, and ideally improve patient outcomes. This article comprehensively reviews relevant spinal cord vascular anatomy, clinical features, radiographic findings, treatment, and prognosis of vascular disorders of the spinal cord.

Vascular Myelopathies

PURPOSE OF REVIEW

Neurologists should be able to identify clinical and neuroimaging features that distinguish vascular disorders from other causes of myelopathy.

RECENT FINDINGS

Although certain clinical features suggest a vascular etiology in acute and chronic myelopathy settings, accurate MRI interpretation within the clinical context is key. Recent studies have shown vascular myelopathies are frequently misdiagnosed as transverse myelitis, and recognition of this diagnostic pitfall is important. Many different vascular mechanisms can cause myelopathy; this article provides a comprehensive review that simplifies disease categories into arterial ischemia, venous congestion/ischemia, hematomyelia, and extraparenchymal hemorrhage.

SUMMARY

It is important to recognize and manage vascular disorders of the spinal cord as significant causes of acute, subacute, and progressive myelopathy.

Acute and subacute myelopathy

Myelopathy is a term referring to any pathologic process affecting the spinal cord, and encompasses a broad spectrum of etiologies. The first step is to categorize myelopathy, according to the time to reach maximum deficit. Myelopathies are commonly classified as acute, subacute or chronic, for which the etiologies are totally different. Myelopathy is considered acute when the symptoms progress to their nadir in maximum 21 days after onset. Due to heterogeneity in pathogenesis, and the overlap in the clinical and imaging presentation among etiologies, acute myelopathy is considered as a diagnostic dilemma. A simple and efficient algorithm for timely identification of the underlying cause is thus useful. In this review, we provide a simplified approach for the differential diagnosis among all causes of acute myelopathies, and describe the principal clinical and imaging features of the main etiologies in adults, including recently characterized antibody-mediated myelitis, and its mimics.

Steroid-Associated Acute Clinical Worsening and Poor Outcome in Patients With Spinal Dural Arteriovenous Fistulas: A Prospective Cohort Study

STUDY DESIGN

A prospective cohort study.

OBJECTIVE

We conducted a prospective cohort study to identify the association between steroids and clinical worsening and compare outcomes between patients with and without preoperative steroid administration.

SUMMARY OF BACKGROUND DATA

Patients with spinal dural arteriovenous fistulas (SDAVFs) often were misdiagnosed and treated with steroids which led to acute worsening.

METHODS

Patients with angiographically confirmed SDAVFs were recruited consecutively between March 2013 and December 2014 in two referral centers. We reviewed the history of all the patients to identify those patients who were treated with steroids before exclusion of the fistulas. Modified Aminoff & Logue scale (mALS) was used to evaluate the spinal cord function at different time points: before and after steroid administration, before operation, and at 1-year follow-up. Paired t tests were used to assess the mALS of patients with steroid administration at different time points. Unpaired t tests and Pearson chi-square test were used to assess differences between patients with and without steroid administration.

RESULTS

Eighteen patients with (18.2%) and 81 patients without (81.8%) steroid administration were included in this study. At baseline, there were no difference between both patient groups, in regards to age, sex, duration, location of fistula, treatment, and preoperative mALS. Patients without steroid administration, however, had statistically significant better outcome according to their mALS at 1-year follow-up (P < 0.05).

CONCLUSION

Steroid administration can induce acute clinical worsening in patients with SDAVFs that may persist despite successful obliteration of the fistula and should thus be avoided.

LEVEL OF EVIDENCE

3.

Clinical and neuroimaging findings of spinal dural arteriovenous fistulas: How to avoid misdiagnosis of this disease

OBJECTIVE

Spinal dural arteriovenous fistulas (DAVFs) are rare but can cause serious gait and micturition disturbances. Delays in diagnosis and treatment result in poor clinical outcomes; however, the process of misdiagnosis is unknown.

METHODS

Forty consecutive patients were retrospectively analyzed.

RESULTS

Thirty-one patients (78%) were initially misdiagnosed with lumbar spinal stenosis or other diseases, mostly by orthopedic surgeons, even though most patients (85%) had specific symptoms or characteristic neuroimaging findings of spinal DAVFs: they often presented with spastic gait (thoracic myelopathy), progressive ascending numbness that begins in the distal lower extremities (epicous syndrome), and urinary tract symptoms (conus medullaris syndrome); initial lumbar MRI showed T2 signal change in the conus medullaris and vascular flow voids around the cord. The median time from onset to treatment was longer in patients with a misdiagnosis than in those with the correct diagnosis (11 vs 4 months). In all patients, the fistula was completely obliterated by the direct microsurgical procedure; however, patients with a misdiagnosis had developed additional disabilities by the time a correct diagnosis was made (Aminoff-Logue gait grade of 3.6 ± 1.4 vs 2.1 ± 1.5 p = 0.013), and achieved markedly smaller improvements after the treatment (Aminoff-Logue gait grade of 3.0 ± 1.6 vs 1.1 ± 1.5, p = 0.006) than those with the correct diagnosis of spinal DAVFs.

CONCLUSIONS

When common spinal stenosis fail to explain the symptoms such as thoracic myelopathy, epiconus syndrome, and conus medullaris syndrome, the possibility of spinal DAVFs should be considered. If lumbar MRI shows conus medullaris lesions, thoracic MRI should be performed to confirm the diagnosis.

Clinical outcomes and prognostic factors in patients with spinal dural arteriovenous fistulas : a prospective cohort study in two Chinese centres

BACKGROUND

The short-term outcomes and prognostic factors of patients with spinal dural arteriovenous fistulas (SDAVFs) have not been defined in large cohorts.

OBJECTIVE

To define the short-term clinical outcomes and prognostic factors in patients with SDAVFs.

METHODS

A prospective cohort of 112 patients with SDAVFs were included consecutively in this study. The patients were serially evaluated with the modified Aminoff and Logue's Scale (mALS) one day before surgery and at 3 months, 6 months and 12 months after treatment. Univariate and multivariate analyses were performed to identify demographic, clinical and procedural factors related to favourable outcome.

RESULTS

A total of 94 patients (mean age 53.5 years, 78 were men) met the criteria and are included in the final analyses. Duration of symptom ranged from 0.5 to 66 months (average time period of 12.7 months). The location of SDAVFs was as follows: 31.6% above T7 level, 48.4% between T7 and T12 level (including T7 and T12) and 20.0% below T12 level. A total of 81 patients (86.2%) underwent neurosurgical treatment, 10 patients (10.6%) underwent endovascular treatment, and 3 patients (3.2%) underwent neurosurgical treatment after unsuccessful embolisation. A total of 78 patients demonstrated an improvement in mALS score of one point or greater at 12 months. Preoperative mALS score was associated with clinical improvement after adjusting for age, gender, duration of symptoms, location of fistula and treatment modality using unconditional logistic regression analysis (p<0.05).

CONCLUSION

Approximately four fifths of the patients experienced clinical improvement at 12 months and preoperative mALS was the strongest predictor of clinical improvement in the cohort.

Acute paraparesis and sensory loss following intravenous corticosteroid administration in a case of longitudinally extensive transverse myelitis caused by spinal dural arteriovenous fistula: case report and review of literature

INTRODUCTION

The underlying causes of longitudinally extensive transverse myelitis (LETM) are broad and include inflammatory processes, compression and spinal dural arteriovenous fistula (SDAVF). Presenting symptoms of SDAVF are nonspecific and often go misdiagnosed. Acute clinical deterioration from SDAVF has been described following exertion or valsalva. However, deterioration has been recently recognized following steroid administration and may contribute to increased morbidity.

CASE PRESENTATION

We describe a 63-year-old woman with a 2-year history of intermittent lower extremity numbness and back pain, lumbar stenosis, who presented with subacute worsening of symptoms following a course of oral steroids for an upper respiratory infection. Initial whole-spine imaging was concerning for LETM and lumbar puncture was concerning for an inflammatory process. The patient was treated with intravenous (IV) methylprednisolone, after which she developed acute onset bilateral lower extremity paraparesis with a sensory level. Angiogram confirmed the diagnosis of SDAVF and the patient was treated surgically. Post-operative course was complicated and subsequent clinical improvement has been slow with incomplete recovery to date.

DISCUSSION

This case illustrates the nonspecific presentation of SDAVF and the difficulty of differentiating it from other causes of LETM. It demonstrates acute clinical deterioration of SDAVF following steroid administration, a recently recognized clinical entity. The most likely mechanism is hydrostatic steroid effect coupled with iatrogenic fluid co-administration causing increased venous congestion. Previous cases have demonstrated this effect to be transient and resolves after discontinuation of steroids. This case highlights a recent association of increased morbidity following steroid administration despite definitive treatment.

Acute Clinical Worsening after Steroid Administration in Cervical Myelitis May Reveal a Subdural Arteriovenous Fistula

Subdural arteriovenous fistula (SDAVF) is a rare condition characterized by clinical manifestations ranging from mild bilateral sensory deficits to quadriplegia. The diagnosis is often delayed due to unspecific neurological symptoms, initially diagnosed as polyneuropathy or myelopathy. The diagnosis can be delayed for as long as 1–15 years. The following report describes a cervical SDAVF case initially misdiagnosed as myelitis transversa and treated with intravenous steroids. A 56-year-old male presented with sensory deficits and mild leg and right arm weakness. Cervical MRI showed a central medullary hyperintense lesion with contrast enhancement. After metabolic, infectious, and malignant causes were excluded, myelitis transversa was presumed and the patient was treated intravenously with methylprednisolone. Shortly after that, he developed quadriplegia. Cervical MRI imaging showed engorged cervical perimedullary vessels, which were not visible on the initial MRI. The diagnosis was revised and a SDAVF identified. Prompt surgical treatment led to a complete recovery. The effect of intravenous steroids in SDAVF is controversial. Acute clinical worsening after steroid administration is previously reported in several publications; however, due to the paucity of clinical studies on SDAVF, this effect remains mostly overlooked or unknown. The findings in this patient support the causative relation between SDAVF clinical worsening and steroid administration. We propose that acute clinical worsening under steroids in patients initially diagnosed with myelitis should raise suspicion of an SDAVF.

Clinical outcomes following corticosteroid administration in patients with delayed diagnosis of spinal arteriovenous fistulas

Background and purpose

There have been several previously reported cases of acute progression of myelopathic symptoms in patients with spinal arteriovenous fistula (SAVF) treated with intravenous methylprednisolone. This usually occurs during or immediately following steroid administration. We examined a small case series of patients with SAVF treated with epidural, oral, or intravenous steroids to determine the association between steroid administration and clinical outcomes in these patients.

Methods

Following Institutional Review Board approval, we conducted a retrospective review of patients with angiographically-confirmed SAVF who received intravenous, oral, or epidural corticosteroids for treatment of their symptoms. We studied patient-reported motor and sensory function following steroid administration using both the modified Rankin Scale and the Aminoff Motor Disability Scale.

Results

Twenty-one patients with SAVF were included in this study. Thirteen patients (61.9%) had intravenous methylprednisolone administered, four patients (19.0%) had epidural steroid injections, and six patients (28.6%) had oral prednisone. Among patients who received intravenous methylprednisolone, seven (53.8%) reported acute worsening of symptoms during or immediately following steroid administration. Among the patients receiving epidural steroids, none reported worsening and one patient reported short-term relief. Among the patients receiving oral steroids, one reported acute worsening of symptoms. Worsened deficits did not consistently resolve after steroid discontinuation.

Conclusions

Our study suggests that intravenous methylprednisolone can cause immediate worsening of motor and sensory symptoms when administered to patients with SAVF. Steroid administration should be avoided in patients with a myelopathy secondary to an untreated SAVF because neurological worsening may not be fully reversible.

Clinical Outcomes of Patients with Delayed Diagnosis of Spinal Dural Arteriovenous Fistulas

BACKGROUND AND PURPOSE

Spinal dural arteriovenous fistulas are commonly missed on imaging or misdiagnosed as inflammatory or neoplastic processes. We reviewed a consecutive series of spinal dural arteriovenous fistulas referred to our institution that were missed or misdiagnosed on initial imaging and studied the clinical consequences of missing or misdiagnosing the lesion.

MATERIALS AND METHODS

We reviewed spinal dural arteriovenous fistulas diagnosed at our institution between January 1, 2000, and November 1, 2014. A lesion was defined as "misdiagnosed" if initial MR imaging or CT myelography demonstrated characteristic imaging features of spinal dural arteriovenous fistula but the patient was clinically or radiologically misdiagnosed. Outcomes included length of delay of diagnosis, increased disability (increase in mRS or Aminoff motor disability of ≥1 point) between initial imaging evaluation and diagnosis date, and posttreatment disability.

RESULTS

Fifty-three consecutive spinal dural arteriovenous fistulas that were initially misdiagnosed despite having characteristic imaging findings on MR imaging or CT myelography were included in our study. Eight patients (18.9%) underwent spinal angiography before referral, which was interpreted as having negative findings but was either incomplete (6 cases) or retrospectively demonstrated the spinal dural arteriovenous fistulas (2 cases). The median time of delayed diagnosis was 6 months (interquartile range, 2-14 months). Fifty-one patients (96.2%) had increased disability between the initial study, which demonstrated features of a spinal dural arteriovenous fistula, and diagnosis. Thirty-two patients (60.4%) developed a new requirement for a walker or wheelchair. Following treatment, 21 patients (41.2%) had an improvement of 1 point on the mRS or Aminoff motor disability scale.

CONCLUSIONS

Delayed diagnosis of spinal dural arteriovenous fistula with characteristic imaging features results in high rates of additional disability that are often irreversible despite surgical or endovascular treatment of the fistula.

Tentorial dural arteriovenous fistula presenting as episodic weakness mimicking periodic paralysis

We report a rare case of episodic limb weakness caused by a tentorial dural arteriovenous fistula (DAVF) draining into the perimesencephalic veins. A middle-aged man presented with episodes of transient quadriparesis preceded by recurrent vomiting. The patient was initially suspected of having periodic paralysis but, due to the presence of recurrent vomiting and brisk reflexes, MR imaging of the brain was performed which revealed marked T2 hyperintensity of the brainstem and cervical cord along with multiple prominent flow voids. Cerebral angiography showed a Borden type 3 DAVF at the left tentorial margin which was draining into the perimesencepahlic and perimedullary veins and refluxing into the cervical epidural veins. The patient made a remarkable recovery after surgical interruption of the fistula.

Paraneoplastic myelopathy

Paraneoplastic causes are a rare but important diagnostic consideration when evaluating myelopathy because neurologic symptoms may herald a diagnosis of cancer. Spinal cord MRI findings of longitudinally extensive, symmetric, tract-specific T2-signal changes occasionally with gadolinium enhancement are characteristic. Detection of neural-specific autoantibodies assists in confirming the diagnosis and guides the cancer search. Initial management involves detection and treatment of the underlying cancer. Combinations of immunotherapies are typically recommended but evidence-based therapeutic guidelines are lacking and morbidity remains high. Autoimmune myelopathies may also occur in association with neural-specific autoantibodies without an underlying cancer and in association with systemic autoimmune disorders.