Dural ectasia with cauda equina syndrome, a rare case report

Abstract

Introduction and importance

Dural ectasia, which is often idiopathic, is seen both in patients with neurofibromatosis and Marfan's syndrome. In neurofibromatosis, the ectasia is most often seen in the thoracic region but can occur at any point along the dura. A complication such as cauda equina syndrome is usually rare.

Clinical presentation

A 48 year old male complaining of recurrent throbbing headache, for 3 years, 2 years ago he developed progressively lower back pain, associated with numbness and tingling sensation of the lower limbs. A year ago he experienced defecation and urinary incontinence. On further questioning the patient reported to have first degree relative with neurofibromatosis.

On examination he has multiple café au laite on the trunk, back and left arm, and plexiform on the left palm, mild right deviation on thoracic region on the back. Lower limb muscle power grade 4/5 bilaterally, sensation was intact.

Laboratory work up Full blood counts, electrolytes, renal and liver function tests were normal, MRI of the lumbar spine demonstrate L3/L4 and L4/l5 mild disc bulge with no significant narrowing of the primary canal and no evidence of existing nerve root impingement, increase antero-posterior diameter of dura sac involving L5-S1, with a Dural Sac Diameter of S1 increased compared to that of L4 with mild scalloping of lower lumbar vertebra and pronounced at S1 vertebral body.

A diagnosis of cauda equina syndrome and dural ectasia secondary to neurofibromatosis was rendered.

Lumbar peritoneal shunting, was reached as a surgical treatment for this patient, but due to inadequate and unavailability of the required shunting equipment, the patient was managed conservatively with anti- inflammatory medications, lumbar CSF tapping, genital hygiene and counselling.

3 months of follow up, the patient was able to walk, with power 5/5 to both lower limbs, however fecal and urine incontinence persisted.

Discussion

this case was particularly unusual due to the combination of cauda equina syndrome and dural ectasia, Dural ectasia is seen with various conditions including Marfan syndrome, Ehlers-syndrome, neurofibromatosis 1, Ankylosing spondylitis, trauma, scoliosis or tumors it may also have no clear cause. In most cases patients with dural ectasia are asymptomatic few may present with low back pain, radicular pain in the buttocks or legs and headache and rarely caudal equina syndrome. The management of dura ectasia may be conservative for asymptomatic patient and for a symptomatic patient surgery such as stabilization, marsupialization and lumbar peritoneal shunt.

Conclusion

Dural ectasia with cauda equina syndrome are rarely complication of neurofibromatosis. Familiarity with its classic imaging and clinical features as described in this case report can help its early detection and management.

Highlights

• •Dural ectasia, which is often idiopathic, is seen both in patients with neurofibromatosis and Marfan's syndrome.
• •Our patient presented dural ectasia and vertebral scalloping localized mainly at the lumbar vertebrae.
• •Dural ectasia with cauda equina syndrome are rarely complication of neurofibromatosis.

1. Introduction

Dural ectasia, which is often idiopathic, is seen both in patients with neurofibromatosis and Marfan's syndrome. In neurofibromatosis, the ectasia is most often seen in the thoracic region but can occur at any point along the dura [1].

The classic radiologic findings of neurofibromatosis-associated dural ectasia include vertebral body scalloping and erosion, pedicle erosion, and neuroforamina enlargement. Bony erosion can lead to deformity and fracture; however, neurologic deficits and cauda equina syndrome in dural ectasia cases are rare, as the spinal canal is widened [2].

To the best of our knowledge, no report has described a patient with neurofibromatosis who developed dural ectasia with cauda equina syndrome. In this case report, we describe a 48-year-old male patient with neurofibromatosis associated with dural ectasia who develop caudal equina syndrome for the past the past one year. This case report was written by following the Surgical Case Report (SCARE) guidelines [6].

2. Case report

A 48 year old male referred to our facility with complain of recurrent headache, throbbing in nature for 3 years, but two years ago started to develop lower back pain with the association of numbness and tingling sensation of the lower limbs. He reported the symptoms were progressive till one year ago when started to experience lower limbs weakness also with defecation and urinary incontinence. On further questioning the patient reported to have first degree relative with neurofibromatosis.

On examination he has multiple café au laite on the trunk, back and left arm, and plexiform on the left palm (Fig. 1), back examination revealed mild right deviation on thoracic region (Fig. 2). Lower limb muscle power grade 4/5 bilaterally, sensation was intact.

Fig. 1.

Multiple café au laite on the trunk, back and left arm, and plexiform on the left palm.

Fig. 2.

Back examination showing mild right deviation on thoracic region.

All laboratory baseline work up, including Full blood counts, electrolytes, renal and liver function tests were normal, Thoracolumbar x ray showed mild scoliosis with convexity to the right (Fig. 3). MRI of the lumbar spine demonstrate L3/L4 and L4/l5 mild disc bulge with no significant narrowing of the primary canal and no evidence of existing nerve root impingement, increase antero-posterior diameter of dura sac involving L5-S1, with a Dural Sac Diameter of S1 increased compared to that of L4 with mild scalloping of lower lumbar vertebra and pronounced at S1 vertebral body (Fig. 4) A small right sided T2W heterogenous cystic lesion measuring 2.5 × 2.7 cm is seen along right L5/S1 neuroforamina consistent with a plexiform neurofibroma. An incidental platybasia was also noted on exposed skull base cervical spine images (Fig. 5).

Fig. 3.

AP and Lateral views thoracolumbar x ray showing mild scoliosis with convexity to the right.

Fig. 4.

Sagittal and axial views MRI of the lumbar spine. Demonstrating L3/L4 and L4/l5 mild disc bulge with no significant narrowing of the primary canal and no evidence of existing nerve root impingement, increase antero-posterior diameter of dura sac involving L5-S1, with a Dural Sac Diameter of S1 increased compared to that of L4 with mild scalloping of lower lumbar vertebra and pronounced at S1 vertebral body.

Fig. 5.

Sagittal view MRI of the cervicothoracic spine. Showing a small right sided T2W heterogenous cystic lesion measuring 2.5 × 2.7 cm is seen along right L5/S1 neuroforamina consistent with a plexiform neurofibroma. An incidental platybasia was also noted on exposed skull base cervical spine images.

Based on the clinical and imaging findings, a diagnosis of cauda equina syndrome and dural ectasia secondary to neurofibromatosis was rendered.

Lumbar peritoneal shunting, was reached as a surgical treatment for this patient, but due to inadequate and unavailability of the required shunting equipment, the patient was managed conservatively with anti- inflammatory medications, lumbar CSF tapping, genital hygiene and counselling.

3 months of follow up, the patient was able to walk, with power 5/5 to both lower limbs, however fecal and urine incontinence persisted.

3. Discussion

Dural ectasia is defined as a ballooning or widening of the dural sac, often associated with herniation of the nerve root sleeves out of the associated foraminae and is seen with various conditions including Marfan syndrome, Ehlers-syndrome, neurofibromatosis 1, Ankylosing spondylitis, trauma, scoliosis or tumors or may have no clear cause [4].

The presenting features include the enlargement of the spinal canal, scalping of vertebral body, reduction of cortical bone thickness of the pedicles and laminae, expansion of the neural foramina and the formation of meningoceles [5].

In most cases patients with dural ectasia are asymptomatic few may present with low back pain, radicular pain in the buttocks or legs and headache and rarely caudal equina syndrome [7,4,9].

Cauda equina syndrome is considered a serious neurological condition with progressive loss of function of the neurologic elements of the spinal canal below the termination of the spinal cord, may be due to prolapse of an intervertebral disc, metastatic disease, direct trauma from lumbar puncture and spinal anesthesia. Also penetrating wounds, spinal stenosis due to a degenerative process, development defects and inflammatory conditions such as Paget's disease and Ankylosing spondylitis [9].

The pathogeneses of dural ectasia are remained unclear, the prevailing theory implicates cerebral spinal fluid pulsations as the primary cause of progressive distention of a weakened dural sac. The most caudal levels of the spine tend to be most affected since CSF pressures are greatest at these levels based on Pascal's law. Increasing in pressure is due to defective resorption of lumbar CSF, which physiologically takes place through arachnoid villi in epidural veins also could contribute to dural sac enlargement. Rapid CSF pressure changes that were not efficiently damped in so far as the epidural space was atrophic and the epidural veins were compressed could have contributed to damage to the nerve root and results in gradual neurological manifestation as the weak dura enlarge due to chronic exposure to pressure from cerebrospinal fluid [1,7,9,10]. Cauda equina syndrome in dural ectasia pathophysiology is due to damage to the nerve roots include small vessel angiitis involving the vasa nervorum, nerve root damage due to increased CSF pressure and decreased the elasticity of the dural sac, and chronic inflammatory process. The inflammatory process is also believed to spread to the perineural soft tissues along the cauda equina nerve roots initiating arachnoiditis and resulting in gradual CES due to nerve damage [5].

The assessment of dural ectasia is based on the presence of at least one of the following four findings: (1) anterior sacral meningoceles (AM), (2) herniation of one or more of the nerve root sleeves, (3) dural sac diameter (DSD) at S1 or inferior>DSD at level L4, and (4) dural sac ratio (DSR) at S1 ≥ 0.59 [11] similar observation was seen in our patient there was increase antero-posterior diameter of dura sac involving L5-S1, with a Dural Sac Diameter of S1 increased compared to that of L4.

The management of dura ectasia may be conservative for asymptomatic patient and for symptomatic patients surgery such as stabilization, marsupialization and lumbar peritoneal shunt [1,5,10].

Our patient presented dural ectasia and vertebral scalloping localized mainly at the lumbar vertebrae with features suggested of cord compression, unexpected there was no evidence of cord compression, vertebral subluxation, or dislocation.

A complication of cauda equina syndrome was seen, surgical treatment with lumbar peritoneal shunting was agreed but not done due to the unavailability of required shunts.

4. Conclusion

Dural ectasia with cauda equina syndrome are rarely complication of neurofibromatosis. Familiarity with its classic imaging and clinical features as described in this case report can help its early detection and management.

Consent for publication

Written informed consent was obtained from the patient for Publication of this case report and accompanying images.

Ethical approval

Not required for case reports at our hospital. Single case reports are exempt from ethical approval in our institution.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Author contribution

Tumwesige R. Kondo and Peter Magembe Mrimba was involved in the conception and drafting of the manuscript.

Mathias S. Ncheye and Godlisten S. Kawiche reviewed literature of the research work.

Honest H. Massawe and Happiness R. Massawe supervised and reviewed the whole research work.

Guarantor

Peter Magembe Mrimba.

Research registration number

N/A.

Conflict of interest statement

The authors declare that there are no conflicts of interest.

Data availability

The datasets of the present study are available from the corresponding author upon reasonable request.