What is the appropriate diagnosis and treatment plan for a patient with myelomalacia?

Myelomalacia: Diagnosis and Management

Myelomalacia is a hemorrhagic infarction of the spinal cord requiring urgent MRI diagnosis, with treatment focused on surgical decompression and lysis of adhesions when progressive neurologic deterioration occurs, though the diffuse ascending form carries a grave prognosis with no effective treatment.

Clinical Presentation and Diagnosis

Key Clinical Features

• Progressive neurologic deterioration following acute spinal cord injury is the hallmark presentation, including progressive motor loss, ascending sensory level changes, increased spasticity, autonomic dysreflexia, loss of bowel/bladder control, and radicular pain 1
• Diffuse myelomalacia presents with cranial migration of neurologic signs ("ascending syndrome") and is typically fatal 2
• Focal myelomalacia may be reversible depending on severity of initial injury 3

Diagnostic Imaging Approach

• MRI is the definitive diagnostic modality and should be obtained urgently in any patient with suspected myelomalacia 3, 1
• Early stage findings on MRI include high-intensity signal changes on T2-weighted images involving the full width of the affected cord 3
• Intermediate stage shows varying degrees of cystic necrosis of central gray matter, best visualized on T2-weighted sequences 3
• Late stage demonstrates central cystic degeneration, syrinx formation, and cord atrophy 3
• Additional MRI features include intramedullary T1/T2 signal prolongation, extramedullary tethering/adhesions, ill-defined lesional borders, cord expansion, and increased T1 signal intensity compared to CSF 1

Etiologic Considerations

• Most common cause is intervertebral disc extrusion (71% in one series) 2
• Other causes include fibrocartilaginous embolus, intradural disc herniation causing CSF leak, and rarely acute leukemia 2, 4, 5
• Myelography findings (when performed) show contrast infiltration into spinal cord (86%) and/or cord swelling (86%) 2

Treatment Algorithm

Early Stage Myelomalacia

• Immediate surgical decompression if compressive lesion identified, as early stage disease may be reversible 3
• Serial MRI monitoring at 6-month intervals to assess for progression or improvement 3
• Two of four early-stage patients showed improvement on follow-up imaging, indicating potential reversibility 3

Progressive Posttraumatic Myelomalacic Myelopathy (PPMM)

• Surgical intervention with lysis of intradural adhesions and untethering of the spinal cord is the treatment of choice 1
• Intraoperative ultrasound should be performed to confirm absence of confluent cyst (distinguishing from progressive posttraumatic cystic myelopathy) and to identify cord tethering 1
• Postoperative outcomes show neurologic improvement in 90% of patients when appropriate surgical untethering is performed 1

Intermediate and Late Stage Disease

• Prognosis is poor with either no change or progression on follow-up imaging 3
• Supportive care becomes the primary focus as surgical intervention is unlikely to reverse established cystic degeneration and atrophy 3

Diffuse Ascending Myelomalacia

• No effective treatment exists for this form 2
• Prognosis is grave with typically fatal outcome 2

Critical Management Pitfalls

• Delayed MRI can miss the window for reversibility in early-stage disease 3
• Failure to distinguish PPMM from progressive posttraumatic cystic myelopathy leads to inappropriate surgical approach; intraoperative ultrasound is essential 1
• Missing underlying CSF leak from intradural disc herniation when engorged cervical epidural veins are present without ventricular shunt 4
• Assuming irreversibility in all cases without attempting surgical decompression in early presentations 3, 1

Prognostic Factors

• Stage at presentation is the most critical determinant of outcome, with early stage offering potential reversibility 3
• Pattern of disease (focal vs. diffuse) determines prognosis, with diffuse ascending form being uniformly fatal 2
• Presence of cord tethering that can be surgically released predicts favorable response to intervention 1