Infectious Myelitis

Transverse myelitis in children and adults

Transverse myelitis is a noncompressive myelopathy of inflammatory origin. The causes are broad, ranging from infective or toxic to immuno-mediated etiology. They can be manifestations of systemic diseases, such as sarcoidosis and systemic lupus erythematous, or phenotypes of neuroinflammation; in a portion of cases, the etiology remains unknown, leading to the designation idiopathic. The clinical presentation of transverse myelitis depends on the level of spinal cord damage and may include sensorimotor deficits and autonomic dysfunction. The age of onset of the disorder can impact the symptoms and outcomes of affected patients, with differences in manifestation and prognosis between children and adults. Spinal cord magnetic resonance imaging and cerebrospinal fluid examination are the main diagnostic tools that can guide clinicians in the diagnostic process, even though the search for antibodies that target the structural components of the neural tissue (anti-aquaporin4 antibodies and anti-myelin-oligodendrocyte antibodies) helps in the distinction among the immune-mediated phenotypes. Management and outcomes depend on the underlying cause, with different probabilities of relapse according to the phenotypes. Hence, immunosuppression is often recommended for the immune-mediated diseases that may have a higher risk of recurrence. Age at onset has implications for the choice of treatment.

Acute infectious myelopathies

PURPOSE OF REVIEW

The patient who presents with an acute spinal cord syndrome with weakness/paralysis of the limbs presents a diagnostic. Two important syndromes are acute transverse myelitis (ATM) and acute flaccid paralysis (AFP). Both can be caused by a number of infectious and noninfectious causes. Since 2014 there have been outbreaks of acute flaccid myelitis (a subgroup of AFP) in the United States, with a national surveillance program underway. In addition, there have been increasing reports of ATM from new and emerging pathogens, and opportunistic infections in immunocompromised hosts.

RECENT FINDINGS

Infectious causes of ATM or AFP need to be ruled out first. There may be important clues to an infectious cause from epidemiologic risk factors, immune status, international travel, MRI, and laboratory findings. We summarize key features for the more common pathogens in this review. Advances in laboratory testing have improved the diagnostic yield from cerebrospinal fluid, including real-time polymerase chain reaction, metagenomic next-generation sequencing, and advanced antibody detection techniques. These tests still have limitations and require clinical correlation.

SUMMARY

We present a syndromic approach to infectious myelopathies, focusing on clinical patterns that help narrow the diagnostic possibilities.

Subacute transverse myelitis with optic symptoms in neuroborreliosis: a case report

Background

Subacute transverse myelitis is one of the late manifestations of neuroborreliosis with only a few cases described to the present day.

Case presentation

We present magnetic resonance imaging, cerebrospinal fluid, and electroneurography findings of a young female patient suffering from neuroborreliosis-associated transverse myelitis with a wide constellation of symptoms including papilloedema. Magnetic resonance imaging of the cervical spine has shown an enlargement of the spinal cord in the mid-cervical region. Cerebrospinal fluid findings included lymphocytic pleocytosis, increased levels of anti - Borrelia antibodies, and increased intrathecal anti -Borrelia antibody index. Following the 28-day course of intravenous ceftriaxone, the patient attained complete recovery.

Conclusions

Subacute transverse myelitis in the course of neuroborreliosis should be considered in the differential diagnosis of patients with abnormal magnetic resonance scans of the spinal cord, lymphocytic pleocytosis, and intrathecal antibody production, especially in the tick-endemic areas, even if the tick bite was not reported. Infrequent accompanying symptoms such as papilloedema are diagnostically challenging and cannot be treated as clinching evidence.

Infectious Myelopathies

Infectious diseases are an important cause of spinal cord dysfunction. Infectious myelopathies are of growing concern given increasing global travel and migration and expanding prevention and treatment with vaccinations, antibiotics, and antiretrovirals. Clinicians must recognize these pathologies because outcomes can dramatically improve with prompt diagnosis and management. We provide a complete review of the most frequent infectious agents that can affect the spinal cord. For each pathogen we describe epidemiology, pathophysiology, anatomic location, characteristic clinical syndromes, diagnostic approach, treatment, and prognosis. The review includes spinal imaging from selected cases.

Infectious Myelopathies

PURPOSE OF REVIEW

This article reviews bacterial, viral, fungal, and parasitic pathogens associated with myelopathy. Infectious myelopathies may be due to direct infection or parainfectious autoimmune-mediated mechanisms; this article focuses primarily on the former.

RECENT FINDINGS

Some microorganisms exhibit neurotropism for the spinal cord (eg, enteroviruses such as poliovirus and flaviviruses such as West Nile virus), while others are more protean in neurologic manifestations (eg, herpesviruses such as varicella-zoster virus), and others are only rarely reported to cause myelopathy (eg, certain fungal and parasitic infections). Individuals who are immunocompromised are at increased risk of disseminated infection to the central nervous system. Within the last few years, an enterovirus D68 outbreak has been associated with cases of acute flaccid paralysis in children, and emerging Zika virus infection has been concurrent with cases of acute flaccid paralysis due to Guillain-Barré syndrome, although cases of myelitis have also been reported. Associated pathogens differ by geographic distribution, with myelopathies related to Borrelia burgdorferi (Lyme disease) and West Nile virus more commonly seen in the United States and parasitic infections encountered more often in Latin America, Southeast Asia, and Africa. Characteristic CSF and MRI patterns have been identified with many of these infections.

SUMMARY

A myriad of pathogens are associated with infectious myelopathies. Host factors, geographic distribution, clinical features, CSF profiles, and MRI findings can assist in formulating the differential diagnosis and ultimately guide management.

Acute transverse myelitis of the cervical spine secondary to psoas abscess

BACKGROUND

Acute transverse myelitis is uncommon and presumably results from an autoimmune process or a preceding infection. Most cases of bacterial myelitis are due to hematogenous dissemination from urinary or respiratory tract infections or contiguous spreading from a neighboring infected structure. A psoas abscess rarely spreads to higher levels of the spinal cord. No cases of acute cervical myelitis due to a psoas abscess have been previously reported.

CASE PRESENTATION

A 34-year-old man was transferred to our hospital due to progressive muscle weakness, sensory deficits and severe hypotension. Two weeks prior to admission, he had received low back injection to relieve back pain in a healthcare clinic. One day prior to admission, his condition had worsened. On admission, he was tetraplegic with absence of sensation below the level of the suprasternal fossa. A lumbar CT scan demonstrated an abscess in the left psoas, and the magnetic resonance imaging (MRI) scan of the entire spinal suggested a cervical spine infection. A cerebrospinal fluid (CSF) analysis performed before surgery indicated the possibility of bacterial infection. An operation was performed to drain the abscess. Microbiological cultivation revealed a Methicillin-resistant Staphylococcus aureus (MRSA) infection. The patient was administered with vancomycin for 10 days and followed by oral formulations of linezolid for 6 weeks. The patient's general condition improved, and he was successfully discharged. Six months later, a follow-up MRI revealed that the lesion of the cervical spine had been ameliorated, and the sensation and myodynamia of his upper limbs had partially recovered.

CONCLUSION

This was a rare case of a high-level cervical spine pyogenic infection complicating psoas abscess. An invasive paravertebral injection procedure was thought to be the initial damaging event that created a port of entry for MRSA into the psoas muscle and caused a subsequent psoas abscess. This case indicated that evaluation of higher levels of the spine is warranted when a psoas abscess coexists with severe weakness.

An Imaging-Based Approach to Spinal Cord Infection

Infections of the spinal cord, nerve roots, and surrounding meninges are uncommon, but highly significant given their potential for severe morbidity and even mortality. Prompt diagnosis can be lifesaving, as many spinal infections are treatable. Advances in imaging technology have now firmly established magnetic resonance imaging (MRI) as the gold standard for spinal cord imaging evaluation, enabling the depiction of infectious myelopathies with exquisite detail and contrast. In this article, we aim to provide an overview of MRI findings for spinal cord infections with special focus on imaging patterns of infection that are primarily confined to the spinal cord, spinal meninges, and spinal nerve roots. In this context, we describe and organize this review around 5 distinct patterns of transverse spinal abnormality that may be detected with MRI as follows: (1) extramedullary, (2) centromedullary, (3) eccentric, (4) frontal horn, and (5) irregular. We seek to classify the most common presentations for a wide variety of infectious agents within this image-based framework while realizing that significant overlap and variation exists, including some infections that remain occult with conventional imaging techniques.

Pathologic approach to spinal cord infections

The pathologic evaluation of spinal cord infections requires comprehensive clinical, radiological, and laboratory correlation, because the histologic findings in acute, chronic, or granulomatous infections rarely provide clues for the specific cause. This brief review focuses on the pathologic mechanisms as well as practical issues in the diagnosis and reporting of infections of the spinal cord. Examples are provided of the common infectious agents and methods for their diagnosis. By necessity, discussion is restricted to the infections of the medulla spinalis proper and its meninges, and not bone or soft tissue infections.