An unusual case of acute transverse myelitis caused by HSV-1 infection

HSV Encephalomyelitis in an Immunocompetent Patient With Prior Splenectomy

A 44-year-old male with history of asplenia, provoked PE, and hyperlipidemia presented with ascending paralysis, bowel and bladder incontinence and altered mental status, and progressively developed acute hypoxic respiratory failure. Initial workup including CT head, magnetic resonance imaging (MRI) brain, and lumbar puncture which was concerning for herpes simplex virus (HSV) meningoencephalitis; out of caution he was started on multiple antibiotics consequently resulting in the development of Clostridium difficile (C.diff). He also received two doses of IVIG. He was transferred to our institution and after interval re-imaging via MRI brain and spinal surveys and repeat lumbar punctures, he was found to have a high CSF HSV titer and positive GAD 65 antibody, the latter likely a false positive due to IVIG administration. IVIG was not continued from the outside hospital due to the development of deep vein thrombosis (DVT), and the risks of plasmapheresis outweighed the benefits. The patient gradually improved after a prolonged course of acyclovir and was downgraded out of the Neuroscience ICU (NSICU), however decompensated due to rectal bleeding, and subsequently went into cardiac arrest. Though this patient underwent a splenectomy, his relative immunocompetency towards non-encapsulated organisms should have been preserved. It has not been clearly described in the literature how and why HSV encephalomyelitis takes a fulminant course in immunocompetent patients, including our asplenic patient. Furthermore, definitive treatment and management of this condition remains unclear. Severity of HSV encephalomyelitis has not been clearly described in the literature, particularly in immunocompetent patients (such as this asplenic patient).

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.

An improved animal model for herpesvirus encephalitis in humans

Herpesviral encephalitis caused by Herpes Simplex Virus 1 (HSV-1) is one of the most devastating diseases in humans. Patients present with fever, mental status changes or seizures and when untreated, sequelae can be fatal. Herpes Simplex Encephalitis (HSE) is characterized by mainly unilateral necrotizing inflammation effacing the frontal and mesiotemporal lobes with rare involvement of the brainstem. HSV-1 is hypothesized to invade the CNS via the trigeminal or olfactory nerve, but viral tropism and the exact route of infection remain unclear. Several mouse models for HSE have been developed, but they mimic natural infection only inadequately. The porcine alphaherpesvirus Pseudorabies virus (PrV) is closely related to HSV-1 and Varicella Zoster Virus (VZV). While pigs can control productive infection, it is lethal in other susceptible animals associated with severe pruritus leading to automutilation. Here, we describe the first mutant PrV establishing productive infection in mice that the animals are able to control. After intranasal inoculation with a PrV mutant lacking tegument protein pUL21 and pUS3 kinase activity (PrV-ΔUL21/US3Δkin), nearly all mice survived despite extensive infection of the central nervous system. Neuroinvasion mainly occurred along the trigeminal pathway. Whereas trigeminal first and second order neurons and autonomic ganglia were positive early after intranasal infection, PrV-specific antigen was mainly detectable in the frontal, mesiotemporal and parietal lobes at later times, accompanied by a long lasting lymphohistiocytic meningoencephalitis. Despite this extensive infection, mice showed only mild to moderate clinical signs, developed alopecic skin lesions, or remained asymptomatic. Interestingly, most mice exhibited abnormalities in behavior and activity levels including slow movements, akinesia and stargazing. In summary, clinical signs, distribution of viral antigen and inflammatory pattern show striking analogies to human encephalitis caused by HSV-1 or VZV not observed in other animal models of disease.

In developed countries, more than 50% of humans are seropositive for the neurotropic Herpes Simplex Virus 1 (HSV-1) and two to four million cases of Herpes simplex encephalitis (HSE) are reported per year worldwide. Primary infection with HSV-1 takes place via the skin or the oral mucosa followed by intraaxonal retrograde spread to sensory ganglia of the peripheral nervous system where HSV-1 usually establishes latency. Further spread to the central nervous system results in HSE, a necrotizing encephalitis effacing predominantly the temporal and frontal lobes of the brain. Mice infected with HSV-1 develop encephalitis, but do not show the typical lesions and exhibit high mortality rates. Here we demonstrate that mice infected with a mutant pseudorabies virus lacking the tegument protein pUL21 and an active viral kinase pUS3 were able to survive the productive infection but developed lymphohistiocytic encephalitis with viral antigen distribution, inflammation and associated behavioral changes comparable to HSE in humans. These striking analogies offer new perspectives to study herpesviral encephalitis in a suitable animal model.

Acute urinary retention and progressive paraplegia with genital infection: A case report of transverse myelitis

Introduction:

Transverse myelitis (TM) is a rare inflammatory disorder involving single or multiple spinal segments. There are various Infectious and parainfectious causes.

Case presentation:

We report the case of 29-year-old female who presented to an emergency department with acute urinary retention, progressive headache and sensory and motor deficits with a genital infection. Cerebrospinal fluid (CSF) analysis revealed WBC 75/μL, protein 96 (15-40 mg/dL), and VZV IgG positive. The magnetic resonance image (MRI) of the spine revealed acute transverse myelitis of C4, C6/C7 and T2-T3, T4-T7. She was treated with steroid pulse therapy, intravenous antiviral therapy, antibiotics, and rehabilitation. Urinary symptoms resolved in six days and her motor deficit resolved. She had mild numbness in the thigh area 2 months later.

Discussion:

Identification of the causes and diagnosis of TM are challenging because there are variable clinical signs and numerous potential pathogens.

Conclusion:

It is essential to diagnosis TM in the early and timely phase, careful, detailed history and thorough physical examination by emergency physicians.