Elsberg Syndrome

Elsberg syndrome is a rare clinical syndrome comprising lumbosacral radiculitis together with associated myelitis. It is most commonly caused by herpes simplex virus type 2, and less commonly by other herpesviruses including varicella zoster virus and cytomegalovirus. It typically occurs in the context of a primary or recurrent genital herpes outbreak.

It presents with the characteristic combination of bilateral lower limb radicular pain and weakness together with bladder and bowel dysfunction, reflecting sacral segment involvement.

Recognition of this specific syndrome is important given its generally favourable prognosis with appropriate antiviral treatment, in contrast to several other causes of acute myeloradiculitis with potentially less favourable outcomes.

Pathophysiology

• Direct viral infection and associated inflammation affect the lumbosacral nerve roots and, in a proportion of cases, the adjacent lower spinal cord.
• This reflects retrograde spread of the causative herpesvirus along the sacral nerve roots from the primary site of genital mucocutaneous infection. It explains the characteristic close temporal and clinical association between this syndrome and a concurrent or recent genital herpes outbreak.
• The resulting inflammatory process produces radiculopathy (nerve root involvement, accounting for the characteristic pain and lower motor neuron pattern weakness). Where it extends to involve the adjacent spinal cord itself, myelitis results.
• The balance and severity of these two components vary between individual patients and directly influence the clinical presentation observed.

• Bilateral, though sometimes asymmetric, lower limb radicular pain and paraesthesia, together with progressive lower limb weakness reflecting the lumbosacral nerve root involvement, develop over days.
• Onset is typically in close temporal association with a concurrent or recent genital herpes outbreak. This may be the patient's first recognised episode, or a recurrence in a patient with established genital herpes.
• Urinary retention and bowel dysfunction are a characteristic and often prominent feature, sometimes the presenting or most functionally significant symptom. They reflect sacral segment and nerve root involvement affecting the parasympathetic innervation of the bladder and bowel.
• Sensory disturbance in a saddle distribution, together with reduced or absent lower limb deep tendon reflexes, completes the characteristic clinical picture. Reduced reflexes reflect the predominant lower motor neuron, radicular pattern of involvement. The specific combination and severity of these features vary according to the extent of the underlying inflammatory process.
• Specifically seek a relevant history of active or recent genital herpes lesions.
• The genital lesions themselves may have already resolved, or been relatively mild and unnoticed, by the time of neurological presentation. The absence of currently visible genital lesions does not exclude this diagnosis where the clinical neurological picture is otherwise compatible.

• Magnetic resonance imaging of the lumbosacral spine shows nerve root enhancement and, where myelitis is present, corresponding spinal cord signal change. It supports the diagnosis and helps exclude alternative structural causes of the presenting radiculopathy and myelopathy.
• Cerebrospinal fluid examination typically shows a lymphocytic pleocytosis and elevated protein.
• Cerebrospinal fluid polymerase chain reaction testing for herpes simplex virus (and, where relevant to the clinical context, other herpesviruses) provides specific microbiological confirmation of the causative organism. This is essential given the direct relevance to targeted antiviral treatment.
• Swab testing of any active genital lesions, where present, for herpes simplex virus polymerase chain reaction or culture provides additional supportive confirmation of the causative organism and current activity of the primary genital infection.
• The differential diagnosis includes other causes of acute lumbosacral radiculitis and myelitis. Guillain Barré syndrome (particularly the specific variant with prominent bladder involvement) generally lacks the characteristic close genital herpes association.
• Other infective myeloradiculitis includes cytomegalovirus polyradiculopathy, particularly relevant in significantly immunocompromised patients, especially those with advanced HIV infection. Inflammatory or demyelinating causes of myelitis are also in the differential.
• Full evaluation to establish the specific underlying cause remains important, rather than assuming Elsberg syndrome based on clinical pattern alone. The treatment implications differ between these causes.

• Intravenous aciclovir 10 mg per kg every eight hours is standard treatment, following the same general dosing principles applicable to other significant central nervous system herpes simplex virus infections. It is typically continued for a course of ten to fourteen days.
• Prompt initiation is important, given the generally favourable response to antiviral treatment when instituted in a timely manner.
• Bladder management is an essential supportive component of acute management, given the frequently prominent and functionally significant nature of these manifestations. It includes intermittent or indwelling catheterisation as clinically required for urinary retention, together with monitoring for and management of the associated bowel dysfunction.
• Provide analgesia for the often significant radicular pain, following standard neuropathic pain management principles where the pain has a clear neuropathic character.
• Physiotherapy addresses the lower limb weakness and functional mobility impact. It supports full symptomatic management alongside specific antiviral treatment.
• The overall prognosis with prompt, appropriate antiviral treatment is generally favourable. The majority of patients show substantial, and frequently complete, recovery of neurological function over subsequent weeks to a few months.
• Bladder dysfunction in particular can show a more protracted recovery in some patients. It warrants ongoing urological follow up and continued bladder management support until adequate function has been restored.
• Given the underlying genital herpes infection, appropriate counselling regarding this diagnosis is an important component of full, holistic management extending beyond the acute neurological presentation. It includes discussion of recurrence risk and transmission risk to sexual partners.
• Where recurrent outbreaks are frequent or severe, consider suppressive oral antiviral therapy (following standard genital herpes management principles).