Progressive Polyradiculopathy in HIV

Updated: Sep 18, 2017
  • Author: Florian P Thomas, MD, PhD, MA, MS; Chief Editor: Niranjan N Singh, MD, DM  more...
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Overview

Overview

Progressive polyradiculopathy typically occurs late in the course of HIV infection, unlike inflammatory demyelinating polyradiculoneuropathies in HIV, which usually occur earlier in the course of disease. [1, 2, 3] Progressive polyradiculopathy in HIV is extremely uncommon, however, is more prevalent in untreated patients with severe immunosuppression. Given its rare occurrence, incidence rate is unknown. HIV-infected patients become susceptible to progressive polyradiculopathy in advanced immunosuppression when the CD4 T-cell count is less than 50/µL. [4]  However, cases of progressive polyradiculopathy have been seen in varying degrees of immunosuppression. [5]  The lumbrosacral region is most often the affected site.

Polyradiculopathy typically results from cytomegalovirus (CMV) infection. The most common manifestation of neurological CMV disease in HIV infection is retinitis followed by encephalitis, myelitis, multifocal polyneuropathy, and polyradiculopathy. [6, 7] CMV co-infection of the retina and other sites is common. An idiopathic form of polyradiculopathy exists, which has a better prognosis than the CMV-related form.

Histologically, polyradiculopathy typically features necrosis of nerve roots and endoneurial and epineurial blood vessels, along with marked inflammation (most pronounced in the lumbar region). In CMV-associated cases, cytoplasmic and nuclear CMV inclusions may be apparent in Schwann cells and fibroblasts. 

CMV polyradiculopathy is rapidly fatal without treatment. Treatment with foscarnet or ganciclovir may improve or stabilize the condition. Clinical stabilization often occurs after initial worsening during the first 2 weeks of treatment. [2]  Even with treatment, mortality is 22%. In idiopathic polyradiculopathy, spontaneous improvement without treatment is common. [8]

Less common causes of polyradiculopathy in HIV infection include spinal lymphomas, diffuse infiltrative lymphocytosis syndrome, and CNS (central nervous system) opportunistic infections such as tuberculosis meningitis, syphilis, cryptococcosis, herpes simplex virus type 2, varicella-zoster virus, and toxoplasmosis. [5]  

Reactivation of HSV-2 after genital herpes with HIV infection can cause lumbosacral radiculitis. [9] Lumbosacral radiculopathy caused by tuberculous meningitis is due to infection of spinal leptomeninges characterized by granulomatous inflammation. This can compress nerve roots or the cord resulting in radiculopathy. [10] A single case of syphilitic lumbosacral radiculopathy has also been reported. [11]

Idanivir-induced epidural lipomatosis in the lumbar canal causing polyradiculopathy has been described, but resolved with discontinuation of the drug. [12]

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Clinical Presentation

Progressive polyradiculopathy presents as a cauda equina syndrome. CMV-related polyradiculopathy is characterized by rapidly progressive ascending numbness, pain, bowel dysfunction, and asymmetric weakness affecting the legs and later occasionally also the arms. [13] These symptoms can develop acutely over days or more subacutely in 1 to 6 weeks. Possibly co-existing CMV-related conditions include retinitis, colitis, and encephalitis. With idiopathic polyradiculopathy, symptoms are more benign and the clinical progression is slower. [14]

Physical examination

The following may be noted in CMV-related polyradiculopathy:

  • Rapidly progressive, ascending course
  • Paresthesias
  • Sensory loss, invariable
  • Rarely, sensory level suggestive of spinal cord involvement
  • Flaccid paraparesis
  • Areflexia
  • Urinary retention, constipation, or incontinence
  • Rarely, cranial neuropathies
  • Severe pain
  • Often asymmetrical, especially in the early stage of disease
  • Late involvement of the upper extremities

Herpes zoster is characterized by pain and itching followed by rash. Trigeminal and thoracic dermatomes are most commonly affected. [15]

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CSF Analysis

Cerebrospinal fluid analysis may be useful for differentiation between the various etiologies: the infectious forms (eg, CMV, cryptococcosis, tuberculosis, toxoplasmosis), the idiopathic form, and the neoplastic form (ie, lymphoma). In addition to routine studies, analysis of the CSF for cytology, CMV, Venereal Disease Research Laboratory test (VDRL), and cryptococcal antigen may be performed. The most sensitive techniques, including polymerase chain reaction (PCR), are required to rule out specific treatable infections.

In CMV-related polyradiculopathy, typical CSF findings are as follows:

  • Decreased glucose level
  • Markedly elevated protein level, but can be normal
  • Polymorphonuclear neutrophil (PMN)–predominant pleocytosis. One case report showed lymphocytic predominance.
  • Positive PCR for CMV
  • Absence of malignant cells

Pleocytosis usually comprises more than 60% PMNs, but the percentage is sometimes lower. In one study, only 50% of patients had PMN-preponderant pleocytosis. Positive CMV-PCR and elevated protein were the most common CSF findings. [16]

PCR of CSF has a 92% sensitivity and a 94% specificity in CMV-associated progressive polyradiculopathy. CMV culture is positive in only 50% of cases.

CSF findings are different in non-CMV-related progressive polyradiculopathy.

in lymphoma, CSF findings include lymphocytic pleocytosis.

In TB-related cases, CSF findings usually include (but not always) elevated protein, decreased protein and glucose, as well as PMN's often mixed with lymphocytes. Mycobacterial cultures as well as lymph node biopsies may also assist in diagnosis.

In idiopathic cases, CSF findings include:

  • Moderate mononuclear pleocytosis
  • Mildly elevated protein
  • Absence of identifiable infectious agents or malignant cells
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Other Tests

A complete blood count may indicate very low CD4 lymphocyte counts. Blood and urine cultures may indicate CMV and other possible etiologic agents.

MRI with contrast or myelography is useful to exclude cauda equina or spinal cord compressive lesions resulting from lymphoma, syphilis, or toxoplasmosis. Possible findings include the following:

  • Meningeal enhancement consistent with arachnoiditis
  • Thickened nerve roots or root enhancement in cauda equina can be seen. This finding is nonspecific and inconsistently seen in CMV- associated polyradiculopathy.

Electromyography and nerve conduction studies may indicate the following:

  • Differentiation from other rapidly progressive neuropathies such as Guillain-Barré syndrome
  • Widespread denervation
  • Prolonged or absent F-waves
  • Low-amplitude or unobtainable tibial or peroneal compound muscle action potentials and sural nerve action potentials
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Treatment & Management

Treatment strategies depend on the etiology. In idiopathic polyradiculopathy, spontaneous improvement without treatment is common. [8]

For CMV, prompt initiation of therapy is critical. Combination treatment with ganciclovir and foscarnet may be preferred as initial therapy to stabilize disease and maximize response, although it has substantial rates of adverse effects. [17] Ganciclovir-resistant CMV may respond to foscarnet, but mortality remains high. CMV polyradiculopathy can be fatal within 2 months making early treatment extremely important. 

CMV polyradiculopathy responds to cidofovir in combination with highly active antiretroviral therapy (HAART). [18] Acyclovir inhibits activity of both HSV-1 and HSV-2.

In cases of subacute lumbosacral radiculopathy in immunocompetent individuals, symptoms can resolve spontaneously over weeks. Others have responded to corticosteroids. [19]

Symptomatic treatment for neuropathic pain include agents such as gabapentin, pregabalin, nortriptyline, amitriptyline, lamotrigine, venlafaxine, and duloxetine. Physical therapy is also recommended.

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