HIV-Associated Multiple Mononeuropathies

Updated: Mar 24, 2017
  • Author: Florian P Thomas, MD, MA, PhD, MS; Chief Editor: Niranjan N Singh, MD, DM  more...
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Overview

Overview

Multiple peripheral mononeuropathies can occur in the setting of HIV-1 disease. The presentation can be similar to multiple mononeuropathies in the non-HIV population. Early multiple mononeuropathy is usually self-limited and can present at the time of seroconversion. [1] Late multiple mononeuropathy in a patient with a CD4 count less than 50 cells/mm3 is usually related to cytomegalovirus (CMV) infection and can progress rapidly. [1, 2, 3, 4, 5, 6, 7, 8, 9]

A limited form of multiple mononeuropathy (1-2 nerves) presents in HIV-seropositive patients without AIDS and may have an autoimmune origin. A more generalized form (>2 nerves) presents in patients with AIDS. While CMV is often shown to be the cause, the occurrence of clinical CMV in AIDS has declined with the advent of highly active antiretroviral therapy (HAART).

The most common cranial mononeuropathy in HIV patients involves the facial nerve usually occurring around the time of seroconversion. Conditions known to accompany HIV such as CNS (central nervous system) lymphoma, diffuse infiltrative lymphocytosis syndrome, tuberculosis meningitis, syphilis, HSV-1, VZV, and vasculitis can also cause various cranial mononeuropathies.

Herpes zoster can occur in HIV patients in the form of trigeminal neuropathy. This is classically asociated with zoster vesicles with dermatomal distribution. Various cranial neuropathies involving the trochlear nerve, facial nerve, and mental branch of the trigeminal nerve can be associated with CNS lymphomas. [10, 11, 12] Diffuse infiltrative lymphocytosis syndrome can cause facial palsy. [13, 10]  Optic neuropathy has been reported in syphilis. [14]  Entrapment neuropathies can occur in advanced HIV disease.

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Clinical Presentation and Diagnosis

The multiple mononeuropathies are typically inflammatory in nature and may involve single or multiple cranial or peripheral nerves. They vary with the stage of HIV infection. [15]

The patient describes multifocal asymmetric sensory or motor complaints in the distribution of cranial nerves, [2] peripheral nerves, or nerve roots. Cranial neuropathies most commonly involve the facial nerve (also known as Bell's palsy) and can be unilateral or bilateral. Facial paralysis in HIV patients does not differ clinically from typical Bell's palsy. 

Physical findings include asymmetric weakness and reflex and sensory loss. More severe involvement suggests cytomegalovirus (CMV) infection. Progression may change presentation from multifocal mononeuropathies to a more generalized polyneuropathy. 

Blood for CMV polymerase chain reaction (PCR) analysis should be sent if HIV-associated multiple mononeuropathy is suspected. [16]

Electromyographic (EMG) and nerve conduction studies show asymmetric multifocal involvement with axonal degeneration, and the CSF will show an elevated protein level and pleocytosis.

Magnetic resonance imaging with contrast can be useful if suspecting CNS lymphoma.

Laboratory studies

Cerebral spinal fluid may indicate the following:

  • Nonspecific
  • Mononuclear pleocytosis
  • Elevated protein

Electromyography/nerve conduction studies may indicate the following:

  • Reduced amplitudes of sensory nerve and compound muscle action potentials
  • Mildly reduced conduction velocities
  • Denervation
  • Asymmetric distribution

Correlation with CD4+ lymphocyte counts (a surrogate marker for stage of HIV infection) may indicate the following:

  • CD4 count >200 cells/mm 3: the limited autoimmune form
  • CD4 count of 50-200 cells/mm 3: more widespread involvement related to autoimmunity
  • CD4 count < 50 cells/mm 3: more widespread form and evidence of CMV infection

Histologic findings

Histologic findings show axonal degeneration with perivascular mononuclear infiltrates. Occasionally, the infiltrate is predominantly polymorphonuclear.

In patients with multiple mononeuropathies due to CMV infection, CMV inclusions can be seen in mononuclear and endothelial cells, and CMV can be identified by culture or polymerase chain reaction. Occasionally, a prominent necrotizing arteritis can be seen.

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Treatment

Intravenous immunoglobulin (IVIG) and plasmapheresis (plasma exchange) are preferred to immunosuppression. During a 7- to 10-day period, 4-5 plasmaphereses may be performed, as described in standard protocols. Potential complications include autonomic instability, hypercalcemia, and bleeding from depletion of clotting factors. The decision whether to use IVIG, plasmapheresis, or steroids should be based on the individual patient. [17, 18]

Treatment for mononeuropathies that are secondary to other co-existing conditions require focused therapy specific to that underlying organism or condition. For example, a more extensive disease state resulting from disseminated CMV infection can be treated with ganciclovir and/or foscarnet if instituted early. Conversely, the limited autoimmune form can be treated with IVIG, plasmapheresis, or steroids. These treatments have proven efficacious in some studies but not in others. 

Facial palsy recovery is similar to those without HIV and typically self-resolve. HAART has been shown to improve symptoms in patients with presumed HIV-induced optic neuropathy. [19]

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