Noninvasive Imaging Technique Can Assist in the Diagnosis of HIV-Associated Sensory Neuropathy

Research findings published in JAMA Ophthalmology suggest that when it comes to assessing HIV-associated sensory neuropathy (HIV-SN), in vivo corneal confocal microscopy (IVCCM) is a useful technique.

According to the US Department of Veteran Affairs, “HIV-SN is a ‘dying-back’ neuropathy, affecting the most distal fibers first, involving myelinated and unmyelinated axons of all sizes.” Furthermore, “on pathologic examination, this pattern of loss is indistinguishable from other toxic neuropathies.”

Peripheral nerve disorders are among the most frequent neurological complications of HIV-infection, according to Johns Hopkins Medicine. HIV neuropathy can manifest in various ways and can affect “multiple sensory and motor nerves in distal parts of the limbs” and result in HIV polyneuropathy. The number of patients with this disorder is increasing worldwide.

IVCCM is an ophthalmic imaging method that could help in the diagnosis and longitudinal monitoring of HIV-SN patients. Due to the fact that IVCCM is a noninvasive imaging technique, “it has huge clinical potential to investigate numerous corneal diseases.”

For the study, investigators sought to assess changes in corneal nerve fiber structure and Langerhans cell density in patients with HIV-SN by using IVCCM.

A total of 40 participants were enrolled in the study, all of whom were male. Twenty of the participants were HIV-positive and recruited from adult outpatient clinics at Chelsea and Westminster Hospital NHS Foundation Trust in England. The prospective, cross-sectional cohort study was conducted between July 24, 2015 and September 17, 2015.

Patients received a structured clinical examination, validated symptom questionnaires, and the Clinical HIV-Associated Neuropathy Tool. The results from patients with HIV were then compared with their healthy control counterparts.

All participants were classified into either the control arm, HIV-positive without SN arm, or HIV-SN arm.

The findings?

Fourteen of the 20 HIV-positive participants had HIV-SN. “This group was older (mean [SD] age, 57.7 [7.75] years) than the group without HIV-SN (mean [SD] age, 42.3 [7.26] years) and the controls (mean [SD] age, 53.8 [10.5] years),” study authors write. Patients with HIV had reduced corneal nerve fiber density compared with the controls, and in patients with HIV-SN compared with those without it.

The investigators also found that corneal nerve branch density and corneal nerve fiber length were reduced in HIV-positive patients, however, no differences were observed between participants with neuropathy and those without it.

The tortuosity coefficient was higher in HIV-positive patients compared with the control group, as well as in those with HIV-SN compared with those without it. The study authors note that no differences had been observed in corneal Langerhans cell density.

“In vivo corneal confocal microscopy could be used in the assessment of HIV-SN, but larger studies are required to confirm this finding,” the authors concluded.