More than a year and a half after the first cases of SARS-COV2 were identified and the pandemic was declared, slightly less than 5 million people in Spain have had the disease. Months after the start of the COVID-19 pandemic, reports of the disease affecting various systems in addition to the respiratory system started to appear. This was followed by cases of post-COVID syndrome, and in the summer of 2020 long COVID was identified, a syndrome with a considerable impact on public health that affects between 10% and 20% of post-COVID patients.
The neurological involvement of SARS-CoV-2 was identified early in the outbreak, and is of major concern in the scientific community. The predominant acute and subacute neurological manifestations are headache, dizziness, altered consciousness, and to a lesser extent, CNS manifestations, such as stroke, encephalitis and myelitis, together with other PNS manifestations with their corresponding neuralgia1.
Previous coronavirus pandemics such as MERS and SARS have already shown the potential of the virus to involve the CNS and the PNS. Now, several possible mechanisms of neuronal damage associated with SARS-CoV-2 have been described2. Other types of neurological damage have been observed in post-COVID syndrome, such as critical illness polyneuropathy, which may be an indirect consequence of long periods of confinement and treatment in intensive care units, and other highly prevalent neurological alterations. Many of the off-label drugs used to treat COVID-19 have shown some type of neurotoxicity.
Finally, the identification of long COVID coincided with the first reports of COVID-related chronic pain symptoms. Today, the most commonly reported COVID-related pain is somatic and visceral, followed by reports of neuropathic pain3, although these are less frequent and probably underdiagnosed. The aetiology of post-COVID neuropathic pain remains unknown, but some authors suggest it is due to either the direct effect of the microbe or to an indirect inflammatory and immunological mechanism.
In health care, as in many other areas, care guidelines for chronic pain in general have been modified as a result of the pandemic4. To make matters worse, the neurological consequences of long COVID can manifest in people who were not initially diagnosed with the disease because they were asymptomatic or presented mild respiratory involvement. This means that we need to clarify the impact of long COVID by identifying new cases of neuropathic pain in specialized care.
On behalf of the Neuropathic Pain Task Force and Study Group of the Spanish Society of Pain and the Spanish Society of Neurology, we would like to warn clinicians involved in treating post-COVID patients that neuropathic pain symptoms can be overlooked, and call on them to watch out for these symptoms among the different manifestations of the disease. This will allow us identify similarities between different types of CNS and PNS involvement, create on-the-spot diagnosis protocols that are so essential for treatment, and eventually identify effective therapeutic strategies. To achieve this, we believe it is important to create the type of patient registries that already exist in other countries5, and we invite the clinical community to launch such registries, or join those that are currently being created. This will allow us to recognise the influence of SARS-CoV-2 in neuropathic pain, and improve treatment of this syndrome.
