Covid-19 could reduce the perception of pain in cancer patients
Doctors from the Geneva University Hospitals (HUG) observed a surprising phenomenon during the second wave of the COVID-19 pandemic: some patients suffering from pain related to cancer experienced a significant decrease or even disappearance of the perception of pain during the acute phase of infection.
This case study would confirm the hypotheses made by the same team on the absence of perceived shortness of breath in a large proportion of patients with severe COVID 19. Although more studies are needed to confirm these observations, these cases suggest that infection with SARS-CoV-2 could induce “atypical” symptoms, possibly through dysfunction of the nervous system. A series of cases to read in the international scientific journal Pain.
So far, several factors related to COVID-19 have been widely accepted as worsening chronic pain. A multidisciplinary team from HUG, led by Dr. Lisa Hentsch, MD senior resident in the Division of Palliative Medicine, and Dr. Matteo Coen, MD, MD-Ph.D. senior resident in the Division of Internal Medicine, surrounded by experts in internal and palliative medicine, neurology, radiology and pathology, revealed for the first time an unexpected phenomenon: a significant, albeit transient, decrease in pain in three oncological patients suffering from of COVID-19[FEMININE[FEMININE
Covid-19 could greatly reduce the perception of pain
The patients, three men aged 67 to 84, were followed by the outpatient palliative care consultation for severe oncological pain refractory to opioid treatment. Hospitalized at HUG for COVID-19, all patients observed a decrease or even disappearance of their pain shortly after infection. The recovery from COVID-19 was also associated with a gradual return of pain in one of the patients. For now, this phenomenon remains unexplained, but the team is making a few assumptions.
Insular cortex dysfunction?
In a previous article published in the Journal of Medical Virology, the authors discussed another very common phenomenon in patients with severe COVID-19: the absence of dyspnea (struggle to breathe) despite lower oxygen levels. to normal (commonly referred to as “happy hypoxemia.”) Pain and dyspnea are both subjective experiences that result from complex mechanisms in which the insular cortex plays a critical role.
The insular cortex, or insula, is a part of the cerebral cortex, buried deep within the folds of the cortex. It plays a role in different bodily functions. In particular, the insula is responsible for the “awareness” of internal perceptions (interoception), which is essential for the construction of experiences such as pain and dyspnea.
A dysfunction of this area, due to a direct effect of the SARS-CoV 2 virus, or as a consequence of the “inflammatory storm” frequent in severe COVID-19, could indeed be responsible for a blunt, or even absent, perception of pain and dyspnea. An alternative hypothesis could be a direct dysfunction induced by SARS-CoV-2 in the peripheral nervous system. Able to interfere with the transmission of the nerve message responsible for pain perception and labored breathing.
Further studies are needed to confirm these observations and validate these hypotheses. Nevertheless, these observations could shed new light on the mechanisms responsible for the perception of pain and ultimately open up new avenues of research and therapy.
These first discoveries on temporary pain reduction are the subject of an article published in the prestigious international scientific journal Pain, the leading journal dedicated to the study of pain.
Geneva University Hospitals (HUG)
Hentsch, L., et al. (2021) Decreased pain perception during acute SARS-CoV-2 infection, a case series. PAIN. doi.org/10.1097/j.pain.0000000000002512.