Post-COVID-19 syndrome: epidemiology, diagnostic criteria and pathogenic mechanisms involved
*Correspondence: Francisco Javier Carod Artal, MD. Neurology Department. Raigmore Hospital. Old Perth Road. IV2 3UJ, Inverness, UK.
E-mail: javier.carodartal@nhs.scot
Introduction: Many patients with mild or severe COVID-19 do not make a full recovery and have a wide range of chronic symptoms for weeks or months after infection, often of a neurological, cognitive or psychiatric nature. The epidemiological evidence, diagnostic criteria and pathogenesis of post-COVID-19 syndrome are reviewed.
Development: Post-COVID-19 syndrome is defined by persistent clinical signs and symptoms that appear while or after suffering COVID-19, persist for more than 12 weeks and cannot be explained by an alternative diagnosis. The symptoms can fluctuate or cause relapses. It is a heterogeneous condition that includes post-viral chronic fatigue syndrome, sequelae in multiple organs and the effects of severe hospitalisation/post-intensive care syndrome. It has been reported in patients with mild or severe COVID-19 and irrespective of the severity of the symptoms in the acute phase. Between 10% and 65% of survivors who had mild/moderate COVID-19 present symptoms of post-COVID-19 syndrome for 12 weeks or more. At six months, subjects report an average of 14 persistent symptoms. The most common symptoms are fatigue, dyspnoea, anxiety, depression, and impaired attention, concentration, memory and sleep. The underlying biological mechanisms are unknown, although an abnormal or excessive autoimmune and inflammatory response may play an important role.
Conclusions: Clinical manifestations are diverse, fluctuating and variable, although fatigue and neurocognitive complaints predominate. There is no defined consensus on post-COVID-19 syndrome and its diagnostic criteria have not been subjected to adequate psychometric evaluation.
Desarrollo El síndrome post-COVID-19 se define por la persistencia de signos y síntomas clínicos que surgen durante o después de padecer la COVID-19, permanecen más de 12 semanas y no se explican por un diagnóstico alternativo. Los síntomas pueden fluctuar o causar brotes. Es una entidad heterogénea que incluye el síndrome de fatiga crónica posvírica, la secuela de múltiples órganos y los efectos de la hospitalización grave/síndrome poscuidados intensivos. Se ha descrito en pacientes con COVID-19 leve o grave y con independencia de la gravedad de los síntomas en la fase aguda. Un 10-65% de los supervivientes que padeció COVID-19 leve/moderada presenta síntomas de síndrome post-COVID-19 durante 12 semanas o más. A los seis meses, los sujetos relatan un promedio de 14 síntomas persistentes. Los síntomas más frecuentes son fatiga, disnea, alteración de la atención, de la concentración, de la memoria y del sueño, ansiedad y depresión. Se desconocen los mecanismos biológicos que subyacen, aunque una respuesta autoinmunitaria e inflamatoria anómala o excesiva puede tener un papel importante.
Conclusiones Las manifestaciones clínicas son diversas, fluctuantes y variables, aunque predominan la fatiga y las quejas neurocognitivas. No existe un consenso definido sobre el síndrome post-COVID-19 y sus criterios diagnósticos no se han sometido a una evaluación psicométrica adecuada.