Somatic Symptom Disorder Identified as Neurological Outcome of Long COVID-19
Data from the single center, observational SOMATiC study (NCT04889313) showed that patients with unexplained neurological symptoms following mild COVID-19 infection may meet criteria for somatic symptom disorder (SSD), thus prompting additional management.1
In a cohort of 50 previously infected patients, nearly two-thirds (64%) met the criteria for SSD according to Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5), with the remaining third not fulfilling the criterion B despite a high Somatic Symptom Disorder-B Criteria Scale (SSD-12) score. To the study authors’ knowledge, this was the first analysis to assess SSD diagnosis in patients with long-lasting unexplained post-COVID-19 neurological symptoms.
Senior investigator Elodie Meppiel, MD, Centre Hospitalier de Saint Denis, and colleagues concluded that "identifying the post-COVID-19 conditions that correspond to SSD would allow early appropriate clinical management for many patients, therefore, limiting the major public-health impact of this disabling condition."
SSD, which affects approximately 6% of the general population, has been shown to lead to severe disability, deterioration of quality of life, and unemployment. Unlike patients who have respiratory or neurological sequelae of a severe COVID-19 case, especially following prolonged intensive care, so-called “long COVID-19” remains medically unexplained in patients with mild disease. Here, Meppiel et al aimed to determine whether a positive diagnosis of SSD can be asserted in patients with long-lasting neurological symptoms following a mild case of COVID-19.
Patients included in the analysis were at least 18 years or older, had mild acute COVID-19 managed on an outpatient basis, had post–COVID-19 symptoms including neurosensorial or neurocognitive disturbances, and had general and infectious workup excluding another disease. Patients who were hospitalized during the acute phase of illness, those with suspected de novo neurological pathology unrelated to COVID-19, and those who refused to participate, were excluded from the study.
Regarding SSD assessment, criterion A, or a Patient Health Questionnaire-15 score of at least 12, was met by nearly the entire cohort (94%), and criterion B, or SSD-12 of at least 23, was met by more than two-thirds (66%) of the cohort. Seventeen (34%) patients did not meet criterion B, three-quarters of whom had an SSD-12 score just below the threshold, between 16 and 23, with a particularly low score for some proposals such as, "I think that doctors do not take my symptoms seriously." Additionally, 14 of the 15 patients who underwent neuropsychological assessment showed exclusively mild impairment of attention.
Previous study findings have shown that an acute infectious disease can trigger persistent somatic symptoms, especially chronic fatigue syndrome (CFS). In this analysis, 90% of the 50-patient cohort fulfilled the criteria for CFS according to the Schedule of Fatigue and Anergia (SOFA) scale. In total, 28% (12 of 43) met the criteria for a COVID-19 related posttraumatic stress disorder. Additionally, 19 (38%) patients declared at least one functional disorder prior to infection, such as digestive disorders, diffuse pain, or abnormal fatigue.
High levels of alexithymia traits, demonstrated by Toronto Alexithymia (TAS20) score of at least 61, was found in 42% (18 of 43) of the cohort, with a statistically significant correlation between TAS20 score and SSD-12 score (r = 0.45; 95% CI, 0.24-0.66; P <.001) and the PHQ15 score (r = 0.11; 95% CI, 0.01-0.22; P = .03). History of trauma, reported in 54% of patients, was not associated with the PHQ15 score (r = 0.83; 95% CI, –1.58 to 3.24; P = .49) or the SSD-12 score (r = 3.82; 95% CI, –1.45 to 9.08; P = .15).
The study had several limitations, including the fact that it was done at a single center with a small sample size and no control group. Additionally, a majority of the individuals included were from a COVID-specialized center, which may have introduced selection biases, such as an overrepresentation of healthcare workers and of particularly severe condition.
"As this study focused on neurological symptoms, we did not collect the details of the exhaustive work-up carried out in a specialized canter for post-COVID condition, which did not reveal any organic abnormality explaining the extraneurological symptoms," Meppiel et al concluded. "It would be interesting in futures studies, to compare these data with those of patients with neurological symptoms related to other conditions, such as traumatic brain injury, systemic lupus or functional neurological disorder, implementing extensive biological investigations such as cerebrospinal fluid neurofilament light chain."