Clinical Characteristics of Patients Initially Suspected of Long COVID: A Case Series From a Specialized Outpatient Clinic.

Background: Sequelae of the acute phase of coronavirus disease 2019 (COVID-19), termed long COVID, are characterized by a variety of symptoms, including neurological manifestations. Diagnosing long COVID requires excluding alternative conditions that could explain the symptoms. The role of primary care physicians is considered essential in managing long COVID, particularly during the initial screening phase. Methods: This observational, retrospective, single-center study was conducted at an outpatient clinic from 1 June 2021 to 31 December 2024. We confirmed final diagnoses for patients suspected of having long COVID and included those ultimately diagnosed with other conditions. Clinical data-including symptoms, demographic characteristics, results of clinical examinations, and final diagnoses-were collected. Results: In total, 44 patients were diagnosed with alternative conditions. Of these, 30 were classified as having post-acute sequelae of SARS-CoV-2 mimic, and 14 patients (2.2% of those who believed they had long COVID and visited our clinic) were diagnosed with other diseases. The median age at the time of their clinic visit was 48 years (range, 42.5-61.5). Diagnoses included collagen diseases (5 patients, 35.7%) and central nervous system disorders (5 patients, 35.7%), among others. Weakness was the most common symptom. In contrast to long COVID, fatigue was less frequently reported in this group. Conclusions: We identified a variety of alternative diagnoses among patients suspected of having long COVID. We recommend that primary care physicians exercise caution when diagnosing long COVID, particularly in patients who do not report fatigue.