Faculty of Medicine, University of Western São Paulo (UNOESTE), Presidente Prudente, SP, Brazil.

6go6ckt5b8|3000F7576AC3|Tab_Articles|Fulltext|0xf1ffa8f8390000009f06000001000b00

The COVID-19 pandemic caused by the highly infectious SARS-CoV-2 virus has posed a global challenge [1,2]. Originating in Wuhan, China in late December 2019, the disease quickly spread throughout the country [3]. COVID-19 exhibits a wide range of manifestations, affecting both the respiratory and non-respiratory systems, which can vary among individuals and may worsen in the presence of advanced age or co-morbidities [4]. While respiratory symptoms such as dry cough, dyspnea, and sore throat, often accompanied by fever above 37°C, headache, loss of taste or smell, and diarrhea, are commonly observed in medical practice, atypical manifestations unrelated to the respiratory system have also been reported in some individuals. These include inappetence, myalgia, abdominal pain, and hypoacusis [5]. It is worth noting that the occurrence of COVID-19 without respiratory manifestations is considered uncommon, as most cases involve symptoms related to the upper and lower respiratory system [6].

A 50-year-old married man with a history of diabetes and hypertension, no history of drug use, and incomplete vaccination for H1N1, traveled with his wife to the Northeast region of Brazil in March 2020. They passed through multiple airports, including Presidente Prudente (PPB), São Paulo (CGH/GRU), and Recife (REC). Three days before returning to their hometown (Day 1 - D1), the patient experienced the onset of myalgia, arthralgia, fever (>37.8°C), and lack of appetite. As his symptoms worsened, he sought medical care at the Emergency Room of a private hospital (D9), six days after returning from the trip. The initial hypothesis was dengue, and a blood count was performed, which showed normal patterns, including a platelet count of 168,000/mm³ (Reference values: 150,000-400,000/mm³). However, the patient was advised to return for a follow-up blood count after 48 hours, following the institution's protocol for dengue. On D11, a new blood count revealed thrombocytopenia (platelet count of 143,000/mm³), confirming the diagnosis of dengue.

COVID-19 primarily affects the respiratory system, with typical symptoms including upper and lower respiratory tract manifestations, dyspnea, dry cough, fever (>37°C), fatigue, malaise, and headache. Additionally, there have been reports of less common symptoms such as gastrointestinal issues, arthralgia, myalgia, dizziness, and loss of appetite [7]. In this reported case, the patient presented with infrequent symptoms such as arthralgia, myalgia, inappetence, and fever (>37.8°C), but without any respiratory manifestations, making his clinical condition atypical for a COVID-19 diagnosis. As a result, due to similarities with dengue and the epidemiological situation in Presidente Prudente, an incorrect assumption of dengue was initially made. Upon reassessment, the patient was eventually diagnosed with COVID-19 based on his wife's diagnosis and the presence of ground-glass opacity observed on chest tomography, which has high sensitivity (97%) but low specificity (25%) in detecting the disease [8]. Real-time PCR testing was also conducted for diagnostic purposes, but there was a delay in receiving the results due to high demand for the test, leading to a 12-day wait.

It is evident that atypical or non-respiratory symptoms can indicate the presence of COVID-19. It is therefore essential for healthcare professionals to carefully evaluate clinical findings and conduct appropriate differential diagnoses to minimize the chances of diagnostic confusion and erroneous treatment. Prompt recognition of atypical presentations can lead to early detection and appropriate management of COVID-19 cases, ultimately improving patient outcomes and reducing the potential for further transmission of the virus.

Contributors: MJCLC, MBM, and MFE contributed to the conception, literature review and design of the manuscript. NWOR, RSF and GHDG contributed to drafting, discussion and critical revision of the manuscript. GHDG will act as a study guarantor. All authors approved the final version of this manuscript and are responsible for all aspects of this study.

Funding: None; Competing interests: None stated.