Atypical presentation of COVID-19 with abdominal pain and no respiratory symptoms: a case series

INTRODUCTION

As of 26 May 2021, the global tally for coronavirus disease 2019 (COVID-19) cases has crossed the 168 million mark, with more than 61,000 COVID-19 cases reported in Singapore. Overseas data suggest that patients with COVID-19 may present with abdominal symptoms such as nausea, vomiting and diarrhoea.[1-3] We report two cases of atypical presentations of COVID-19, who presented with only severe abdominal pain mimicking surgical emergencies, without fever or respiratory symptoms.

CASE DESCRIPTION

Case 1

A 42-year-old Malay woman presented to a private hospital on 5 February 2020 with 3 days of low-grade fever and lower abdominal pain, described as being akin to labour pains. There was no nausea, vomiting, diarrhoea or other focal infective symptoms. She had visited Changi Airport and Singapore Zoo in late January 2020. She reported no travel to China or contact with returning travellers from China or cases of COVID-19.

On arrival at the emergency department, she was febrile at 38°C, but her vital signs were otherwise stable. There was mild lower abdominal tenderness. Initial clinical suspicions were those of pancreatitis and pelvic inflammatory disease. Chest radiography (CXR) was normal. Her laboratory investigations were significant for leucopenia (normal range 4.0–9.6 × 10⁹/L) and mildly raised amylase (131 [normal range 35–120] U/L). Otherwise, C-reactive protein and urine dipstick were normal. Computed tomography (CT) of the abdomen and pelvis was normal, but showed posterior bibasal subpleural consolidation [Figure 1]. The nasopharyngeal swab done at the private hospital returned positive for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in real-time reverse transcription polymerase chain reaction assays on 6 February. She was eventually profiled as the 32^nd confirmed case of COVID-19 in Singapore. She was then transferred to National Centre for Infectious Diseases (NCID) on 7 February. Her fever lysed on day 3 of admission (7 February), and a repeat CXR on day 6 of admission (10 February) showed right lower zone changes. On day 15 of admission (19 February), there was complete resolution of her symptoms and fever. She was discharged home after two consecutive nasopharyngeal swabs for SARS-CoV-2 returned negative.

Figure 1.

Case 1: Coronal CT images show bilateral ground-glass opacities in the lung fields.

Case 2

A 68-year-old Chinese woman presented to the hospital with a 2-week history of constant dull epigastric pain. There was associated nausea but no vomiting, diarrhoea or early satiety. She had no fever or respiratory symptoms. There was no contact with known COVID-19 cases or clusters. She had travelled to Jakarta, Indonesia, from 11 to 14 February 2020. Her symptoms started 12 days after her return to Singapore.

On examination, she was afebrile with stable vital signs, and epigastric tenderness without guarding was noted. Her chest was clear to auscultation. Complete blood count including differential was normal. Serum amylase was normal (83 U/L), and liver function tests were only significant for a mildly elevated alkaline phosphatase level (124 [normal range 40–120] U/L). Abdominal X-ray and CRX were unremarkable [Figure 2].

Figure 2.

Case 2: Normal (a) chest and (b) abdominal radiographs on admission.

Esophagogastroduodenoscopy (EGD) performed on the second day of admission revealed only mild antral gastritis. In view of her persistent epigastric pain, contrast CT of the abdomen and pelvis was performed. No intra-abdominal pathology was detected; however, patchy ground-glass opacities were incidentally noted in bilateral lung fields [Figure 3], which were not apparent on her plain films. In view of the pulmonary findings, she was transferred to a single isolation room and two nasopharyngeal swabs for SARS-CoV-2 PCR were collected 24 h apart. The first SARS-CoV-2 PCR was negative; however, the second SARS-CoV-2 PCR returned positive. She remained afebrile with no respiratory symptoms throughout admission.

Figure 3.

Case 2: Coronal CT images show bilateral ground-glass opacities in the lung fields.

DISCUSSION

The diagnosis of SARS-CoV-2 infection has been complicated by the diversity of (or sometimes absence of) symptoms, imaging findings and severity of disease at the time of presentation.[1] In our local experience, the most common symptoms reported were fever (72%), cough (83%) and sore throat (61%).[4] These findings echo the initial clinical characteristics reported in China, where fever and cough were the predominant symptoms, while gastrointestinal symptoms were less common.[1] One early study from Wuhan that comprised 138 patients with COVID-19 reported three patients who presented with abdominal pain, but it was unclear if this was their only symptom. One of these patients had a delayed diagnosis and was admitted to the surgical department, resulting in ten healthcare workers and four other patients in the same ward being infected.[5] There are other published case reports and a retrospective study of SARS-CoV-2-associated gastrointestinal symptoms in different countries.[6-8] Both our patients were admitted with abdominal pain without any upper respiratory symptoms or diarrhoea, and no documented fever, although one reported subjective fevers.

In a local study, 6/18 (33%) COVID-19 cases had an abnormal CXR finding or lung crepitations, although no radiological abnormalities were noted in the initial presentation.[4] In China, 86.2% of CT performed at the time of admission revealed abnormalities.[1] The most common patterns on chest CT were ground-glass opacities (56.4%) and bilateral patchy shadowing (51.8%),[1] which were mostly peripheral and basal.[9] In both our patients, CT showed bilateral basal and peripheral patchy shadowing with ground-glass opacities.

Case 2 was initially sent to a general (non-isolation) ward with four other patients without isolation due to her atypical presentation. The CT changes of her lungs were incidentally noted and acted upon by her managing clinicians, leading to the patient’s prompt isolation and contact tracing. The other patients in the five-bed cubicle had been exposed, but were not infected.[10] The healthcare workers who were exposed practised self and temperature monitoring, which had been in place since the start of the COVID-19 outbreak in Singapore, and none of these healthcare workers tested positive subsequently.

In conclusion, COVID-19 may present atypically with abdominal or incidental radiographic findings, and clinicians should consider its possibility even in the absence of respiratory symptoms, as these carry important implications for diagnosis, infection control and public health actions.

Financial support and sponsorship

Nil.

Conflicts of interest

Vasoo S is a member of the SMJ Editorial Board, and was thus not involved in the peer review and publication decisions of this article.