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\begin{document}

\title{Atypical COVID-19 Infections -- The Challenge of Predicting the
Unpredictable}



\author[1]{Shuwei Zheng}%
\author[1]{Jade Xiao Jue Soh}%
\author[1]{Jiashen Loh}%
\author[1]{Pushpalatha Bangalore  Lingegowda}%
\affil[1]{Sengkang General Hospital}%


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  \date{May 04, 2024}


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\emph{Letter to the Editor~}

\textbf{Introduction~}

Since December 2019, severe acute respiratory syndrome coronavirus
(SARS-CoV) 2 has caused an unprecedented public health crisis. Till
date, more than two million cases have been diagnosed worldwide. In
Singapore, where all confirmed cases are hospitalized early in the
outbreak, immense pressure has been placed on the public healthcare
system given the personal protective equipment and isolation needs in
caring for these highly infectious patients. Coronavirus disease 2019
(COVID-19) transmission within healthcare facilities is a serious threat
to medically vulnerable patients and healthcare workers. {[}1{]} We
describe our experiences with regards to three atypical COVID-19 cases,
seen in our institution.

\textbf{Case Reports}

Case 1 is a 67-year-old man, with ischemic heart disease, diabetes
mellitus, hypertension, dyslipidemia. He presented with a three-day
history of dyspnea without preceding fever or respiratory complaints. He
had low grade pyrexia of 37.8\selectlanguage{ngerman}°C but unremarkable pulmonary auscultation.
His initial chest radiograph was unremarkable (Figure 1A). Oropharyngeal
swab for SARS-CoV-2 real-time polymerase chain reaction (RT-PCR)
returned positive. In the two weeks preceding his symptom onset, he had
largely confined himself at home in compliance with nationwide measures
to curb the ongoing outbreak. His only household contact was his wife,
who had been asymptomatic. He developed fever of 38.7°C on his fourth
hospitalization day, associated with clinical deterioration. Repeat
chest radiograph showed interval development of bilateral mid-to-lower
zone air space changes suggestive of pneumonia (Figure 1B). He was given
lopinavir/ritonavir and his maximum oxygen requirement was 2 L/min via
nasal prongs during his ten-day hospitalization stay.

Case 2 is a 52-year-old female with poorly controlled diabetes mellitus,
hypertension and dyslipidemia. She presented with acute onset left flank
pain associated with dysuria, fever, chills and rigors, but no
respiratory symptoms. Clinical examination on presentation revealed
fever (40.6°C), tachycardia (pulse rate 120 beats/min) and left
costovertebral tenderness. Urine dipstick was positive for leucocytes
and nitrites, with subsequent urine culture growing \emph{Escherichia
coli} . Procalcitonin was raised at 121.92 ug/L. She was screened for
SARS-CoV-2 RT-PCR via oropharyngeal swab in view of incidental right
lower zone opacities seen on chest radiograph (Figure 1C), as part of
our hospital's SARS-CoV-2 pneumonia surveillance program. Results were
positive on two consecutive swabs, confirming the diagnosis of COVID-19.
Left perinephric fat stranding (Figure 1D) was seen on abdominal
computed tomography (CT) scan. Its basal lung views revealed patchy
ground glass consolidation (Figure 1E). She improved clinically without
need for supplemental oxygen. The diagnosis of COVID-19 would have been
missed had she presented prior to chest radiographic changes or if no
chest radiograph was performed.

Case 3 is a 49-year-old man without known medical history. He presented
with a five-day history of left breast lump, suggestive of an abscess.
He had no preceding fever, myalgia, headache, respiratory symptoms,
gastrointestinal symptoms, anosmia or dysgeusia. He was found to have
newly diagnosed diabetes mellitus. Admission chest radiograph was
unremarkable (Figure 1F). Bacterial culture of abscess aspirate
grew\emph{Staphylococcus aureus} . In view of an ongoing SARS-CoV-2
outbreak in the dormitory where this patient had been staying, he was
screened for SARS-CoV-2 RT-PCR from an oropharyngeal swab, which
returned positive.

\textbf{Discussion}

We illustrate three cases of atypical COVID-19. All patients were
admitted into single room facilities, where they were screened positive.
These patients could otherwise have been admitted to cohort cubicles
where the propensity for secondary spread, would have been higher.

The 2003 SARS-CoV-1 outbreak in Singapore saw sequential spread
involving three major acute care hospitals, the first arising following
the hospitalization of a returning traveller with atypical pneumonia.
Nosocomial transmission of SARS-CoV-1 resulted, taking a total of three
weeks to control in the first hospital cluster. {[}2{]} The index
patient central to another cluster of 60 patients at a second hospital
in March 2003, had presented with atypical features, masked by \emph{E.
coli} bacteremia. {[}2-3{]} Our small case series illustrate the
vulnerability of our inpatient cohort where atypical COVID-19
presentation can potentially result in secondary nosocomial
transmission.

Contrary to the earlier SARS-CoV-1 outbreak, Singapore's first local
case of SARS-CoV-2 was diagnosed promptly on January 23, 2020 in a
traveller from Wuhan, China. He presented with typical febrile
respiratory symptoms, and was diagnosed with pneumonia upon
hospitalization. {[}4{]} Asymptomatic transmission of SARS-CoV-2 adds to
the challenge of SARS-CoV-2 diagnosis and containment. Asymptomatic
ratio of COVID-19 has been estimated to be as high as 30.8\% amongst
Japanese nationals evacuated from Wuhan, China. {[}5{]} This is
well-illustrated by our Case 3, where an ongoing outbreak in that
setting, raises the pre-test probability of infection and underscores
the immense challenge at curtailing transmission.

A high index of suspicion, strict infection control and prompt isolation
measures are crucial in protecting our healthcare system from nosocomial
SARS-CoV-2 outbreaks.

\textbf{Funding:}

Nil

\textbf{Conflict of Interest}

Nil

\textbf{References}

{[}1{]} Epidemiology of COVID-19 in a Long-Term Care Facility in King
County, Washington. N Engl J Med. 2020 Mar 27. {[}Epub ahead of print{]}

{[}2{]} Gopalakrishna G, Choo P, Leo YS, Tay BK, Lim YT, Khan AS, Tan
CC. SARS Transmission and Hospital Containment. Emerg Infect Dis. 2004
Mar;10(3):395-400.

{[}3{]} Tan TT, Tan BH, Kurup A, Oon LLE, Heng D, Thoe SYS, Bai XL, Chan
KP, Ling AE. Atypical SARS and \emph{Escherichia coli} Bacteremia. Emerg
Infect Dis. 2004 Feb;10(2):349-352.

{[}4{]} Ministry of Health, Singapore. Confirmed Imported Case of Novel
Coronavirus Infection in Singapore; Multi-Ministry Taskforce Ramps Up
Precautionary Measures. 2020 Jan 23.
https://www.moh.gov.sg/news-highlights/details/confirmed-imported-case-of-novel-coronavirus-infection-in-singapore-multi-ministry-taskforce-ramps-up-precautionary-measures

{[}5{]} Nishiura H, Kobayashi T, Suzuki A, Jung SM, Hayashi K, Kinoshita
R, Yang Y, Yuan B, Akhmetzhanov AR, Linton NM, Miyama T. Estimation of
the asymptomatic ratio of novel coronavirus infections (COVID-19). Int J
Infect Dis. 2020 Mar 13;S1201-9712(20)30139-9.\selectlanguage{english}
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