A 36-year-old man presented with a fever of 102.7°F, calf pain, and rash on his legs for 2 weeks. Initial treatments with doxycycline and prednisone did not improve his symptoms. During his 7-day hospitalization, his fever persisted without improvement. Testing revealed elevated levels of parvovirus IgM and IgG antibodies, indicating that parvovirus B19 was the cause of his prolonged fever. This case highlights how parvovirus can present in an unusual manner and cause a fever of unknown origin in adults, requiring systematic testing to arrive at the correct diagnosis.

1. Fever of Unknown Origin, An Unusual Presentation of Parvo
B19
Youssef Yaacoub MD , Franco Vallejo MD, Pierre El Hachem MD,
Jonathan Shammash MD
Icahn School of Medicine at Mount Sinai
Englewood Hospital and Medical Center Program
INTRODUCTION
Fever of unknown origin (FUO) is a febrile illness defined as having a temperature greater than 101˚F for at least 3 weeks, or not having a diagnosis once admitted to the hospital after 3
days or after 3 outpatient visits. FUO has a broad differential diagnosis and determining the cause of fever is a challenge for physicians. Up to 50% of FUO cases remain undiagnosed.
Parvovirus is one of many infections that can cause FUO. Parvovirus B19 is a small double stranded DNA virus that infects both children and adults. The clinical presentation of parvovirus
can vary widely from mild fever and rash in children, known as erythema infectiosum, to non-specific symptoms of fatigue, fever, myalgia, or rash in adults. The heterogeneous
manifestation of parvovirus makes this infection difficult to diagnose.
PRESENTATION
A 36-year-old Asian male presented to his primary care physician
because of fevers, calf pain, and rash on both of his legs after
summer vacation in upstate New York. The patient was started on
doxycycline 100mg bid for possible tick borne illness but was told
to stop taking the medication after 2 days. He then went to a
rheumatologist who started him on prednisone 60mg for 5 days
for possible vasculitis. The patient presented to the hospital 2
weeks after the symptoms began because his fever, myalgia, and
rash were not improving.
In the emergency room, the patient had a fever of 102.7˚F. The
patient’s physical examination was unremarkable except for an
erythematous macular rash bilaterally on the ankles and severe
calf pain on palpation or movement.
HOSPITAL COURSE
He was treated empirically for presumptive tick borne disease
with doxycycline 100mg bid but over the course of his 7 days in
the hospital he remained febrile with his temperature spiking
each day with no discernable pattern. The patient was unable to
walk due to his calf pain. On the 7th hospital day, his parvovirus
antibody test revealed an IgM of 7.2 and IgG of 3.8, indicating
that the cause of the patient’s FUO was parvovirus.
CONCLUSION
As more tests/imagings become readily available for the
diagnosis of fever, viruses that have a more indolent and
variable presentation are beginning to form a bigger percentage
of fever of unknown origin. This case represent the systematic
approach for the diagnosis of FUO and the variable
presentation on parvovirus B19.
References
Hemoglobin
Leukocytes
Neutrophils
Platelets
UA
ESR
CRP
Ferritin
Procalcitonin
LDH
Cultures: Blood (6 times) and Urine
Virus: Hep A/B/C, HIV, EBV, CMV
Bacterias: anaplasma, bartonella,
lyme, erlichia Rickettsia rickettsii,
M. tuberculosis
Parasites: babesia
cryoglobulin, ANA, ANCA, SSA/SSB,
C3/C4
Images: CXR, CT chest/abd/pelvis,
LE dupplex, 2D echo
12.5 mg/dL
19,500
15.4 (79%)
500
Normal
85
>15
512
<0.09
393
NEGATIVE
NORMAL
NORMAL
LABORATORY RESULTS
DISCUSSION
The shape of the rash illustrated in this case is unusual for a
parvo B19 infection especially in adults. Furthermore the
history pointed towards a tick borne disease or a vasulitis due
to the shape of the rash and the duration of the symptoms.
That is why it is always important to rule out viral etiologies as a
cause of FUO especially when the patient continues to have a
fever after inital treatment. Although the treatment of this
disease is mainly supportive, knowing that this is the cause can
minimize the use of unnecesary procedures, lab tests, cost and
hospital stay.
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1997;14:638–42.
March 13, 2015