Case Presentation
A 33‐year‐old male was admitted with a history of fever, malaise,
arthralgia, and myalgia for one day. Two weeks ago, he was started on
RTX (1000mg IV 2 times per week) for the treatment of severe pemphigus
vulgaris in addition to his previous treatment with intravenous
immunoglobulin (IVIG) (2 g/kg per cycle), azathioprine (2.5 mg/kg), and
prednisolone (2 mg/kg per day) which were started earlier. The symptoms
appeared 11 days after the second dose.
Subsequent physical examination revealed fever (a temperature of
38.5°C), hemodynamic instability with sinus tachycardia of 130 - 140
bpm, mild tachypnea, malaise, generalized body rash (cutaneous
blisters), and generalized body pain. He reported severe pain while
moving his elbows, shoulders, knees, wrists, ankles, spine,
metacarpophalangeal joints, and temporomandibular joints. However, no
effusions, swelling, and erythema were noted. He was immediately started
on a wide-spectrum antibiotic at the beginning in view of suspected
sepsis and was discontinued shortly after admission.
Subsequent laboratory investigations revealed leukocyte count 26.4 (4 –
10 x10^3/uL), neutrophils 84.3%, platelet count 267 (150 – 400
x10^3/uL), erythrocyte count 6.4 (4.5 – 5.5 x10^6/uL), C-reactive
protein level 112 (0.0 – 5.0 mg/L), uric acid level 7.7 (3.4 – 7.0
mg/dL), creatinine 144 (62 – 106 umol/L). Coagulation profile,
electrolytes, C3 and C4 levels within normal ranges, Urinalysis was
within normal range except a trace of blood, and blood cultures and
viral panel were negative.
Based on his history of recent administration of RTX and on his physical
examination and laboratory findings, the patient was presumptively
diagnosed as having acute serum sickness secondary to RTX and was
treated with methylprednisolone of 1mg/kg/day divided to 2 doses, ample
analgesia with paracetamol, morphine, and fentanyl patches. He was
immediately started on a wide-spectrum antibiotic at the beginning in
view of suspected sepsis and was discontinued shortly after admission.
His symptoms resolved within 48 hours after initiation of the
above-mentioned treatment, his follow-up laboratory test results were
normal. Four days later, he was discharged home and referred to a
dermatology and allergy clinic where the treating physician has
discussed with the primary physician the treatment options and possible
complications for resuming the patient on RTX.