Severe fever with thrombocytopenia syndrome complicated with subdural hematoma: A rare case and literature review

Abstract A 79‐year‐old woman presented with fever and general malaise. Examination revealed hepatic injury, thrombocytopenia, skin lesions, and regional lymphadenopathy; severe fever with thrombocytopenia syndrome (SFTS) was diagnosed using polymerase chain reaction. The patient developed impaired consciousness that worsened after 4 days. Magnetic resonance imaging of the head revealed a subdural hematoma in the occipital region with an uncertain onset time. As SFTS rarely causes intracranial hemorrhage, the associated risk factors are unknown. Clinicians may overlook potential intracranial hemorrhage in stuporous SFTS patients.


Abstract
A 79-year-old woman presented with fever and general malaise. Examination revealed hepatic injury, thrombocytopenia, skin lesions, and regional lymphadenopathy; severe fever with thrombocytopenia syndrome (SFTS) was diagnosed using polymerase chain reaction. The patient developed impaired consciousness that worsened after 4 days. Magnetic resonance imaging of the head revealed a subdural hematoma in the occipital region with an uncertain onset time. As SFTS rarely causes intracranial hemorrhage, the associated risk factors are unknown. Clinicians may overlook potential intracranial hemorrhage in stuporous SFTS patients. On day 5, we suspected Rickettsia sp. infection and initiated a minocycline hydrochloride drip (200 mg/day). On day 6, bone marrow aspiration cytology revealed an increased proportion of macrophages (13%) with phagocytosed platelets. She had a high fever lasting > 1 week, progressively decreasing red blood cell and platelet counts, and hemophagocytic cells that accounted for ≥3% of her bone marrow nucleated cells. Based on these criteria, 3 we diagnosed hemophagocytic syndrome; intravenous dexamethasone (13.2 mg/ day) was initiated. Re-examination of plain chest and abdominal CT scans revealed swelling of the right external iliac and superficial inguinal lymph nodes (right flank region) without splenomegaly. As the skin lesion was asymptomatic, the hospital dermatologist attributed the rash to a tick bite.
Although her fever resolved after day 7, she became stuporous 4 and mostly slept except during meal times (GCS score, 14 points = E3V5M6). On day 8, serological Rickettsia examination yielded negative findings. On day 9, an SFTS polymerase chain reaction test yielded positive results (viral RNA load, 1.4 × 10 6 copies/ mL); 5 thus, we diagnosed SFTS. She received blood platelets (10 units) following a decrease in platelet count to 17 000/μL. We also diagnosed atrial fibrillation, which did not disappear until day 10; thus, we initiated oral rivaroxaban (10 mg/day).
On day 11, she became deeply stuporous (GCS, 11 points = E3V3M5). 4 She responded affirmatively to all questions but determining whether she was in pain was difficult. She had no other visible symptoms (eg, quadriplegia, facial paralysis, anisocoria). Head magnetic resonance imaging showed a small subdural hematoma in the same right occipital site where a hematoma had developed 2 years earlier ( Figure 1A). Her atrial fibrillation disappeared on day 11, and rivaroxaban was stopped.
After day 12, her AST, ALT, and lactate dehydrogenase (LDH) levels began to decrease. On day 14, her consciousness improved to drowsiness (GCS, 14 points = E4V4M6); 4 on day 19, plain head CT confirmed no increase in the subdural hematoma ( Figure 1B). She was discharged without sequelae on day 47. Figure 2 shows her clinical course. In our case, we supposed that the subdural hematoma did not expand because it involved venous microbleeding rather than arterial bleeding. 10 However, even if the subdural hemorrhage is not arterial, hematoma expansion remains possible. The steps required to prevent expansion of SFTS-related subdural hematomas remain unclear, and SFTS-associated intracranial hemorrhage may be fatal.

ACK N OWLED G EM ENTS
We are grateful to Dr. Masayuki Shimojima and Dr. Masayuki Saijo for providing the SFTSV nucleoprotein gene positive control.

CO N FLI C T S O F I NTE R E S T
The authors have stated explicitly that there are no conflicts of interest in connection with this article.

E TH I C S A PPROVA L
Informed consent was obtained to publish this case report.