Acute Myocarditis with Severe Fever and Thrombocytopenia Syndrome

Abstract

A 67-year-old man, hospitalized with fever and pancytopenia, experienced cardiogenic shock on the 3rd day of hospitalization. He complained of chest pain and exhibited cardiac dysfunction, upregulated serum troponin levels, and an ST elevation on electrocardiogram. Severe fever with thrombocytopenia syndrome (SFTS) was suspected based on the symptom course after a tick bite and was definitively diagnosed using the serum polymerase chain reaction (PCR) test. An endomyocardial biopsy performed in the convalescent phase revealed a sign of myocardial inflammation with increases in CD3- and CD68-positive cells. We herein report the first case of acute myocarditis complicated with SFTS.

Keywords: myocarditis; severe fever with thrombocytopenia syndrome.

Figure 1.

Skin findings. Observations of crusted skin lesions (arrows) (A) and aggregated papules (arrow) (B).

Figure 2.

The clinical courses during hospitalization.

Figure 3.

Bone marrow biopsy. Bone marrow biopsy. Hemophagocytic image (arrow, ×1,000). Mature myeloid series cell counts were decreased, and monocytoid cells and lymphoid cell counts were increased. immunohistological examination; CD3- and CD4-positive T cells, MUM-1-positive lymphoid cells, and CD68- and CD163-positive histiomonocytes cell counts were increased (×400). Image of anti-SFTSV antibody staining was positive (arrow, ×1,000). HE: Hematoxylin and Eosin staining, MUM-1: multiple myeloma oncogene 1

Figure 4.

ECG data obtained on day 3 of hospitalization. The ECG shows a slight ST elevation in the V1-2 leads (A), and it recovered to the normal level on day 14 of hospitalization (B).

Figure 5.

Endomyocardial biopsy of the right ventricle. It revealed a non-specific pathology with mild/indefinite inflammatory infiltration (×100). Mild myocardial hypertrophy and nuclear swelling relative to the myocardial size are present (×200), with areas of marked regularization and mildly crude myofibrils (×100). Intrinsic deflection or explicit active inflammatory cell infiltration are not detectable. Immunostaining reveals increases in CD3-positive (T-cells), CD68-positive cells (macrophages) (×200), and tenascin-C expression (×100).