23 y.o. female with no significant PMH presented to OSH ED 1 week post brown recluse spider bite. She had fever of 102.4 and was started on abx. Over the next several days, she developed AKI[creatinine:2] and severe hemolytic anemia with haptoglobin of <8 and hemoglobin[hb] of 3.6 [14 on admission] and was noted to have elevated bili of 16 (directand indirect), DAT negative. CT abdomen with no hepatosplenomegaly. She got 3 units of PRBC but continued to have drop in hb.
On day 7, she was admitted to our hospital. On admission-BP: 107/57, Temp: 37 °C, HR: 109, RR: 16. Skin: 2 by 1 inch area of black eschar was noted. Labs: hb-6.4, platelets-54, wbc-23.5, ANC-19.28, INR-1.4, APTT-normal, fibrinogen-95, d-dimer-15483, haptoglobin-normal, LDH-1410, Triglycerides[TG]-688, ferritin->15000. Peripheral smear showed 7 schistocytes/hpf, neutrophilia with L shift, monocytosis, normal platelet morphology. US Abdomen showed mild hepatomegaly and moderate splenomegaly. Bone marrow[BM] biopsy: Normocellular BM (70%) with increased megakaryopoiesis and 16% ring sideroblasts. There was no morphologic evidence of hemophagocytic syndrome on BM biopsy. Pt was given cryoprecipitate for low fibrinogen and was started on IV steroids for disseminated intravascular coagulopathy[DIC]/hemolysis mediated by toxin. She was switched to po prednisone 1 mg/kg after clinical improvement.
Loxoscelism is the term for the medical manifestations of bites by recluse spiders. Local findings range from red plaque, vesiculation to dark depressed center with subsequent eschar formation and ulceration. Systemic symptoms may appear several days after bite: Malaise, Nausea and vomiting, Fever, Myalgias. Rare complications include acute hemolytic anemia, DIC, rhabdomyolysis, myonecrosis, renal failure, coma, and death.
Hemophagocytic LymphoHistiocytosis[HLH]: Diagnosis is based on Molecular identification of an HLH-associated gene mutation OR Five of the following eight findings: Fever ≥38.5°C, Splenomegaly, Peripheral blood cytopenia-at least 2 out of 3[hb <9 g/dL; platelets <100K; ANC<1000/microL], fasting triglycerides >265 mg/dL and/or fibrinogen <150 mg/dL, Hemophagocytosis [BM, spleen, lymph node, or liver], Low or absent NK cell activity, Ferritin >500 ng/mL and Elevated soluble CD25.
Extremely high ferritin levels (>10,000 ng/mL) in the absence of genetic or transfusional iron overload may be found in juvenile idiopathic arthritis, adult onset Still’s disease, SLE and HLH. HLH should be an important part of the differential diagnosis when ferritin >10,000 is seen in an acutely ill child or adult.
Our pt had most of the rare complications of Loxoscelism and also had 5 out of 8 findings of HLH including ferritin >15,000 but BM did not show hemophagocytosis and clinically pt improved without specific intervention.
DIC can present as a late complication of Spider bite. In our case, HLH was high on differential given fever, splenomegaly, elevated Ferritin, TG and cytopenias. If present, HLH requires prompt recognition and treatment given associated high mortality.