Age: 16.0
Sex: M
Vaccine: RAB
Symptoms: White blood cell count decreased
Clinical narrative: Case number PHHY2015US121837, is a combined initial and follow-up literature report received from other healthcare professional on 02 Oct 2015. The author discussed about a case of immune thrombocytopenic purpura (ITP) after rabies vaccination. This report refers to a 16 year old male patient. Concomitant medication was not reported. The patient was current with all immunizations per the Advisory Committee on Immunization Practices recommendations except for the second dose of varicella vaccine. Past medical history was negative for any chronic illness or episodes of easy bruising, epistaxis, or petechiae. He reported no prior history of exposure to doxycycline or any rabies vaccine. Family history revealed no history of platelet or bleeding disorders. Review of systems was negative for other concerning symptoms of acute or chronic illness, including headaches or neurological changes. The patient's parents denied any history of recent symptomatic viral infection. The patient was attacked by several stray dogs (day 0) during a visit to another country. The patient sustained multiple penetrating lesions to his right lower extremity. The same day, he was taken to the emergency room and received doxycycline and the first dose of VERORAB (other manufacturer, batch number: unknown). While still in the other country, he received second dose of VERORAB (batch number: unknown) on day 3 after the injury. Upon return home, he presented to the emergency room (day 5) and received rabies immunoglobulin near the bite sites intramuscularly. The patient received doses 3 and 4 with RABAVERT (batch number: unknown) in the right arm intramuscularly (days 7 and 14). On day 15, the patient's mother noted petechiae and development of bruises. He had no epistaxis, hematuria or blood in his stool. The patient was evaluated in urgent care on day 18 and found to have a platelet count of 5000/mcL. Repeated lab tests on day 18 demonstrated a white blood cell count of 6870/mcL, hemoglobin of 14.7%, hematocrit of 41.5 gm/dL, platelet count of 2000/mcL, absolute neutrophil count of 3880/mcL with the rest of the differential in the normal range, and normal red blood cell indices. The immature platelet fraction, measured by Sysmex, was 28.1%  resulting in an absolute immature platelet count of 562 peripheral blood smear revealing giant platelets. Epstein-Barr virus and cytomegalovirus titers were consistent with a history of past infection, but no evidence of acute infection. His liver enzymes, electrolytes, and kidney function were within normal limits. Examination was positive for 2 small purpuric lesions on his oral mucosa membranes, multiple petechiae on his chest, back, abdomen, and legs, and a large bruise on his right knee. Lymphadenopathy and hepatosplenomegaly were not noted on examination. He was diagnosed with presumed ITP. No treatment was initiated due to the lack of active bleeding on examination, the patient's ability to abide by activity restriction and the known risks of treatment-related side effects. On a repeat complete blood count 1 month later, platelets had increased to 57,000/mcL with a normal immature platelet fraction of 3.7%. Several months later, platelets increased to within the normal range. Because of the timing of the development of ITP after the rabies vaccines administration and without other identified causes of thrombocytopenia or a viral prodrome, the most likely trigger for ITP in this case presented is the rabies vaccine. Either the VERORAB or the RABAVERT could be implicated as the symptoms occurred 14 days from the first dose of VERORAB and 7 days after the RABAVERT, which is within the biological time. Final outcome of the events was completely recovered. The author concluded that because of the rare occurrence of this adverse event relative to the severity of rabies infection, the benefits of rabies vaccination, when indicated, outweigh the low and possible risk of ITP.