Age: 64.0
Sex: M
Vaccine: FLUX, FLUX, FLUX, FLU3
Symptoms: Haemorrhagic cerebral infarction, Heart rate normal, International normalised ratio increased, Platelet count normal, Rectal haemorrhage
Clinical narrative: Initial report (abstract) received 12 May 2009 from a literature citation. A 64-year-old male was admitted to the hospital after becoming unresponsive four and a half weeks after he had received an inactivated Influenza vaccine (manufacturer unknown, lot number not reported). The family reported a two day history of rectal bleeding prior to admission and the patient was unresponsive for one hour prior to presentation. He had a past history of atrial fibrillation, chronic obstructive pulmonary disease, hypercholesterolemia, type II diabetes mellitus, depression, hypertension, and gastroesophageal reflux disease. The patient had been taking warfarin 5 mg every other day alternating with 2.5 mg for stroke prophylaxis, secondary to atrial fibrillation. Additional concomitant medications included Celecoxib, ipratropium/albuterol inhaler, Diltiazem, Metformin, Hydrochlorthiazide/losartan, escitalopram, Lansoprazole, Propranolol and Ezetimibe/simvastatin. The patient had no recent changes in medical conditions or medication regimens and their international normalized ration levels were relatively stable during the previous six months, ranging between 1.4 and 4.7. At the time of vaccination, the patient's INR 2.0. Upon hospital admission, the patient's INR was greater than 15. The patient's blood pressure was 166/60, heart rate 62, and respiration's 16. Additional laboratory test results included hemoglobin 8.3 g/dL (ref 14-18), hematocrit 24% (ref 42-52), platelet 412x10(3)/uL (ref 150-430), serum albumin 3.1 g/dL (ref 3.5-5.0) and normal total bilirubin 0.8 mg/dL (ref 0.2-1.0), aspartate aminotransferase 16 IU/L (ref 10-42) and alanine aminotransferase 12 IU/L (ref 10-40). A CT scan of the head showed large parenchymal hemorrhagic infarction involving the left temporal, parietal, and occipital lobes; significant mass effect including 12mm rightward midline shift and impending uncal herniation. Corrective treatments included a nitroglycerin infusion to maintain systolic blood pressure in the range of 140-160- mm Hg, an infusion of four units of fresh frozen plasma, and 10 mg of vitamin K. Following a neurosurgery evaluation, it was determined that treatments could not improve the patient's outcome positively, comfort measures were implemented, and the patient died approximately 17 hours after admission (date not reported). The authors noted that drug interactions involving Celecoxib, Lansoprazole, and Simvastatin were considered unlikely potential causes of the high INR as there were no recent changes in medication regimens or usage. It was further noted that the patient had received previous inactivated Influenza vaccine administration during Warfarin therapy with no observed complications. According to the authors, the Horn Drug Interaction Probability Scale indicated a possible interaction between warfarin and Influenza vaccination, and the patient's significant INR elevation, after being relatively stable for at least six months, was thought to be due to an interaction between warfarin and the influenza vaccination. Documents held by sender: None.