Age: 64.0
Sex: M
Vaccine: FLUX, FLUX, FLUX, FLU3
Symptoms: Haemorrhagic infarction, International normalised ratio increased, Platelet count normal, Rectal haemorrhage, Unresponsive to stimuli
Clinical narrative: Report obtained from literature case report. A 64 year old male patient (Initials and Date of Birth unknown) received the influenza vaccine on an unknown date. Brand and batch number is unknown. The patient had a medical history of atrial fibrillation, chronic obstructive pulmonary disease, hypercholesterolaemia, type 2 diabetes mellitus, depression, hypertension and gastroesophageal reflux disease. Concomitant medications included warfarin 5mg every other day alternating with 2.5mg, celecoxib 200mg as needed for pain, ipratropium/albertol combination with dose of 2 puffs twice daily, diltiazem 120mg twice daily, metformin 500mg twice daily, hydrochlorothiazide/losartan combination 25mg/100mg daily, escitalopram 20mg daily, lansoprazole 30mg daily, propranolol 40mg twice daily and ezetimibe/simvastatin 10mg/40mg daily. All medication regimens were unchanged for at least 6 months. At the time of vaccination the patient had an INR (international normalised ratio) value of 2.0. The patient has previously received influenza vaccine during warfarin therapy with no complications. In the previous year, the patient's INR was 2.4 on the day of influenza vaccination with a follow-up INR of 3.0 7 weeks later. On an unknown date, 4.5 weeks after the patient received the influenza vaccine, the patient presented to the emergency department and was unresponsive for approximately 1 hour. The patient had rectal bleeding over the previous 2 days prior to admission. The INR value at admission was greater than 15. INR values over the previous 6 months were relatively stable. Refer to attached literature article for INR values. Investigations revealed the following results. Presenting haemoglobin was 8.3g/dL (14-18), hematocrit 24% (42-52) and platelet values 412 X 10 (3) (150-430). Additional laboratory data included a low serum albumin of 3.1g/dL (3.5-5.0) and normal measures for total bilirubin of 0.8mg/dL (0.2-1.0), aspartate aminotransferase of 16 IU/L (10-42), alanine aminotransferase 12 IU/L (10-40). Vital signs included blood pressure 166/60 mmHg, heart rate of 62 beats per minute, respiratory rate of 16 breaths per minute. A noncontrast CT scan of the head revealed a large parenchymal haemorrhagic infarction involving the left temporal, parietal and occipital lobes. There was a significant mass effect including 12mm rightward midline shift and impending uncal herniation. Treatment included a nitroglycerin infusion to maintain systolic blood pressure and infusion of 4 units of fresh frozen plasma and 10mg of Vitamin K. The patient died 17 hours after admission. This case is reported as serious due to death of patient. The company considered events as unlikely in regards to the interaction between the influenza vaccine and warfarin. The time between FLUVAX administration and the patient presenting to hospital with symptoms was 4.5 weeks. It must be noted, however, that the patient tolerated the vaccine in the past whilst concomitantly taking warfarin and there is the possibility of multiple interacting medications. Information derived from this AE report does not change the current safety profile of the product.