New headache in heart transplant patient receiving tacrolimus

Case presentation: We saw a 51-year-old patient, heart transplant recipient (October 2022), with recurrent headache since the transplant, which changed pattern at the end of September 2023. Patient wakes up at the end of the night or in the morning with a headache that is more intense than the previous one, throbbing, periorbital, with mild phonophobia and photophobia and no nausea. Headache improves spontaneously in the late morning or early afternoon. He also presents episodes of flashes in his vision. A new pattern emerged one week after a 50% increase in the previous dose of tacrolimus. Fundus of eye with bilateral grade 3 papilledema. Skull tomography with angiotomography showed left frontal ischemic sequelae, venous sinuses and patent superficial and deep veins. Brain MRI was unremarkable. Liquor with opening pressure 260mmH20, crystalline appearance, 1 leukocytes, proteins 45.9, glucose 58 (glycemia 110) | viral, bacteriological, bacterioscopic panel, PCR for mycobacterium tuberculosis, Syphilis, negative fungi and Cryptococcus research. He had a normal renal function, BMI of 21 and has not gained weight in the last year. The patient was managed with acetazolamide up to 1.5g and bilateral occipital nerve block (with good headache control). The papilledema was resolved within 1 month of his initial visit. As the patient has a long history of rejection, we did the option to not suspend the tacrolimus until now. But it is still in discussion. Discussion: Tacrolimus, a calcineurin inhibitor, is an immunosuppressant used globally to prevent rejection after organ transplantation. Posterior Reversible Encephalopathy syndrome, psychosis, intracranial hemorrhage has already been described as side effects of tacrolimus. We saw in literature one case of idiopathic intracranial hypertension (IIH), in a child submitted to a kidney transplantation and receiving tacrolimus. The elevated intracranial pressure and the response to acetazolamide makes us believe that it’s one more case of IIH by tacrolimus. Final comments: With the growing number of people receiving transplantation it’s very important to know the side effects of the immunosuppressant drugs used to manage those patients. Here we report a case of a 51 years old man, with ischemic cardiomyopathy that received a heart transplant and developed IHH secondary of tacrolimus, with good response to acetazolamide treatment.