S Lopinavir/ritonavir HIV encephalitis after acquiring intermediate resistance: case reportA 45-year-old man developed HIV encephalitis after acquiring intermediate resistance to lopinavir during treatment with lopinavir/ritonavir. The man, who had been diagnosed with a wild-type HIV-1 genotype acquired immunodeficiency syndrome, was receiving antiretroviral therapy (ART) with lopinavir/ritonavir [route and dosages not stated], abacavir and lamivudine. His viral load was kept under control (<20 copies/mL) and CD4 count was 700 cells/mL. At admission, his neurologic examination revealed drowsiness, confusion and bilateral Babinski sign for 3 months. During the first 24 hours, he experienced generalised tonic-clonic seizures without recovering consciousness and electroencephalographic studies showed a left frontoparietal partial status epilepticus. He was transferred to ICU where CSF analysis revealed 20 leukocytes/µL, 47 RBCs/µL, glucose 59 mg/dL and proteins 51 mg/dL. The HIV virus load in the plasma and the CSF at that time were 56 copies/mL and 28400 copies/mL, respectively. A discordance of resistance patterns between CSF and plasma was noted. An intermediate resistance to lopinavir was detected in CSF. A brain MRI revealed hyperintensity on T2weighted images and isointensity on T1-weighted images, without enhancements, of the periventricular white matter, corpus callosum, left basal ganglia and middle cerebellar peduncles.According to the resistance studies, the man's ART was changed to darunavir/ritonavir, raltegravir, etravirine, abacavir and maraviroc. At follow-up after 29 months, he was noted asymptomatic with CSF virus load <20 copies/mL and with resolved CNS lesions.Author comment: "[I]ntermediate resistance to fosamprenavir, indivavir, lopinavir and nefinavir and low-level resistance to darunavir were detected in CSF." "In conclusion, HIV encephalitis should not be excluded in patients with neurologic symptoms, CSF pleocytosis and white matter hyperintensities on MRI even when plasma virus load is <20 copies/mL." Perez-Rodriguez MT, et al. HIV encephalitis related to the development of a discordant resistant virus in CNS. Clinical Microbiology and Infection 21: e59-e60, No. 8, Aug 2015. Available from: URL: http://doi.