MRI of the brain/spinal cord, cerebrospinal fluid analysis with viral PCR and program blood assessments were normal, and tacrolimus neurotoxicity was ruled out. main biliary cirrhosis (PBC) and positive anti-GQ1b antibodies. Despite its clinical rarity, the prognosis is excellent with potential treatment modalities extrapolated from those of Guillain-Barr syndrome (GBS). Serial anti-ganglioside screening, including titres, may be the future in predicting both disease severity and a monophasic or polyphasic course, which is commonly seen in other autoantibody-mediated conditions. Case presentation A woman in her late 70s presented with a 2-week history of progressive bilateral lower leg weakness, unstable gait and fluctuating drowsiness with Pyrroloquinoline quinone moments of confusion. This followed a 4-week history of a progressive bilateral lumbosacral herpes zoster (HZ) contamination that spread down her right groin and right leg. Medical history included: two liver transplants due to PBC, immunosuppression with tacrolimus, post-transplant Rabbit polyclonal to AMPK2 lymphoproliferative disorder (PTLD) in remission and chronic pancreatitis. On presentation, she was drowsy yet able to maintain conversation and obey simple commands. Once verbal stimulus was eliminated, she would fall asleep, displaying indicators of hypersomnolence. Examination of the cranial nerves revealed a bilateral upward gaze palsy and horizontal nystagmus on easy pursuit. There was deep tendon areflexia, bilateral extensor plantar reflexes and a 2/5 symmetrical flaccid paraparesis in the lower limbs, with preserved firmness and power in the upper limbs. A prolonged non-painful paraesthesia in a glove-and-stocking distribution remained but normally sensory belief was globally preserved. Finally, there was no history of foreign travel, nor evidence of insect bites that may have resulted in a tickborne encephalitis. Investigations Full blood count, liver function, renal function and repeat blood cultures were all normal. Tacrolimus levels were low at 3.3 g/L (reference range 5.0C15.0 g/L) and SARS-CoV-2 RNA computer virus was not detected. Anti-mitochondrial antibody M2, anti-M2-3E and anti-Ro52 were strongly positive. This was consistent with her previous diagnosis of PBC. MRI with and without contrast of the brain and spinal cord did not reveal indicators of encephalitis or myelitis. There was no conus medullaris syndrome, cauda equina syndrome, demyelination, stenosis, infarction, haemorrhage or oedema. Cerebrospinal fluid (CSF) analysis did not reveal protein-cytological dissociation (protein 0.37?g/L, glucose 3.2?mmol/L and white cell count of 0.0109/L). Importantly, viral PCR of the CSF did not detect herpes virus type 1, type 2, varicella zoster, enterovirus or adenovirus DNA. Nerve conduction studies at 8 weeks post-symptom onset were unremarkable, with no discernible demyelinating or axonal features, nor large fibre peripheral neuropathy noted. This would not have necessarily excluded a previous inflammatory event, which may have resolved. Lastly, serum anti-ganglioside screening revealed positive anti-GQ1b IgM antibodies while both anti-GM1 and anti-GD1b subtypes were unfavorable. CSF testing revealed negative anti-GM1; however, there was insufficient sample to total analysis for anti-GQ1b. We plan to repeat serum anti-ganglioside screening on a 6-month basis for this individual. Differential diagnosis The initial presumptive diagnosis was an acute infectious herpetic encephalomyelitis, owing to the recent HZ contamination. Acellular CSF with unfavorable viral PCR and a normal MRI of the brain and spinal cord made this unlikely. The patient was taking long-term tacrolimus but its neurotoxic effects were ruled out by a normal MRI and by low serum levels. Additionally, despite the history of PBC and subsequent liver transplants, there was no gross concurrent hepatic dysfunction portrayed around the blood results that may have impeded the clearance of tacrolimus. Another differential was an acute inflammatory Pyrroloquinoline quinone demyelinating polyneuropathy such as GBS and its variants, acute motor axonal neuropathy (AMAN) and acute sensorimotor axonal neuropathy. Nerve conduction studies, however, did not show evidence of demyelination or axonal pathology, and this case experienced other positive Pyrroloquinoline quinone and negative features that are not seen in the aforementioned syndromes. Acute disseminated encephalomyelitis (ADEM) was ruled out by a normal MRI of the brain and spinal cord. A final diagnosis of BBE, as part of the anti-GQ1b syndrome, was made, based on the clinical features, as a diagnosis of.