A 13-year-old boy presented 30 min after symptom onset with a sudden weakness of the right side and slurred speech. In the 3 weeks before, he had complained about headache, mild flu-like symptoms, fatigue, and myalgia. Neurological examination revealed a right directional nystagmus, dysarthria, brachiofacial hemiparesis, hemihypesthesia, and extensor plantar sign on the right side. The pediatric National Institute of Health stroke scale score (pedNIHSS) was 10. Emergency laboratory examinations were normal.
Cerebral magnetic resonance imaging [MRI; DWI/ADC (diffusion-weighted imaging/apparent diffusion coefficient), FLAIR (fluid-attenuated inversion recovery, SWI (susceptibility weighted imaging), and TOF (time-of-flight) angiography] showed a hyperintense area on DWI with ADC restriction in the medulla oblongata on the left side; FLAIR and SWI were normal. Imaging was affected by metal artifacts generated by the patient's orthodontic braces.
Systemic IVT was started 73 min after onset of symptoms in the MRI with a total dose of 45 mg alteplase in 1 h (0.9 mg/kg, 10% as initial bolus). Door-to-needle time was 43 min. Extracranial duplex sonography and transcranial color-coded duplex sonography (TCCS) revealed a slightly reduced flow velocity in the left vertebral artery (extracranial v2 segment and intracranial v4 segment) and a reduced diameter of the left vertebral artery compatible with congenital hypoplasia of the left vertebral artery. Flow in the extra- and intracerebral blood vessels was otherwise normal.
Follow-up MRI (DWI/ADC, T1, FLAIR, SWI, and gadolinium-enhanced MR-angiography) on day 1 (after removal of the braces) showed a hyperintense area on DWI with ADC restriction and very subtle hyperintensity in FLAIR in the medulla oblongata on the left side. Gadolinium-enhanced MR-angiography revealed a minimum irregularity in the diameter of the proximal basilar artery (BA) and a reduced diameter of the left vertebral artery (Figure 1). Axial T1 weighted images of the neck showed no signs of dissection. PedNIHSS 24 h after IVT was 10.
Lumbar puncture on day 2 yielded a lymphocytic cerebrospinal fluid (CSF) pleocytosis, elevated protein, and intrathecal B. burgdorferi IgG antibody synthesis (see Table 1). Other pathogens were excluded [severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), Tick-borne encephalitis (TBE), Varicella-Zoster Virus (VZV), herpes simplex virus (HSV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), Treponema pallidum, Mycobacterium tuberculosis, human immunodeficiency virus (HIV), Parainfluenza Virus, Parvovirus B19, Candida, Mycoplasma, Listeria monocytogenes]. Antibiotic treatment was started with cefotaxime (6 g/day for 14 days), acyclovir, and ampicillin being stopped after negative results for HSV/VZV and L. monocytogenes. A steroid pulse of 500 mg methylprednisolone was administered for 5 days, then 50 mg of prednisolone were given per os and tapered over a period of 1 month. ASA 100 mg daily was administered continuously.
On day 3, dysarthria worsened and a marked dysphagia developed. Hiccup occurred constantly, hemiparesis and nystagmus were unchanged, and pedNIHSS was 12. He developed a febrile episode and an ampicillin rash.
A third MRI showed a new right side medulla oblongata infarct; the left side medulla oblongata DWI/FLAIR lesion was slightly larger than in the second MRI. In a control lumbar puncture on day 18, there was a mild lymphomonocytic pleocytosis and normal protein; B. burgdorferi-specific antibody index (AI) was again positive (Table 1). Further extensive laboratory examinations, including thrombophilia, were normal. Transesophageal echocardiography and electrocardiogram were normal. The patient and his family live in northern Germany, frequent hiking tours in the forest were reported, but no tick bites or erythema were recorded.
PedNIHSS on day 7 was 9; dysarthria and dysphagia slowly improved. On discharge to neurological rehabilitation, he was able to feed without a nasogastric tube but unable to walk. On follow-up 9 months later, he was able to walk unaided, pedNIHSS was 2, modified Rankin Scale (mRS) 2, and Barthel Index 95. Extracranial duplex sonography and TCCS were unchanged showing hypoplasia of the left vertebral artery and were otherwise normal. Platelet inhibition with ASA 100 mg/day was the only ongoing medication. He is able to live with his family and attend his former school.