A 39‐year‐old woman with a history of migraine without aura presented to an institution (located in the borough of Queens, New York, USA; no academic affiliation) in an acute confusional state with concurrent headache and left‐sided weakness and numbness. A lumbar puncture showed acellular cerebrospinal fluid (CSF) with a slightly increased protein concentration. She was treated presumptively for herpes encephalitis on the basis of an increased herpes simplex virus (HSV)‐2 IgG titre in the serum and CSF (IgM not analysed and CSF polymerase chain reaction negative), as well as bifrontal polar gyral‐enhancing brain lesions on magnetic resonance imaging (MRI). Her symptoms resolved over 2 weeks without residual deficit. After 18 months, the patient presented again with a similar constellation of symptoms, including acute‐onset headache, confusion, left visual field flashes, and left‐sided numbness and weakness. An MRI showed new occipital–parietal leptomeningeal‐enhancing lesions; lumbar puncture again showed acellular CSF with raised protein concentration (128 mg/dl). She was transferred to The Neurological Institute of New York for further management.
The patient worked at a perfume counter and identified odours of certain perfumes as a trigger for her migraine attacks. She had no respiratory complaints including asthma, rash, constitutional symptoms or allergies. Other than a multivitamin, she took no drugs regularly, including non‐prescription supplements. Further history and physical examination showed no features suggestive of systemic vasculitis, including lymphadenopathy or rash. Neurological examination was notable for mildly impaired attention, a left homonymous lower quadrantanopsia, left hemiparesis and left patchy hemihypesthesia.
Brain MRI showed right occipital, anterior frontal and bilateral parietal cortical lesions with leptomeningeal enhancement on the T1‐weighted post‐contrast images (fig1A, black arrowheads). Gradient echo showed patchy low signal in sulci, consistent with persistent intracellular deoxyhaemoglobin or methaemoglobin. FLAIR images showed high signal of the cortical mantle as well as the subarachnoid space in the adjacent gyri (fig1B, white arrowheads) that showed prolonged diffusion rates on diffusion‐weighted images and apparent diffusion coefficient maps, consistent with inflammatory oedema or subacute ischaemia. The bifrontal lesions observed on MRI during the patient's previous hospitalisation were faintly visible on the FLAIR sequence (fig1B, white arrow) and showed low signal in the sulci on the gradient echo images, consistent with haemosiderin deposition from a prior haemorrhage.
Serum inflammatory markers were increased, with erythrocyte sedimentation rate 35 mm/h (normal range 0–22 mm/h) and C reactive protein level 92.6 mg/l (normal <3 mg/l; table 1). The patient had a normal blood count including only 1% eosinophils. Serum electrolytes, creatinine, liver enzymes and urine analysis were also normal. Antithyroglobulin and antimicrosomal antibodies were not detected. Stool was negative for ova and parasites. CSF examination showed 2 leucocytes/mm3 (100% lymphocytes), 300 erythrocytes/mm3, a protein level of 119 mg/dl and normal glucose. CSF cultures were negative, as were polymerase chain reaction studies for HSV‐1 and HSV‐2 and varicella zoster virus. Serum rapid plasma reagin was non‐reactive and the patient was HIV negative. Rheumatological studies, including antinuclear antibodies, anti‐DNA, anti‐extractable nuclear antigens, antineutrophil cytoplasmic (cANCA, pANCA), rheumatoid factor and lupus anticoagulant, were negative. A DNA analysis was carried out to look for mitochondrial myopathy, encephalopathy, lactic acidosis and stroke‐like episodes (MELAS), but there was no A3243G mutation. Cerebral angiography showed no evidence of focal arterial narrowing. Computed axial tomography of the chest was normal.
Table 1Laboratory studies on the patient
Brain biopsy showed transmural, predominantly eosinophilic, inflammatory infiltrates of medium‐sized leptomeningeal arteries (fig1C, D, black arrows). Small cortical vessels showed focal fibrinoid necrosis and swollen endothelial cells, without granulomas. Immunoperoxidase staining for amyloid‐β peptide in cortical and subpial vessels showed no evidence of amyloid angiopathy. Gram stain, bacterial culture, staining for acid‐fast bacilli and mycobacterial culture of the brain biopsy were all negative. No viral inclusions were identified, and immunohistochemical stains for HSV‐1, HSV‐2 and varicella were negative.
Figure 1(A) Brain magnetic resonance imaging (MRI) post‐gadolinium T1 sequence shows right occipital, anterior frontal, and bilateral parietal cortical lesions with leptomeningeal enhancement on the T1‐weighted images (black arrowheads). (more ...)
The patient received high‐dose intravenous dexamethasone with rapid improvement in symptoms. She had normal erythrocyte sedimentation rate and C reactive protein levels within 2 weeks of steroid therapy, and was discharged on a prednisone taper followed by a low maintenance dose. One year later she has mild residual left‐sided sensory loss without recurrence of symptoms; MRI showed gyral volume loss and encephalomalacia.