Subject(s)
Neurology/history , Parkinson Disease, Postencephalitic/history , COVID-19 , Coronavirus Infections , Encephalitis/epidemiology , Encephalitis/history , Encephalitis/physiopathology , Epidemics , History, 20th Century , Humans , Influenza Pandemic, 1918-1919 , Parkinson Disease, Postencephalitic/epidemiology , Parkinson Disease, Postencephalitic/physiopathology , SARS-CoV-2 , Severe Acute Respiratory Syndrome , United KingdomABSTRACT
Lactate is produced from anaerobic glycolysis, which occurs in most tissues in the human body. Blood lactate is tested in most physiologically unwell patients in the Emergency Department and helps to guide treatment and prognosis. Cerebrospinal fluid (CSF) lactate, however, is not often measured. Various central nervous system (CNS) conditions lead to a rise in CSF lactate, including acute neurological infection, stroke, seizures and mitochondrial pathologies. This article discusses the utility and limitations of CSF lactate, highlighting specific clinical situations where it can help in the diagnosis of CNS infections and unexplained encephalopathy.
Subject(s)
Enterovirus/isolation & purification , Lactic Acid/cerebrospinal fluid , Meningitis, Bacterial/cerebrospinal fluid , Meningitis, Viral/cerebrospinal fluid , Mitochondrial Encephalomyopathies/cerebrospinal fluid , Staphylococcal Infections/cerebrospinal fluid , Adult , Biomarkers/cerebrospinal fluid , Brain Diseases/cerebrospinal fluid , Brain Diseases/diagnosis , Central Nervous System Infections/cerebrospinal fluid , Central Nervous System Infections/diagnosis , Female , Humans , Male , Meningitis, Bacterial/diagnosis , Meningitis, Viral/diagnosis , Middle Aged , Mitochondrial Encephalomyopathies/diagnosis , Staphylococcal Infections/diagnosisABSTRACT
BACKGROUND: Encephalitis has many causes, but for most patients the cause is unknown. We aimed to establish the cause and identify the clinical differences between causes in patients with encephalitis in England. METHODS: Patients of all ages and with symptoms suggestive of encephalitis were actively recruited for 2 years (staged start between October, 2005, and November, 2006) from 24 hospitals by clinical staff. Systematic laboratory testing included PCR and antibody assays for all commonly recognised causes of infectious encephalitis, investigation for less commonly recognised causes in immunocompromised patients, and testing for travel-related causes if indicated. We also tested for non-infectious causes for acute encephalitis including autoimmunity. A multidisciplinary expert team reviewed clinical presentation and hospital tests and directed further investigations. Patients were followed up for 6 months after discharge from hospital. FINDINGS: We identified 203 patients with encephalitis. Median age was 30 years (range 0-87). 86 patients (42%, 95% CI 35-49) had infectious causes, including 38 (19%, 14-25) herpes simplex virus, ten (5%, 2-9) varicella zoster virus, and ten (5%, 2-9) Mycobacterium tuberculosis; 75 (37%, 30-44) had unknown causes. 42 patients (21%, 15-27) had acute immune-mediated encephalitis. 24 patients (12%, 8-17) died, with higher case fatality for infections from M tuberculosis (three patients; 30%, 7-65) and varicella zoster virus (two patients; 20%, 2-56). The 16 patients with antibody-associated encephalitis had the worst outcome of all groups-nine (56%, 30-80) either died or had severe disabilities. Patients who died were more likely to be immunocompromised than were those who survived (OR = 3·44). INTERPRETATION: Early diagnosis of encephalitis is crucial to ensure that the right treatment is given on time. Extensive testing substantially reduced the proportion with unknown cause, but the proportion of cases with unknown cause was higher than that for any specific identified cause. FUNDING: The Policy Research Programme, Department of Health, UK.
