Researchers at Boston’s Children’s Hospital and Harvard Medical School published a paper this week that offers assistance to doctors trying to differentiate Lyme meningitis in children from other causes of cerebrospinal fluid pleocytosis.
Serology results from children with suspected Lyme disease can take several days to process, creating a significant danger due to the rapid progression of meningitis, which can be fatal or permanently disabling. The clinical prediction tool known as the ‘Rule of 7s” was found to be a reliable way of identifying children at low risk of Lyme meningitis, thus giving physicians a better opportunity to appropriately treat the children when immediate decisions have to be made.
Tests for Lyme Meningitis in Children
Pleocytosis is the increased presence of white blood cells in body fluid, and this can be a sign of Lyme disease or other bacterial infection. Blood tests for Lyme disease are more routine than tests on cerebrospinal fluid but where neurological symptoms of Lyme disease are present both tests may be run. Children identified as being at low risk of Lyme meningitis would be able to be managed as outpatients whilst serological test results returned, thus reducing their need to stay in an unfamiliar hospital environment that can often be quite scary for children. Other predictive tools are good at identifying those at low risk of bacterial meningitis but such tools do not rule out the possibility of Lyme meningitis, thus leaving the potential for children to be sent home with a life-threatening infection.
Symptoms of Lyme Meningitis in Children
The new test developed by the researchers was outlined in the journal Pediatrics and published online this week. Physicians working in Lyme-endemic areas are likely to find this tool particularly helpful in cases where they need to decide if a child requires hospitalization and immediate parenteral antibiotics following the detection of CSF pleocytosis. Lyme meningitis in children may manifest as headaches, cranial neuritis, and increased white blood cell counts in cerebrospinal fluid. The new tool has three specific criteria for accurately classifying low risk of Lyme meningitis in children:
- Headache for less than seven days
- Less than 70% CSF mononuclear cells
- No cranial neuritis or nerve palsy
Predicting Lyme Disease in Children
The researchers worked at three large urban paediatric centers and looked at children between the ages of 90days old and 19yrs old who presented with CSF pleocytosis. The patients were all in Lyme endemic regions, namely Massachusetts, Delaware, and Philadelphia and 423 children were included, of which 117 had Lyme meningitis. Aseptic meningitis was present in 306 of the children, none had bacterial meningitis. The use of the Rule of 7s identified 130 children as low risk for Lyme meningitis, of these just five had the infection, giving a sensitivity of 96% (112/117), and a specificity of 41% (125/302). No erythema migrans Lyme disease rash was present in 390 children and just three of the 127 patients identified as low-risk for Lyme meningitis had the condition.
Treating Children with Suspected Lyme Meningitis
Another clinical predictive tool is available but the Rule of 7s appears to be easier to apply than the Avery tool which requires mathematical calculations of a more complex nature to predict Lyme meningitis. Identifying those patients at low risk for Lyme meningitis means that unnecessary admissions to hospital can be avoided, along with potentially dangerous parenteral antibiotic treatment. The cost of patient care is also reduced, which can be helpful for both the child’s family and the hospital, as well as insurance companies of course. Patients admitted to hospital are also at risk of acquiring an infection in the clinic, suffering a reaction to the Lyme disease antibiotics, or being subject to inpatient medical error. Children with high CSF white blood cell counts are still recommended to be monitored closely even if they are not admitted to hospital with suspected Lyme meningitis. Any change in symptoms in children should be investigated immediately and the child’s parents should be made aware of possible complications of Lyme meningitis in children such as papilloedema, pseudomotor cerebri, and even the rare event of blindness.
Cohn, K.A., Thompson, A.D., Shah, S.S., Hines, E.M., Lyons, T.W., Welsh, E.J., Nigrovic, L.E., (2011), Validation of a Clinical Prediction Rule to Distinguish Lyme Meningitis From Aseptic Meningitis, Published online December 19, 2011, (doi: 10.1542/peds.2011-1215).