Delays in diagnosing potentially fatal meningitis and inappropriate treatment for the infection in hospitals have been highlighted in a hard-hitting report.
One in four meningitis patients had to wait more than 29 hours for a lumbar puncture to distinguish between the bacterial and viral form of the bug – a procedure that should be done within a few hours.
The study, published in The Lancet Infectious Diseases journal, also shows that the introduction of vaccines has successfully reduced the prevalence of bacterial meningitis and most cases in the UK today are caused by viruses.
Although generally seen as a benign condition, the research shows that recovery from viral meningitis can be a long haul for patients, with many still experiencing memory and mental health problems months after they are released from hospital.
The findings also reveal “substantial delays” in diagnostic testing and unnecessary treatment in hospitals across England, which are associated with longer hospital stays.
The median time from admission to a lumbar puncture to distinguish between bacterial and viral meningitis was 17 hours, but in a quarter of patients it took more than 29 hours.
Study leader Dr Fiona McGill, of the Institute of Infection and Global Health at the University of Liverpool, said: “Ideally, this crucial diagnostic test should be completed within a few hours.
“It’s possible that the four-hour accident and emergency treatment target is creating unintended pressure, leading to key investigations like lumbar puncture being postponed until patients have been admitted to a ward.
“Additional delays of several days can also occur if samples are sent to offsite laboratories for analysis.”
The study is the first of its kind to examine the incidence, causes, and impact of viral meningitis in British adults.
Meningitis occurs when there is inflammation of the membranes that protect the brain and spinal cord caused by infection with viruses, bacteria, other microorganisms, and less commonly, drugs.
Although symptoms can be similar, people with viral meningitis usually get better in a few weeks, while bacterial meningitis can kill within hours and requires urgent treatment with antibiotics.
International guidelines stress the urgency of lumbar puncture in order to rule out bacterial meningitis and reduce unnecessary antibiotic treatment, shorten hospital stays, and lessen healthcare costs.
However, this testing is often delayed, leading to difficulties in making a diagnosis.
Since the 1990s, widespread introduction of conjugate vaccines have seen the incidence of bacterial meningitis decline across England.
While meningitis cases caused by viruses seem to be on the rise, until now the true burden of viral meningitis was unknown.
The study included more than 1,100 patients with suspected meningitis presenting to 42 hospitals – including all 24 acute hospitals in the north western region – across England between September 2011 and September 2014.
All the participants either had a lumbar puncture or a bacterial or viral pathogen identified in their blood test or culture.
The researchers examined the association between time to lumbar puncture and receiving a microbiologically proven diagnosis.
The participants were sent questionnaires to assess their quality of life and cognitive function a year after admission.
Of 1,113 patients included in the final analysis, more than half (638) were diagnosed with meningitis. Of these, more than a third of cases (231) were caused by a virus; 99 cases (16 per cent) were bacterial; 267 (42 per cent) had an unknown cause; and 41 cases (six per cent) had other causes identified.
Enteroviruses were the most common viruses identified, accounting for 55 per cent of viral meningitis cases, and 20 per cent of all meningitis cases.
Streptococcus pneumoniae was the most common bacterial cause, responsible for 54 per cent of bacteria cases, but just eight per cent of overall meningitis cases.
Results showed that unnecessary treatment with antivirals was associated with longer hospital stays – with patients infected with viral meningitis who did not have treatment staying for an average of three days compared with nine days in those treated with antivirals.
There was also evidence that earlier lumbar puncture resulted in more patients having a specific cause identified than those in whom testing was delayed – with the chances of having a pathogen detected in viral meningitis reduced by one per cent for every hour delay in lumbar puncture following admission.
Dr McGill said: “Improved rapid diagnostic testing so that more patients can have a specific cause determined quickly could reduce unnecessary use of antimicrobials -both antibiotics and antivirals – and therefore reduce hospital stays and other investigations.”
All people with viral meningitis reported substantially poorer quality of life in the year following illness compared with the age-matched UK population, with an excess of pain, anxiety, depression, and reduced activity levels up to 48 weeks after admission.
Using data on the incidence of viral meningitis in the northwest region, the researchers estimate that the annual incidence of viral meningitis in UK adults is 2.73 per 100,000 compared with 1.24 per 100,000 for bacterial meningitis.
Dr McGill added: “It’s becoming increasingly clear that individuals with viral meningitis experience many lasting effects on their mental health and quality of life.
“We must better support them during and after hospitalisation with more rapid diagnostics and better treatments and rehabilitation to ensure quicker recovery and to help improve outcomes.”