Rapid response – diagnosing bacterial meningitis in primary healthcare settings

Prompt diagnosis of bacterial meningitis in children improves their chances of survival. However, many primary healthcare workers have limited training. Researchers at the MRC Laboratories in the Gambia and the London School of Hygiene and Tropical Medicine assessed guidelines to help health workers make these important decisions.

Acute bacterial meningitis is one of the most severe infectious diseases in childhood. There are at least 1.2 million cases worldwide each year, causing 135 000 deaths. About half of these occur in Africa.

Staff at primary healthcare facilities must be able to recognise symptoms and signs of meningitis, so that they can urgently refer suspected cases to hospital. To help them make these decisions, the World Health Organisation (WHO) has developed guidelines for identifying sick children in need of referral. These form part of the Integrated Management of Childhood Illness (IMCI).

Two features of these guidelines are critical to their success: sensitivity and specificity. Sensitivity is the percentage of children with bacterial meningitis that is detected using these criteria. If the sensitivity is too low, this potentially life-threatening illness will be missed. Specificity is the proportion of children without bacterial meningitis who are correctly diagnosed as negative using these guidelines. If the specificity is too low, the system will be overburdened with unnecessary referrals. Parents will have to bear the time and expense of travel to a hospital that may be far away.

How well do these guidelines perform in practice? What other signs and symptoms are good indicators of bacterial meningitis? Researchers studied 2097 children between the ages of two months and three years at hospitals in Banjul and Fajara, The Gambia. They found that:

• 51 had a confirmed diagnosis of bacterial meningitis.
• Meningitis is associated with the appearance of being very ill, being lethargic or unconscious, or having a stiff neck or a bulging fontanel (swelling of the head caused by the accumulation of fluid in the skull cavity).
• Parents of children with meningitis are also more likely than parents of other children to say yes when asked if their child is feeding less.
• A combination model of a history of fits, or being lethargic or unconscious, or having a stiff neck, as used in the WHO-IMCI, has a sensitivity of 98 per cent and a specificity of 72 per cent to predict meningitis.

The WHO guidelines perform well, but mean that more than 10 times as many children without meningitis would be referred than children with meningitis in this setting. However, some of these children had other conditions requiring hospital treatment, such as severe pneumonia.

The researchers suggest that:

• The recognition of simple clinical signs can help in the identification of patients with severe infections, including meningitis, which need to be referred.
• The identification of simple clinical signs is not always easy. Primary healthcare staff need training to ensure they can do this.
• Training needs reinforcing through regular contact between front line workers and their supervisors.

Source(s):
‘Clinical predictors of bacterial meningitis in infants and young children in The Gambia’, Tropical Medicine and International Health 7 (9): 722-731, by M. Weber, et al., 2002
HINARI subscribers can access the full-text article here. > Full document.

Funded by: USAID; WHO; UNICEF; Children’s Vaccine Initiative; UNDP

id21 Research Highlight: 22 January 2003

Further Information:
Martin Weber
WHO/CAH
1211 Geneva 27
Switzerland

Tel: +41 22 791 2603
Fax: +41 22 791 4853
Contact the contributor: weberm@who.int

London School of Hygiene and Tropical Medicine, UK

Brian Greenwood
Department of Infectious and Tropical Diseases
London School of Hygiene and Tropical Medicine
Keppel Street
London
WC1E 7HT
UK

Tel: +44 (0) 207 299 4707
Fax: +44 (0) 207 299 4720
Contact the contributor: Brian.Greenwood@lshtm.ac.uk

Medical Research Council Laboratoires, Gambia

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