meningitis
Online learning module on bacterial meningitis and septicaemia
Assessment
The classic presentation of acute bacterial meningitis is headache, fever, neck stiffness and altered mental status, although only 44-66% of patients will present with each of these symptoms.
However, virtually all patients (99 to 100 percent) have at least one of the tetrad of symptoms (Attia et al., 1999) and nearly all patients have at least two symptoms. Complete absence of fever, stiff neck, altered mental status, and headache makes a diagnosis of bacterial meningitis very unlikely (van de Beek et al, 2004).
In three large trials of adults with meningitis, fever was present in 77 to 85 percent, neck stiffness in 83 to 94 percent, headache in 79 to 94 percent, and altered mental status in 83 percent, including coma in 14 to 16 percent (de Gans and van de Beek, 2002; van de Beek et al, 2004; Aronin et al, 1998).
However, no isolated finding is diagnostic, and the most accurate combination of signs and symptoms to aid diagnosis is unclear (Curtis et al, 2010)
History
-
Gather as much history as possible from bystanders and the surroundings and relay this to the ED staff, as it can aid in diagnosis.
-
Elicit any history regarding the child's recent state of health, in particular recent history of upper respiratory tract or sinus infections.
-
Keep meningitis in your list of differential diagnoses for unwell children.
Primary Survey
-
Assess airway for patency.
-
Ensure adequate ventilation, observing respiratory rate, depth and regularity
-
Ensure adequate cardiac output by assessing peripheral perfusion, pulses, capillary refill time and circulation to skin.
-
Ensure adequate cerberal perfusion in the presence of signs of raised intracranial pressure (ICP).
-
Observe for signs of raised ICP such as alterations to respiratory pattern, bradycardia, widening pulse pressure, pupil irregularity and altered mental status.
Secondary Survey
-
A full physical examination should be performed - however, studies show that physical examination alone is inadequate to identify meningitis accurately (Fitch, 2007)
-
Heart rate, blood pressure, and respiratory rate should be monitored regularly with appropriate frequency.
-
Point-of-care testing can be performed if available, notably serum lactate and VBG values (iSTAT CG4+) and serum electrolytes to identify any abnormalities (iSTAT Chem8+)
Rash
-
Present in a small percentage of cases, the presence of a non-blanching rash is indicative of meningococcal septicaemia, but is not a foolproof technique.
-
There may be no rash at all, or a blanching rash which fades with pressure.
-
Although it carries a strong likelihood ratio as demonstrated by Curtis et al (2010) this was based on one small study.
-
It is 100% specific, but only 6% sensitive for meningitis (i.e. you can use the presence of a rash to rule in meningitis, but not use the absence of a rash to rule it out)
Altered Mental Status
-
Children who are being treated for bacterial meningitis should be monitored carefully for complications (eg, increased intracranial pressure, seizure activity)
-
Seizures can present in up to 40% of children presenting with bacterial meningitis (Roos and Greenlee, 2015)
-
A complete neurologic examination should ideally be performed, and the patients level of consciousness should be assessed.
Fever
-
Fever is a common sign of bacteraemic infection
-
A fever >40°C carries a strong likelihood of bacterial meningitis when accompanied by other signs and symptoms (Curtis et al, 2010), with a lower grade fever also being indicative when combined with other clinical findings.
