2023-06-02 15:01:39
Bacterial meningitis is a neurological emergency and, if left untreated, is usually fatal. Refresh your knowledge with the most important facts about the disease!
Depending on the causative pathogen, up to 20% of patients die from bacterial meningitis; if left untreated, the mortality rate is almost 100%. Recently the new S2k guideline “Community-acquired bacterial meningoencephalitis in adulthood” was published. Even if at first glance there is not much that is new compared to the previous version from 2015, the following things are not only interesting for neurologists.
Incidence is decreasing due to vaccination
The incidence of bacterial meningitis decreases and the pathogen spectrum changes. Thus, due to the regular vaccinations carried out according to STIKO recommendations, meningitis has passed Haemophilus influenzae now a rarity. Also meningitis through Neisseria meningitidis (meningococci) are becoming increasingly rare. Vaccination against Streptococcus pneumoniae (pneumococci), on the other hand, has not yet led to a noticeable reduction in the number of pneumococcal meningitis cases. This is probably because only certain serotypes are covered by the vaccine.
The most common pathogens
The three most common causative agents of community-acquired bacterial meningitis in adults are Streptococcus pneumoniae, Neisseria meningitidis and Listeria monocygotenes. The latter pathogen is relevant for therapy. The otherwise broadly effective Cephalosporins have a listeria vulnerability. Therefore, additional therapy with ampicillin is required.
Key symptoms not always present
The four main symptoms of bacterial meningitis are headache, fever, meningism and impaired vigilance – so far, so known. However, the absence of one or more of the cardinal symptoms is more the rule than the exception. Only about half of the patients have three of the four key symptoms. It follows that if you have two of the four symptoms mentioned, you should think of bacterial meningitis and act accordingly.
Time is brain
“Time is brain” – this applies not only to acute stroke therapy. The longer the initiation of drug therapy for bacterial meningitis is delayed, the poorer the prognosis. According to the guideline, no more than three hours (preferably no hour) should elapse after admission to the hospital before the therapy can be initiated. However, many patients do not initially appear in the clinic, but rather with their family doctor or in the emergency practice. Here, too, therapy can and should be started if there is reasonable suspicion. At last year’s DGN Congress, Prof. Meyding-Lamade from Frankfurt reported a case from a young patient. The doctor in the emergency practice to whom the young woman was presented, accompanied by her mother, had made the correct suspected diagnosis of bacterial meningitis. The transport to the clinic was then delayed for organizational reasons, the initiation of therapy was delayed and the patient died – although the right medication would have been available in the practice.
Diagnosis/therapy algorithm in patients without focal neurological deficit, impaired consciousness, epileptic seizure or immunosuppression
The procedure in patients with V. a. Bacterial meningitis differs depending on whether the above symptoms are present. In any case, the first step is always to take blood with the creation of blood cultures (2 pairs from 2 different collection sites). In patients without the warning symptoms mentioned, the lumbar puncture. Immediately afterwards, the drug therapy with an antibiotic and dexamethasone iv started
Diagnosis/therapy algorithm in patients with focal neurological deficit, impaired consciousness, epileptic seizure or immunosuppression
In patients with the above warning symptoms, an obstacle to the puncture must be ruled out using imaging before the lumbar puncture. This is a cerebral space-occupying process or an increase in intracranial pressure which, in the event of a pressure drop in the spinal area due to the lumbar removal of liquor, could lead to entrapment. In these patients, too, the first step is to take blood and create blood cultures. In order not to lose any time, the drug therapy is then started immediately. Only then does the imaging take place (usually CT due to faster availability) and then, if nothing speaks against it, the lumbar puncture.
Liquordiagnostic
The cell count including cell differentiation, the protein, the lactate and the liquor/serum glucose quotient are determined in the liquor. Typical findings in bacterial meningitis are granulocytic pleocytosis with > 1000 cells/µl, an increase in protein, an increase in lactate and a reduced CSF/serum glucose quotient. But be careful: Atypical CSF findings occur in up to a third of patients. The diagnosis is confirmed by direct detection of the pathogen, either in Gram staining, PCR or bacteriological culture. The latter is the only method that allows resistance testing and should therefore always be attempted. New in the current guideline is the recommendation of multiplex PCR panels that record the most common viral and bacterial pathogens of meningitis.
| follow the channel pin for further infectiology topics. Follow |
The right antibiotic therapy
For community-acquired bacterial meningitis, the recommended antibiotic regimen is the combination of Ceftriaxone (2 x 2g/day) and Ampicillin (6 x 2g/day). Bacterial meningitis after neurosurgical operations, craniocerebral trauma or immunosuppression is treated even more broadly: the combination of Vancomycin (2 x 1g/day) and Meropenem (3 x 2g/day) is then the therapy of choice. In addition to antibiotic therapy, dexamethasone (4 x 10mg/day), in the case of proven pneumococcal meningitis, dexamethasone is continued for 4 days. If another pathogen is detected, dexamethasone can usually be stopped, since it has not yet been finally clarified whether adjuvant therapy with dexamethasone is also helpful here.
ENT focus search
In up to a third of patients with bacterial meningitis there is an infection focus in the ENT area. In these cases, rapid surgical focus sanitation should be carried out to prevent further spread of the pathogen. Thus, after the diagnosis has been made, the search for an ENT focus should be carried out promptly using cMRI and an ENT medical examination.
Complications are common
Half of the patients develop neurological and/or systemic complications in the acute phase of the disease. The most common neurological complications include cerebral edema, vascular complications (vasculitis, vasospasm, sinus thrombosis), hydrocephalus, and epileptic seizures. Here, too, the diagnostic tool of choice is cMRI, which should be performed at the latest when neurological symptoms progress. Systemic complications such as consumption coagulopathy or electrolyte imbalances are also not uncommon. Because of the serious complications that frequently occur, all patients with bacterial meningitis in the acute phase of the disease should be treated in an intensive care unit.
Due to the declining incidence, the experience and routine in dealing with patients with bacterial meningitis is also declining. It is all the more important to know the 10 points mentioned in order to be able to react quickly in an emergency.
| Those Pfister H.-W., Klein M. et al., Community-acquired bacterial meningoencephalitis in adults, S2k guideline, 2023, in: German Society for Neurology (ed.), Guidelines for diagnostics and therapy in neurology. On-line: www.dgn.org/leitlinien. |
Image source: Markus Spiske
#Bacterial #meningitis #facts