Purulent Meningitis 2020

Annual Report on Purulent Meningitis 2020

2020 saw a total of 72 notified cases of purulent meningitis. Figure 1 presents the development in the number of cases of purulent meningitis by aetiology in the 2000-2020 period. Table 1 shows the distribution by aetiology and age groups.

Meningococcal meningitis (ten cases) in 2020 is described in EPI-NEWS 3-5/21 and in the 2020 annual report on meningococcal disease.

Information about underlying diseases and sequelae are categorised into groups based on diagnosis codes collected from the National Patient Registry. Infections were included as from one month prior to the current meningitis case, but no time restrictions were applied for the remaining underlying diseases/predispositions.

Pneumococci

2020 saw a total of 41 notified cases of meningitis caused by Streptococcus pneumoniae of which 40 were notified. A total of 30 cases were detected by culture of cerebrospinal fluid (CSF). Another ten cases were detected by PCR in CSF. Seven of these cases also had a positive blood culture. One case was notified based on a positive blood culture, but no spinal fluid tests had been performed.

Ten persons below 18 years of age fell ill due to meningitis caused by pneumococci, including a two-year-old child affected by a serotype included in the Prevenar 13 vaccine (serotype 19A). The child had been vaccinated as recommended for its age with Prevenar 13, i.e. it had received all three doses previously, and the case was therefore notified as vaccine failure.

An additional three cases among persons below 18 years of age were caused by serotypes included in the Prevenar 13 vaccine; two cases of serotype 3 and one case of serotype 19F. The eldest of the three was approx. three months old. Due to their very young age, none of the patients were covered by vaccination.

Six cases caused by serotypes included in the Prevenar 13 vaccine occurred in persons above 18 years of age. All six patients were unvaccinated.

A total of 21 of the 41 cases had serotypes included in the 23-valent Pneumovax vaccine (23-valent/PPV23), Table 2.

One of the cases had been vaccinated with PPV23. This person was 84 years old and had been vaccinated in 2017 and 2018, but had a risk factor in the form of splenectomy.

Among the 41 cases, information about other underlying conditions was available for 26 patients among whom two also had an infection focus that had been described before the person developed meningitis. Additionally, two persons had a specific infection focus before falling ill with meningitis but no other underlying disease. Among the four cases who were notified as having an infection focus before falling ill with meningitis, two had an ear focus, and in two cases a presumed ear focus was described in the notification.

In 15 cases, sequelae caused by the meningitis illness had been recorded. The most frequently recorded sequela was hearing impairment (five persons) followed by visual defects/loss of vision (four persons) and epilepsy (three persons).

A total of eight persons died due to their pneumococcal infection, including two children aged less than one year, both of whom had no other underlying disease. The remaining six deceased persons were 27-92 years old, and four of these had other underlying disease.

Other streptococci

Meningitis due to other streptococci than pneumococci was detected in six cases. All six cases were caused by beta-haemolytic streptococci: one with group A streptococci (GAS), four with group B streptococci (GBS) and one with group C streptococci (GCS).

The patient with meningitis caused by GAS was a three-year-old child with no risk factors, who had sequelae to the disease in the form of hearing loss.

Of the four GBS cases, three had become infected 7-90 days after birth (termed LOD - late onset disease). Two of the three infants had risk factors in the form of prematurity and one had sequelae to the GBS infection. The infant who had no risk factors also had sequelae to the disease in the form of epilepsy and loss of vision. The final GBS case occurred in a person aged more than 80 years with a risk factor in the form of cancer disease. This person had no sequelae to the infection.

The patient with meningitis caused by GCS was 89 years old and had other underlying CNS disease but experienced no sequelae to meningitis.

Of the six cases that had been detected by CSF culture, two were detected by PCR of CSF in addition to a positive blood culture, and the final case was notified on the basis of a positive blood culture combined with clinical symptoms of meningitis.

Haemophilus influenzae

Three cases were notified with Haemophilus influenzae; in patients aged 1, 73 and 76 years of age, respectively. Two of these cases had Haemophilus influenzae of serotype b (Hib), whereas the bacterium in the final case could not be typed. All three cases were detected by CSF culture.

The one-year-old child had meningitis caused by Hib, but had not been vaccinated in accordance with the Danish childhood vaccination programme. The child had no other underlying disease and did not experience any sequelae to the Hib infection.

Vaccination against Hib became part of the childhood vaccination programme in 1993 and the adult patient with Hib infection had therefore not been vaccinated. One of the adult patients had a risk factor in the form of CNS surgery but experienced no sequelae after the infection. The other patient had no underlying disease but experienced a sequela to meningitis disease in the form of epilepsy.

Listeria monocytogenes

Seven cases of meningitis were caused by Listeria monocytogenes; one case aged 49 years, two cases aged 65-75 years and five cases aged 75+ years. All had become infected in Denmark. All seven patients had underlying disease, and two died due to their listeria infection.

In three patients, the diagnosis was made on culture of CSF, in one patient by PCR in CSF and in two patients on the clinical picture in conjunction with a positive blood culture. The latter case also had a positive blood culture and cerebral abscess was detected. Microbiologic tests were not performed on the cerebral abscess.

Other aetiology

In 2020, one case was notified of meningitis caused by Staphylococcus aureus (Staph. A), detected by PCR on CSF. This case also had a positive blood culture. The person in question had underlying disease but experienced no sequelae to the Staph A. infection

One meningitis case was caused by Pseudomonas aeruginosa (P. aeruginosa). This case was notified on suspicion of postoperative meningitis and had a P. aeruginosa positive blood culture and microscopy of spinal fluid with some polymorphonuclear and a limited number of mononuclear leukocytes. The person did not experience sequelae following the infection.

Unknown aetiology

In a total of three cases (aged 15-21 years), the disease was notified on the basis of the clinical picture and/or CSF cell counts and microscopy consistent with purulent meningitis, but without detection of bacteria by culture or PCR. In one case, empirical treatment was given for meningococcal infection, whereas pneumococci were the presumed agent in one of the cases. One of the three patients had underlying disease and one had sequelae to meningitis. No patients died.

This annual report is also described in EPI-NEWS no. 36/21.