Meningitis is an inflammation of the meninges (the membrane covering of the brain and spinal cord) and characterized by an increase the number of white blood cells (WBCs) in cerebrospinal fluid (CSF). (Nudelman & Tunkel., 2009). Meningitis is a serious infection that required early diagnosis and immediate therapy. Bacterial meningitis is an endemic disease in Egypt, and sporadic cases occur during the year (Abdel Ghani SM et al., 2002).
Meningitis has been divided into bacterial meningitis and aseptic meningitis. Bacterial meningitis is an acute inflammation of meninges secondary to bacterial infection that generally evokes a polymorphonuclear response in the CSF. Aseptic meningitis refers to inflammation of meninges without evidence of bacterial infection on bacterial culture, Gram’s stain and usually accompanied by a mononuclear pleocytosis (Mace, 2008).
The commonest cause of bacterial meningitis in infant and adult is Neisseria meningitides, Haemophilus influenzae type b, Streptococcus pneumonia (Watt JP et al., 2009) While the most common cause of aseptic meningitis is viral meningitis as enteroviruses, arboviruses, herpes family viruses, mumps, rubella, rubeola, rabies and lymphochoriomeningitis virus, Immunodeficiency virus (HIV), influenza virus types A and B (Fowler et al., 2008).
Differentiation between bacterial from viral meningitis is an old problem. The distinction is important because bacterial meningitis requires immediate intravenous administration of antibiotic in the hospital whereas aseptic meningitis is self-limiting. A reliable and valid marker is required to make this differentiation (Prasad and Sahu, 2011).
Positive CSF bacterial culture, Gram staining, or detection of bacterial antigen in CSF considered the gold standard in bacterial meningitis diagnosis. However, they have high specificity but the sensitivity is poor. Furthermore, the bacterial culture is time-consuming. The serum and CSF markers currently used as supplementary markers in bacterial meningitis diagnosis, as C-reactive protein, are also characterized by inadequate sensitivity and specificity. Therefore, searching for more sensitive and specific markers for bacterial meningitis is required (Mekitarian Filho et al., 2014).
The CSF lactate concentration has been considered as a useful marker for differentiation bacterial meningitis from viral meningitis. Level of cerebrospinal fluid (CSF) lactate depends mainly on production from CNS glycolysis and is independent of serum lactate [at physiological pH, lactate is ionized and pass the blood-CSF barrier at a very slow rate], submit another advantage over CSF glucose assay (Tunkel et al., 2004).
Procalcitonin (PCT) is an 116-amino-acid protein that is formed primarily by the C cells of the thyroid gland and secreted from leukocytes in the peripheral blood. In healthy individuals, procalcitonin (PCT) is secreted at levels that are below the detectable limit. However, serum PCT levels increase markedly in patients suffering from bacterial infections. Therefore, elevated PCT levels may serve as a useful marker for diagnosis bacterial meningitis (Meisner, 2014)
Rationale
Meningitis is a serious public health problem require early diagnosis. The combining of CSF lactate and serum procalcitonin are a good parameter to be used in the differentiation between bacterial and viral meningitis.
Research question:
What are the value of combined cerebrospinal fluid (CSF) lactate and serum procalcitonin (PCT) levels in the early diagnosis of bacterial meningitis?
Hypothesis:
The concentration of CSF lactate and serum procalcitonin will be elevated in patients with bacterial meningitis than patients with aseptic meningitis.
Aim of the work:
The aim of this work is to assess the value of combined serum procalcitonin and CSF lactate as reliable markers in patients with bacterial meningitis.
Objectives:
(1) Detecting/diagnosing bacterial and aseptic meningitis patients using routine CSF analysis methods.
(2) Determining CSF lactate level in all of these patients.
(3) Determining serum procalcitonin level in all of these patients.
(4) Evaluating the accuracy of combination between CSF lactate and serum procalcitonin levels as diagnostic tools for bacterial meningitis and differentiate it from aseptic meningitis.
Subjects and methods
Technical design:
A) Site of study: Zagazig Fever Hospital And Zagazig University Hospitals
B) Sample size: All case of meningitis admitted from outpatient clinic and emergency department are about (7) cases in month, (42) cases in six month will be included in the study.
C) Inclusion criteria:
• Patients with symptoms and signs suggesting meningitis including; headache, fever and projectile vomiting and signs including; nuchal rigidity, Kernig’s and Brudzinski’s signs.
D) Exclusion criteria:
• Patients with other disease that causes an increase in CSF lactate such as epilepsy, intracranial hemorrhage or malignancy.
• Other causes of fever (presence of another site of infection in additional to meningitis).
• Antibiotic treatment for 2 day before admission
• Other causes of impaired conscious levels as hepatic encephalopathy or respiratory failure associated with infection.
.
Operational design:
• Type of study: Cross-sectional descriptive study.
• Methods:
1. Detailed history taking including personal data, the presenting complaint, general symptoms and neurological symptoms.
2. Thorough clinical examination including general examination and neurological examination.
3. Routine laboratory investigations including complete blood count, erythrocyte sedimentation rate, C-reactive protein and blood glucose at time of CSF withdrawal.
4. Conventional CSF analysis (Physical and Chemical and Bacteriological analysis)
5. Cerebrospinal fluid lactate estimation.
6. Serum procalcitonin estimation.