Overview of Meningitis
Meningitis caused by purulent bacterial infection mainly manifests as fever, headache, vomiting, consciousness disorder, etc. Most of the prognosis is good; a small number of people left with mental retardation, epilepsy and other sequelae may be transmitted through the respiratory tract, gastrointestinal tract, blood and other channels.
What is purulent meningitis?
Definition
Septic meningitis is an inflammation of the cerebrospinal membrane caused by a purulent bacterial infection and is an extremely serious intracranial infection.
Streptococcus pneumoniae, Neisseria meningitidis (also known as Neisseria meningitidis), and Haemophilus influenzae type b are the most common causative organisms, some of which are infectious.
Most of the cases have a sudden or acute onset, and are often combined with pyogenic encephalitis or brain abscess, and the morbidity, mortality and disability rates are still high.
Classification
The common types are categorized according to the causative organisms, and are listed below:
Streptococcus pneumoniae meningitis.
Epidemic cerebrospinal meningitis: caused by meningococcus.
Haemophilus influenzae meningitis.
Staphylococcus aureus meningitis.
Enteric gram-negative bacilli meningitis: most commonly Escherichia coli, followed by Proteus mirabilis and Pseudomonas aeruginosa.
Other types of meningitis.
Morbidity
Morbidity varies with the causative organism.
Streptococcus pneumoniae, Meningococcus meningitidis and Haemophilus influenzae type b cause more than 80% of purulent meningitis.
Prevalence
Haemophilus influenzae meningitis occurs in the spring and winter months.
Streptococcus pneumoniae meningitis can occur throughout the year, but the prevalence is higher in spring and winter.
Enterovirus meningitis is more prevalent in summer and fall.
Prevalent Population
Epidemic cerebrospinal meningitis has declined significantly due to vaccine penetration and is more prevalent in the elderly, infants and children.
Enteric gram-negative bacillus and Staphylococcus aureus meningitis is most common in infants aged 0 to 2 months.
Haemophilus influenzae meningitis occurs in infants and children aged 3 months to 3 years.
Streptococcus pneumoniae meningitis occurs in older adults and children over 5 years of age.
Questions you may be concerned about
Can purulent meningitis be cured?
Currently, the death rate and disability rate of purulent meningitis are still high, but if timely and standardized diagnosis and treatment, most patients have a good prognosis.
Once the disease is diagnosed, sensitive antibiotics, such as ceftriaxone and cefotaxime, should be used as soon as possible. And according to the symptoms can be given to reduce intracranial pressure, antiepileptic, inhibit inflammatory factors and other treatments.
If the treatment is not timely, life-threatening complications such as increased intracranial pressure and cerebral hernia may occur. A few patients may be left with sequelae such as intellectual disability, epilepsy and hydrocephalus.
How to prevent purulent meningitis?
Prevention of purulent meningitis focuses on vaccination, cutting off the transmission route and protecting susceptible people.
The main causative organisms of this disease are Streptococcus pneumoniae, Meningococcus meningitidis and Haemophilus influenzae type b. Vaccination can be given in time to prevent the disease.
Avoid going to crowded places during the epidemic season, wear a mask when going out, and avoid squeezing facial boils.
For the elderly, infants and children, immunocompromised people (e.g. cancer patients, diabetic patients, etc.) should avoid close contact with patients with this disease.
What are the sequelae of purulent meningitis?
Sequelae of purulent meningitis include mental retardation, epilepsy, and hydrocephalus.
In severe cases, the disease may involve the brain parenchyma and cortical damage may occur, leading to mental retardation, psychiatric abnormalities, and seizures.
Arachnoid fibrosis and adhesions can occur in this disease, causing impaired absorption and circulation of cerebrospinal fluid, leading to hydrocephalus.
Hydrocephalus can further affect brain function, exacerbate intellectual and psychiatric symptoms, and can lead to limb movement disorders.
Causes
Causes
Causative Bacteria
A variety of purulent bacteria can cause purulent meningitis, with Streptococcus pneumoniae, Diplococcus meningitidis and Haemophilus influenzae type b being the most common.
Staphylococcus aureus, Escherichia coli, Proteus, anaerobic bacilli, Salmonella and Pseudomonas aeruginosa are the next most common.
Infection mode and route
Pathogenic bacteria can invade the meninges through the following ways, and an inflammatory response occurs under the action of bacterial toxins and a variety of inflammation-associated cytokines.
The pathogenic bacteria reach the meninges through the blood and blood-brain barrier through the foci of infection in the body (upper respiratory tract, gastrointestinal tract mucosa, skin, umbilical cord invasion, etc.).
Some pathogenic bacteria are infectious, e.g., Streptococcus pneumoniae, Meningococcus meningitidis, Haemophilus influenzae type b, etc. are mainly transmitted via the respiratory tract.
Through the adjacent tissue and organ infection (such as sinusitis, otitis media, etc.) spread to the meninges.
Because of skull fracture, skin sinus tract, cerebrospinal fluid bulge, etc., the cranial cavity to form a direct channel, bacteria can directly enter the meninges or subarachnoid space.
Intracranial infections can be caused by cerebrospinal fluid drainage, postoperative brain surgery, and other causes of medical infections.
High risk factors
Close contact with patients with Streptococcus pneumoniae meningitis, epidemic cerebrospinal meningitis, and Haemophilus influenzae meningitis.
Infants and children who have not been immunized.
History of cerebrospinal fluid drainage, brain surgery, and traumatic brain injury.
Have sinusitis, otitis media, mastoiditis and other diseases.
History of skin, gastrointestinal mucosal or umbilical infection.
Pathogenesis
After bacterial invasion of the central nervous system, inflammatory activation of vascular endothelial cells, invasion of a large number of neutrophils, release of inflammatory mediators, and destruction of the blood-brain barrier.
Bacterial multiplication and autolysis generate a large number of bacterial toxins, which mediate the inflammatory response, leading to cerebral edema, increased intracranial pressure, and neuronal cell damage.
Symptoms
Main Symptoms
The clinical manifestations of purulent meningitis caused by various purulent bacterial infections are similar, as follows.
Symptoms of infection
Fever, chills, cough, sore throat, peripheral body aches, weakness of limbs, loss of appetite, etc. appear.
Signs of meningeal irritation
Neck stiffness and limitation of movement, inability of the jaw to approach the chest, etc.
Meningeal irritation is often not obvious in newborns, the elderly or comatose people.
Increased intracranial pressure
Severe headache, projectile vomiting, and irritability.
Young infants do not express headache and may only have spitting up, screaming, or separation of the cranial sutures.
As the condition worsens, the patient’s mental status may progressively change from depression, lethargy, somnolence, coma to deep coma.
Focal symptoms
Partial seizures, hemiparesis, aphasia, and deflective sensory deficits (no perception of stimuli such as pain, temperature, touch, pressure, or vibration) may occur.
Other symptoms
Epidemic cerebrospinal meningitis has more specific clinical features as follows.
In some patients, petechiae or ecchymosis of the skin, conjunctiva or mucous membranes of the soft palate appear a few hours after the onset of the disease.
In severe cases, they progress to the skin all over the body and rapidly merge into large subcutaneous hemorrhages with purple-black necrosis or macules in the center due to thrombosis.
Complications
Hydrocephalus
With the progression of the disease, arachnoid fibrosis and arachnoid adhesions may cause cerebrospinal fluid absorption and circulatory disorders, resulting in hydrocephalus.
Infants and young children may present with an oversized head that is disproportionate to the length of the torso and strabismus.
Epilepsy.
Inflammation can irritate or damage cells in the cerebral cortex, triggering various types of seizures.
They are often characterized by involuntary jerking of the body, loss of consciousness, and neck stiffness.
Seek Medical Treatment
Department of Medicine
Neurology
If fever, persistent headache, vomiting, chills, cough, etc. occur, prompt medical attention is recommended.
Pediatrics
For infants and children with recurrent fever, vomiting, screaming and crying, frequent spitting up, etc., timely consultation is recommended.
Emergency Department
For severe headache, neck stiffness and limitation of movement, coma, etc., it is recommended to go to the Emergency Department as soon as possible or call the “120” emergency number.
Preparation
Preparing for medical treatment: registration, preparation of information, common problems
Tips for medical treatment
If the patient loses consciousness, clear foreign objects from the patient’s mouth and tilt the patient’s head to the side to prevent choking.
Children may not be able to describe their symptoms accurately. Parents can help to record the symptoms they have experienced so as to give the doctor more reference.
Preparation Checklist
Symptom list
Pay particular attention to the time of onset of symptoms, special manifestations, etc.
Is the headache severe? Is it accompanied by other symptoms?
Do you have a fever? How long did the fever last? What is the highest temperature?
Is the child’s appetite normal? What is his mental status?
List of medical history
Has there been recent close contact with patients with Streptococcus pneumoniae meningitis, epidemic cerebrospinal meningitis, or Haemophilus influenzae meningitis?
Has the child been immunized?
Is there a history of cerebrospinal fluid drainage, brain surgery, or traumatic brain injury?
Are there any diseases such as sinusitis, otitis media, mastoiditis?
Any recent skin, gastrointestinal mucosal or umbilical infections?
Checklist
Test results from the last six months, which can be brought to the doctor’s office
Cranial CT
Cranial magnetic resonance imaging
Diagnosis
Diagnostic basis
Medical history
Close contact with patients with Streptococcus pneumoniae meningitis, epidemic cerebrospinal meningitis, and Haemophilus influenzae meningitis.
The child has not been immunized.
There is a history of cerebrospinal fluid drainage, brain surgery, and traumatic brain injury.
There is a history of sinusitis, otitis media, mastoiditis, etc.
There is a history of skin, gastrointestinal mucosa or umbilical infection.
Clinical manifestations
Symptoms
The main manifestations are fever, chills, cough, severe headache, vomiting, neck stiffness and limitation of movement, lethargy or coma.
Physical signs
Examination reveals neck stiffness and impedance when the neck is passively flexed.
Kernig’s sign is positive and Brudzinski’s sign is positive.
Kernig’s sign: the patient is lying on his back, one side of the lower limb hip and knee joints are flexed at a right angle, and the examiner raises the patient’s calf to extend the knee with restriction. If the extension of the knee is obstructed and accompanied by pain and spasm of the flexor muscles, it is positive.
Brudzinski’s sign: the patient lies on his back with the lower limbs straightened, the examiner lifts the patient’s occiput with one hand and presses the other hand on his chest. When the head is flexed forward, there is a sense of resistance and pain in the neck, while both hips and knees are flexed is positive.
Laboratory Tests
Blood tests
Check the white blood cell count and neutrophil count.
The total number of leukocytes and neutrophils in the patient’s peripheral blood are significantly elevated.
Blood bacterial culture and drug sensitivity test
Helps to identify the cause of the disease and guide the subsequent treatment and medication.
Positive blood culture and detection of pathogenic bacteria can help to clarify the diagnosis.
Cerebrospinal fluid examination
Cerebrospinal fluid is usually analyzed by lumbar puncture.
The examination shows that the cerebrospinal fluid pressure is increased, the appearance of cerebrospinal fluid is turbid or purulent; the number of cells in the cerebrospinal fluid is obviously elevated, with neutrophils predominating. Protein was elevated; sugar content and chloride were decreased.
The positive rate of cerebrospinal fluid bacterial culture is above 80%.
Precautions
Decubitus lying for 4~6 hours after examination.
Patients with high intracranial pressure with severe symptoms are not suitable for this test.
It is an invasive test, if there is redness or swelling after the test, please inform the doctor for treatment.
Imaging
Cranial CT
Pathological changes such as cerebral edema and ventricular enlargement can be identified.
In the early stages of purulent meningitis, most CT scans show no abnormal findings. As the disease progresses, it may show increased density or occlusion of the sulcus, cerebral pools, cerebral fissures, especially the basal cerebral pools, due to meningeal congestion and arachnoid leakage.
Cranial MRI
MRI has a higher diagnostic value than CT for the diagnosis of septic meningitis.
Early stage of purulent meningitis and CT show normal, with the progression of the disease MRI T1-weighted image shows subarachnoid high signal, can be irregularly strengthened, T2-weighted image shows meningeal high signal. In the later stage, it may show diffuse meningeal enhancement and cerebral edema.
Differential diagnosis
The clinical symptoms of purulent meningitis are similar to those of viral meningitis, tuberculous meningitis, cryptococcal meningitis and other meningitis, and it is difficult to differentiate them solely on the basis of clinical manifestations, and it is necessary to make a clear diagnosis through laboratory examination, cerebrospinal fluid examination and imaging examination.
Viral meningitis
Acute meningeal infections caused by viruses are aseptic meningitis, and enterovirus and mumps virus are the most common infections.
The disease is most common in children under 10 years old, and rare in those over 40 years old.
Cerebrospinal fluid examination, virologic examination, blood bacterial culture, and cranial CT are helpful in differentiation.
Tuberculous meningitis
Non-suppurative inflammation of the meninges caused by Mycobacterium tuberculosis, most have a history of contact with a TB patient, especially with a patient with open TB within the family.
There is afternoon low-grade fever or tuberculous lesions on lung CT, and choroidal milia nodules may be found on fundus examination.
Cerebrospinal fluid examination, Mycobacterium tuberculosis antigen test, X-rays and CT of the head help in differentiation.
Cryptococcal meningitis
The most common fungal infection in the central nervous system, caused by Cryptococcus neoformans infection, with severe condition and high mortality rate.
Cerebrospinal fluid examination, blood bacterial culture, cranial CT and MRI are helpful for differentiation.
Treatment
Drug treatment
Antibacterial drugs
Patients with purulent meningitis require early use of antimicrobials, usually broad-spectrum antibiotics until the causative organism has been identified, and sensitive antimicrobials if the causative organism has been identified.
Drugs for undetermined causative organisms
Ceftriaxone or cefotaxime is often used as the first choice, and has been shown to be effective against meningitis caused by meningococcus, Streptococcus pneumoniae, and Haemophilus influenzae.
Drugs for identified causative organisms
Sensitive antimicrobial drugs should be selected according to the causative organism.
For Streptococcus pneumoniae, for those sensitive to penicillin, high-dose penicillin can be injected intravenously in divided doses; for those resistant to penicillin, ceftriaxone can be considered, and vancomycin can be combined with vancomycin treatment if necessary.
Meningococcus, preferred penicillin, resistant patients choose cefotaxime or ceftriaxone, can be combined with ampicillin or chloramphenicol; allergic to penicillin or β-lactam antibiotics, chloramphenicol can be used.
Gram-negative bacilli, meningitis caused by Pseudomonas aeruginosa, ceftazidime can be used; other gram-negative bacilli meningitis, ceftriaxone, cefotaxime or ceftazidime can be used.
Precautions
Antibacterial drugs need to be applied under the guidance of a doctor, and should not be self-administered to avoid drug resistance.
People with a history of allergy, especially drug allergy need to inform the doctor.
Cerebrospinal fluid is usually reviewed within 24 to 36 hours after starting antibiotic therapy to evaluate the effect of treatment.
Other medications
Those with high fever and significant discomfort may be given a physical cooler or a non-steroidal anti-inflammatory drug (antipyretic) such as ibuprofen or acetaminophen as prescribed by the doctor.
For those with increased intracranial pressure, mannitol can be administered intravenously to reduce cranial pressure by dehydration.
For epileptic seizures, antiepileptic drugs such as diazepam and phenobarbital can be used for treatment.
Glucocorticoids (e.g., dexamethasone) can be applied along with antimicrobial drugs to help reduce intracranial adhesions and hydrocephalus.
Prognosis
Cure
The mortality and disability rates of purulent meningitis are still high, but the prognosis of most patients is good with early and adequate application of antimicrobial drugs.
Hazards
If the use of antibacterial drugs is inappropriate, insufficient course of treatment, it is easy to be transformed into chronic purulent meningitis, and a small number of patients may be left with mental retardation, epilepsy and other sequelae, the severity of which mainly depends on the severity of the initial symptoms, the timeliness of the diagnosis and treatment.
Septic meningitis caused by Streptococcus pneumoniae, Meningococcus meningitidis, Haemophilus influenzae type b and other pathogens are contagious and can easily make others sick.
Daily
Daily Management
Dietary management
Give the patient a light diet that is high in calories, protein, vitamins and easy to digest, such as milk, fish, fruits and vegetables.
If there are symptoms such as nausea, vomiting, etc., you can eat some easy-to-digest food, small and frequent meals to prevent vomiting from occurring, and give nasal feeding or intravenous fluids if necessary.
If you are conscious, you can drink more water under doctor’s guidance.
Do not eat spicy, greasy and other stimulating food.
Life management
Keep patients’ skin and mouth clean.
Patients who are infectious should be isolated and treated according to medical advice.
Comatose patients should have their heads tilted to one side to avoid inhalation of vomitus, resulting in aspiration pneumonia.
When severe headache, be careful to avoid strong light stimulation to avoid inducing convulsions.
For those who are agitated, bed rails can be added or limbs can be restrained to prevent falling out of bed.
Disease monitoring
During treatment, family members should closely monitor the patient’s vital signs and state of consciousness, and inform the doctor if there are signs of agitation, severe headache, projectile vomiting, convulsions or coma.
Follow-up and review
Regularly review the blood routine, head CT and MRI according to the doctor’s recommendation.
Take medication according to the doctor’s instructions, and do not stop or change medication on your own.
Prevention
Take vaccinations on time according to individual conditions, such as pneumococcal vaccine, meningococcal vaccine, Haemophilus influenzae type b conjugate vaccine, etc.
Avoid crowded places during the epidemic season and wear a mask when going out.
Avoid close contact with meningitis patients and take isolation measures when there are patients at home.
Actively treat sinusitis, otitis media, mastoiditis and other diseases.
Pay attention to dietary safety and skin hygiene of the umbilical cord and other parts of the body to reduce the risk of infection.