Purulent meningitis
Release time : 01/18/2025 18:13:27
Sepsis is one of the high-incidence and high-mortality diseases worldwide, caused by suppurative bacterial infection of meninges, which is a common suppurative infection of central nervous system.
Generally speaking, the incubation period for this disease is 1-7 days, with infants and young children being more prone to developing it. Therefore, new mothers must pay close attention to their baby's health condition.
Septic meningitis is a septic infection of the central nervous system caused by bacteria, also known as meningitis. It is a common disease in children and often occurs in infants and young children.
Pathogens commonly include Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus, etc., with different pathogens associated with varying age groups.
At present, purulent meningitis is still one of the high incidence and mortality rate diseases in the world.
The epidemiological situation varies from country to country and region to region.
The incidence rate in the United States is 3/100,000 per year, while it is higher in developing countries possibly due to a lack of vaccinations.
Generally speaking, the incubation period for purulent meningitis is 1-7 days. Clinically, purulent meningitis can be classified into three types based on the symptoms and signs: 1. Common type: 90% of cases present with an acute onset, characterized by upper respiratory tract symptoms such as sore throat and runny nose. After entering the sepsis phase, high fever, chills, and shivering occur.
70% of cases, skin and mucous membranes appear dark or purplish red, with irregularly-sized and unevenly-distributed petechiae and ecchymoses.
1 to 2 days later, the condition enters the meningitis phase, with symptoms such as increased intracranial pressure manifested by severe headache, frequent vomiting (with a spraying action), and signs of meningeal irritation (i.e., neck stiffness, hyperextension of the angles, Kernig's sign positive, and Brudzinski's sign positive). Blood pressure may rise, often accompanied by photophobia, restlessness, and respiratory failure.
Additionally, symptoms such as body pain, irritability, and expression of dullness are also common manifestations in patients with ordinary meningitis. In severe cases, there may even be episodes of staring or coma.
Infants and young children (under 2 years old) presenting with symptoms of meningitis often have non-specific manifestations, such as high fever, vomiting, refusal to eat, restlessness, and even convulsions, despite the absence of signs of meningeal irritation. The presence of a prominent fontanelle can be indicative of the diagnosis.
2. Infantile encephalopathy, a type of sudden onset encephalopathy, is most commonly seen in children and has a severe course. If not treated promptly, it can lead to death within 24 hours.
Frequently high fever, headache, vomiting, severe mental lethargy, consciousness disorder, occasional convulsions, oliguria or anuria, the patient rapidly enters coma due to brain tissue damage, frequent convulsions, hemiplegia, hypertension, one side of pupil dilated, light reflex lost, and stagnant pupils appear soon after breathing failure.
This type is further divided into: fulminant shock syndrome and fulminant encephalitis.
In shock-type septicemia, besides the common symptoms, it is characterized by severe systemic toxicity. The patient exhibits profound lethargy, pale complexion, cold extremities, and petechiae on the skin. Urine output is reduced, blood pressure decreases, cerebrospinal fluid is clear, with a slight increase or normal cell count.
Furthermore, attention should be paid to the positive results of blood culture and petechiae smear.
In the fulminant form, the most prominent symptoms include severe headache, restlessness, frequent vomiting, convulsions, rapid coma, and ultimately, brain herniation and respiratory failure.
Patients presenting with both shock and encephalitis symptoms are categorized as mixed, with a very high mortality rate.
3. Mild types of purulent meningitis, characterized by only skin and mucous membrane hemorrhages, can be diagnosed with bacteriological staining of the smear. This type is more common in children.
The majority of cases are acute onset, commonly occurring in infants and young children, as well as in the elderly population aged 60 and above.
What are the symptoms of purulent meningitis? The symptoms of purulent meningitis are mostly similar, and there are mainly the following symptoms: 1. Symptoms of infection including fever, chills, or signs of upper respiratory tract infection.
2. The signs of meningeal irritation include neck stiffness, Kernig's sign, and the positive Brudzinski sign.
However, in newborns, the elderly, or patients in a comatose state, meningeal signs are often not prominent.
3. Elevated intracranial pressure can present with severe headache, vomiting, and consciousness disturbances.
During lumbar puncture, it is evident that intracranial pressure significantly increases. In some patients, this may even lead to a condition of brain herniation.
4. Localized Symptoms Some patients exhibit symptoms of localized neurological impairment, such as hemiplegia and aphasia.
5. Other symptoms are characterized by specific clinical manifestations in some patients, such as meningococcal meningitis (also known as septicemic meningitis), rashes that appear during bacteremia, initially presenting as scattered red maculopapular rashes that rapidly evolve into petechiae on the trunk, lower limbs, mucous membranes, and conjunctiva, with occasional occurrences on palms and soles.
What is the etiology of purulent meningitis? What exactly leads to the development of purulent meningitis? The most common pathogens causing purulent meningitis are Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae type B. Subsequently, other pathogens such as Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Aeromonas species, anaerobic bacteria, Salmonella, and Pseudomonas aeruginosa also cause this condition.
The pathological changes caused by different pathogens of purulent meningitis are basically the same.
Pathogenic bacteria invade the subarachnoid space through the bloodstream and, due to the lack of effective immune defense in cerebrospinal fluid, proliferate extensively. The antigen components of the bacterial cell wall and certain cytokines that induce inflammatory responses stimulate endothelial cells, leading to the infiltration of neutrophils into the central nervous system and inducing a series of inflammatory pathological changes on the meninges.
1. The dura mater and superficial cerebral vessels exhibit dilation and congestion, with a substantial amount of purulent exudate covering the surface of the brain and depositing in the sulci and basal cisterns.
2. The color of purulent exudate is related to the type of pathogen. Streptococcus pyogenes and Staphylococcus aureus are grayish yellow, Streptococcus pneumoniae is pale green, Haemophilus influenzae is grayish, and Pseudomonas aeruginosa is verdant.
3. When pus exudates obstruct the arachnoid granulation or cerebrospinal fluid channels, affecting the absorption and circulation of cerebrospinal fluid, it leads to communicating or obstructive hydrocephalus.
4. Under the microscope, there are a large number of polymorphonuclear leukocytes and fibrin exudates in the subarachnoid space. After Gram staining, both inside and outside the cells can find the pathogens.
Mild cerebral edema adjacent to the pia mater, and more serious cases may develop arteritis, vasculitis, or thrombosis.
If symptoms of purulent meningitis are discovered, how should the diagnosis be conducted? Based on the acute onset of fever, headache, and vomiting, examination reveals signs of meningeal irritation upon physical examination. The cerebrospinal fluid has increased pressure and a marked elevation in white blood cells is observed, which strongly suggests this condition.
To confirm the diagnosis, pathological evidence is also required, including detection of pathogens in cerebrospinal fluid by bacterial smear and positive blood cultures for bacteria.
1. Standard laboratory examinations: routine blood tests reveal a marked increase in total white blood cell count and neutrophils.
Anemia is common in meningitis caused by Streptococcus pneumoniae.
Blood culture: Early positive results are obtained in patients not receiving antibiotics.
Can help determine the causative pathogen.
Throat swab culture: the isolation of pathogenic bacteria is of reference value.
Cerebrospinal fluid smear: In the examination of skin petechiae from cerebrospinal fluid, a positive rate of over 50% can be observed in cases of bacteremia.
2. Cerebrospinal Fluid Examination: Normal: Typical purulent changes are observed.
Cerebrospinal fluid appears turbid or like muddy rice soup, with an increased pressure.
Microscopic examination reveals numerous white blood cells, reaching up to several billion per liter.
Biochemistry: Sugar quantification can not only assist in distinguishing between bacterial and viral infections but also reflect the therapeutic response.
Protein qualitative tests are often strongly positive, with quantitative determinations exceeding 1g/L.
Bacterial examination: The cerebrospinal fluid can be centrifuged and sedimented, stained with a smear, and pathogens can often be identified. This may serve as the basis for early choice of antibiotic treatment.
Immunological examination: (1) Conducted immunoelectrophoresis: This involves using known antibodies (specific antiserums), to detect antigens (such as soluble capsular polysaccharides) in cerebrospinal fluid. It has a high specificity and is commonly used for the rapid diagnosis of meningococcal meningitis, as well as for the detection of influenza bacteria and Streptococcus pneumoniae. The positivity rate can reach 70% to 80%.
(2) The results of meningococcus and influenzae were similar to those obtained by CIE method, while the sensitivity to pneumococcus was poor.
This method is more sensitive than CIE, but it may have false positives.
(3) Fluorescent labeled antibodies were used for the detection of antigens (such as cerebrospinal fluid, blood specimens), and then observed under a fluorescence microscope.
This method has high specificity and sensitivity, can make a quick diagnosis, but it requires some equipment.
(4) Enzyme-linked immunosorbent assay.
(5) Lumbriculin solubility test: (1) The concentration of IgM in normal cerebrospinal fluid is very low.
In encephalopathic children, the IgM levels are significantly elevated, and if greater than 30mg/L, it is essentially impossible to rule out viral infection.
(2) Normal mean LDH levels in cerebrospinal fluid: neonates, 53.1 IU.
Infant 32.6 IU.
A 29.2 IU?
Age 28.8 IU.
LDH isoenzyme normal values.
The newborn's LDH levels are 127%, 235%, 334%, 243%, and 51%.
1 month old infant: LDH 137%, LDH 232%, LDH 328%, LDH 42%, LDH 51%.
Lactate dehydrogenase (LDH) values in encephalopathy children were significantly elevated, and LDH4 and LDH5 isoenzymes showed significant increases.
3. In imaging examinations, the final diagnosis of purulent meningitis often involves the use of imaging studies, but the diagnostic and differential diagnostic significance of imaging studies is limited.
Some patients exhibit enhancement of the meninges and cerebral cortex upon contrast administration, but absence of enhancement does not rule out the diagnosis.
The true purpose of imaging studies is to understand complications of central nervous system involvement in meningitis such as brain abscess, cerebral infarcts, hydrocephalus, epidural abscess and sinus thrombosis.
Once the diagnosis is established, how should it be confirmed? (1) Viral meningitis.
If it is viral meningitis, the cerebrospinal fluid leukocyte count is usually below 1000 × 10^6/L, glucose and chloride levels are generally normal or slightly low, and bacterial culture results are negative.
(2) Tuberculous meningitis.
Generally speaking, tuberculous meningitis is usually subacute in onset, with common cerebral nerve involvement. The elevation of white blood cells in cerebrospinal fluid examination is often not as obvious as that in purulent meningitis. Pathological examination can help further differentiate.
(3) Aspergillosis meningitis.
This disease often has a latent onset and protracted course, with optic nerve involvement being common. Cerebrospinal fluid white blood cells are usually below 500×10^6/L, predominantly lymphocytes, and new fungus can be detected by mycelium staining. Rhesus macaque serum can detect the antigen of Cryptococcus neoformans.
What are the treatment methods for purulent meningitis? The treatment of purulent meningitis is mainly conducted from the following three aspects: 1. Antibiotic treatment. The principle of antibiotic treatment is to use antibiotics promptly.
Usually, broad-spectrum antibiotics are used before the pathogen is determined; if the pathogen is identified, then the appropriate antibiotic should be selected.
a) In cases where the pathogen is not definitively identified, ceftazidime or ceftriaxone from the third-generation cephalosporins are often chosen as the first-line antibiotic for purulent meningitis, with comparatively reliable effectiveness against meningococci, pneumococci, influenzae and group B streptococci.
The choice of antibiotics should be based on the sensitivity of the pathogen.
If the bacterium is Pneumococcus, then those who are sensitive to penicillin can use a large dose of penicillin. The adult should take 20 million to 24 million units per day, and children should take 40000 U/kg per day, given intravenous drip in divided doses.
For sulfonamide-resistant penicillin, ceftriaxone can be considered. When necessary, co-administration with vancomycin is recommended.
A course of treatment is 2 weeks, usually a cerebrospinal fluid examination should be performed within 24-36 hours after starting antibiotic therapy to evaluate the therapeutic effect.
For meningococcal infections, penicillin is the first choice. For drug-resistant cases, ceftriaxone or cefotaxime should be used, which can be combined with ampicillin or chloramphenicol.
Patients allergic to penicillin or cephalosporins may be given chloramphenicol.
If the bacterium is a Gram-negative bacillus, then for meningitis caused by Pseudomonas aeruginosa, ceftriaxone can be used. For other Gram-negative bacillary meningitis, ceftriaxone, cefoperazone, or ceftibuten can be used, and the course of treatment is usually 3 weeks.
2. Hormonal therapy can suppress the release of inflammatory cytokines and stabilize blood-brain barrier.
For patients with severe conditions and without obvious contraindications to steroid use, consideration should be given.
Usually, dexamethasone 10mg is given by intravenous drip infusion for 3-5 days.
3. Symptomatic supportive treatment for patients with increased intracranial pressure may involve dehydration to reduce intracranial pressure.
Individuals with high fever should use physical methods of cooling or take antipyretic agents.
Epileptic seizures are treated with antiepileptic drugs to terminate the attacks.
* The medical content discussed in this text is for reference only.
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