Neonatal purulent meningitis is often part of sepsis or secondary to sepsis, and is a serious condition in newborns. Although the use of antibiotics has reduced its mortality rate, the combined incidence of mortality and sequelae (such as hydrocephalus and intellectual disability) can still reach 70-80%. Its clinical manifestations are atypical, requiring heightened vigilance and early diagnosis. The causative pathogens vary with the age of the infant. Infections occurring within the first week of life are mostly caused by Gram-negative bacilli, primarily Escherichia coli, Klebsiella pneumoniae, group B hemolytic streptococci, and Listeria. After 1-2 weeks of life, infections are often caused by skin, umbilical, or respiratory infections, with Gram-positive cocci such as staphylococci and pneumococci being more common. Preterm infants, low birth weight infants, and those with congenital neurological defects (such as meningocele or congenital spina bifida) have a higher incidence rate.

bubble_chart Diagnosis

(1) Clinical manifestations are often atypical, with infants showing refusal to feed, lack of crying, hypothermia, cyanosis, pallor, apnea, drowsiness, irritability, or convulsions. Seizures may present in various forms, ranging from staring, strabismus, eyelid twitching, breath-holding, and apnea to limb jerking. Bulging of the anterior fontanelle, opisthotonos, convulsions, and unconsciousness are all signs of advanced stage. (2) Laboratory tests

1. Routine blood tests may reveal leukocytosis, neutrophilia, and a left shift.
2. For suspected cases, lumbar puncture should be performed early to examine cerebrospinal fluid (CSF) for routine and generation and transformation tests, with bacterial smear and culture being particularly crucial. If the first lumbar puncture yields normal CSF results but the disease cannot be entirely ruled out, a second puncture should be performed.
3. For cases where antibiotic use leads to negative CSF smear and bacterial culture results, the following methods can improve pathogen diagnosis: (1) Limulus lysate test: A positive result confirms Gram-negative bacterial infection, whereas other bacterial or viral meningitis yields negative results. (2) Counterimmunoelectrophoresis, latex agglutination test, and immunofluorescence techniques use specific antibodies to detect bacterial antigens in CSF. (3) Lactate dehydrogenase (LDH) assay: Isoenzymes 4 and 5 are elevated, while isoenzyme
   1. 2 is decreased. 4. Skull transillumination test: Helps diagnose subdural effusion. 5. B-mode ultrasound and CT scans assist in determining the presence of ventriculitis
   2. , subdural effusion
   3. , brain abscess, or hydrocephalus, and are useful for follow-up comparisons.

bubble_chart Treatment Measures

﹝Treatment﹞

(1) Antibiotic therapy Early selection of bactericidal drugs that easily penetrate the blood-brain barrier is crucial. Specific medications can refer to the treatment of neonatal sepsis. When the pathogen is unknown, ampicillin plus aminoglycosides are still used. To maintain effective drug concentrations in the cerebrospinal fluid, high-dose intravenous administration is required, with the total daily dose divided into 3–4 administrations. In recent years, ceftriaxone, moxalactam, or amikacin have shown good efficacy. Chloramphenicol penetrates the blood-brain barrier well, with a daily dose of 25–50 mg/kg. Blood levels should be monitored during use to prevent bone marrow suppression and gray baby syndrome.

(2) Supportive therapy Small, frequent transfusions of blood or plasma, attention to warmth and caloric intake, and ensuring fluid and electrolyte balance are necessary.

(3) Symptomatic treatment For cerebral edema, 20% mannitol can be administered at 1–1.5 g/kg per dose, or combined with dexamethasone and furosemide. For convulsions, sedatives such as phenobarbital sodium (10–15 mg/kg per dose intramuscularly), diazepam (0.5–1 mg/kg per dose), or 10% chloral hydrate or paraldehyde may be used.

(4) Subdural effusion Puncture and drainage can be performed. If the fluid volume remains high after 2 weeks, surgical drainage should be considered.

(5) For complicating ventriculitis, ventricular puncture or catheterization may be performed, retaining the catheter for daily administration of sensitive antibiotics. If localized purulent lesions are present, surgical treatment is required. Common intrathecal or intraventricular antibiotic doses include gentamicin (1 mg/dose), penicillin (5,000–10,000 U/dose), ampicillin (50–100 mg/dose), cephalosporin (12.5–25 mg/dose), and kanamycin (5–10 mg/dose).