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Obtaining cerebrospinal fluid (CSF) for the diagnosis of central nervous system (CNS) disorders such as meningitis/encephalitis. Infections that can be diagnosed are bacterial, viral, fungal, and TORCH (toxoplasmosis, other [usually syphilis], rubella, cytomegalovirus, and herpes simplex virus). Meningitis can be present in as many as 15–25% of cases of neonatal sepsis.
Aid in the diagnosis of intracranial hemorrhage. CSF studies are indicative but not diagnostic for intracranial hemorrhage: large number of red blood cells (RBCs), xanthochromia, increased protein content, and hypoglycorrhachia (abnormally low CSF glucose content).
Diagnose an inborn error of metabolism. CSF amino acid analysis can be obtained to rule out nonketotic hyperglycinemia. Postmortem CSF (1- to 2-mL specimen, frozen) is recommended: suspected inborn error of metabolism.
Draining CSF in communicating hydrocephalus associated with intraventricular hemorrhage. (Serial lumbar punctures for this are controversial.) Cochrane review states that early repeated CSF tapping cannot be recommended for neonates at risk of developing posthemorrhagic hydrocephalus.
Administration of intrathecal medications. Chemotherapy, antibiotics, or anesthetic agents or contrast material.
Monitoring efficacy of antibiotics used to treat CNS infections by examining CSF fluid.
Diagnose CNS involvement with leukemia.
For the initial sepsis workup (controversial). If CNS involvement is suspected or blood cultures are positive, some recommend a lumbar puncture (LP). Because signs and symptoms of neonatal meningitis are so vague and unspecific, some clinicians advise that all infants with proven or suspected sepsis undergo LP.
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Lumbar puncture kit (usually contains three sterile specimen tubes; four sterile tubes are often necessary); sterile drapes; sterile gauze; 20-, 22-, or 24-gauge 1.5-inch spinal needle with stylet (do not use a butterfly needle, as it may introduce skin into the subarachnoid space and form a dermoid cyst); 1% lidocaine; 25- to 27-gauge needle, 1-mL syringe; sterile gloves; mask; gown; hat; and skin disinfectant (10% povidone-iodine solution).
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Contraindications include increased intracranial pressure (risk of CNS herniation), uncorrected bleeding abnormality, severe bleeding diathesis, infection near puncture site, severe cardiorespiratory instability, and lumbosacral abnormalities that may interfere with identification of key structures.
If significant increased intracranial pressure is suspected obtain a computed tomography (CT) or magnetic resonance imaging (MRI) of the head. Herniation rarely occurs in the neonate with open cranial sutures, but is reported.
Pain management
AAP recommends that topical anesthetics (EMLA [eutectic mixture of lidocaine and prilocaine] or other topical agents) be applied 30 minutes before the procedure. Nonpharmacologic pain management, if appropriate, can be used.
Lidocaine 0.5–1% (in a 1-mL syringe with a 25- or 27-gauge needle) can be injected subcutaneously. Note: Physiologic instability is not reduced with lidocaine use and is not recommended by some sources.
Systemic therapy. Other recommendations include sedation with a slow IV opiate bolus if the infant is intubated; if not intubated, a bolus of midazolam in a term infant can be used (see Chapter 76).
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