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Evidence‐based approaches

Rationale

A number of tests can be performed on CSF to aid diagnosis (Tortora and Derrickson [243]):

Culture and sensitivity: identifying the presence of micro‐organisms confirms the diagnosis of bacterial or fungal meningitis or a cerebral abscess. Organisms may include atypical bacteria, Mycobacterium tuberculosis or fungi. The isolation of the causative organism enables the initiation of appropriate antibiotic or antifungal therapy (Pagana and Pagana [177]).
Virology screening: isolation of a causative virus enables appropriate therapy to be initiated promptly.
Serology for syphilis: tests include the Wassermann Reaction (WR), Venereal Disease Research Laboratory (VDRL) and Treponema pallidum Immobilization (TPI) tests.
Cytology: central nervous system tumours and secondary meningeal disease tend to shed cells into the CSF, where they float freely. Examination of these cells morphologically after lumbar puncture determines whether the tumour is malignant or benign (Pagana and Pagana [177]).

Indications

A lumbar puncture and withdrawal of CSF, with or without the introduction of therapeutic agents, is performed for the following purposes:

It can be used to exclude subarachnoid haemorrhage.
It can be used to investigate neurological disorders such as multiple sclerosis and to exclude or investigate meningitis (Doherty and Forbes [50], Pagana and Pagana [177]).
It can be used to manage disorders of intracranial pressure (ICP) such as spontaneous intracranial hypotension and idiopathic intracranial hypertension (Doherty and Forbes [50], Lee and Lueck [124]).
It can be used to administer therapeutic and diagnostic agents. A number of drugs do not cross the blood–brain barrier, so in the treatment and prophylaxis of some malignant diseases (such as leukaemia and lymphoma) a lumbar puncture is used to insert the drugs. Cytarabine, methotrexate and corticosteroids are the drugs most commonly administered intrathecally. Other drugs include intrathecal antibiotics to treat infection, radiopaque contrast to provide myelograms of the spinal cord and the administration of a local anaesthetic agent (such as bupivacaine) into the CSF to enable lower body surgery and/or to provide pain relief (Bottros and Christo [19], Doherty and Forbes [50], Gilbar [68], Tortora and Derrickson [243]).

Contraindications

The procedure should not be undertaken in the following circumstances:

In patients in whom raised ICP is suspected or present due to the risk of brain herniation (Lindsay et al. [126], Pagana and Pagana [177]).
In patients with papilloedema, bacterial meningitis or deteriorating neurological symptoms in whom raised ICP or an intracranial mass is suspected. In this situation, neuroimaging (CT or MRI scan) should be undertaken prior to lumbar puncture in order to avoid resultant potentially fatal brainstem compression, herniation or coning (Engelborghs et al. [56]). However, a normal CT scan does not always ensure that it is safe to perform a lumbar puncture so, until better non‐invasive procedures to monitor ICP become available and are routinely used, the decision to proceed must be left to clinical expertise and judgement (Engelborghs et al. [56]).
Local skin infection may result in meningitis by passage of the bacteria from the skin to the CSF during the procedure. Cutaneous or osseous infection at the site of the lumbar puncture may be considered an absolute contraindication (Chernecky and Berger [32], Pagana and Pagana [177]).
In patients who are unable to co‐operate or who are too drowsy to give a history. Patient co‐operation is essential to carry out a baseline neurological examination and to minimize the potential risk of trauma associated with this procedure (Chernecky and Berger [32], Pagana and Pagana [177]).
In patients who have severe degenerative spinal joint disease. In such cases, difficulty will be experienced both in positioning the patient and in accessing the spaces between the vertebrae (Chernecky and Berger [32], Pagana and Pagana [177]).
In those patients undergoing anticoagulant therapy or who have coagulopathies or thrombocytopenia (less than 50 × 10⁹/L). These patients are at increased risk of bleeding and therefore coagulopathies and thrombocytopenia must be corrected prior to undertaking lumbar puncture (Lindsay et al. [126], Pagana and Pagana [177]).

Principles of care

The principles of lumbar puncture are to gain access to the CSF of the patient while maintaining sterility and patient comfort throughout the procedure. For patients receiving intrathecal medication, it is essential that the correct agent is given. For diagnostic procedures, it is imperative that accurate measurements are taken and that the sample is handled and labelled correctly. The role of the nurse in caring for a patient undergoing a lumbar puncture procedure may include helping to explain the procedure to the patient, preparing the patient, supporting both the patient and the doctor or practitioner during the procedure, and close follow‐up monitoring (Doherty and Forbes [50], Pagana and Pagana [177]).