A lumbar puncture (LP) is a commonly performed medical procedure, and when done correctly, is safe with a low risk of serious complications. A number of patients who undergo an LP however can develop a side effect known as post lumbar puncture headache (PLPH), and this can be accompanied by other symptoms of meningismus.
What is Lumbar Puncture?
A Lumbar Puncture or LP is a procedure in which a needle is inserted between two vertebrae (bones of the spine) in the lower part of the back, to gain access to the subarachnoid space in the spinal canal. This space contains cerebrospinal fluid (CSF) which flows around and covers the spinal cord as well as the brain.
An LP is often done to diagnose possible pathologies such as meningitis. The pressure of the CSF is recorded and a sample of the fluid is taken for analysis. An LP is also done to inject medications into the spinal canal, such as a spinal block as an alternative to general anaesthesia in surgery involving the lower part of the abdomen and legs.
What is Meningismus?
The meninges consist of three layers which cover the brain and spinal cord that are sensitive to pain, and any condition causing irritation or stretching of these layers will result in the characteristic symptoms of nausea, headache, neck stiffness and light sensitivity.Other symptoms can also include visual blurring, tinnitus (ringing or buzzing sound in the ears) and vertigo. Meningismus refers to these symptoms occurring without infection or inflammation of the meninges.
Meningismus and Post Lumbar Puncture Headache
The reason why meningismus occurs following an LP is thought to be due to the loss of CSF as a result of a persistent leak of this fluid from the puncture site. This loss of CSF volume means that the cushioning action on the brain is reduced and this leads to increased stretching of the meninges.
Headaches occur in up to 30% of patients who undergo an LP, and the symptoms start within 48 hours but may be delayed by as much as 12 days. The headaches will occur when the patient is standing or sitting up, worsened with head movements and relieved when the patient lies down, and is experienced as a dull or throbbing pain in the front and back areas of the head. Straining, sneezing and coughing may also aggravate symptoms. Meningismus usually lasts for a few days and it can continue for up to weeks and months.
Patients at high risk of suffering from meningismus following an LP include those between 18-30 years of age, women with a low body mass index, pregnant women and patients who struggle with headaches in general.
What can you do if you develop post lumbar puncture headache and meningismus?
The doctor performing the LP should always describe to you what to expect and how to manage meningismus following an LP. Mild symptoms can be treated with simple pain medication, bed rest and by keeping well-hydrated.
Immediate medical help should be sought if:
- Symptoms are severe, especially if you are experiencing neck stiffness, nausea and light sensitivity.
- The headache is not postural, as this could indicate the presence of other complications.
- Symptoms begin almost immediately after an LP.
- Other symptoms such as hearing loss, visual loss, facial paralysis or abnormal sensations on the head and face occur.
Meningismus following a lumbar puncture is usually self-limiting, but severe cases are managed by giving the patient an intravenous caffeine sodium benzoate injection that terminates symptoms in 75% of such patients. In patients who don’trespond to caffeine, an epidural blood patch may be performed to seal the CSF leak, but this treatment is controversial.