Lumbar Puncture

Lumbar puncture, also called a spinal tap, is the procedure doctors use to obtain a sample of cerebrospinal fluid (the liquid that surrounds the brain and spinal cord) for tests. Cerebrospinal fluid (CSF) is formed in special areas of the brain called ventricles. It flows down from the ventricles into the area around the spinal cord. CSF is usually clear and contains small amounts of proteins and glucose (sugar).

REASONS FOR HAVING A LUMBAR PUNCTURE
Suspected meningitis (infection of the covering of the brain and spinal cord)
Leukemia or lymphoma
Evaluation for neurological diseases, such as multiple sclerosis, neuropathy, or recurrent seizures Fever of unknown origin
Lumbar puncture is also done by anesthesiologists to administer spinal anesthesia (also known as subarachnoid block) for some types of surgery.
For cancer treatment, chemotherapy medications are sometimes injected directly through the lumbar puncture needle into the CSF. The medicine flows freely in the CSF and can go to the brain or spinal cord where it is needed.
WHAT TO EXPECT DURING A LUMBAR PUNCTURE
During a lumbar puncture, you either lie on your side or sit upright. Your back is scrubbed with an antiseptic solution. Local anesthetic medicine is injected into the skin. When the skin is numb from the local anesthetic, a small needle is inserted into your back at the level of the hip bones below the bottom of the spinal cord. The needle is pushed forward gently until the CSF is found. For testing, 1 to 2 teaspoonfuls of fluid are removed and put into special sterile tubes. If you are receiving spinal anesthesia for surgery, no spinal fluid is drained out. The anesthetic medicine is injected directly into the CSF, and your legs and buttocks will begin to feel numb.
Sometimes lumbar puncture can be difficult to perform. Persons who have had back surgery, who have an abnormal back shape such as scoliosis (curvature of the spine), are pregnant, or are very obese are at risk for difficulty in the lumbar puncture. Lumbar puncture is easier to perform if the patient follows positioning instructions completely.


FOR MORE INFORMATION
American Academy of Pediatrics http://www.aap.org/
American Society of Anesthesiologists http://www.asahq.org/patienteducation.htm
Video

Meningitis

Meningitis (infection of the coverings of the brain and spinal cord) is a serious illness. Meningitis can occur in adults and children, even in infants, and can be caused by viruses, bacteria, fungi, or parasites. Bacterial meningitis can be fatal or cause severe impairment, particularly if the diagnosis of bacterial meningitis is delayed, but can be treated, especially when diagnosed early in the disease. The common types of bacteria that can cause meningitis are Neisseria meningitidis (also known as meningococcus) and Streptococcus pneumoniae (pneumococcus). These bacteria are highly contagious, spread rapidly, and can be deadly. Nursing homes, college dormitories, day care centers, and schools are often sites of outbreaks of meningitis. Vaccines are available for some bacteria and can be helpful to stop spread of contagious meningitis. The January 3, 2007, issue of JAMA includes an article about meningitis in children.


SIGNS AND SYMPTOMS OF MENINGITIS
Stiff neck
Fever
Headache
Nausea and vomiting
Red or purple rash that does not change color if pressed on
Fatigue or extreme sleepiness
Seizures
Irritability or lethargy—in infants, along with poor feeding, may be the only symptoms of meningitis
Recent flu-like illness or an ear or sinus infection may precede the development of meningitis
DIAGNOSIS AND TESTING
Questions about the history of the illness and a physical examination help determine the likelihood of meningitis.
Lumbar puncture (sampling of the cerebrospinal fluid [CSF]) is the primary test for meningitis and is important for the critical distinction between a bacterial or viral cause. A small needle is inserted into the lower back under sterile conditions and CSF is withdrawn. The CSF may show the presence of bacteria, indicating bacterial infection. White blood cells in the CSF may be related to bacterial meningitis, viral meningitis (no bacteria would be seen in this case), or fungal meningitis. The CSF also is cultured to look for growth of organisms in order to identify them.
Blood tests may show an increased white blood cell count, indicating infection. Other tests may be suggested by your doctor depending on the individual situation.
TREATMENT
If bacterial meningitis is suspected based on the lumbar puncture results, immediate antibiotic therapy is necessary. Intravenous (through a vein into the bloodstream) antibiotics are given to penetrate into the CSF that bathes the spinal cord and brain. Supportive therapy, including medications to reduce fever, can help with other types of meningitis. In serious cases of meningitis, intensive care (including life support medications and ventilators) may be necessary.
FOR MORE INFORMATION
National Institute of Neurological Disorders and Stroke http://www.ninds.nih.gov/
American Academy of Pediatrics http://www.aap.org/
Centers for Disease Control and Prevention http://www.cdc.gov/