Lumbar Puncture Student Stanciu Elena What is it

Lumbar Puncture Student: Stanciu Elena

What is it? � It is a procedure in which a needle is inserted into the spinal subarachnoid space, usually to colect CSF to establish a diagnosis, but it can also be used for therapeutical reasons.

When to do it? Lumbar puncture should be performed for the following indications: � Suspicion of meningitis � Suspicion of subarachnoid hemorrhage (SAH) � Suspicion of central nervous system (CNS) diseases such as Guillain-Barre syndrome and carcinomatous meningitis � Therapeutic relief of pseudotumor cerebri

When not to do it? Absolute contraindications are: � the presence of infected skin over the needle entry site � the presence of unequal pressures between the supratentorial and infratentorial compartments. Relative contraindications are: � Increased intracranial pressure (ICP) � Coagulopathy � Brain abscess � Vertebral deformities

Complications � Hematoma � post. LP headache � Before the doctor removes the needle he should reinsert the stylet so as to not clamp a nerve or to have a CSF leak (causing a headache) � Nausea � Punction of the nerves or spinal cord (weekness, loss of sensation, *paraplegia) � Adhesive arachnoiditis

Things to do before LP Neurological examination � Imaging � Laboratory tests � Explain the procedure, benefits, risks, complications, and alternative options to the patient or the patient’s representative, and obtain a signed informed consent � Hydrate so as to avoid a dry tap � Organizing your kit � Positioning � Analgesia-lidocaine � *Lorazepam against anxiety � *Antibiotics after blood culture, prior to imaging if patient is suspected of having meningitis �

Indications for performing brain CT scanning before lumbar puncture in patients with suspected meningitis include the following: Patients who are older than 60 years � Patients who are immunocompromised � Patients with known CNS lesions � Patients who have had a seizure within 1 week of presentation � Patients with an abnormal level of consciousness � Patients with focal findings on neurologic examination � Patients with papilledema seen on physical examination, with clinical suspicion of an elevated ICP � Cranial CT scanning should be obtained before lumbar puncture in all patients with suspected SAH

Where to do it?

Where to do it? Part 2 LP can be performed with the patient lying on one side or siting on the bed. The election site for LP is the intervetebral space L 3 -L 4 which can be easily found on the imaginary line that unites the postero-superior iliac crests. In more difficult cases, ultrasound guidance can be used.

How to do it? � � � LP is performed in a sterile environment: sterile gloves and sterile fields. Povidone-iodine is used to clean the patient’s skin. Local anestesia with Lidocaine (injected progresively, layer by layer) It is recommended to wait 10 to 15 minutes after local anestesia (studies showed that patients feel less pain if done so) The needle is inserted with the bevel superiorly oriented. In grown-ups, the doctor moves forward about 4 -5 cm until he can feel a release of resistance, meaning that he reached SAS. If the needle is in the correct place, drops of CSF should come out. These are colected, and not vacuumed with a seringe. About 20 -30 ml of CSF is collected for tests. The doctor can atach a manometer to measure the CSF presure (N=180 mm. Hg) The stylet is reinserted and the needle is taken out. It is recommended that the patient should rest in a comfortable position for an hour before standing up.

Tests � Cell count � Proteins � Glucosis � Latex aglutination � PCR (for Herpes simplex or Enteroviruses) � Antibodies( for detecting neurosiphylis or Lyme diseasse) � Imunoelectrophoresis � Citology � Bacterial, fungal, viral cultures � Smears

Cell count The presence of white blood cells in cerebrospinal fluid is called pleocytosis. The presence of granulocytes is always an abnormal finding. A large number of granulocytes often heralds bacterial meningitis. � White cells can also indicate reaction to repeated lumbar punctures, reactions to prior injections of medicines or dyes, central nervous system hemorrhage, leukemia, recent epileptic seizure, or a metastatic tumor. � The finding of erythrophagocytosis, where phagocytosed erythrocytes are observed, signifies haemorrhage into the CSF that preceded the lumbar puncture. Therefore, when erythrocytes are detected in the CSF sample, erythrophagocytosis suggests causes other than a traumatic tap, such as intracranial haemorrhage and haemorrhagic herpetic encephalitis �

Microbiology � Gram staining may demonstrate bacteria in bacterial meningitis. � Microbiological culture is the gold standard for detecting bacterial meningitis. Bacteria, fungi, and viruses can all be cultured by using different techniques.

Gram-stain findings illustrating the presence of (A) white blood cells and a few gram-positive cocci in the cytocentrifuged sediment of the patient's CSF, (B) rare gram-negative cocci (circle) in another field of the Gram stain shown in (A), and (C) many gram-negative cocci and coccobacilli in the Gramstained smear of a colony from the TSA blood agar culture.

Chemistry Glucose is present in the CSF; the level is usually about 60% that in the peripheral circulation. � Decreased glucose levels can indicate fungal, tuberculous or pyogenic infections; lymphomas; leukemia spreading to the meninges; meningoencephalitic mumps; or hypoglycemia. Increased glucose levels in the fluid can indicate diabetes Increased levels of lactate can occur the presence of cancer of the CNS, multiple sclerosis, heritable mitochondrial disease, low blood pressure, low serum phosphorus, respiratory alkalosis, idiopathic seizures, traumatic brain injury, cerebral ischemia, brain abscess, hydrocephalus, hypocapnia or bacterial meningitis.

Chemistry- part 2 � Changes in total protein content of cerebrospinal fluid can result from pathologically increased permeability of the blood-cerebrospinal fluid barrier, obstructions of CSF circulation, meningitis, neurosyphilis, brain abscesses, subarachnoid hemorrhage, polio, collagen disease or Guillain-Barré syndrome, leakage of CSF, increases in intracranial pressure or hyperthyroidism. � Very high levels of protein may indicate tuberculous meningitis or spinal block. � Ig. G synthetic rate is calculated from measured Ig. G and total protein levels; it is elevated in immune disorders such as multiple sclerosis, transverse myelitis.

Bibliography � Medscape. com � Netter’s Neurology � Harrison’s Neurology in clinical Medicine