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6. NSD auxiliary inspection
Neurology, the knowledge framework of NSD auxiliary examination chapters, all covered in one picture. Including lumbar puncture and cerebrospinal fluid examination, neuroelectrophysiological examination, NS imaging examination, etc.
Editado a las 2023-11-12 17:22:52,
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NSD auxiliary inspection
Section 1 Lumbar puncture and cerebrospinal fluid examination
Cerebrospinal fluid (CSF)
Produced in the choroid plexus of each ventricle, mainly the lateral ventricular choroid plexus
interventricular aperture
third ventricle
mesencephalic aqueduct
Median foramen of fourth ventricle Two side holes
subarachnoid space and cisterns
Absorbed through arachnoid granules on the fornix surface of the brain
lumbar puncture
(1) Indications
1. Collect CSF for various examinations to assist in the diagnosis of the following diseases: central nervous system infection, subarachnoid hemorrhage, immune-inflammatory diseases and demyelinating diseases, meningeal cancer, etc.
2. Suspected abnormal intracranial pressure
3. Dynamically observe CSF changes to help determine the condition, prognosis and guide treatment
4. Inject radionuclides for brain and spinal cord scanning
5. Inject liquid or release CSF to maintain and adjust intracranial pressure balance, or inject drugs to treat corresponding diseases
(2) Contraindications
1. Intracranial pressure is significantly elevated, or there are signs of brain herniation, especially if space-occupying lesions are suspected in the posterior fossa.
2. There is infection focus, spinal tuberculosis or open injury at the puncture site
3. Those with obvious bleeding tendency or critical condition should not be moved
4. In spinal cord compression, the spinal cord function is in a critical state of imminent loss.
(3) Complications and their prevention and treatment
1. Hypocranial pressure syndrome (cerebrospinal fluid pressure in lateral decubitus position <60~80H2O)
Therefore, a thin, non-invasive needle should be used for puncture, and the patient should lie flat for at least 4 to 6 hours after surgery. Once symptoms of low intracranial pressure occur, it is advisable to drink more water and rest in bed. In severe cases, 1000 to 1500ml of normal saline can be infused daily.
2. Cerebral herniation (how to prevent it?)
The indications for lumbar puncture must be strictly understood. Those with suspected space-occupying lesions in the posterior fossa should first undergo imaging examinations to confirm the diagnosis. Those with signs of intracranial hypertension can use dehydrating agents before performing lumbar puncture. If the lumbar puncture confirms that the pressure is elevated, no or less cerebrospinal fluid should be released, and dehydration and diuretic treatment should be given immediately to reduce intracranial pressure.
3. Nerve root pain
4. Others: infection, bleeding, spinal cord injury, etc.
Adequate evaluation, necessary imaging, and surgical management
(4) Operation and pressure measurement
operate
body position
Usually, the patient is in a lateral lying position (mostly on the left side) with the patient bending his neck and holding his knees, keeping his back as close to the bed as possible. The back should be perpendicular to the examination table and the spine should be parallel to the table.
puncture site
Make a connecting line along the highest points of the bilateral iliac spines, and the intersection with the midline of the spine is the spinous process of the fourth lumbar vertebra, and then select the 4th to 5th or 3rd to 4th intervertebral space to insert the needle.
anaesthetization
After routine local disinfection and draping, use 2% lidocaine to perform intradermal and subcutaneous anesthesia at the puncture point. Then, insert the needle into the ligament, draw back no blood, and inject anesthetic while withdrawing the needle.
puncture
After the anesthesia takes effect, fix the skin of the puncture site with one hand and slowly insert the puncture needle along the direction of the spinous process. When the needle tip encounters bone during needle insertion, the needle should be withdrawn under the skin and the angle should be corrected before puncturing. When an adult inserts the needle about 4~6cm, it can penetrate the dura mater and reach the subarachnoid space. The needle core can be withdrawn to drain out the cerebrospinal fluid.
ending
After measuring the pressure and collecting cerebrospinal fluid, insert the needle core and pull out the puncture needle. Apply sterile gauze and secure with tape. Lying down for 4 to 6 hours after surgery.
manometry
When the cerebrospinal fluid rises to a certain height in the pressure tube and stops rising, the pressure at this time is the initial pressure. The pressure measured again after a certain amount of cerebrospinal fluid is released is the final pressure.
Pressure value range
The normal pressure for adults is: 80~180mmH2O;
High intracranial pressure: >200mmH2O;
Intracranial space-occupying lesions, brain trauma, intracranial infection, subarachnoid hemorrhage
Intracranial hypotension: <80mmH2O.
Low intracranial pressure, dehydration, shock, subarachnoid obstruction
cerebrospinal fluid examination
Traits
Three-tube test method
Continuously use 3 test tubes to collect CSF
Uniform blood color is subarachnoid hemorrhage;
The color of each tube before and after gradually fades to indicate bleeding from puncture injury;
If bloody CSF turns colorless after centrifugation, it may be fresh bleeding or injury;
Yellow after centrifugation indicates old bleeding
Cloudy:
It is often caused by an increase in the number of cells caused by bacterial infection and is seen in various purulent meningitis.
In severe cases, it looks like rice soup.
Number of cells
leukocyte:
increase
Inflammatory lesions seen in the meninges and brain parenchyma.
Significant increase in cells
Predominantly multiple nuclei, seen in acute suppurative meningitis.
mild or moderate increase
Mainly mononuclear cells; seen in viral encephalitis
Mainly an increase in a large number of lymphocytes or monocytes
Mostly subacute or chronic infections
Brain parasitic infection: more eosinophils are seen.
Significant increase in protein
Commonly seen in purulent meningitis, tuberculous meningitis, Guillain-Barré syndrome, central nervous system malignant tumors, cerebral hemorrhage, subarachnoid hemorrhage and spinal canal obstruction.
Significantly lower sugar content
Suppurative meningitis.
If there is an intact cell structure, sugar will be consumed, and viral meningitis will not be significantly reduced.
multiple sclerosis
protein electrophoresis
Increased gamma globulin but normal total protein
Increased CSF-Ig
Oligoclonal band OB
OB refers to a discontinuous area that appears in the gamma globulin zone and cannot be seen in peripheral blood.
Most common
CSF ink staining method
Positive indicates Cryptococcus neoformans infection
High specificity, insufficient sensitivity
Section 3 neuroelectrophysiological examination
Electroencephalogram (EEG)
epileptiform discharges
(1) Spike wave: a sudden and transient waveform with a sharp top
(2) Sharp wave: similar to spike wave, only the time limit is wider than spike wave
(3) 3Hz spike and slow wave synthesis: a spike followed by a slow wave
common in Typical absence seizure.
(4) Polyspike:
Common in myoclonic and tonic-clonic seizures
(5) Sharp-slow complex wave: composed of a sharp wave followed by a slow wave
(6) Polyspiny slow wave complex: more than one spike followed by a slow wave
myoclonic epilepsy
(7) High-amplitude arrhythmia: high-amplitude sharp waves and spike waves are released, followed by a period of quiescent electrical activity.
Infantile spasms, phenylketonuria, etc.
Evoked potential (EP)
Currently, it can detect sensory pathways such as somatosensory, vision and hearing, as well as motor pathways and cognitive functions.
Electromyography EMG
Various electrical activities recorded in muscles at rest and in varying degrees of voluntary contraction
Repetitive electrical nerve stimulation (RNES)
It is an important means to detect the function of neuromuscular junction
for myasthenia gravis
Carotid artery ultrasound
Bilateral common carotid artery (CCA), extracranial segment of internal carotid artery (ICA), external carotid artery (ECA), extracranial segment of vertebral artery (VA), subclavian artery, innominate artery, etc.
carotid atherosclerosis
Observe the location and shape of the plaque, the integrity of the surface fibrous cap and the acoustic characteristics within the plaque, and measure the size of the plaque
Transcranial Doppler Ultrasound TCD
Detection of intracranial arterial blood flow
Application in diagnosis and treatment of acute ischemic stroke
It is non-invasive, convenient, bedside, and can monitor vascular recanalization in real time.
Section 2 NS imaging examination
digital subtraction angiography (DSA)
Contrast media will burden liver and kidney functions and increase intracranial pressure to a certain extent.
Indications
Vascular disease
Testing for causes of hematoma or subarachnoid hemorrhage
Observe the relationship between the blood supply of space-occupying lesions and adjacent blood vessels and the qualitative characteristics of certain tumors
DSA manifestations of vascular lesions
1. Intracranial aneurysm
2. Cerebral arteriovenous malformation
3. Intracranial and intracranial artery stenosis
4. Sinus thrombosis
5. Diagnosis of arterial dissection by DSA
DSA is a reliable means of diagnosing carotid artery dissection, and the most common manifestation is the line sign.
There are certain limitations, that is, the thickness and shape of the artery wall are not visible, and the hematoma shape within the wall cannot be visualized.
computed tomography (CT)
First choice for cerebrovascular disease
Used to distinguish cerebral hemorrhage from cerebral infarction
Cerebral hemorrhage is a high-density lesion
Cerebral infarction is a low-density lesion
CT angiography CTA
It can provide important diagnostic basis for occlusive vascular lesions and can clarify the degree of vascular stenosis.
CTA does not require arterial cannulation and is simple and fast, but it cannot show lesions in small blood vessel branches.
It can display blood vessels and bony structures at the same time, clearly display the three-dimensional vascular system of the head and neck, and observe lesions from multiple angles.
Magnetic Resonance Imaging (MRI)
The most accurate technology for diagnosing acute cerebral infarction lesions
Diffusion weighted imaging (DWI)
CT is the first choice for bleeding
Advantage
Clearer view of bones and soft tissues