Disorders of Cerebrospinal Fluid Dynamics 1 Flashcards
Lumbar puncture indications
A) To investigate or exclude meningitis
Bacterial
Viral
Tuberculous
Cryptococcal
Chemical
Carcinomatous
B) To investigate neurological disorders
Multiple Sclerosis
Sarcoidosis
Guillian Barre, Chronic Inflammatory Demyelinating Polyneuropathy
Mitochondrial Disorders
Leukencephalopathies
Paraneoplastic Syndromes
C) To demonstrate and manage disorders of Intracranial Pressure
Idiopathic Intracranial Hypertension
Spontaneous Intracranial Hypotension
D) To administer therapeutic or diagnostic agents
Spinal anaesthesia
Intrathecal chemotherapy
Intrathecal antibiotics
Intrathecal baclofen
Contrast media in myelography or cisternography
Tests frequently performed on CSF
- Microbiology
Cell count, culture and sensitivity - Biochemistry
Protein and glucose - Xanthochromia
Spetrophotometry - Oligoclonal bands
Investigation of CNS inflammation - Cytology
Investigation of malignant meningitis - Cytospin
Investigation of CNS lympoma - Viral PCR
PCR for viral DNA - ACE
Investigation of neurosarcoidosis - Lactate
Investigation of neurodegenerative disorders
Post lumbar puncture headache: Incidence, risk factors, symptoms, management
Incidence: 32%
Risk Factors:
younger age, female gender, and headache before or at the time of the procedure
Symptoms:
The symptoms of PLPH usually develop within 24 hours of Lumbar Puncture, and the natural history is for symptoms to resolve by about 10 days. The pain is usually diffuse, global or bitemporal headache, which can be accompanied by nausea, altered hearing, tinnitus, photophobia or neck stiffness. Low pressure may produce diplopia due to traction on the fourth or sixth cranial nerve
Management:
Maintaining a supine posture
Oral or intravenous fluids
Symptomatic management with analgesia and antiemetics
There is some evidence for the use of intravenous caffeine or intravenous theophylline
The definitive treatment if conservative management fails is epidural blood patching
Lumbar puncture: complications
Local discomfort and radicular pain
Spinal hematoma
Meningitis
Post lumbar puncture headache
Epidermoid tumor
Abducens palsy
Lumbar puncture: Red flags
Platelet count <40
International normalized ratio (INR) >1.5
Local skin infection
Local developmental abnormality, e.g., myelomeningocele
Raised intracranial pressure (with a pressure gradient across the CNS compartments)
When is a head CT before LP recommended?
Suspicion of raised intracranial pressure
Age >60 years
Immunocompromised patient
Previous CNS disease
Recent seizure
Reduced consciousness
Papilloedema
Abnormal neurological examination
Lumbar puncture: Risk of CNS herniation pathophysiology
CNS herniation occurs if there is a change in the pressure gradient within the CNS compartment sufficient to cause movement of CNS tissue out of its normal position.
This can involve brain, spinal cord, and nerve root tissue, often with devastating and fatal consequences. In these cases, an abnormal pressure gradient already exists, and it is the further transient lowering of pressure, as a result of CSF withdrawal from an LP, which allows the raised pressure compartment above the LP to move along the pressure gradient and consequently move CNS tissue.
This is in contrast to states of uniformly raised intracranial pressure within the whole CNS compartment, e.g., idiopathic intracranial hypertension (IIH), where no internal pressure gradient has developed so is it is safe to perform an LP
Normal Intracranial Pressure in adults
10-20 cm
Differential diagnosis of neurological disease according to intracranial pressure: Hypotension
A) Primary
- CSF leak
Atraumatic/ spontaneous
B) Secondary
- CSF leak
Post LP
Post surgical
Trauma
- Post-coital
- Drugs
Acetazolamide
Bendroflumethiazide
Furosemide
Indometacin
Topiramate
Differential diagnosis of neurological disease according to intracranial pressure: Normotension
- Normal pressure hydrocephalus
- CNS demyelination
- Bechet’s syndrome
- CNS vasculitis
- Neuropathy
- Encephalitis
Differential diagnosis of neurological disease according to intracranial pressure: Hypertension
Increased intracranial pressure can be secondary to intracranial masses (eg, neoplasm, infection, hematoma, infarction), to generalized brain swelling (eg, anoxia/ischemia, Reye syndrome, hypertensive encephalopathy), or to increased
venous pressure (eg, congestive heart failure, cerebral venous thrombosis).
It can also be the result of impaired cerebrospinal fluid (CSF) circulation.
- Idiopathic intracranial hypertension
- Intracranial hypertension without papilloedema (IWOP)
- Intracranial space-occupying lesiona
- Choroid plexus papilloma
- Arachnoid granulation agenesis
- Hydrocephalus (communicating and noncommunicating)
- Infective meningitis
Acute bacterial
Cryptococcal
Tuberculosis
Viral
Fungal - Cerebral venous sinus thrombosis
- Acute hemorrhagic leucoencephalitis
- Neurosarcoidosis
- Guillian-Barre´ syndrome
- Malignant meningitis
Which parameter indicates subdural hematoma and how to interpret it correctly
Subdural hematoma is indicated by xanthochromia
Xanthochromia is correctly assesed if
• Normal serum bilirubin levels.
• Delaying CSF sampling until the red cells have broken
down to bilirubin (12-h post-event is recommended).
• Using the least blood-stained CSF sample, usually the
last CSF sample collected.
• Transporting the CSF sample in the dark with minimal
agitation.
• Analyzing the sample with spectrophotometry rather
than visual inspection.
Normal CSF Findings
Appearance:
Clear
White cells:
0-5
Protein:
<0,5 g/L (23-38 mg d/L)
Glucose
>60-75% of serum glucose
CSF Findings in Viral Infecion
Appearance:
Clear/ opaque
White cells:
10-2000
Protein:
0,5-0,9
Glucose:
Normal
CSF Findings in Bacterial Infection
Appearance:
Turbid
White cells:
100-60000
Protein:
>0,9 (1-5)
Glucose:
<40 % of serum glucose
