CSF Pathology Flashcards

1
Q

What is the mean CSF pressure?

A
  • 10mmHg.

- 14cm CSF.

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2
Q

Values above what level indicate abnormally high CSF pressure?

A

> 15mmHg or >20cm CSF.

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3
Q

Rate of CSF formation per minute?

A

0.35ml/min.

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4
Q

What forms CSF?

A
  • Choroid pelxus (75%).

- Brain ISF (25%).

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5
Q

What drug reduces CSF production by >50%?

A

Acetazolamide.

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6
Q

CSF undergoes substantial absorption via?

A

Arachnoid granulations.

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7
Q

CSF absorption depends upon?

A

ICP being greater than the pressure in sagittal sinus.

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8
Q

Valsalva like manoeuvres have what effect on the brain?

A

Transient venous engorgement.

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9
Q

Physical functions of CSF?

A
  • Buoyancy (reduces brain weight by 96% - 1500g to 60g).

- Accommodation of physiological changes in vascular volumes in the head (- displaced into spinal canal).

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10
Q

Chemical functions of CSF?

A
  • Provides micronutrients to cerebral tissue (e.g. Vitamin C, thyroxine).
  • Clears some waste products of nerve cell metabolism e.g. 5HIAA.
  • Ionic homeostasis.
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11
Q

Spinal arachnoid webs may be idiopathic or secondary to what?

A

Previous inflammatory processes due to infection or intracranial haemorrhage.

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12
Q

Due to the spinal arachnoid web CSF in the spinal canal is unable to disperse normally, leading to what?

A

Focal hydraulic pressure on the spinal cord.

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13
Q

Give an example of a CNS water pathology where there is an abnormal accumulation of water within parenchyma of CNS.

A
  • Cerebral oedema.
  • Benign intracranial hypertension.
  • Spinal dural arteriovenous fistula.
  • Syringomyelia and cord oedema.
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14
Q

Classification of hydrocephalus?

A
  • Obstructive.
  • Communicating.
  • Infantile.
  • Childhood/adult.
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15
Q

Practically speaking, hydrocephalus should be labelled as communicating only if?

A

It can safely be decompressed via lumbar puncture.

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16
Q

What physical signs at birth may suggest hydrocephalus?

A
  • Unusually large ehad.
  • Thin and shiny scalp with easily visible veins.
  • Bulging or tense fontanelle.
  • Downward looking eyes.
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17
Q

Congenital hydrocephalus may cause what symptoms?

A
  • Poor feeding.
  • Irritability.
  • Vomiting.
  • Sleepiness.
  • Muscle stiffness and spasms in a baby’s lower limbs.
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18
Q

Common congenital causes of paediatric hydrocephalus?

A
  • Chiari malformation or Spina Bifida.
  • Aqueductal stenosis.
  • Dandy Walker complex.
  • Congenital arachnoid cysts.
  • Atresia of foramen of Munro.
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19
Q

Aqueductal stenosis has which mode of inheritance?

A

X-linked.

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20
Q

Common acquired causes of paediatric hydrocephalus?

A
  • Haemorrhage (IHV - intraventricular haemorrhage).
  • Infection (post-meningitis).
  • Traumatic head injury.
  • Tumour.
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21
Q

What function do valves have in the management of hydrocephalus?

A
  • Fixed differential pressure.
  • Adjustable.
  • Anti-syphon.
  • Switch able.
  • Constant flow.
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22
Q

What percentage of valves used in the management of hydrocephalus are no longer functioning after 12 years?

A

80%.

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23
Q

Complications of shunts used in hydrocephalus?

A
  • Overdrainage.
  • Underdrainage.
  • Infection.
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24
Q

How may the risk of infection be reduced in the use of shunts in hydrocephalus?

A
  • Antibiotics or silver impregnated shunts.

- Iodine +++.

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25
Q

Underdrainage of a shunt used in the management of hydrocephalus may be due to?

A
  • Blockage.

- Displacement/disconnected catheter.

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26
Q

Overdrainage of a shunt used in the management of hydrocephalus may be due to?

A
  • Acute subdural haematoma.

- Slit ventricles.

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27
Q

Uncommon complications of shunts used in the management of hydrocephalus?

A
  • Intracerebral haemorrhage.
  • Seizures.
  • Craniosynostosis.
  • Dissemination of tumour cells.
  • Umbilical fistula.
  • Erosion into abdominal viscera.
  • Ascites, hydrocele, inguinal hernia.
  • Silicone allergies.
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28
Q

What is craniosynostosis?

A

Premature fusing of one or more of the fibrous sutures in an infant’s head.

May be a complication of a shunt.

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29
Q

What symptoms may be indicative of a blocked shunt in children?

A
  • Sunsetting (eyes look down).
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30
Q

What symptoms may be indicative of a blocked shunt in adults?

A
  • Lack of upgaze.
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31
Q

What symptoms may be indicative of a blocked shunt in both adults and children?

A
  • Headache and vomiting.
  • ## Blurred vision (papilloedema precedes blindness- may be rapid).
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32
Q

Management of blocked shunt in extremis?

A

Tap the shunt valve.

- NB there is a risk of infection may CSF can be sent to microbiology.

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33
Q

Management of a blocked shunt?

A
  • CT head to show hydrocephalus.
  • Urgent surgery to replace shunt.

Tap the shunt valve if patient in extremis (point of death) but note risk of infection so can send CSF to microbio.

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34
Q

Alternative to shunt in hydrocephalus?

A

Ventriculostomy.

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35
Q

A ventriculoperitoneal shunt may be used to treat hydrocephalus, but has a revision rate of?

A

40% in the first year.

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36
Q

How do ventriculoperitoneal shunts work?

A

Shunt drains spinal fluid from ventricles to the abdomen.

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37
Q

Why do shunts (particularly LP) have limited life expectancy?

A

Terminal slit valves in peritoneal cavity tend to fail with time.

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38
Q

What is normal pressure hydrocephalus?

A

Enlarged cerebral ventricles with normal/intermittently raised ICP.

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39
Q

What triad of symptoms is seen in normal pressure hydrocephalus?

A
  • Ataxia.
  • Memory decline.
  • Incontinence.
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40
Q

Normal pressure hydrocephalus may respond to CSF diversion, with a success rate of?

A

70% but not permanent.

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41
Q

Who does normal pressure hydrocephalus typically affect?

A

Older age groups.

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42
Q

Causes of normal pressure hydrocephalus?

A
  • Idiopathic.

- Post-inflammatory: subarachnoid haemorrhage, meningitis, trauma, craniotomy.

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43
Q

Describe symptoms of dementia associated with normal pressure hydrocephalus?

A
  • Delay in answering questions.
  • Loss of spontaneity.
  • May progress to akinetic mutism.
  • Often fluctuating severity.
  • Urinary incontinence.
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44
Q

What is akinetic mutism?

A

Patient no longer speaks or moves.

45
Q

What signs suggest normal pressure hydrocephalus ataxia?

A

Ataxia precedes all other symptoms in NPH.

  • Difficulty rising from chair.
  • Tendency to fall backwards.
  • Difficulties initiating gait.
  • Broad based, shuffling gait.
46
Q

Differential diagnosis to normal pressure hydrocephalus?

A

Ataxia: cerebellar, myelopathy.
Dementia: Alzheimer’s, Cerebrovascular.

47
Q

Genetic/inherited causes of dementia?

A
  • Huntington’s.
  • Wilson’s.
  • Porphyria.
48
Q

Infectious/transmissible causes of dementia?

A
  • Syphilis.
  • Prions.
  • Encephalitis.
49
Q

Metabolic/toxic causes of dementia?

A
  • Hypothyroidism.

- Thiamine (alcohol).

50
Q

Which cerebral tumour usually causes dementia?

A

Bifrontal.

51
Q

Degenerative causes of dementia?

A
  • Alzheimer’s.
  • Fronto-temporal.
  • Parkinson’s.
52
Q

Trauma causes of dementia?

A
  • Major head injury.

- Punch-drunk syndrome.

53
Q

What is punch drunk syndrome?

A

Typically seen in alcoholics and boxers.
Due to repeated cerebral concussions.
Characterised by lower limb weakness, unsteady gait, slow muscle movements, tremor, hesitant speech and “mental dullness”.

54
Q

What disease processes may cause dementia?

A
  • Cerebrovascular disease.
  • Demyelination.
  • Normal pressure hydrocephalus.
55
Q

Investigations used in diagnosing normal pressure hydrocephalus?

A
  • Clinical reasoning and CT.
  • MRI.
  • Tracer diffusion studies.
  • ICP measurement.
  • Lumbar puncture “tap-test”.
  • Lumbar drainage tests.
  • Infusion studies.
56
Q

Arithmetical calculation of resistance to outflow of CSF is a direct application of which law?

A

Ohm’s law: V= IR.

Rout = P0 - Pe / rate of infusion.

Rout = resistance to outflow.
P0 = mean opening pressure.
Pe = mean pressure at equilibrium.
57
Q

What are the units used in calculating resistance to CSF outflow?

A

mmHg/ml/minute.

58
Q

What is the principle of infusion studies?

A
  • Record baseline ICP for a period.
  • Challenge absorptive mechanisms with saline infusion.
  • After 10 minutes new plateau is reached:
    NORMAL: (modest increase in pulse pressure) and plateau mean within 10mm of mercury of opening pressure
    IMPAIRED CSF ABSORPTION: both amplitude of pressure wave and mean pressure increases dramatically.
59
Q

How is CSF diversion performed?

A
  • “Tap test” lumbar puncture or lumbar drain.
  • Measure normal pressure hydrocephalus triad pre- and post- CSF drainage.

If there is an improvement then shunt.

60
Q

Normal pressure hydrocephalus may be treated by CSF diversion via one of three methods, which are?

A
  • Lumboperitoneal shunts.
  • Ventriculoperitoneal shunts.
  • Endoscopic ventriculostomy.
61
Q

Benign/idiopathic intracranial hypertension is a disorder of what?

A

CNS water movement.

62
Q

who does idiopathic intracranial hypertension typically affect?

A

Young overweight/obese females.

63
Q

Conditions associated with idiopathic intracranial hypertension?

A
  • Obesity/weight gain.
  • Sleep apnoea.
  • Hypothyroidism.
  • Addison’s.
  • Uraemia.
  • SLE
  • Vitamin A, Lithium, antibiotics, hormones.
  • Steroid withdrawal.
64
Q

Symptoms of idiopathic intracranial hypertension?

A
  • Headaches.

- Visual loss (intervene when visual fields affected before visual acuity is lost).

65
Q

Do symptoms of idiopathic intracranial hypertension require treatment?

A
  • Headaches: optional treatment.

- Visual failure: mandatory treatment.

66
Q

Loss of visual acuity is a late sign of idiopathic intracranial hypertension and usually preceded by?

A

Constriction of visual fields.

67
Q

Signs of idiopathic intracranial hypertension?

A
  • Papilloedema.
  • Visual field constriction.
  • Loss of visual acuity.
68
Q

Investigation results of idiopathic intracranial hypertension?

A
  • LP pressure: >25cm CSF.
  • Normal CSF chemistry and cytology.
  • Normal CT and MRI.
  • No evidence of venous sinus thrombosis.
69
Q

Treatment of idiopathic intracranial hypertension?

A
  • Resolution with weight loss in majority of cases.
  • Treat underlying medical disorder.
  • LP.
  • Diuretics.
  • Lumbo-/Ventriculo-peritoneal shunt.
  • Optic nerve sheath fenestration.
  • Sub-temporal decompression.
  • Venous stents.
70
Q

Complications of lumboperitoneal shunts?

A
  • Blockage.
  • Infection.
  • Nerve root irritation.
  • Low pressure headaches.
  • Subdural haemorrhage.
  • Arachnoiditis.
  • Tonsillar herniation.
71
Q

Tonsillar herniation is one complication of lumboperitoneal shunts, causing headaches due to what?

A

CSF pressure dissociation.

72
Q

Symptoms of spontaneous intracranial hypotension?

A
  • Orthostatic headaches.
  • Neck/ interscapular / arm pain.
  • Diplopia/ visual field defects.
  • Dizziness.
  • Muffled hearing.
  • Galactorrhoea.
  • Impaired sphincter control.
  • Symptomatic subdural haematoma.
73
Q

What are the causes of spontaneous intracranial hypotension?

A
  • Idiopathic.
  • Collagen disorders.
  • Dural diverticula.
  • Trauma (often minor).
74
Q

Management of spontaneous intracranial hypotension?

A
  • Conservative: bed rest, fluids, analgesia.
  • Epidural blood patches.
  • Surgical repair.
75
Q

What is an epidural blood patch?

A

Surgical repair of holes in the dura mater of the spinal cord by using autologous blood patches as seals.

76
Q

In the investigation of spontaneous intracranial hypotension, what might an MRI head show?

A
  • Meningeal enhancement.
  • Chronic subdural haematomas.
  • Hindbrain herniation.
77
Q

In the investigation of spontaneous intracranial hypotension, what might a lumbar puncture show?

A
  • Low pressure.
  • Pleocytosis.
  • Raised protein.
  • Xanthochromia.
78
Q

What is pleocytosis?

A

Abnormally large numbers of lymphocytes in cerebrospinal fluid.

79
Q

What is xanthochromia?

A

Yellowing of CSF due to presence of bilirubin.

80
Q

What investigations should be performed in suspected spontaneous intracranial hypotension?

A
  • MRI head.
  • LP.
  • CT myelography.
  • Spinal MRI.
  • Isotope myelography.
81
Q

In spontaneous intracranial hypotension, low CSF pressure causes what?

A

Compensatory hyperaemia in the meninges.

82
Q

What accounts for cases of galactorrhoea in spontaneous intracranial hypotension?

A

Hyperaemia through the pituitary.

83
Q

What is hyperaemia?

A

Increased/excessive blood flow to an organ/part of the body.

84
Q

Mean age at presentation of syringomyelia?

A

31-35.

Does range from childhood to seventies.

85
Q

Syringomyelia is extremely common in which population?

A

Traumatic paraplegia victims.

86
Q

What is the latent interval of syringomyelia?

A

A few months to many years.

87
Q

What are the broad classifications of syringomyelia?

A
  • Craniovertebral junction.
  • Spinal canal.
  • Idiopathic.
88
Q

What is syringomyelia?

A

Fluid filled Cyst/cavity formation in the spinal cord. Expands and lengthens over time and may compress and damage spinal cord.

89
Q

Syringomyelia may arise from what?

A
  • Spondylotic narrowing of spinal canal.
  • Fibrosis at craniovertebral junction.
  • Idiopathic.
90
Q

How does syringomyelia classically present?

NB this is rarely seen now.

A
  • Dissociated sensory loss.
  • Clawed hands.
  • Cuts and burns on hands.
  • Small muscle wasting.
  • Loss of upper limb reflexes.
  • Increased lower limb reflexes.
91
Q

Syringomyelia causes what abnormalities in sweating?

A
  • Hyperhydrosis in early stage.
92
Q

What does hyperhydrosis indicate in Syringomyelia?

A

Hyperactivity in preganglionic neurons.

93
Q

Involuntary movements seen in Syringomyelia are a result of what?

A

Possible excitability of spinal neurons.

94
Q

What symptoms may a patient occasionally present with?

A
  • Segmental myoclonus.
  • Paroxysmal arm posturing.
  • Isolated Horner’s.
  • Orofacial pain (syringobulbia).
  • Limb hypertrophy.
  • Orthostatic hypotension.
  • Reduced intestinal mobility.
95
Q

Common presentations of hindbrain hernia (commonly associated with Syringomyelia)?

A

HEADACHES following:
- coughing, sneezing, straining, laughing, bending forward.

  • Visual disturbances.
  • Dizziness.
  • Deafness/tinnitus.
  • Dysarthria/dysphagia.
  • Somatic sensory disturbances.
96
Q

Occasional presentations of hindbrain hernia (commonly associated with Syringomyelia)?

A
  • Papilloedema.
  • Trigeminal neuralgia.
  • Glossopharyngeal neuralgia.
  • Respiratory failure.
  • Sleep apnoea.
  • Blepharoclonus.
  • Abnormal masseter/ corneal reflexes.
  • Postural evoked vomiting.
  • Chronic fatigue.
  • Syncope.
97
Q

Management of syringomyelia?

A
  • Open up obstructed CSF channels.
  • Drain syrinx cavity (if opening up channels fails as myelotomy is required).
  • Lower overall CSF pressure: less risky CSF shunts?
  • Conservative management.
98
Q

How may CSF conduits be opened up?

A
  • Craniovertebral decompression.
  • Laminectomy and duroplasty.
  • Others: e.g. excision of intramedullary tumour and division of arachnoid web.
99
Q

Often, blood and other products released into CSF pathways during surgery lead to?

A

Recurrent adhesion formation and persistence of syrinx cavity.

100
Q

Collapse of the syrinx cavity is related to the extent of what?

A

Arachnoid adhesions/fibrosis.

101
Q

Which type of fibrosis may prevent creation of a conduit for CSF flow?

A

extensive intradural fibrosis.

102
Q

What are the CSF receptacles into which CSF fluid may be diverted?

A
  • Spinal subarachnoid channels.
  • Pleural cavity.
  • Peritoneal cavity.
103
Q

When should conservative management be utilised in cases of syringomyelia?

A
  • Spindles.
  • Dilated central canals.
  • Clinically stable cavities.
  • Extensive fibrosis.
  • Medically unfit.
104
Q

Following craniovertebral decompression for hindbrain hernia, what commonly persists?

A

Sensory symptoms e.g. Dysaesthetic pains.

105
Q

What is dysaesthesia pain?

A

Uncomfortable, abnormal sensation of neuropathic pain.

Commonly associated with MS.

106
Q

Craniovertebral decompression for treating hindbrain hernia usually relieves what?

A
  • Pressure dissociation headaches.
  • 80% rate of syrinx collapse.
  • Motor deterioration arrests.
107
Q

Revision/blockage rate for syringopleural shunts used for post-traumatic syringomyelia?

A

30-50%.

108
Q

The degree of difficulty in operating on syringomyelia is proportional to?

A

The extent of intradural fibrosis.