3. Name:Ayush
Age: 1 yr
Resident of Bharatpur
Date of admission : 9/11/11
Admitted in neurosurgery unit 2
Presenting complaint : Increase in head size
vomiting
Irritability
4. Parents of the patient first noticed the Increase in
head size at the age of 3 months and Since then, the
deformity gradually increased.Patient was operated at
the age of 6 months for hydrocephalus and was
discharged.
2 months back patient came with complains of fever
and irritability. Infection was found at shunt site and
shunt removed.
Head size again increased from 5-7 days before
admission which was associated with c/o vomiting
and irritability. Patient was diagnosed with
hydrocephalus and was decided to be operated for
shunt surgery again.
5. Past medical history – No history of TB, DM ,
Asthma,convulsion
Drug history – no history of any drug allergy.
Family history- not significant
No history of congenital disease
H/O Full term normal delivery
6. Normal bowel and bladder habits
Average built and nourished,
proper breast feeding,
normal developmental milestones
7. Pt is conscious
Average built and nourished
Afebrile
Pallor- / Icterus-/ Cyanosis-/ clubbing-
Neck veins not engorged
Pulse –110/min, regular, normal volume , all
peripheral pulses palpable
8. Respiratory examination
Chest movements symmetric.
B/L equal air entry,no added sounds
No abnormality detected
Cardiovascular examination
s1, s2 normal.
No murmur,
No abnormality detected
Central nervous examination
• Conscious , Motor function – muscle tone, power and DTR within
normal limits
• Sensory function within normal limits
9. Head examination:-
Large head (increased circumference)
Shiny scalp with dilated veins
Fullness of the ant.fontanele
Sun set appearance of the eyes.
Eye exam. And reflexes are normal
Developmental goals which includes smiling,
crawling, walking, being able to roll over,palmer
grisp and pincer grisp are developed acc.to age.
10. Hb-9.2 g%
Hct-30%;
Platelet Count –1.3 Lakh/cumm
TLC-8600/cumm
RBS-69mg/dl
Urea-21 mg/dl
Creatinine –0.8 mg/dl
ECG : Within normal limits
Chest x ray : no abnormality detected
Echocardiography : all normal measurements
No abnormality detected
11. Post fossa-fourth ventricle and basal cistern appear
normal,cerebellar hemisphere normal
Gross dilated B/L lateral ventricles and III ventricle
with B/L cerebral pressure atrophy
Partially absent septum pellucidum that is likely
sequele of Aqueductal stenosis.
Rest of cerebral parenchyma,basal ganglia,thalami
show normal CT attenuation.
No midline shift seen.
14. CSF is a dynamic fluid, its main function is to keep
the internal environment of Central Nervous System
(C.N.S) constant. It also play a role in mechanical
protection of the brain and spinal cord.
CSF is secreted and reabsorbed continuously.
CSF is secreted by choroid plexus, the main bulk of
choroid plexus is present in the Lateral Ventricles,
but third Ventricle and Fourth Ventricle also
contains choroid plexus.
15. Total volume of CSF (adult) = 125-150 ml
Total volume of CSF (infant) = 50 ml
Turnover of entire volume of CSF= 3 to 4 times per day
Rate of production of CSF = 0.35 ml/min (500 ml/day)
pH of CSF = 7.33
Specific gravity of CSF= 1.007
Color of normal CSF = clear and colorless
White blood cell count in CSF = 0-3 per mm3
Red blood cell count in CSF = 0-5 per mm3
16. Normal intracranial pressure(adult) = 150 - 180 mm of
water
Normal intracranial pressure(newborn)=80-100 mm of
water
CSF pass from lateral ventricles through Foramina of
Monro to the third ventricle, then through Aqueduct of
Sylvius to the fourth ventricle.
17.
18. The fourth ventricle have three apertures or
foramina:-
One midline (Foramen of Magendi) and
two lateral foramina (Foramena of Luschka).
Through these Foramina CSF passes from the
ventricular system to the subarachnoid space.
It accumulate first in Cisterna Magna, part of CSF
descends downwards around the spinal cord, but the
majority passes upwards through the Tentorial
Hiatus over the surface of both cerebral
hemispheres to be absorbed by the Arachnoid villi in
the Superior sagittal sinus (SSS).
19.
20. Any disturbance in CSF secretion, circulation and
absorption will results in abnormal accumulation, so
the pathogenesis may be :
◦ Obstruction of CSF pathway (main factor).
◦ Excessive formation of CSF as in case of choroid
plexus papilloma ( rare ).
◦ Decreased absorption of CSF as in SSS thrombosis
around arachnoid villi.
21. Congenital anomalies:
Commonly seen in the area of Aqueduct, such as
forking of Aqueduct, gliosis or obstruction.
(CNS is the commonest system in the body liable to
congenital anomalies).
Post–traumatic or Post–Hemorrhagic: Subarachnoid
hemorrhage, whether spontaneously (as in Ruptured
Intracranial aneurysm or AVM) or after head trauma may
result in inflammatory reactions, adhesions, and
obstruction of subarachnoid space and so
Hydrocephalus
22. Post–Inflammatory or Post-meningitic: Inflammation of
Meninges usually heals by Fibrosis and adhesions within
the subarachnoid Spaces, so can obstruct CSF pathway.
Neoplasm: Any abnormal mass such as tumor or
abscess along the pathway of CSF may result in
obstruction.
In some cases of Hydrocephalus, we can not diagnose
the underlying etiological cause, this is called
Hydrocephalus of undetected cause. These cases are
mostly due to mild unnoticed Head trauma or sub
clinical Meningitis.
23. Based on its underlying mechanisms,
hydrocephalus can be classified into-
1)communicating (non obstructive)
2) non-communicating (obstructive).
Both forms can be either congenital or
acquired
24. ,
It is due to functional impairment of the arachnoidal
granulations ( Pacchioni's granulations), which are
located along the superior sagittal sinus and is the
site of CSF resorption back into the venous system.
Neurologic conditions may result in communicating
hydrocephalus, includes:-
subarachnoid/intraventricular hemorrhage,
meningitis and
congenital absence of arachnoid villi.
25. Communicating
hydrocephalus occurs
when full
communication occurs
between the ventricles
and subarachnoid
space.
It is caused by :-
1)overproduction of
CSF (rarely),
2)defective absorption
of CSF (most often),
3) venous drainage
insufficiency
(occasionally).
26. Normal pressure hydrocephalus (NPH) is a particular
form of communicating hydrocephalus, characterized
by enlarged cerebral ventricles, with only intermittently
elevated CSF pressure.
The diagnosis of NPH can be established only with the
help of continuous intraventricular pressure recordings
(over 24 hours or even longer).
Dynamic compliance studies may be also helpful.
Altered compliance (elasticity) of the ventricular walls,
as well as increased viscosity of the CSF, may play a role
in the pathogenesis of normal pressure hydrocephalus.
27. It is caused by a CSF-flow obstruction ultimately
preventing CSF from flowing into the subarachnoid
space (either due to external compression or
intraventricular mass lesions).
Foramen of Monro obstruction may lead to dilation of
one or, if large enough,both lateral ventricles.
The aqueduct of Sylvius obstruction may lead to
dilation of both lateral ventricles as well as the third
ventricle.
29. Fourth ventricle obstruction will lead to dilation of
the aqueduct as well as lateral and third ventricles
(e.g.Chiari malformation)
Foramina of Luschka and foramen of Magendie may
be obstructed due to congenital failure of opening
(e.g.Dandy-Walker malformation).
30. Clinical picture of Hydrocephalus depends on the age
at the time of presentation.
The skull of the infant is malleable and soft with open
sutures and fontanels, so it can accommodate large
amount of CSF without any increase in the intracranial
pressure.
The skull of the adult is rigid, hard, so any increase in
the contents will result in increase in the Intracranial
pressure.
31. Large sized head or
progressive enlargement of the
size of the head.
The scalp over it well be
stretched, shinny with dilated
veins.
The Anterior Fontanel (AF) well
be open, wide and bulged. The
posterior fontanel may be still
open.
32.
33. Sun set appearance of the
eyes.
Disproportion between the
size of the head and size
of the face.
Disproportion between the
size of the head and size
of the body.
In advanced cases, delayed
development of the normal
milestones and Mental
retardation may be present
or developed, also history
of fits may be given.
34.
35.
36. It is simply a manifestation of increased
Intracranial pressure:
◦ Headache
◦ Vomiting
◦ Blurring of vision and papilloedema
◦ Deterioration of level of consciousness.
The underlying cause may be detected such as
history of trauma, Meningitis or tumor.
37. Ultrasonography (US):
◦ It is simple, non invasive and cheep.
◦ It is the method of choice to diagnose intrauterine
cases.
Plain x-ray skull:
◦ No role in diagnosis of infantile cases.
◦ In adults, it may show pathological intracranial
calcification, suture diastases or erosion of the
dorsum sella.
38. Computerized Tomography (CT):
◦ It is main diagnostic tool of Hydrocephalus
◦ confirms diagnosis
◦ localizes the site of obstruction
◦ show the underlying cause if present
Magnetic Resonance Imaging (MRI):
◦ MRI have nearly the same diagnostic value of CT
◦ but it is expensive
◦ not available at any place
◦ needs long time (nearly one hour) to finish and
in children it’s usually done under general
anesthesia
39.
40. The best line of treatment is to remove the cause of
disease, such as fulguration of choroid plexus
papilloma or removal of post fossa tumor.
This is not possible in the majority of cases i.e. we
can not correct congenital malformation or remove
glioma from brain stem, so in these cases we divert
CSF pathway to overcome site of obstruction by
using shunt.
41.
42.
43.
44. Shunt is still the most common method used to
treat hydrocephalus.
This is done by implanting a tube in the lateral
ventricle and the distal end of the tube is put in
the right atrium of the heart through internal
jugular vein (V–A shunt),or pass subcutaneously
in front of the chest wall to be implanted in the
peritoneal cavity (V–P shunt).
45. Medical treatment have no role in the management of
hydrocephalus.
Carbonic anhydrase inhibitor ( Diamox ), will decrease
the rate of secretion of CSF to some extent, but does
not relief the obstruction.
Medical treatment may be used in doubtful cases or if
there is contraindication for surgery such as
bronchopneumonia or infection at the site of
operation.
46.
47. Successful management of patients undergoing VP
shunt insertion is dependent on understanding the
relationship between ICP and CPP and how this is
affected by any disease process, anaesthetic agents
and surgery
CPP = MAP – (ICP + CVP)
MAP- mean arterial pressure
CVP- central venous pressure
ICP- intracranial pressure
48. There are several causes of hydrocephalus
which may necessitate the insertion of a VP shunt
Causes of hydrocephalus
Congenital :
Myelomeningocele
Stenosis of the cerebral aqueduct
Arnold-Chiari malformation
Arachnoid cysts,Vascular malformations
Idiopathic
Acquired :
Infection
Intraventricular haemorrhage
Tumour
Trauma
Nutritional deficiencies
49. The preoperative visit is an essential component of
any anaesthetic technique.
This should include:-
standard anaesthetic history of problems with
previous anaesthetics,
family history of reactions to anaesthesia,
past medical history,
current medication (e.g. anticonvulsants,
acetazolamide,furosemide),
allergies and last oral intake.
50. Examination includes:-
Assessment of the airway
Cardiorespiratory system
Neurological systems, which in cases of raised ICP
may demonstrate reduced level of consciousness
(LOC) and therefore increased risk of pulmonary
aspiration.
Volume status should be determined as prolonged
vomiting and dehydration may necessitate intravenous
fluid preoperatively.
Blood results should be reviewed.
Urea and electrolytes should be checked.
51. Sedative premedication should be considered
carefully as it may exacerbate or mask signs of
neurological dysfunction.
The patient should be carefully monitored signs of
neurological deterioration.
Particular attention should be paid to the possibility
of co-morbidities including problems with the
cardiovascular (e.g. congenital cardiac disease) and
respiratory systems (e.g. bronchopulmonary
dysplasia, kyphoscoliosis, recurrent respiratory
infections secondary to neurological dysfunction).
52. Prior to induction all anaesthetic equipment and
drugs should be checked to ensure they are available
and in good working order.
Standard monitoring should include:-
pulse oximetry
electrocardiogram
non-invasive blood-pressure
oxygen concentration
capnography.
53.
The method of induction is determined by the
circumstances of the case and the preference of the
patient and the anaesthetist.
Proprofol 2-4 mg/kg, thiopentone 3-5 mg/kg can be
used as inducing agent.
Hypotension should be avoided because of the risk of
decreasing CPP in the face of raised ICP.
Ketamine should not be used as it can increase ICP.
54. Suxamethonium can be used if the risk of
aspiration outweighs the problems of transient
increases in ICP, otherwise non-depolarising NMB
are preferable.
Gaseous induction is an acceptable alternative with
a non-irritant volatile anaesthetic agent such as
sevoflurane or halothane.
Hypercarbia should be avoided as it causes
cerebral vasodilation and may worsen raised ICP
especially in combination with laryngoscopy and
airway manipulation.
55. The airway should be secured by an appropriate sized
tracheal tube.
This should be a reinforced (armoured) tube if
available but a standard tube can be used providing
this information is communicated to the surgeon, as
the tube will be more likely to kink during positioning.
The tube should be firmly secured with waterproof
tape and dressing and the eyes should be padded and
taped.
56. The patient should be positioned to allow good
access for the surgeon and to avoid any undue
pressure on vulnerable areas.
Consideration should be given to optimizing venous
drainage to increase CPP, reduce venous bleeding and
improve the surgical field.
The core temperature of the patient should be
monitored (rectal or oesophageal) and warming
devices (e.g. warm air blankets) used as required to
maintain normothermia
57. Normally, cerebral blood flow
(CBF) is maintained at a
constant level in the face of a
wide range of mean blood
pressure (MBP) and PaO2.
Below the critical minimum
level (approximately 50
mmHg PaO2 and 50-55
mmHg MBP, in adults), CBF
increases as PaO2 decreases,
and it decreases as MBP
decreases. The precise
minimum thresholds of MBP in
infants and children are
unknown
59. Anaesthesia can be maintained with a volatile agent
and a mixture of oxygen and air.
The aim is to maintain CPP until the raised ICP is
relieved by positioning of the VP shunt.
To do this hypotension should be avoided and minute
ventilation controlled to maintain normocarbia (end
tidal CO2 4-4.5 kPa) to optimise CPP and avoid
increases in ICP.
Positive end-expiratory pressure (PEEP) should be
minimised to avoid venous congestion in the head but
may be used if there are difficulties in maintaining
oxygenation.
The most stimulating parts of the surgery include the
initial incision and tunnelling under the skin.
60. A short acting opioid, such as fentanyl (1-3 mcg/kg)
or remifentanil (1 mcg/kg), or increased depth of
anaesthesia, can be used to attenuate the increase in
heart rate and ICP.
Post-operative analgesia can be provided by a
combination of infiltration of local anaesthetic such
as bupivicaine 0.25% (0.5-0.75 ml/kg) and
paracetamol (15 mg/kg) either intravenous or per
rectum.
High doses of long acting opioids should be avoided
because of potential detrimental effects on conscious
level.
61. At the end of the procedure neuromuscular blockade
can be antagonized using neostigmine (50 mcg/kg)
combined with an anticholinergic (e.g. atropine 25
mcg/kg).
Most patients can be extubated once awake, avoiding
hypercarbia, and with a technique which minimizes
the risk of aspiration (lateral or sitting).
The patient should be monitored in a suitable
environment by those familiar with paediatric
neurosurgical cases and able to carry out regular
neurological observations.
62. A reasonable proportion of patients requiring VP
shunt insertion are neonates.
Neonates are physiologically immature and so present
additional considerations for the anaesthetist.
Many of these patients are premature, with a low birth
weight, with congenital hydrocephalus needing urgent
surgical treatment in the first days of life.
This group are more likely to have complications with
their VP shunts and so return more frequently for
further surgery to correct these problems.
63. Preoperative assessment should look for problems
associated with neonates and prematurity such as
anaemia, coagulopathy, jaundice, respiratory
disease and congenital cardiac problems.
Additional investigations such as an
echocardiogram may therefore be indicated.
Blood and any other required products should be
readily available prior to surgery.
Gaseous induction of anaesthesia with sevoflurane
provides good cardiovascular stability
64. Particular attention must be paid to securing tracheal
tubes and intravenous cannulae as endobronchial
intubation and extravasation are commonly
encountered problems.
Congenital hydrocephalus may have distorted the
anatomy of the skull which can make management of
the airway more difficult.
Often a pillow placed under the body of the neonate
can facilitate laryngoscopy.
The use of a naso-gastric tube is an important
component of managing the neonatal airway and
ventilation.
65. Neonates have a high surface area to volume ratio and so lose
heat quickly and their mechanisms for maintaining thermal
homeostasis are poorly developed.
Core temperature must be recorded and active measures taken to
maintain body heat. These include, increasing the ambient
temperature, warm air blankets, overhead heaters, heat-moisture
exchangers to warm inspired gases, warming intravenous fluids
and covering of exposed areas.
Drug metabolism is different in neonates with an immature liver
but a relatively higher volume of distribution.
Paracetamol, local anaesthetics, volatile anaesthetic agents and
opioids are all used in relatively lower doses
66. Careful attention must be paid to fluid balance as
renal function is also immature in the neonate.
An infusion of 10% glucose may be required to
maintain blood glucose within the normal range but
hypo and hyperglycaemia should be avoided.
Regular monitoring of blood glucose and electrolytes
allows for adjustment of fluid regimens as required.
Postoperatively some neonates will require further
respiratory support (especially pre-term infants with
bronchopulmonary dysplasia).
Patients that can be extubated will need apnoea
monitoring for 24-hour hours in addition to regular
neurological observations.
67. The shunt may become blocked. Symptoms of such a
blockage include headache and vomiting.
There may be other problems with the shunt, such as
kinking, tube separation, or infection in the area of
the shunt.
Other complications may include:
- Complications of surgery
- Infections such as meningitis or encephalitis
- Intellectual impairment
- Nerve damage (decrease in movement,
sensation, function)
- Physical disabilities
68. Clinical symptoms and signs to predict Fluid
tracking
Headache
Fever
Irritability
Bulging fontanelle
Nausea and vomiting
Loss of developmental milestones
Increased head circumference
69.
70.
71.
72.
73. Endoscopic third ventriculostomy (ETV) is a procedure
used to treat hydrocephalus,as an alternative to a
shunt.
Traditionally surgeons have used shunts to drain the
CSF from the ventricles in the brain to another part of
the body, and this is still the main method of
treatment for hydrocephalus.
Third ventriculostomy, on the other hand, does the
opposite to a shunt. Instead of draining the CSF
away,it keeps it within the brain and spinal cord.
The neurosurgeon makes a hole in the thin membrane
at the base of the third ventricle, which allows the
fluid into the sub arachnoid space.
74. The ETV technique is performed via a hole similar
to that of a shunt, usually at the front of the head,
just behind the hairline, using an endoscope.
This is a beautiful technique, which drains the CSF
more naturally.
The patients for whom ETV is going to work well
are people who have pure obstructions within the
brain such as aqueduct stenosis, or patients who
have tumours.
75.
76. Advantages
No foreign object (shunt tubing and valve)
implanted in the body, lowering the risk of
infection.
Fewer incisions mean slightly less discomfort.
A lower long term complication rate compared to
a shunt.
Disadvantages
The chances of improving may be lower with ETV
compared to a shunt
Although very unlikely, the risk of serious
complications with ETV compared to a shunt
operation
