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Abreast Of Ear, Nose &
Throat / Head & Neck Advances
11, February, 2006
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Hello, All. Welcome
to this week's ORL Update. Sorry the newsletter was
not released last week due to logistic reason. I was
at Accra attending the WACS annual meeting. I do hope you find my picks
for this week exciting and useful |
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Biodun Olusesi,
Newsletter Editor |
CSF Dilution reduces Labyrinthitis Ossificans.......?
A recent UCSF Study examined the effect of
irrigation of the cerebrospinal fluid of
experimental gerbils who had induced streptococcal
meningitis and concluded that Irrigation of CSF
resulted in a significant reduction in
post-meningitic cochlear injury when compared to
controls. This EBM category 4 study was reported
by Yeung AH et al in the recent edition of
Otolaryngology - Head & Neck Surgery (Otolaryngol
Head Neck Surg. 2006 Feb;134(2):214-24.)
Abstract: OBJECTIVE: Labyrinthitis
ossificans, the pathologic ossification of the
otic capsule associated with profound deafness and
loss of vestibular function occurs frequently as a
sequella of bacterial meningitis and subsequent
purulent labyrinthitis. Experimentally, in
Streptococcus pneumoniae meningitis, it has been
shown that a vigorous inflammatory response to
teichoic acids in the bacterial cell wall
contributes to cochlear damage and subsequent
fibrosis and ossification. The hypothesis of this
study is that a dilution of concentration of
inflammatory mediators through cerebrospinal fluid
(CSF) irrigation will lead to a reduction in both
inner ear pathology and permanent hearing loss.
STUDY DESIGN AND SETTING: Auditory brainstem
response testing was used to determine baseline
hearing thresholds in 20 Mongolian gerbils (12
irrigated, 8 sham irrigated animals) at 32 kHz, 16
kHz, 8 kHz, and 4 kHz frequencies. Their
thresholds at 14 days and 120 days post-procedure
were also obtained. Streptococcus pneumoniae
meningitis was induced in both groups of animals
by intrathecal (i.t.) injection of bacteria. Both
groups received penicillin treatment. Forty-eight
hours after inoculation, both groups were
implanted with i.t. inflow and outflow catheters.
The irrigated group was infused continuously with
artificial CSF over 36 hr at a rate of 70 muL/hr
and the outflow sampled. The tubing in the sham
irrigated group was clamped (without sampling).
They were sacrificed at 120 days post-procedure
and histomorphometric analysis carried out. The
concentration of interleukin 1beta (IL-1beta) for
the CSF samples from the irrigated group were
compared to samples collected from an additional
control group of 8 non-irrigated meningitic
gerbils. IL-1beta was chosen to study because it
is a potent pro-inflammatory cytokines in
bacterial meningitis that is unaffected by the
neurosurgical trauma of the experimental protocol.
RESULTS: Twenty animals survived the meningitis (6
irrigation, 6 sham irrigation, 8 non-irrigation
meningitic controls). At Days 14 and 120
post-infection, the irrigated animals manifested
significantly less hearing loss with a mean loss
of 28.82 dB compared to the sham irrigation group
mean loss of 40.76 dB (P < 0.03). The degree of
hearing loss in both groups was
frequency-dependent with greater loss at higher
frequencies (mean loss = 22.4 dB at 32 kHz, 23.0
dB at 16 kHz, 18.6 dB at 8 kHz, and 12.5 dB at 4
kHz). Histomorphometric analysis demonstrated a
marked reduction in degeneration of the spiral
ligament, spiral ganglion cells, and stria
vascularis in experimental animals as compared to
controls. Immunohistochemistry showed a
significant reduction in IL-beta1 concentrations
in the irrigated animals compared to the
non-irrigated, infected controls (P < 0.03).
CONCLUSIONS: Irrigation of CSF resulted in a
significant reduction in post-meningitic cochlear
injury when compared to controls. This model for
continuous cerebrospinal fluid irrigation provides
a means to evaluate the effects of a dilution of
inflammatory mediators on hearing loss and
labyrinthitis ossificans after bacterial
meningitis. SIGNIFICANCE: Despite advances in the
prevention of meningitis and improved antibiotic
treatment, bacterial meningitis continues to have
significant associated morbidity. This study
provides insight into some of the mechanisms
responsible for post-meningitic hearing loss and
labyrinthitis ossificans and presents a novel
approach to reduce these complications.
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TOP PICKS
 Steroid
+ Antibiotics reduces post meningitic cochlear injury
...?
Another study by Addison, Kim and Richter (
Laryngoscope. 2006 Feb;116(2):279-82) also utilized
experimental Mongolian gerbils post meningitic models
and concluded that Dexamethasone therapy in conjunction
with antibiotic therapy preserves cochlear function in
cases of S. pneumoniae meningitis in these models
Abstract: OBJECTIVE/HYPOTHESIS:: The objective
of the present study was to determine whether treating
pneumococcal meningitis with a combined antibiotic and
steroid regime will prevent cochlear damage, a common
pneumococcal meningitis side effect. STUDY DESIGN:: This
was a prospective animal study. METHODS:: Gerbils were
randomly assigned to three experimental groups. Animals
in group 1, the control animals, received intrathecal
saline injections. Animals in groups 2 and 3 received
intrathecal injections of Streptococcus pneumoniae to
induce meningitis. Although group 2 solely was treated
for 7 days with intraperitoneal penicillin injections
(48,0000 units), group 3 received, in addition to the
antibiotic for 4 days, 0.5 mg/kg intraperitoneal
dexamethasone injections. Three months after the
meningitis was induced, the animals' cochlear function
was determined using auditory brainstem responses (ABRs).
Fifteen frequencies were tested, five octaves at three
steps per octave between 2 and 50 kHz. RESULTS:: ABR
thresholds were significantly elevated only in group 2.
When compared with group 1, ABR thresholds were 19 dB
higher (P < .05). Frequencies at the low-frequency end
of the hearing range were affected more than the
midfrequencies. Animals that received dexamethasone had
2-dB higher thresholds than the control group (P > .05).
CONCLUSIONS:: Dexamethasone therapy in conjunction with
antibiotic therapy preserves cochlear function in cases
of S. pneumoniae meningitis in the Mongolian gerbil
model
Coming Events of Importance to Otolaryngologists in
Africa...
-
BRITISH
ACADEMIC CONFERENCE IN OTOLARYNGOLOGY - Humanitarian
Award, 2006. For Details
click
HERE
- Annual West Africa
College of Surgeons Conference, Accra, Ghana, Feb
2006.
-
Association of Paediatric Otolaryngologists of
India 12th Annual Conference and CME in Paediatric
Otolaryngology
February 25-26, 2006; New Delhi, India
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8th International Otology Course of the Jean Causse
Ear Clinic
June 22-24, 2006; Béziers, France
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110th American Academy of ORL,Head & Neck Surgery
Annual Meeting & OTO EXPO
September 17-20, 2006;
Toronto, Canada.
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42nd South African ENT Congress joint meeting with
the British Association of Otolaryngology - Head &
Neck Surgery
October 29-November 1, 2006;
Cape Town, South Africa.
For more Worldwide otolaryngological events and conferences....Click
Here
Middle Ear Surgery and Anaesthesia.....?
A Turkish study (Ozturk O, Demiraran Y, Ilce Z et al;
Int J Pediatr Otorhinolaryngol.
2006 Feb 6) examined the effect of total
intravenous anaesthesia (TIVA) + Propofol Versus
Sevoflurane on middle ear pressure and concluded that
Sevoflurane may increase the middle ear pressure and
TIVA with propofol may be used in middle ear operations
more safely than sevoflurane.
 Abstract:
OBJECTIVE: To evaluate the effects of sevoflurane and
TIVA with propofol on middle ear pressure and to show
the importance of anesthesia without using any
inhalational agents during middle ear surgery. STUDY
DESIGN: A prospective, randomized controlled clinical
study. METHODS: In this study, 25 male children that
were scheduled for circumcision were randomised into two
groups. Group I (n=13) received TIVA with propofol and
group II (n=12) received sevoflurane. Baseline
tympanometry reading was performed on each ear just
before anesthesia. The next tympanometry reading was
taken 10min after applying the laryngeal mask. Data were
analysed by Mann-Whitney U (between groups) and Wilcoxon
tests (within groups). RESULTS: Mean MEP values in 26
ears of 13 boys in group I did not show any significant
difference before and after the anesthesia with propofol
(p>0.05). In group II mean MEP values in 24 ears of 12
boys showed a significant increase after the anesthesia
with sevoflurane (p<0.001). No significant difference
was found between the MEP values of the two groups
before the anesthesia (p>0.05), and MEP values measured
during the anesthesia were significantly higher in group
II (p=0.007). CONCLUSION: Sevoflurane may increase the
middle ear pressure and TIVA with propofol may be used
in middle ear operations more safely than sevoflurane
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CLINICAL PHOTO OF THE WEEK |
 A
30-year old male presented with recurrent painful
swelling on the left side of his face. He
occasionally experiences left rhinorrhoea
associated with intermittent relieve of anterior
facial swelling and pain. The
clinical examination revelaed the finding (white
arrows) seen on this
picture.
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What is the diagnosis?
- Parting Shot...
If you have an interesting
case to discuss or share with other Otolaryngologists
all over Africa, feel free to email
Me or at best go to
otolaryngology in Africa blogsite
and post your case
- Also, if you are among those who requested for a copy
of DODA at the last ORLSON Meeting @ Port Harcourt,
please take time to view the
DODA - FAQ page,
you should have received your copy by now. If you have
difficulty on using the program, please text
+2348032472069.
- An online video demonstration of doda is available
at
http://www.otolaryngologyinafrica.net/doda_video.htm
This
video takes about 30 - 45 minutes to fully load on a
broad band network the first time, but once fully
loaded could be viewed over and over again
- It appears as if the website of ORLSON -
http://www.orlson.org/ is no longer active
or visible on the web! Please For a list of active web
sites of otolaryngological societies in Africa, click
HERE
- If you have anything you want to communicate with
other Otolaryngologists - news, request, etc, feel
free to email your communication to
orl-mailer@
otolaryngologyinafrica.net.
Your request will appear in member's page soon to be
created.
- Reviewers wanted for otolaryngology news journals
watch page. If you are an Otolaryngologist in Africa
and will like to be our journal reviewer, please feel
free to email
orl-mailer@otolaryngologyinafrica.net
Till Next Week,
Biodun
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© Copyright Dr 'Biodun
Olusesi,
2005 - 2006 |
