This site will help students of otolaryngology in their exam preparations. Various important topics in otolaryngology will be discussed here.
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Sunday, 25 December 2011
Tuesday, 20 December 2011
Monday, 19 December 2011
Thursday, 15 December 2011
Monday, 12 December 2011
Sunday, 27 November 2011
Eosinophlic oesophagitis
Introduction:
Eosionophlic
oesophagitis 1 is a relatively new disease entity. It is
characterised by chronic / intermittent dysphagia, reflux like
symptoms and intermittent oesophageal food impaction.
This condition
was first reported by Landres in 1978 2. In 1993 Attwood
and DeMeester reported 12 cases of dysphagia with no evidence of
anatomic obstruction. They also reported dense eosinophilic
infiltrates in the oesophagus. Attwood hence applied the criteria of
presence of more than 20 eosinophils / high power field as
histological criteria for diagnosing this condition 3.
Incidence:
True incidence
of this disorder is still uncertain 4. Review of
literature puts this figure as high as
1% 5.
It is more common in men than in women. Male : female ratio is 3:1.
Age of presentation may vary between 2nd – 4th
decades.
Conditions
associated with oesophageal eosinophilia:6
- Eosinophlic oesophagitis
- GERD
- Collagen vascular disorders
- Parasitic infections
- Eosinophlic gastroenteritis
Pathophysiology
of eosinophlic oesophagitis:
- This is a primary disorder involving oesophagus
- Biopsy of oesophageal mucosa should contain atleast 50 eosinophils / high power field.
- There should not be associated eosinophlic infiltration of stomach / intestine.
- Eosinophlic microabscess can be see in the oesophagus extending up to its lumen
- The caliber of oesophageal lumen is drastically reduced.
- Asthma / atopia +
- Peripheral eosinophilia common
Endoscopic
features:
Linear
furrowing of oesophageal mucosa.
Presence of
white plaques / exudates
Presence of
concentric rings / strictures of oesophageal mucosa.
Appearance of
crepe paper mucosa is diagnostic.
Multiple
biopsies should be studied before a categorical diagnosis of this
condition could be made. Multiple biopsy specimen increases the
accuracy of diagnosis.
Diagnosis of
eosinophlic oesophagitis should not be made until GERD has been
categorically ruled out by performing ambulatory pH testing or
performing repeat biopsy after a 8 week trial course of proton pump
inhibitor.
Clinical
features:
- Abdominal pain
- Chest burns
- Dysphagia
- These patients are very slow eaters
Classification
of eosinophlic oesophagitis:
Vasilopoulous 7
proposed the first classitication of eosinophilic oesophagitis.
Type I : Early
small caliber oesophagus
Type II:
Advanced small caliber oesophagus
Type III:
Ringed oesophagus
Managment:
- Avoidance of food allergen
- Topical steroids
- Oral steroids
- Leukotriene inhibitors
Oesophageal
dilatation is reserve for patients with extreme dysphagia
References:
1.
Furuta GT, Liacouras CA, Collins MH, et al. Eosinophilic esophagitis
in children and adults: a systematic review and consensus
recommendations for diagnosis and treatment. Gastroenterology.
2007;133:1342-1363.
2.
Landres RT, Kuster GGR, Strum WB. Eosinophilic esophagitis in a
patient with vigorous achalasia. Gastroenterology 1978;74:1298-1301.
3.
Attwood SEA, Smyrk TC, DeMeester TR, et al. Esophageal
eosinophilia
with dysphagia: a distinct clinicopathological syndrome.
Dig Dis
Sciences 1993;38:109-116.
4.
Ronkainen J, Talley NJ, Aro P, et al. Prevalence of
oesophagealeosinophils and eosinophilic oesophagitis in adults: the
population-based Kalixanda study. Gut. 2007;56:615-620.
5.
Arora AS, Yamazaki K. Eosinophilic esophagitis: asthma of the
esophagus? Clin Gastroenterol Hepatol 2004;2:523-530.
6.
Rodrigo S, Abboud G, Oh D, et al. High intraepithelial Eosinophil
counts in esophageal squamous epithelium are not specific for
eosinophilic esophagitis in adults Am J Gastroenterol
2008;103:435-
442.
7.
Vasilipoulos S, Shaker R. Defiant dysphagia: small-caliber esophagus
and refractory benign esophageal strictures. Current
Gastroenterology
Reports 2001;3:225-230.
Wednesday, 16 November 2011
Esthesioneuroblastoma
Introduction:
This tumor
arises from the olfactory nerve. These are rare malignant tumors
arising from the olfactory epithelium situated at the roof of the
nasal cavity, cribriform plate, upper portion of supeior turbinate
and corresponding upper portion of nasal septum. These tumors
typically involve the upper portion of nasal cavity and the
cribriform plate area. These tumors classically arise from the basal
cells of olfactory neuroepithelium. No clearl cut genetic / other
causes have been attributed for this tumor. This tumor represents
about 3% of all malignant tumors involving the nasal cavity.
This tumor
was first reported by Berger etal in 1924. Since then only less than
1000 cases have been reported in literature.
Incidence:
Affects both
male and female patients with equal frequency.
Age incidence
shows a bimodal peak (peaking at the second and the sixth decades of
life).
Etiopathogenesis
(theories):
- Belongs to peripheral neuroectodermal family. (Not supported by immunohistochemistry)
- Presence of Trisomy 8 has been documented in these tumor cells
None of these
theories convincingly explain etiopathogenesis of this tumor.
Clinical
features:
This tumor
classically involves the nasal cavity with extension into the ethmoid
sinus, anterior skull base and orbit. Since these tumors are very
aggressive ones they tend to metastasize extensively. Spread to
cervical nodes are common. Retropharyngeal nodes are the first
echelon node. Rarely these tumors may be active in an endocrine
sense. These tumors have known to cause ectopic secretion of ACTH
causing Cushing's syndrome.
Common
presenting symptoms were usually associated with the nasal cavity:
- Nasal block
- Epistaxis
- Anosmia
Staging system:
Staging a tumor
helps in deciding the optimal management modality and also in
determining the prognosis of the disease.
Kadish staging
system:
This system
stages Esthesioneuroblastoma into three stages:
Stage A: Tumor
limited to nasal cavity
Stage B: Tumor
extending to paranasal sinuses
Stage C: Tumor
extending beyond paranasal sinuses
Major
inadequacy of this staging system is too broad a staging at the level
of Stage C.
Modified TNM
staging system:
Tumor
T1 – tumor
involving nasal cavity and / or paranasal sinuses (excluding
sphenoid) sparing most of the superior ethmoidal cells
T2- tumor
involving nasal cavity and / or paranasal sinuses including sphenoid
with extension to the cribriform plate
T3 – tumor
extending to orbit with involvement of extradural anterior cranial
fossa
T4 – tumor
involving brain
Node
N0 – No nodal
metastasis
N1 – any form
of nodal metastasis
Metastasis
M0 – No
metastasis
M1 –
Metastasis present
Hyam came out
with a histopathological grading system which turned out to be more
accurate than the preceding two staging systems.
Hyam's
Histopathological grading system
Grade
|
LA preservation
|
Mitotic index
|
Nuclear polymorphism
|
Fibrillary matrix
|
Rosettes
|
Necrosis
|
I
|
+
|
Zero
|
None
|
Prominent
|
HW
|
None
|
II
|
+
|
Low
|
Low
|
Present
|
HW
|
None
|
III
|
+/-
|
Moderate
|
Moderate
|
Low
|
FW
|
Rare
|
IV
|
+/-
|
High
|
High
|
Absent
|
None
|
Frequent
|
Fw –
Flexner-wintersteiner
HW – Homer –
Wright
Management:
This tumor is
managed with wide surgical resection with adequate tumor margins.
Radiotherapy is indieated as primary treatment modality in
unresectable tumors and as a follow up to surgical debulking.
Friday, 4 November 2011
Tuesday, 1 November 2011
Pathophysiology of allergic fungal sinusitis
Introduction:
Allergic fungal
sinusitis is known to cause extensive sinonasal polyposis. This
article discusses the pathophysiologic mechanisms involved. Studies
have revealed that this is a form of non invasive fungal sinusitis
causing sinonasal polyposis. Hypersenstivity to fungus has been
implicated as the probable cause. Hypersensitivity to Aspergillus /
dematiaceous fungi (this group of fungi secrete melanin in their cell
walls) have been commonly implicated to the cause.
Role of
hypersensitivity:
Eventhough
hypersensitivity to fungus has been implicated as the cause for
allergic fungal sinusitis the precise nature of this hypersensitivity
is still not clear. Studies reveal that patients with allergic
fungal sinusitis show elevated levels of IgE and IgG to fungal
proteins. Hence a combination of Coomb's Type I and Type III
hypersensitivity to these fungal allergens could play a role.
Type I
hypersensitivity reaction is rather immediate and is caused by IgE
and IgG4 immunoglobins.
Type III
hypersensitivity reaction is known to be causeed by immune complex
formation and is caused by IgG and complements.
Current
hypothesis suggests that allergic fungal sinusitis develops in
susceptible persons due to a combination of local anatomic as well as
environmental factors. Fungi enter the nose and trigger immune
response causing inflammatory changes. This inflammation induces
polyp formation and accumulation of allergic mucin. Fungi which are
trapped within the mucosa of nasal cavity causes continuing
stimulation of immune reaction causing a vicious cycle leading on to
extensive nasal polyp formation.
Saturday, 29 October 2011
Diagnostic criteria of Allergic fungal sinusitis
Introduction:
Diagnosis of
allergic fungal sinusitis is made from a combination of clinical,
radiological, microbiologic and histopathologica information. Hence
the diagnosis of allergic fungal sinusitis cannot be made with
certainty till surgery is over.
Diagnostic
criteria include:
- Presence of allergic mucin: Allergic mucin is thick tenacious and dark colored. It is very difficult to remove this secretion with a suction. When suction is applied it resembles an elastic strand of tissue. In rare cases this allergic mucin may assume the shape of fungal ball. Microscopically allergic mucin contains onion skin laminations of necrotic and degranulating eosinophils on mucin background. Occasionally charcot layden crystals can also be seen. Fungal hyphae may be present but are scarce. Fungal stains are necessary to demonstrate these hyphae. These hyphae don't invade tissue. If evidence of tissue invasion is present then diagnosis of allergic fungal sinusitis should not be entertained.
- Presence of nasal polypi with evidence of eosinophilic inflammatory infiltrate.
- Evidence of Type I hypersensitivity
- Imaging: CT scan paranasal sinuses reveal multiple opacified sinuses with central hyperattenuation, mucocele formation, erosion of lamina papyracea / skull base, pushing borders. Bone erosion in patients with nasal polyposis should raise suspicion of allergic fungal sinusitis
Role of MRI in
the diagnosis of AFRS:
This is
indicated when there are intracranial and orbital complications due
to allergic fungal sinusitis. MRI reveals central low signal on T1
and T2 weighted images. These areas correspond to allergic mucin
associated with peripheral high signal intensity due to the presence
of oedematous mucosa.
Friday, 28 October 2011
Drainage system of paranasal sinuses a review
Introduction:
Study of
drainage system of paranasal sinuses is important in the present day
context of Functinal endoscopic surgery and Baloon dilatation
techniques in managing sinus infections and ostial obstruction.
These minimally invasilve tools have thrown further light into the
drainage pattern of various paranasal sinuses.
The
following are the documented various racial variations:
- The volume of maxillary sinus varies between races and sexes
- White population has a higher incidence of concha bullosa of middle turbinate and paradoxical bending of middle turbinate when compared to that of other races
- Infra orbital / suprabullar cells are commonly seen in white races
- Sphenoethmoidal cells are commonly seen in chinese
- Bent uncinate process and complete absence of sinuses are common in chinese
Studies
have revealed extensive intercommunication between various paranasal
sinuses. It can be safely construed that all paranasal sinuses in
addition to their major drainage channel also contains openings
connecting one with the other.
Development
of nose and paranasal sinuses:
Study
of embryology of nose and paranasal sinuses will go a long way in
enhancing our understanding of the drainage patterns of various
paranasal sinuses. The whole nasal cavity and adjoining paranasal
sinuses develop from a cartilagenous anlage called the nasal capsule.
This nasal capsule appears between the 7th
and 8th
weeks of embryonal life. The first area where this cartilage begins
to develop is in the nasal septal area. The lateral nasal wall
develops much later. The following are the chronology of development
of lateral nasal wall:
- The cartilage of inferior turbinate develops during the 8th week of gestation
- Middle turbinate begins its development during the 9th week of gestation
- Superior turbinate begins to develop during the 12th week of gestation.
- Uncinate begins to develop during the 9th week
- Ethmoidal bulla begins its development during 12th week
- Anterior ethmoidal cells starts their develoment during 22nd week
- Posterior ethmoid cells begin their development during 40th week
The
nasal capsule has tight connections to its surroundings, especially
to the cartilagenous anlage of body and minor ala of sphenoid bone.
This factor helps in the normal development of sphenoid bone thus
ensuring normal develpment of sphenoid sinus.
Expansion
of mucous membrane forms the paranasal sinuses. The first air filled
sacs in the ethmoid bone begins from the bulla ethmoidalis area.
Bulla ethmoidalis gives rise to anterior and middle ethmoid air
cells. Ventral to anterior ethmoidal cells the developing primordial
ethmoidal infundibulum extends infero laterally towards the
inferiorly placed precursor of maxillary bone. This forms the
primordial maxillary sinus. At birth only the ethmoid and rudimental
maxillary sinus are present. The frontal and sphenoid sinus develops
after birth due to gradual pneumatization of frontal and sphenoid
bones respectively.
During
the process of pneumatization mucous membranes encounter each other.
When this happens the underlying mesenchymal layer may disappear
causing intersinus communications to form. Eventhough these channels
of communication plays very little role in ventilation and drainage
of sinuses infections can spread to other sinuses via these channels.
Drainage
pathways of paranasal sinuses:
Frontal
sinus: May show three types of drainage patterns.
- Direct drainage via frontal recess
- Drainage via ethmoido nasal route
- Drainage via ethmoido maxillar route
Multiple
drainage patterns are commonly seen in frontal sinus. Direct
drainage is seen only in a fraction of patients. If the frontal
sinus drains directly via frontal recess presence of anterior
ethmoidal cells can cause obstruction to drainage of frontal sinus
leading on to frontal sinus infection.
Ethmoidal
cells:
These
cells drain directly via upper / middle meatus.
These
cells may share common drainage channel with maxillary sinus
These
cells may drain via maxillary sinus
Sphenoid
sinus:
Drains
directly into the nasal cavity.
Coronal
view showing various drainage patterns
- Natural ostium / accessory ostium of maxillary sinus
- Maxilloethmoid nasal route
- Nasal ostia of ethmoidal sinus
4a. Ethmoideo-nasal route
4b. Ethmoideo-maxillary route
Saggital
view showing the drainage patterns of paranasal sinuses
Fs
– Frontal sinus
Ms-
maxillary sinus
Ss-
Sphenoid sinus
The
following points should be borne in mind before performing Balloon
sinuplasty / FESS procedures for chronic sinus infections:
- Accessory sinus ostia exist for each paranasal sinuses
- Many sinuses do not drain directly into the nasal cavity but indirectly drains via adjacent sinuses. For example sphenoid sinus drains both via posterior ethmoidal cells and directly into the nasopharynx.
- Major drainage pathway of frontal sinus is over the ethmoidal sinus, via the ethmoids into the maxillary sinus and then into the nasal cavity
- These pathways are not normally accessible during normally performed endonasal surgeries. Inadvertant manipulation can cause fractures of thin septa between these sinuses thereby impairing normal drainage patterns
- Presence of secondary / accessory ostia is a definite sign of chronic sinus infection
- Presence of accessory / secondary ostia ensures recirculation of mucous due to mucociliary mechanism which tends to beat towards the natural ostium
- If accessory ostium is present Balloon sinuplasty invariable ends up dilating the accessory ostium instead of natural one.
It
makes real sense if these drainage patterns could somehow be
ascertained prior to surgical procedure instead of performing blind
dilatation.
Courtesy drtbalu's otolaryngology online
Thursday, 27 October 2011
Online journal of otolaryngology
Introduction:
Publishing an article in an indexed journal is a patience testing process which involves lot of expenditure also. This online journal of otolaryngology makes the whole process of article publishing a little easier and totally expense free procedure. This journal has been started with the only intention to help out the potential publisher.
This journal will publish articles submitted by you after subjecting them to peer review which is the standard in medical journal publishing.
How to submit article to this journal?
You can go through the entire tutorial of article submission from here:
You can enter the website by clicking the image below:
Publishing an article in an indexed journal is a patience testing process which involves lot of expenditure also. This online journal of otolaryngology makes the whole process of article publishing a little easier and totally expense free procedure. This journal has been started with the only intention to help out the potential publisher.
This journal will publish articles submitted by you after subjecting them to peer review which is the standard in medical journal publishing.
How to submit article to this journal?
You can go through the entire tutorial of article submission from here:
You can enter the website by clicking the image below:
Monday, 24 October 2011
Saturday, 22 October 2011
Anatomy of chordatympani nerve
Introduction:
The chorda
tympani nerve is a branch of facial nerve. It exits the facial nerve
just before it exits via the stylomastoid foramen. It is one of the
three cranial nerves that is involved in transmission of taste fibers
from the tongue. Chorda tympani nerve conveys taste fibers from the
anterior 2/3 of tongue. Mechanism of taste sensation is rather
unique in that it involves a complicated feed back loop with each
nerve acting to inhibit the signal of other nerves. The chorda
tympani exerts stong inhibitory influence on other taste fibers as
well as pain fibers from the tongue. When chorda tympani nerve is
damaged its inhibitory function is disrupted, causing the other taste
fibers to act in an uninhibited manner.
The chorda
tympani nerve carries with it two types of fibres which traverse via
lingual nerve to reach their destination. These fibers include:
- Special sensory fibers providing taste sensation from anterior 2/3 of tongue.
- Presynaptic parasympathetic fibers to submandibular ganglion providing secretomotor fibers to submandibular and sublingual salivary glands
- Presynaptic parasympathetic fibers is also supplies the blood vessels of the tongue. When stimulated the chorda tympani nerve causes dilatation of blood vessels of the tongue.
Central
connections:
Chorda tympani
nerve contains fibers from two brain stem nuclei. They are:
Superior
salivatory nucleus: This nucleus houses cell bodies of secretomotor
preganglionic parasympathetic neurons
Nucleus of
tractus solitarius: The superior portion contributes to chorda
tympami fibers. It receives central processes of taste neurons which
have their cell bodies in the ganglia of the three cranial nerves
conveying taste sensation. After synapsing in this nucleus secondary
axons ascend in the lateral lemniscus to relay in the thalamus. This
pathway then passes through the posterior limb of internal capsule to
reach the primary gustatory cortex.
Connections
seen within the facial canal:
Sensory branch
of facial nerve Nervus intermedius of Wrisberg joins the facial nerve
here. It conveys special sensory fibers from taste buds present in
the anterior 2/3 of tongue and soft palate. It also contains
secretomotor fibers to salivary glands present below the oral cavity.
Nerves intermedius exits the brain stem adherent to the vestibuo
cochlear nerve. At the level of internal auditory meatus it leaves
this nerve to merge with that of facial nerve.
Chorda tympani
nerve exits from the facial nerve before the facial nerve exits via
the stylomastoid foramen. It is the largest branch of facial nerve
in its intrapetrous compartment. It arises below the nerve to
stapedius. It traverses antero superiorly via the posterior
canaliculus usually accompanied by posterior tympanic branch of
stylomastoid artery. This canaliculus opens into the middle ear
cavity through an aperture situated at the junction of posterior and
lateral walls of tympanic cavity. This opening lies just medial to
the fibrocartilagenous annulus. The posterior canaliculus is roughly
0.5 mm in diameter. Chorda tympani nerve shows a large number of
variations. In some patients the chorda tympani nerve may arise from
more proximal portion of facial nerve, even close to the geniculate
ganglion. The length of the posterior canaliculus is also highly
variable ranging from 3 – 14 mm. In 10% of individuals there may
not be a posterior canaliculus at all but could be replaced by a
groove.
If the chorda
tympani nerve originates outside the temporal bone then the posterior
canaliculus will be separate from that of the facial nerve canal.
In fetus and young infants the chorda tympani nerve leaves the facial
nerve outside the skull, but the postnatal growth of mastoid process
causes it to migrate to a more proximal position. Since the facial
canal grows more than the mastoid segment of facial nerve the chorda
tympani nerve typically diverges from the facial nerve in an infant
of 1 yr of age.
Course of
chorda tympani in the tympanum:
The chorda
tympani arches across pars flaccida medial to the upper part of the
handle of malleus and traverses above the insertion of tensor
tympani. In patients with congenital anamolies of malleus chorda is
also displaced laterally.
Chorda tympani
nerve exits the middle ear via a separate bony canal, the anterior
canaliculus also known as the canal of Hugier. This canal runs in
the medial portion of petrotympanic fissure. Anterior tympanic
branch of maxillary artery accompanies this nerve along this canal.
Chorda exits the skull through a small foramen behind the base of
spine of the sphenoid. At its exit it is closely related to the
medial surface of temporomandibular joint.
Course of
Chorda in the infratemporal fossa:
In the
infratemporal fossa the chorda tympani nerve descends medial to the
spine of sphenoid and angles forward to join the lingual nerve about
2 cms below the skull base. This junction lies close to the lower
border of lateral pterygoid muscle.
Diagram
showing relationship of chorda to middle ear structures
Functions of
chorda tympani nerve:
- It carries taste sensation from the anterior 2/3 of tongue
- Supplies secretomotor fibers to the salivary glands in the floor of the mouth
- Conveys general sensation from the anterior 2/3 of tongue which includes pain and temperture
- Supplies secretomotor fibers to the parotid gland
- Supplies efferent vasodilator fibers to the tongue
Friday, 21 October 2011
BIPP Pack
Introduction:
Bismuth iodine
paraffin paste is routinely used to pack nasal cavities. This was
first used by James Morrison Rutherford Professor of surgery Durham
to dress first world war soldier's wounds.
BIPP Pack:
This is a
sterile gauze (ribbon) impregnated with a paste containing:
- one part bismuth subnitrate
- Two parts iodoform
- One part sterile liquid paraffin by weight
Role of Bismuth
subnitrate:
It is a topical
astringent and antiseptic. It is soluble in weak acid but insoluble
in water and alcohol. It contributes to the antibacterial properties
of BIPP pack by releasing dilute nitric acid on hydrolysis.
Bismuth is not
completely safe from complications. It is considered to be less
toxic than antimony and polonium. It has a half life of 5 days in
the body but is known to remain in kidney for a long time. Bismuth
can cause neurotoxicity because it is known to interfere with
oxidative metabolism of brain. This complication is very rare when
BIPP pack is used to pack the nasal cavity.
Symptoms of
Bismuth toxicity:
- Head ache
- Nausea
- Stomatitis
- Bismuth line in the gingiva (Bismuth line)
Absorption of
bismuth is more when packing is made on tissues that has already been
injured. Hence considerable amount of caution should be exercised
before repeated nasal packing due to epistaxis.
Iodoform:
Its chemical
name is triiodomethane.
This is another
component of BIPP pack. It has a dinstinctive color and smell. It
is insoluble in water and is highly soluble in chloroform / ether.
Iodoform decomposes to release iodine which is an antiseptic. Iodine
toxicity is common when BIPP packing is used to pack large wounds.
Paraffin:
Serves to
lubricate the area packed. It minimizes trauma which could occur
during packing.
Uses of BIPP
Packs:
- Used to pack ears following surgery
- Used to pack nasal cavities after nasal surgeries
Bismuth is
radio opaque. BIPP packs also contain a radio opaque marker strip
which makes its identification easier when it is lost inside the
cavities. Plain radiograph of the area is sufficient to identify the
pack.
Thursday, 20 October 2011
Chronic otitis externa
Introduction:
Chronic otitis
externa is a chronic inflammation involving the skin lining of the
external auditory canal of unknown etiology. Diverse mechanisms from
allergy to autoimmune reaction has been implicated. Things which are
pretty clear about this condition are that:
- It is not acute & painful as acute otitis externa
- It is not an invasive condition involving the skull base (like malignant otitis externa)
Characterstic
features:
- It waxes and wanes showing intervening periods of remissions and exacerbations affecting the quality of life
- It is bilateral in more than half of these patients
- Pruritis is common
- Clear / seromucinous discahrge is seen during periods of exacerbations
- Aural fullness is also common
Two types of
chronic otitis externa have been encountered.
Chronic otitis
externa with seborrhoea:
This condition
is characterised by lack of cerumen. These patients may have clear
ear discharge, sometimes this discharge could be seen admixed with
white flakes. The skin lining the external canal may be erythematous
and shiny in appearance.
Chronic
exematous otitis externa:
This condition
is characterised by weepy, moist, erythematous and tender skin in the
external auditory canal. It can also spread to involve the pinna
causing perichondritis.
Causes of
chronic otitis externa:
- Allergy
- Contact dermatitis
- Wegner's granulomatosis
- Reduced cerumen production
- Cerumen produced ineffective against pathogens ?
Studies also
reveal that the relative humidity is higher and pH is also higher in
these ears. If pH could be lowered it would make the environment
inhospitable for pathogens.
Role of
Dermatophytid reaction in chronic otitis externa:
Low grade
fungal infections elsewhere in the body can set up inflammatory
allergic reaction in the skin lining the external auditory canal.
Hence it is worthwhile making a meticulous search for the presence of
fungal infections elsewhere in the body and treating it aggressively.
Yeast elimination from diet is strongly advocated. If serum IgE is
elevated then immunotherapy could be considered.
Management:
- Removal of all / potential irritants
- Topical steroid therapy
- A course of oral steroid can be administered in refractory cases
- Topical application of 1% Tacrolimus ( a nonsteroidal immunosuppresant) has been used with reasonable success
Monday, 17 October 2011
Grommet insertion Revised indication guidelines
Introduction:
Myringotomy
with grommet insertion was introduced by Poltizer of Vienna in 1868.
He used this procedure to manage “Otitis media catarrhalis”.
Soon it became the common surgical procedure performed in children.
Indications:
Bluestone and
Klein (2004) came out with revised indications for grommet insertion
which took into consideration the prevailing antibiotic spectrum.
- chronic otis media with effusion not responding to antibiotic medication and has persisted for more than 3 months when bilateral or 6 months when unilateral.
- Recurrent acute otitis media especially when antibiotic prophylaxis fails. The minimum episode frequency should be 3/4 during previous 6 months / 4 or more attacks during previous year.
- Recurrent episodes of otitis media with effusion in which duration of each episode does not meet the criteria given for chronic otitis media but the cumulative duration is considered to be excessive (6 episodes in the previous year)
- Suppurative complication is present / suspected. It can be identified if myringotomy is performed.
- Eustachean tube dysfunction even if the patient doesnt have middle ear effusion. Symptoms are usually fluctuating (dysequilibrium, tinnitus, vertigo, autophony and severe retraction pocket).
- Otitis barotrauma inorder to prevent recurrent episodes.
Problems with
Grommet insertion:
This procedure
is not without its attendant problems. Common problems include:
- Segmental atrophy of tympanic membrane
- Tympanosclerosis
- Persistent perforation sydrome (rare)Before treating patients with otitis media with effusion the following factors should be borne in mind.
Pneumatic
otoscopy should be used to differentiate otitis media with effusion
from acute otitis media.
Duration of
symptoms should be carefully documented.
Children with
risk for learning / speech problems should be carefully identified.
Hearing should
be evaluated in all children who have persistent effusion for more
than 3 months.
Grommet
insertion can be performed under local anesthesia.
Incision is
made in the antero inferior quadrant of ear drum. The incision is
given along the direction of radial fibers of the middle layer of ear
drum. This causes minimal damage to the radial fibers. It also
enables these fibers to hug the grommet in position.
Sunday, 16 October 2011
Management of vestibular schwannomas current trends
Introduction:
Management
of vestibular schwannomas has undergone lots of changes during the past
decade. Review of published literature
exemplifies this fact. Various currently
available management modalities to treat this condition are:
1. Observation
2. Stereotactic radiosurgery
3. Microsurgery
Among these
three modalities stereotactic radiosurgery is evincing keen interest because of
the precision of the procedure and lesser incidence of side effects. Advances in imaging technology have enabled
early diagnosis of these lesions. About
a decade back the sensitivity of imaging techniques used to identify lesions
measuring 30 mm. Recent imaging modalities
are accurate enough to identify even lesions measuring less than 10 mm. A stage has reached when surgeons are
managing more intracanalicular lesions than ever before.
The current
management modality of these tumors focusses on:
Preservation
of hearing
Preservation
of facial nerve functions.
Observation
/ Watchful waiting: This modality is
preferred in managing patients with small asymptomatic / minimally symptomatic
intracanalicular tumors. Since tumor
doubling time of these lesions is prolonged (1-2 mm / year) this method
warrants a trial. Advantages of this
method are preservation of hearing and facial nerve function in these
patients. Studies have also revealed
that growth rates between intracanalicular and extracanalicular tumors are not
significantly different. It is ideal to
perform imaging at least twice a year within the first year of diagnosis and
once a year from there on.
Positive
features that could warrant this management modality include:
1. Excellent speech discrimination
scores
2. Growth rate of less than 2.5 mm /
year
Microscopic
surgery:
This is
indicated for small intracanalicular lesions with vestibular symptoms. Amount of tumor growth also is one important
factor that could force the hands of a surgeon.
Growth rate of more than 3mm / year is an indication for surgical
intervention. Hearing can be conserved
by using retrosigmoid / middle cranial fossa approach.
Stereotactic
radiosurgery:
This is
indicated in residual lesions after microscopic excision or rapidly enlarging
canalicular lesions. Advantages of radiosurgery
include:
1. Hearing preservation
2. Conservation of facial nerve function