Wednesday, November 30, 2011

Eosinophilic otitis media a literature review


Abstract:
Eosinophilic otitis media is actually a recent introduction. These patients may manifest with sudden hearing loss. There may be associated bronchial asthma and allergic rhinitis. Diagnostic criteria of this condition are rather vague. A review of literature shows that demonstration of eosinophils in the middle ear secretion of these patients could be considered to be pathognomonic of this condition.



Introduction:

Eosinophils are considered to be effectors for allergic reactions. Eosinophilic otitis media 1 is a newly recognised entity causing intractable middle ear pathology. This condition is characterised by excessive accumulation of eosinophils in the middle ear cavity and is associated with persistent middle ear effusion. These patients usually suffer from bronchial asthma. The first description of this condition should be credited to Koch 2 who first reported some patients with middle ear effusion which contained lots of eosinophils. He also added that these secretions were highly viscous and the middle ear mucosa was pinkish in color. The term eosinophilic otitis media was coined by Tomioka et al 3 in 1993.

Pathophysiology:
Pathophysiology of this condition is obviously allergy. These patients commonly had associated allergic rhinitis and branchial asthma. Eosinophils could have been probably attracted to the middle ear cavity by the presence of IL 5 4 inside the middle ear cavity.

Features of Eosinophilic otitis media 5:

  1. Sudden deterioration of hearing
  2. Bronchial asthma
  3. Allergic rhinitis
  4. Intractable otitis media
  5. Persistent otorrhoea


Incidence:

Incidence of eosinophlic otitis media is not clearly known. Literature search puts it to be rather common cause of otitis media with effusion.

Managment:

Patients diagnosed with this condition should be warned of the possibility of sudden deterioration of hearing.
Administration of systemic / topical steroids 6 could be of benefit in these patients.
Antihistamines and leukotreine receptor antogonists can also be used with benefit.
Grommet insertion is indicated in patients with acute sudden hearing loss.







References:

  1. Iino Y, Kakizaki K, Katano H, Saigusa H, Kanegasaki S. Eosinophil chemoattractant in middle ear patients with eosinophilic otitis media. Clin Exp Allergy 2005;35:1370–6.
  2. Koch H. Allergical investigations of chronic otitis. Acta Otolaryngol 1947;62(Suppl.):1–201.
  3. Tomioka S, Yuasa R, Iino Y. Intractable otitis media in cases with bronchial asthma. Recent advances in otitis media. In: Mogi G, HonjoI, Ishii T, Takasaka T, editors. Proceedings of the second extraordinary international symposium on recent advances in otitis media. Amsterdam, New York: Kugler Publications; 1993. p. 183–186.
  4. NonakaM, Fukumoto A, Ozu C, Mokuno E, Baba S, pawankar R, et al. IL-5 and eotaxin levels in middle ear effusion and blood from asthmaticswith otitis media with effusion. Acta Otolaryngol 2003;123:383–7.
  5. Suzuki H, Matsutani S, Kawase T, Iino Y, Kawauchi H, Gyo K, et al. Epidemiologic surveillance of ‘‘eosinophilic otitis media’’ in Japan. Otol Jpn 2004;14:112–7 (In Japanese).
  6. Iino Y, Nagamine H, Kakizaki K, Komiya T, Katano H, Saruya S, et al. Effectiveness of instillation of triamcinolone acetonide into middle ear for eosinophilic otitis media associated with bronchial asthma. Ann Allergy Asthma Immunol 2006;97:761–6.

Monday, November 14, 2011

VOL 1, NO 1 (2011) ONLINE JOURNAL OF OTOLARYNGOLOGY ISSN 2250- 0359

First volume of Online journal of otolaryngology (JORL) is given here. VOL 1, NO 1 (2011) ONLINE JOURNAL OF OTOLARYNGOLOGY ISSN 2250- 0359

Friday, November 04, 2011

Online journal of otolaryngology (JORL) First issue

First issue of online journal of otolaryngology (JORL) is available.  This free to access and free to publish e journal will be published 4 times a year.  You can start submitting  your work to the next issue right now following author submission guidelines mentioned in the website.

Just click on the image below to access the first issue of the journal.





Saturday, October 29, 2011

Retrotympanic Recesses


Introduction:

The posterior wall of middle ear cavity (Tympanum) is also known as retrotympanum. Important anatomic structures are lodged in this area. This area has assumed significance because of the difficulties encountered in clearing cholesteatoma from this area. This area is so narrow and has lot of crevises, it is very difficult to clear disease from this area.
This area is supposed to contain 4 important recesses. Each of these four recesses could hide cholesteatoma causing the surgeon to leave residual disease which could later recur. Precise knowledge of anatomy of this region is vital for the surgeon who wants to clear disease from this area. The recesses present in the retrotympanic area are:

  1. Sinus tympani
  2. Lateral tympanic sinus
  3. Posterior tympanic sinus
  4. Facial recess
Pyramidal eminence is the most prominent anatomical landmark of this area. This eminence hold the pyramidalis muscle. There are other prominences arising from this area projecting in various directions. They include:

  1. External: Chordal ridge
  2. Inferior: Pyramidal ridge
  3. Superior: Suprapyramidal ridge
  4. Internal: Ponticulus

The 4 types of retrotympanic recesses are found under these eminences.


Sinus tympani:
This is the most common and constant depression present in the retrotympanic area. Anatomically this sinus is located at the junction of the lateral and posterior walls of the tympanic cavity. Phylogentically this recess is considered to ba analogue of bulla tympanica seen in mammals. It lies between ponticulus superiorly and subiculum inferiorly. This recess is bounded by pyramidal ridge externally and promontory internally. Visualization of this area during middle ear surgery proves to be a challenge. During yester years small angled mirrors known as zinne mirrors were used. Now angled telescopes serves this function rather brilliantly. The sinus tympani is known to extend posteriorly up to the round window niche.

Types of sinus tympani:

Sinus tympani has been classified into three types depending on its depth. Note in type III it extends up to the level of lateral semicircular canal.






Lateral tympanic sinus:

Proctor described this sinus in 1969. This sinus lies between three eminences of styloid prominence. These eminences include:

Pyramidal eminence
Styloid eminence
Chordal eminence

Posterior tympanic sinus:

Posterior sinus of middle ear cavity is one of the recently identified anatomical sinus inside the middle ear cavity.
Serial temporal bone dissections have shown that it is present in nearly 90% of dissected bones.

Position: It lies just posterior to the oval window.

Depth: 1mm or less
Width: 1.5 mm or less

In nearly 60% of dissected specimen a ridge of bone arising from the floor of middle ear cavity separates it from sinus tympani.

In 8% of dissected specimen, the sinus tympani and posterior sinus merged together to form one confluent sinus.

It has been demonstrated that cholesteatoma / granulation tissue may lie within this sinus making removal difficult leading on to residual disease.
Retraction pockets may also occur close to this area.

Facial recess:

This recess lies between the promontory and tympanic annulus. It is bounded medially by the facial nerve and laterally by tympanic annulus. Running between these two structures at varying angulations is the chorda tympani nerve. Chorda tympani nerve always runs medial to the ear drum. Drilling in this area between the facial nerve, annulus and the angle formed by the chorda tympani nerve will lead into the middle ear cavity without causing a breach in the ear drum. This approach is used in cochlear implant surgery to place the electrode in the round window area. Hypotympanum can also be approached through this approach.



Subiculum:

This is the posterior extension of promontory separating oval and round windows.

Ponticulus:

Rarely a spicule of bone arises from the promontory above the subiculum and runs to the pyramid on the posterior wall of the middle ear cavity. This spicule of bone is known as the ponticulus.



Thursday, October 27, 2011

Submission of articles to online journal of otolaryngology

Introduction:

Online journal of otolaryngology has been started.  It is free to access and free to publish.  You can read / submit articles to this journal by going through a simple registration process which is free.  Articles submitted will be peer reviewed before publication.  Publication of selected articles is absolutely free.

Click on the image below to read a short tutorial on article submission to this journal.







Click on the image below to access the journal.



Effect of altered core body temperature on glottal closure force. Can it explain SIDS (Sudden Infant death syndrome?)


Introduction:

The important basic function of larynx is to provide sphincteric protection to the lower airway. This is achieved by adduction of vocal folds in response to stimulation from the internal division of superior laryngeal nerves. This mechanism is initiated by complex brain stem response which is polysynaptic in nature. This reflex is sensitive to variations in body core temperature. In febrile neonates, a hypersensitive glottal closure reflex have been known to cause sudden infant death syndrome.

Role of animal studies in verifying this hypothesis:

Haraguchi etal in their canine experiments demonstrated that hyperthemia enhances the glottal closure reflex by decreasing the latency of nerve stumulation thereby aumenting their conduction. In hypothermic conditions they also demonstrated depression of glottal closure reflex. The following are the inferences of this study:

  1. When the core body temperature raises axonal body temperature also raises.
  2. Conduction of sodium and potassium ions increase nearly 3 times with every 10 ° C increase in body temperature.
  3. Temperature drop caused delay in the release of neurotransmitters at the neuronal junctions.

Sunday, October 23, 2011

Velopharyngeal insufficiency and its management

velopharyngeal_insuff

Thursday, October 20, 2011

Mandibular swing approach a step by step guide


Mandibular Swing

Monday, October 17, 2011

Grommet insertion Current conceptsIntroduction: 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. 1. 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. 2. 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. 3. 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) 4. Suppurative complication is present / suspected. It can be identified if myringotomy is performed. 5. Eustachean tube dysfunction even if the patient doesnt have middle ear effusion. Symptoms are usually fluctuating (dysequilibrium, tinnitus, vertigo, autophony and severe retraction pocket). 6. Otitis barotrauma inorder to prevent recurrent episodes. Problems with Grommet insertion: This procedure is not without its attendant problems. Common problems include: 1. Segmental atrophy of tympanic membrane 2. Tympanosclerosis 3. 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.



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.

  1. 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.
  2. 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.
  3. 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)
  4. Suppurative complication is present / suspected. It can be identified if myringotomy is performed.
  5. Eustachean tube dysfunction even if the patient doesnt have middle ear effusion. Symptoms are usually fluctuating (dysequilibrium, tinnitus, vertigo, autophony and severe retraction pocket).
  6. Otitis barotrauma inorder to prevent recurrent episodes.

Problems with Grommet insertion:

This procedure is not without its attendant problems. Common problems include:

  1. Segmental atrophy of tympanic membrane
  2. Tympanosclerosis
  3. 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, October 16, 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
    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


Wednesday, October 12, 2011

Susac syndrome


Introduction:

Susac syndrome was first described by Susac etal in 1979. This syndrome is characterised by rapidly progressing encephalopathy, blindness and hearing loss.

Pathophysiology:

This is actually an endotheliopathy affecting precapillary arterioles. This endotheliopathy could probably be immune mediated. This causes rapid tissue infarction which leads to these problems.

Women are commonly affected than men. Typical vulnerable age group is between 20 – 40.


Clinical features:

  1. Severe head ache
  2. Rapid dementia
  3. Micro infarcts seen in corpus callosum demonstrable in MRI scans
  4. Photopsia and black spots due to retinal artery occlusion
  5. Scintillating scotoma
  6. Rapidly progressive sensori neural hearing loss on both sides
  7. Vertigo
  8. Nystagmus


Management:

High dose steroid therapy is the main treatment modality.

Intravenous administration of immunoglobulin.

Cyclophosphamide administration.

Rituximab is the currently used drug in the management. This is a monclonal antibody against CD20 protein. This receptor protein is found on the surface of B lymphocytes.

Friday, September 30, 2011

Recent management concepts in the management of Atrophic rhinitis and empty nose syndrome


Introduction:

The presence of normal sized nasal turbinates covered by normal moist mucosa is vital for the normal function of the nose.  It should also be remembered that the receptors for initiating nasobronchial / nasal cardiac reflexes are found embedded in the mucosal lining of the nasal turbinates.  Surgical augmentation of atrophied turbinates and nasal mucosa will help in the restoration of nasal function and regeneration of nasal mucosa.  Usually various types of implant materials are considered for this purpose.

Commonly used implant materials:

1. Bone
2. Cartilage
3. skin
4. Fat
5. Plastic
6. Calcium hydroxyapatite


Role of Hyaluronic acid as an implant:

Hyaluronic acid is a naturally found polysaccharide consisting of a linear chain of fragments of D-glucoronic acid and N-acetlyglucosamine that alternate in the structure.  In its pure form it is not an allerge and does not stimulate immunogenic rejection process.  In view of its negative struture it absorbs large quantities of water.  On absorption of water hyaluronic acid forms a gel like structure.  It is extensively being used in plastic and reconstructive surgical procedures.  Its important unique property is that it maintains its liquid form when it is under pressure, the moment the pressure reduces it solidifies.  Hence it can be injected through a small needle.    It has another important property i.e. Isovolumetric degradation, which indicates single molecules of this substance undergoes periodic degradation while the remaining molecules absorb large amounts of water thereby enabling it to maintain its volume.  The overall volume of the gel maintains a constancy.



Hyaluronic acid can be injected submucosally thereby enlarging the size of the turbinates.  It can also be injected under the septal mucosa.  This not only cause narrowing of the nasal cavity but also promotes regeneration of nasal mucosal lining.  If a cannula is used to inject hyaluronic acid instead of needle it causes less mucosal trauma thereby minimizing the risk of accidental intravascular injection.  It would be better if the quantity of hyaluronic acid injected is the same on both sides.  Studies conducted by Marek Modrzynski, M.D.
 showed promising results.

Tuesday, September 20, 2011

Preauricular sinus compete excision is the only way out.


Preauricular sinus is an embryological aberration involving the developing pinna.

Theories of preauricular sinus formation:

Embryological fusion theory:

This commonly accepted theory suggests the preauricular sinus develops due to fusion defects involving the 6 hillocks which develop into the future pinna.

Ectodermal infolding theory:

This theory attributes preauricular sinus to ectodermal infolding defects that occur during development of pinna. Ofcourse this theory has no takers. This theory assumes that preauricular sinus forms part of other branchogenic malformations.

Various syndromes associated with preauricular sinus formation are:

  1. Branchio oto renal syndrome
  2. Branchio oto urethral sundrome
  3. Branchio otic syndrome
  4. Branchio oto costal syndrome
  5. Cat eye syndrome
  6. Trisomy 22

Surgical options for management of preauricular sinus:

Jensma technique is commonly preferred surgical treatment modality. In this technique the tract is identified after injecting dye (GV paint) via the punctum. A circular incision is made to encircle the opening of the preauricular sinus and the whole sinus is followed using dye diffusion as a guide. Major problem of this technique is that the recurrence rate is very high. It is not a suitable approach in patients with infected preauricular sinus.

Common causes of recurrence:

  1. Incomplete removal of lesion
  2. Failure to use magnification during surgery
  3. Skill of the surgeon

Supra auricular approach:

This is a more radical approach. Major benefit of this procedure is it low recurrence rate. This surgery is performed using a comet incision. The head of the comet incision is around the external opening of the sinus. The tail of the comet is fashioned in such a way that it passes anterior to the helix, superior to the pinna over the temporal area. The temporalis fascia is the medial limit of the dissection. All the tissue superficial to the temporalis fascia should be removed. It is also important to remove a cuff of cartilage around the outer opening of the preauricular sinus.


Picture showing preauricular sinus


Comet incision shown


Removal of sinus along with a bit of helical cartilage


View of wound closure



You can view the procedure below;






Sunday, September 18, 2011

Pleomorphic adenoma parotid gland


Clinical details:

13 years old boy came with complaints of:
Swelling over left side of cheek - 3 years duration
Swelling showed progressive increase in size
The swelling was non tender, not associated with febrile illness.

FNAC report:

Fine needle aspiration cytology from the mass was reported as pleomorphic adenoma.

Surgery:

Since this is a surgical problem the patient was taken up for surgery under general anesthesia.




Discussion:

Pleomorphic adenoma is the commonest benign tumor involving the salivary glands. This is characterised by proliferation of glandular cells along with myoepithelial components. This tumor has a tendency for malignant transformation.
Histologically this tumor is highly variable and variations are evident even within individual tumors.
Classically these tumors show biphasic manifestation with admixture of varying amounts of polygonal salivary gland cells and spindle shaped myoepithelial cells. The underlying stroma could be mucoid / myxoid / cartilagenous / hyaline. Even though these tumors are not encapsulated but thickening of parotid fascia around the mass gives it an encapsulated appearance (pseudocapsule).
The main cause for this tumor is juxtapositioning of PLAG gene to the gene for beta catenin. This causes activation of catenin pathway leading on to inappropriate cell division.


Tuesday, September 13, 2011

An interesting case of metallic foreign body (Nail) right orbit being removed

Case report:
13 years old male patient came to the OPD with h/o injury just below right eye.  When he came the injury was 4 days of duration.  He had undergone wound suturing as soon as he sustained the injury.

On examination:
Proptosis (mild) of right eye+
Sutured wound seen just below right orbit.  wound had healed.
Upwards movement of eye was restricted.
Lateral movements of the eye was normal

Imaging:

Plain x-ray skull lateral view was taken immediately.

















It showed the presence of metallic foreign body


CT scan showed:




















Metallic foreign body in the floor of right orbit with evidence of # of orbital floor

Patient was taken up for surgery under general anesthesia.  The metallic foreign body was removed via right infraorbital incision.  This was preferred because he already had the sutured scar in that area.

Surgical video clipping:




Discussion:

This case is presented for its rarity.  Without proper history it is very difficult to diagnose orbital foreign bodies inside the orbit.  Retained foreign bodies in the orbit can cause:

1. Orbital hematoma
2. Orbital cellulitis
3. Ocular dysmotility
4. Proptosis
5. Orbital abscess
6. Blindness

Thursday, September 08, 2011

Olfactory groove meningioma


Introduction:

Meningiomas are benign and rather slow growing tumor arising from arachnoidal cap cells. Statistically speaking meningiomas constitute about 20% of all primary intracranial tumors. Out of these 20% olfactory groove meningiomas constitute 10%. It was the Italian surgeon Francesco Durante who first reported the first successful resection of olfactory groove meningioma in 1885. In 1938 Cushing reported the largest series of olfactory groove meningioma which were resected via frontal craniotomy / subfrontal approach. It is really worthwhile to differentiate olfactory groove meningioma from other intracranial menigiomas as they differ in their presentation, symptomatology and management.

Sex ratio:

The female : male ratio is 2:1. Exact explanation for this variation is not available.

Pathophysiology:

Meningiomas arise from meningothelial cap cells that are largely distributed through the arachnoid trabeculations. The greatest concentration of meningothelial cells are seen in the arachnoid villi lining the dural sinuses, cranial nerve foramina, middle cranial fossa and cribriform plate area. This accounts for the common location of meningiomas i.e. Over the convexity, along the skull base and along the falx. Meningiomas are usually attached to the dura and are well encapsulated. Blood supply to these tumors arise usually from the dura and the anterior and posterior ethmoidal arteries.

Histology:
Histologically these tumors show features of bening lesions. These lesions classically appear as whorls of arachnoid cells surrounding a central hyaline material that eventually calcifies. These calcified areas are known as Psammoma bodies. These cells are arranged in sheaths separated by connective tissue trabeculations.

Subtypes of meningiomas:

Meningotheliomas
Fibrous types
Transitional types – Psammamatous tumors
Secretory meningiomas – Secretes Vascular endothelial growth factor. These tumors are characterized by the presence of marked oedema. They may be papillary or rhabdoid variants. These tumors are usually considered to be malignant in nature.

WHO histological grading of meningiomas:

Grade I: This grade is usually benign and 90% of all meningiomas belong to this category. They also carry the best prognosis and a very low recurrence rate.

Grade II: Atypical meningiomas come under this category. About 5% of all meningiomas belong to this grade. Tumors belonging to this grade have a high recurrence rate (about 50%).


Grade III: This grade of meningioma is frankly malignant constituting about less than 3% of all meningiomas.

Molecular biology:

Majority of meningiomas are associated with one / more focal chromosomal deletions. Malignant versions of meningiomas involve multiple chromosomal aberrations. These multiple chromosomal abberations cause extreme instability to the genomic structure thereby increasing the risk of malignant transformation.
Deletion and inactivation of NF2 gene on chromosome 22 is the predominant feature in sporadic meningiomas.

Risk factors contributing to meningioma:

  1. Exposure to ionizing radiation – Studies have demonstrated that survivors of atom bomb explosion showed increased incidence of meningioma
  2. Role of Hormones – Histologically meningiomas present with oestrogen, progesterone and androgen receptors. This could explain the increased incidence of menigioma in females.
  3. Head injuries have been shown to increase the incidence of meningiomas.

Location of olfactory groove meningioma:

These tumors are seen in the midline and arise over the cribriform plate and frontosphenoidal suture area. A majority of these tumors occupy the floor of anterior cranial fossa extending from crista galli up to the tuberculum sella. Extension to ethmoidal sinuses occur in about a third of these patients. There are obvious similarities existing between posteriorly extending olfactory groove meningiomas and tuberculum sellae meningiomas. These two masses can be differentiated by studying their relationship with that of the optic apparatus. Olfactory groove meningiomas have a tendency to push optic nerves and chiasma downwards and posteriorly as they grow, where as tuberculum sellae meningiomas push the optic nerves and chiasma upwards and superolaterally as they grow because of their subchiasmal position.

Blood supply of olfactory groove meningiomas:

These tumors are supplied by:

  1. Anterior ethmoidal artery
  2. Posterior ethmoidal artery
  3. Anterior branches of middle meningeal artery
  4. Meningeal branches of ophthalmic artery

Clinical features:

These tumors are very slow growing ones and they are seen in the silent area. Hence to become symptomatic they need to enlarge their size to a great extent. Usually these lesions are incidental findings during routine imaging.

MRI is the most preferred imaging modality as this would clearly show the origin of the tumor from dura. These lesions appear isointense / hypointense to gray matter of brain in T1 weighted images and isointense to hyperintense in T2 weighted images. When gadolinum is used as contrast these lesions demonstrate homogenous enhancement.

Majority of meningiomas show marginal dural thickening that tapers peripherally. This tapering is classically known as the dural tail which is the characteristic feature which is revealed in the images.


Management:

This entirely depends on the age and physical fitness of the patient. If the tumors are small and seen in elderly and ill patients then serial imaging and observations would do. In symptomatic cases irradiation can be resorted to,

Surgical resection is the best option. Removal of these lesions is similar to that of any other skull base tumor.

Surgical management:

Cushing was the first to describe surgical resection of the tumor via unilateral frontal craniotomy. Other approaches available include:

  1. Bifrontal craniotomy
  2. Subfrontal approach
  3. Pterional approach
  4. Endoscopic approach

Bifrontal craniotomy combined with subfrontal approach: This approach provides wide exposure for complete removal of tumor. In this approach it is easy to drill out the hyperostotic area in the cribriform plate area. In this approach optic nerves also can be deroofed if need be. Major disadvantage of this approach is the amount of brain retraction that is needed.

Unilateral frontal craniotomy with subfrontal approach: This approach has the advantage of sparing the opposite frontal lobe and superior saggital sinus. The disadvantages include:

Smaller exposure
Excessive brain retraction


Pterional approach:

This is a rather new approach. It is less invasive than frontal craniotomy approaches. It avoids CSF leaks because the frontal sinus is not damaged. The optic nerve can be localised and exposed before tumor manipulation. Major disadvantage of this approach is the lack of working space. The wole dissection process needs to be carried out within a narrow angle.

Endoscopic resection:

This procedure is performed binaurally with the endoscope introduced through one nose and the surgical instruments via the other.
This procedure involves:
  1. Bilateral maxillary antrostomies
  2. Complete ethmoidectomies
  3. Sphenoidotomies
  4. Frontal sinusotomy

Unilateral / bilateral nasal septal flaps are harvested first. This helps in covering the dural defect.These flaps are tucked into the nasopharynx well out of the way of surgical field.
Modified Lothrop procedureis performed. The frontal intersinus septum should be completely removed.

Controlling the bleeding to the mass is the top most priority. The anterior ethmoidal artery should be identified and ligated. Anterior ethmoidal arteries should be sought and ligated on both sides. Posterior ethmoidal arteries also should be drilled out and ligated. Image guidance is used to identigy the anterior and posterior extent of the mass. The anterior cut is usually made at the level of posterior wall of frontal sinus and continued along the fovea ethmoidalis using drills and kerrison punch. The posterior resection is made as posterior as possible. This is usually governed by the posterior extent of the mass. It can be as posterior as the planum of sphenoid.

Dura is incised exposing the entire olfactory groove meningioma. Dissection is completed using a combination of blunt dissection, debrider and CUSA. Tumors involving the medial wall of the orbit may be considered to be rather suboptimal for endoscopic resection. While performing the resection of the tumor care should be exercised to dissect it between the tumor and arachnoid plane. The defect in the skull base is repaired using abdominal fat, reinforced with fascia lata and tissue glue is used to fix them in place.

Advantages of endoscopic approach:

  1. The main site of recurrence i.e. The floor of the anterior cranial fossa is completely resected / drilled out.
  2. Allows two surgeons to operate simultaneously there by ensuring clear surgical field
  3. Very useful from the cosmetic point of view.


Role of irradiation in the management of meningiomas:

  1. RT is indicated only in patients with recurrent tumors following surgical resection
  2. In patients with atypical / malignant meningiomas after surgical extirpation of the tumor

Role of stereotactic radio surgery:

The major advantage of this procedure is that the irradiation dose at the edge of the neoplasm is greatly reduced thereby sparing the normal adjacent tissues. This procedure can be safely used to treat even large volume tumors close to critical intracranial structures.

Targetted molecular therapy:

This type of therapy aims at blocking the various signals leading to unbridled proliferation of cells. These include:

  1. Inhibitor of PDGFR – This is infact a key driver of cell proliferation in meningiomas. Drugs that block this can help in arresting the growth of meningiomas. Classic example of these drugs is Imatinib.
  2. Inhibitors of angiogenesis factor – Sorafenib and Sunitinib are examples of drugs belonging to this group

Wednesday, August 31, 2011

Role of viruses and vaccines in head and neck malignancies

Introduction:
Oncovirus is a virus that causes cancer. Majority of viruses dont cause tumors due to their long evolutional history and coexistance with the human host. It has been estimated that about 20% of all malignant lesions are caused by oncogenic viruses. These oncogenic viruses can either be a RNA virus or DNA virus. Oncogenic tumors can hence be prevented by developing vaccines against appropriate oncoviruses.

Characteristics of oncogenic viruses:

1. The oncogenic viruses doesn't obey Koch's postulates
2. These viruses cause little or no symptoms after infection
3. Oncoviruses can either be DNA virus or RNA virus

Bradford Hill criteria is usually used to ascertain the association between oncogenic viruses and causation of tumors since oncogenic viruses don't fullfill Koch's criteria.

Hill criteria:

1. Strength – Also known as strength of assoication. A small association doesn't mean that it is not a causal effect. Larger the association more likely it is to be causal.
2. Consistency – Consistent findings observed by different examiners from different locations strengthens the likelihood of causal effect
3. Specificity – More specific the association between a factor and an effect the higher the probablity of causal relationship
4. Temporality – The effect has to occur after the cause
5. Biological gradient – Greater exposure leads to greater incidence of the effect
6. Plausibility – Plausible mechanism between cause and effect is helpful
7. Coherence – Between epidemiological and laboratory findings increases the likelihood of the effect
8. Experiment – If possible experimental evidence should be sought
9. Analogy – Effect of similar factors should always be considered

Classification of oncoviruses:

1. Viruses with DNA genome – Adenoviruses
2. Viruses with RNA genome – Hepatitis C virus
3. Retroviruses having both DNA and RNA genome – Human T lymphotrophic virus / Hepatitis B virus
4. Viruses that present as Eisomes / plasmids with an ability to replicate separately from host cell DNA e.g. Epstein Barr virus and Kaposi sarcoma associated herpes virus.

Mechanism of viral tumerogenecity:

1. Direct mechanism which involves insertion of oncogenetic material to the host cell
2. Enhancing already present oncogenetic genes (proto oncogenes) in the genome



Direct tumor viruses should atleast have one virus copy in each tumor cell. This viral genome is capable of expressing atleast one protein / RNA. These cells express surface viral antigens to which immune mechanism can be sensitized. In normal individuals the immune mechanism is capable of destroying these cells in a targetted manner. These type of viruses hence commonly cause tumors in patients who are immunosuppressed.

Common viruses causing Head and Neck malignancies:

1. Human papilloma viruses (Squamous cell carcinoma of oropharynx)
2. Epstein Barr virus (Nasopharyngeal carcinoma)
3. Kaposi sarcoma associated Herpes virus (Kaposi sarcoma)

Role of vaccines in preventing virus induced head and neck malignancies:

Most commonly available vaccine is HPV vaccine (Human Papilloma virus vaccine). It is of two types containing serotypes 16 and 18.

Hepatitis B and Hepatitis C vaccines are also commonly used to prevent Hepatitis B and C infections.

Another vaccine which is undergoing extensive clinical trial is the Epstein Barr virus vaccine. This again holds much promise.

Sunday, August 28, 2011

Fat myringoplasty

Introduction:

Various graft materials have been used to close tympanic membrane perforations. The commonly used being temporalis fascia. Among the other graft materials used Fat fits the billing appropriately. Ringenberg was the first to use fat tissue to seal ear drum perforations.

Advantages of using fat graft:

The surgical procedure is rather simple. It can be inserted through the perforation after freshening the edges. Fat tissue available in the lobule of the ear can be utilized for this purpose. It is really wonderful to use fat to seal small perforations of ear drum.
Fat from ear lobe is considered to be better than that present in the abdomen / buttock area by Ringenberg as it is more dense and exhibits better scafolding for epithelial and mucosal overgrowth over the perforation.

Fat plugging does not require support at the level of anterior annulus which is actually a bane in conventional temporalis fascia myringoplasty.

Fat is actually a highly active material which could promote scarring and revascularization of adjcent areas.

Role of physiological saline in the management of patulous eustachean tube

Introduction:
The pharyngeal end of eustachean tube is normally closed. It usually opens temporarily during swallowing and yawning during which time middle ear drainage and pressure equalisation takes place. Abnormalities involving this opening mechanism may lead to middle ear pathologies like otitis media with effusion.

Patulous eustachean tube is a difficult entity to treat. The phenomenon of autophony which is caused by this condition is a difficult entity to treat. Patients have been driven to sucide because of this problem.

Patulous eustachean tube can be identified by the presence of the following features:

Aural fullness
Autophony
Hearing of self breathing

Sonotubometry is used to identify this condition.

Causes of patulous eustachean tube:

1. Weight loss (chronic)
2. Wasting disorders
3. Chronic inflammation followed by tissue atrophy at the pharyngeal end of eustachean tube

Management:

Various surgical modalities have been attempted with very little success.

Role of nasal topical instillation of physiological saline:

Instillation of physiological saline has been proved to be beneficial in nearly 60% of these patients. This therapy can be continued till there is sufficient weight gain which could obviate the need for this medication. Instillation of saline in the pharyngeal end of eustachean tube may cause it to close. This effect should be considered to be purely temporarly till normal saline is present close to the pharyngeal end of eustachean tube. The same can be instilled again if symptoms recur. Physiological saline administration can be continued till there is spontaneous recovery which is also common. Simple weight gain can obviate the symptoms.

Thursday, August 18, 2011

Thyroid storm

Introduction:

This condition is also known as thyrotoxic crisis caused by hypermetabolic state induced by excessive secretion and release of thyroid hormones in individuals with thyrotoxicosis. In children this could be the initial presentation of thyrotoxicosis. This is more so in neonates.

Clinical manifestations:

1. Marked hypermetabolism
2. Excessive adrenergic response
3. Hyperpyrexia (reliable finding)
4. Flushing / sweating / tachycardia /atrial fibrillations / elevated pulse pressure / cardiac failure
5. CNS symptoms include – agitation / psychosis / restlessness / delirium / coma.
6. GI symptoms include – diarrhoea / jaundice
7. Hypertension may be present. * Normal blood pressure doesn't rule out thyroid strom.
8. Elderly patients may manifest atypical symptoms like (apathetic thryoid strom).
9. Heat intolerance

Diagnosis is primarly made on clinical grounds, as no specific lab test is going to clinch the diagnosis.


Triggering factors include:

1. Thyroid surgery
2. Radio active iodine therapy
3. Pregnancy / during delivery
4. Acute iodine load
5. Trauma
6. Acute infection
7. Drug reaction
8. Trauma
9. Myocardial infarction (rare)
10. Graves disease

Incidence:

It is 5 times more common in women than in men.
It is more common in prepeubertal children.
Common in children born to mothers with Graves disease.
More common in adolescents.

Pathophysiology:

Thyroid crisis is the most extreme state of thyrotoxicosis. It should be considered to be a decompensated state of thyroid hormone. Studies have shown that there is no clear evidence that increased secretion of thyroid hormones lead to thyroid strom. Increased levels of catecholamines and increased sensitivity of catecholamine receptors have been suggested to play a role. Decreased binding to thyroid binding globulin can also play a vital role as this would lead to a relative increase in the risk of increasing levels of serum T3 and T4.

Management:

All patients with suspected thyroid strom should be managed only in an ICU setup.

Treatment should be considered to be a triangular one.

Iv life line is to be started.
Dextrose is to be administered because of the increasing biological demand for glucose.
Serum electrolytes should be estimated and abnormalities if any should be corrected.
Cardiac arrythmias if present should be treated aggressively.
Hyperthermia can be managed by ice packs / acetaminophen 15 mg/kg orally.
Propranalol should be administered to block sympathomimetic effects of thyroxine.
Anti thyroid medications are to be administered. High dose of propyl thiouracil is preferred because it blocks peripheral conversion of T4 to T3. Hepatic parameters should be monitored while administering propylthiouracil.
Administration of Lugol's iodine will help by blocking the release of thyroid hormones. Lugol's iodinee is preferred.
Glucocorticoids are also administered in order to reduce peripheral conversion of T4 to T3.
Plasma pheresis can be resorted to in cases of accidental / suicidal ingestion of large doses of thyroxine.
Underlying cause should be looked for and treated.


Theories explaining thyroid strom:

1. These patientts have relatively high levels of thryoid hormones than normal controls. This may not be the case always.
2. Adrenergic receptor activation theory. Sympathetic nerves are supposed to innervate thyroid gland. Increased sympathetic stimulation causes an increase in thyroid hormone synthesis and secretion. This increase in thyroid hormone levels increase the density of beta receptors.
3. Excess hormones could be liberated when the gland is manipulated during surgery.
4. Rapid reduction in the levels of thyroid binding globulin levels cause increased levels of thyroid hormones
5. Alterations in tissue tolerance to thyroid hormones.


Differential diagnosis:

1. Anxiety disorder
2. Cardiac failure
3. Hypertension
4. Hyperthyroidism
5. Phaeochromocytoma
6. Atrial tachycardia / fibrillation



Friday, July 15, 2011

An interesting case record of a patient with glomus tympanicum

Clinical details:

54 years old female patient came with complaints of:
1. Pulsating noise in her right ear - 5 years
2. Hard of hearing right ear - 5 years

Past history:

No history of trauma to the ear
No history of bleeding from the ear
Pt is not a known diabetic / hypertensive










Imaging:












These CT scan images show contrast enhancing soft tissrue lesion occupying the whole of the middle ear cavity. The same mass could be seen extending on to fill the attic, aditus and mastoid cavity. Tegmen plate appears to be eroded.


Provisional diagnosis:


Glomus tympanicum