Head and Neck Flashcards
Helpful Videos
EUSTACHAIN TUBE DYSFUNCTION
https://www.youtube.com/watch?v=H29571Ex-kY
SALIVARY GLAND TUMOURS
https://www.youtube.com/watch?v=bQVlqTx18ds
Le Fort
LEFORT ONE (HORIZONTAL) Anterolateral margin of nasal fossa. Palate separated from maxilla 'floating palate'
LEFORT TWO (PYRAMIDAL) Inferior orbital rim and orbital floor. Maxilla separated from face 'pyramidal'
LEFORT THREE (TRANSVERSE) Zygomatic arch and lateral orbital rim. Face separated from cranium 'floating face'
All three types have fractured pterygoid plates
Mucocoele
If fracture disrupts frontal sinus outflow tract (nasal-orbital-ethmoid types) you can develop adhesions with obstruct sinus and result in mucocoele development
‘airless expanded sinus’
T1 bright with thin rim enhancement. Frontal sinus most common due to trauma
CSF leak
Fractures of facial bones, sinus walls and anterior skull base can all lead to CSF leak. Anterior skull base most common. Recurent bacterial meningitis is association
Temporal bone fractures
LONGITUDINAL Long axis of temporal bone (ear to apex) More common. More ossicular dislocation. Less facial nerve damage 20% More conductive hearing loss.
TRANSVERSE Short axis tempral bone (perpendicular) Less common. More vascular injury (carotid/jugular) More facial nerve damage >30% More sensorineural hearing loss
Facial bone fractures
Nasal bone most common.
ZMC fracture is most common pattern and involves zygoma, inferior orbit and lateral orbit.
Le Fort high yield (1 floating palate, 2 pyramidal, 3 floating face)
Temporal bone fractures longitudinal and transverse. Otic capsule violation is better predictive factor.
Ear divisions
EXTERNAL
Everything superficial to tympanic membrane
MIDDLE
Tympanic membrane to medial wall tympanic cavity.
Epitympanum (attic) is everything above tip of scutum
Hypotympanum everything below tympanic membrane
Mesotympanum inbetween
INNER
Everything deep to medial wall of tympanic cavity.
Scutum is a shield like osseous spur formed via lateral wall of tympanic cavity. Involved with cholesteatomas
Cholesteatoma
Exfoliated/dead skin growing in wrong place. Creates inflammation ball that wrecks temporal bone and ossicles.
Restrict diffusion, can erode scutum.
PARS FLACCIDA
Flimsy part of tympanic membrane is superior.
Acquired more common, grow into Prussaks space.
Scutum eroded early.
Malleus head displaced medially
Long process of incus most common segment of ossicular chain to be eroded
Fistula to semicircular canal most commonly involves lateral segment
PARS TENSA
Inner ear structures involved earlier and more often.
Less common than pars flaccida type.
Prussaks space and scutum erosion
PRUSSAKS SPACE
Superior to scutum between lateral wall and ossicle (incus).
Most common location of pars flaccida choleseatoma (incus most commonly eroded)
SCUTUM
Shield like bony protuberance superomedial to tympanic membrane. Eroded first.
Labyrinthine/perilymphatic fistula
Potential complication of cholesteatoma (or iatrogenic/trauma).
Bony defect creating abnormal communication between fluid filled inner ear and air filled tympanic cavity.
Lateral semicircular canal most often involved.
‘sudden fluctuating sensorinerual hearing loss and vertigo’
Want to see soft tissue cholesteatoma eating through otic capsule into semicircular canal. Air in semicircular canal (pneumolabyrinth) is difinitive evidence of fistula, though uncommon.
Otitis media OM
Effusion and infection of middle ear. More common in children and Downs due to more horizontal Eustachian tube. Chronic if >6 weeks
COMPLICATIONS
Coalescent mastoiditis (erosion mastoid septae)
Facial nerve palsy (inflammation tympanic segment)
Dural sinus thrombosis (then venous infarct or otitic hydrocephalus)
Meningitis or labyrinthitis
Chronic OM vs cholesteatoma
CHRONIC OTITIS MEDIA Poorly pneumatized mastoids Middle ear can completely opacify Thickened mucosa Erosions of ossicles rare No displacement ossicular chain
CHOLESTEATOMA Poorly pneumatized mastoids Middle ear can completely opacify Non-dependent mass Erosions of ossicles common Can displace ossicular chain
Labyrinthitis ossificans
History of childhood meningitis, kids 2-18months.
Classic on CT with ossification of membranous labyrinth.
Sensorineural hearing loss
Calcification of cochlea is often considered contraindication to cochlear implant.
LABYRINTH
Vestibule, cochlea and semicircular canals
Bony is the series of canals tunneled out of bone and membranous is soft tissue lining them. Membranous can then be divided into cochlear or vestibular labyrinths.
Labyrinthitis
Inflammation of membranous labyrinth, usually viral infection. Acute otomastoiditis can also spread directly to inner ear. Bacterial meningitis can cause bilateral labyrinthitis
Cochlea and semicircular canals will be enhancing
Facial nerve
Intracranial (cisternal)
Meatal (canalicular in IAC)
Labyrinthine (from IAC to geniculate ganglion)
Tympanic (from geniculate ganglion to pyramidal eminence)
Mastoid (from pyramidal eminence to stylomastoid foramen)
Extratemporal (SMF onwards)
NORMAL ENHANCEMENT
Tympanic and mastoid segments, sometimes labyrinthine
NO ENHANCEMENT
Cisternal, canalicular or extratemporal
ABNORMAL ENHANCEMENT
Bells Palsy (viral) in canalicular segment
Ramsay Hunt (reactivation zoster)
Think cancer if nodular enhancement
Otosclerosis/otospongiosis
Classic conductive hearing loss in adult female. Bone becomes more lytic
FENESTRAL
Bony resorption anterior to oval window at fissula antefenestrum. If not addressed, footplate will fuse to window.
RETROFENESTRAL
More severe form progressed to demineralization around cochlea. Usually has sensorineural component and is bilateral and symmetric nearly 100%
May treat with flouride. Later may need stapedectomy with implantation of prosthetic device, or a cochlear implant.
Superior semicircular canal dehiscence
Longstanding elevated ICP. Noise induce vertigo “Tullios phenomenon”.
See on CORONAL, absence of bony roof over superior semicircular canal.Goes through into middle cranial fossa
Large vestibular aqueduct syndrome
Vestibular aqueduct is a bony canal that connects inner ear to endolymphatic sac. Enlargement >1.5mm is aunt minnie. Progressive sensorineural hearing loss. Apparently failure of endolymphatic sac to resorb endolymph
Most common cause of congenital sensorineural hearing loss. Usually bilateral. Associated with cochlear deformity nearly 100%. Not born deaf, get progressive sensorineural hearing loss.
See AXIAL, should be same diameter as adjacent (lateral) posterior semicircular canal.
Congenital malformations of inner ear
Earlier things go wrong, more severe malformation.
MICHELS APLASIA
Earliest and most severe.
Complete labyrinthine aplasia (CLA). Absence of cochlea, vestibule and vestibular aqueduct. Completely deaf. Association with anencephaly and thalidomide exposure.
MONDINI MALFORMATION
Cochlear hypoplasia where basal turn is normal but middle and apical turns fuse into cystic apex. 1.5 turns instead of 2.5. Association with enlarged vestibule and enlarged vestibular aqueduct. Sensorineural hearing loss but high pitch is preserved.
Mondini vs Michels
MONDINI Happens later, 7th week. Preserved high frequency Cochlea shows cystic apex Vestibule enlarged Vestibular aqueduct enlarged Frequency common
MICHELS Early, 3rd week. Total deafness Cochlea, vestibule and VA absent. Very rare
Endolymphatic sac tumour
Rare. Most are sporadic, first think VHL.
Almost all have internal amorphous calcification. T2 bright and intensely enhance. Very vascular with flow voids and tumour blush on angiography.
Next to aperture of vestibular aqueduct.
Paraganglioma
Can invade occipital bone and adjacent petrous apex.
40% time hereditary and multiple.
Most common presenting symptom is hoarseness from vagal nerve compression.
Salt and pepper appearance. Enhance avidly.
FDG avid
Petrous apex anatomical variation
ASYMMETRIC MARROW
Typically contains fat. When asymmetric can trick into thinking there is a mass, or overlook a cholesteatoma. Use STIR or fat sat imaging.
CEPHALOCOELES
Herniation of CNS content through defect. In petrous apex this can be cystic expansion and herniation of posterolateral portion of Meckels cave into superomedial petros apex. Unilateral or bilateral (more common)
ABERRANT INTERNAL CAROTID
Pulsatile tinnatus. Cervical segment ICA has underdeveloped and middle ear collaterals develop (enlarged caroticotympanic artery). Runs through tympanic cavity and joins horizontal carotid canal. Vascular mass pulsating behind eardrum.
Petrous apex anatomical variation
APICAL PETROSITIS
Rare complication of infectious otomastoiditis. Can progress to osteomyelitis of skull base, vasospasm of ICA, subdural empyema, venous sinus thrombosis, temporal lobe stroke, and meningitis. Children it can be primary process, adults in setting of chronic otomastoiditis or recent mastoid surgery.
GRADENIGO SYNDROME
Complication of apical petrositis when Dorellos canal (CN6) is involved. Lateral rectus palsy. Dorellos canal is most medial point of petrous ridge between pontine cistern and cavernous sinus.
Otomastoiditis, trigeminal neuropathy and lateral rectus palsy
Petrous apex inflammatory lesions
CHOLESTEROL GRANULOMA
Most common primary petrous apex lesion. Obstruction of air cell with repeated cycles of haemorrhage and inflammation leading to expansion and bone remodelling. Symptom is hearing loss. CT margins sharply defined. T1 and T2 bright. T2 dark haemosiderin rim with faint peripheral enhancement.
CHOLESTEATOMA
Basically an epidermoid (ectopic epithelial tissue). Petrous apex ones are congenital. Slow growing and produce well smooth expansile bony change. T1 dark, T2 bright and restrict diffusion.
External ear
REGULAR AND NECROTIZING OTITIS EXTERNA
Usually bacterial of external auditory canal. Necrotizing/malignant form almost only in diabetics and is more aggressive. Swollen EAC soft tissues, bunch of small abscesses and adjacent bony destruction. Usually diabetics and infected with pseudomonas.
EXTERNAL AUDITORY CANAL EXOSTOSIS
‘Swimmers ear”. Overgrowth of soft tissue in ear canal, classically surfers with repeated bouts of ear infections. usually bilateral and when chronic looks like bone. These patients are immunocompetent and not diabetic,
EXTERNAL AUDITORY CANAL OSTEOMA
Overgrowth of normal bone. Usually incidental and unilateral occuring near junction of bone and cartilage in ear canal.
EXTERNAL AUDITORY CANAL ATRESIA
Developmental. External auditory canal doesnt form. May or may not be mashed up ossicular chain. Key is whether tissue covering the area normally open is soft tissue or bone (atretic plate). Also need to know if there is aberrant course of facial nerve.
Pagets
Can have osteolysis circumscripta which is well defined large radiolucent region favoring frontal and occipital bones. Both inner and outer table involved.
Pagets skull related complications: Deafness Cranial nerve paralysis Basilar invagination to hydrocephalus to brainstem compression Secondary osteosarcoma
Chordoma and Chondrosarcoma
Midline and off midline - discussed in MSK
Fibrous Dysplasia
Ground glass. Can look similiar to Pagets but FD is young <30 and Pagets older.
Fibrous dysplasia spares otic capsule classically
McCune Albright syndrome is multifocal FD, cafe au lait spots and precocious puberty
Outer table favoured
Sinus disease strategy
CT for anterior 2/3 orbit. MRI for posterior 1/3 and cavernous sinus.
CT useful for characterization of anatomical variation, MRI for tumour progression/extension/PNI/marrow involvement
Fungal sinusitis
ALLERGIC FUNGAL SINUSITIS
Opacification of multiple sinuses, usually bilateral favouring ethmoid/maxillary.
Normal immune system (asthma common)
CT hyperdense centrally or with layers. Can erode and remodel sinus walls when chronic.
MRI T1 and T2 dark, high protein and heavy metals. Can mimic aerated sinus. Inflammed enhancing mucosa.
ACUTE INVASIVE FUNGAL SINUSITIS
Opacificaiton of multiple sinuses.
Stranding/extension into fat around sinuses is key.
Immunocompromised. Apergillus or Zygomycetes
CT opacified sinus not hyperdense. Fat stranding in orbit, masticator fat, pre antral fat or PPF suggests invasion. Does not require bone destruction
MRIT1 and T2 dark, mucosa doesnt enhance. Extension of disease out of sinus will be bright on STIR and enhance
Chronic inflammatory sinonasal disease
Inflammation of paranasal sinuses lasting at least 12 weeks. Issue is primarily anatomical patency of sinus ostia
See p254 vol 2 yellow book
INFUNDIBULAR PATTERN
Most common. Disease limited to maxillary sinus and occurs from obstruction at ipsilateral ostium/infundibulum
OSTIOMEATAL UNIT PATTERN
Second most common. Centred at middle meatus with disease involving ipsilateral maxillary, frontal and ethmoid sinuses. Contributors are: hypertrophied turbinates, anatomic variants, concha bullosa, middle turbinates curling wrong way, septal deviation.
SINONASAL POLYPOSIS PATTERN
Combination of soft tissue nasal polyps and variable degrees of sinus opacification. Fluids levels can be present. Bony remodelling and erosion are key. Widening of infundibula. Need to differentiate between erosion/remodelling and expansion (mucocoele). Associations are CF and aspirin sensitivity.
MUCOCOELE
Obstructed sinus. May have had prior trauma. May have CF with secretions clogging things up. Mucus accumulates, sinus becomes completely filled and starts to expand. buzzword is expanded airless sinus. Frontal sinus most common. Periphery may enhance.
Antrochoanal polyp
Young adults 30-40. Presents with congestion/obstruction. Arises within maxillary sinuses and passes through and enlarges sinus ostium.
Buzzword widening of maxillary ostium. Smooth enlargement of the sinus with no bony destruction.Polyp will extend into nasopharynx. Monster inflammatory polyp
Juvenile Nasal Angiofibroma JNA
Male teenager with nose bleeds.
Centred in sphenopalatine foramen. Bony remodelling (not destruction). Very vascular and enhancing with intratumoral flow voids on MRI.
Presugical embolization common via internal maxillary and ascending pharyngeal artery.
Maxillary sinus in front smaller due to bony remodelling.
Inverted papilloma
Uncommon tumour. Lateral wall of nasal cavity most frequently related to middle turbinate. Impaired maxillary drainage expected.
Focal hyperostosis occurs at tumour origin. 10% harbour a squamous cell Ca.
Cerebriform pattern.
Enthesioneuroblastoma
Neuroblastoma of olfactory cells, starts at cribriform plate. Dumbbell appearance with growth up into skull and down into sinuses with a waist at the plate. Often cysts in mass. Bimodal age distribution.
Dumbbell shape
Intracranial posterior cyst classic
octreotide scan positive - neural crest origin
Squamous cell/SNUC (sinonasal undifferentiated carcinoma)
Squamous cell is most common tumour head and neck. Maxillary antrum is most common location. Highly cellular, low T2. Relative to other sinus masses it enhances less. SNUC is monster version of regular squamous cell.
Epistaxis
Usually idiopathic though can be iatrogenic. Could be in setting of HHT (hereditary haemorrhagic telangiectasia). also called osler weber rendu).
Anterior septal area (Kiesselbach plexus) is most common and can be compressed manually. Posterior ones are less common but bleed more. Main supply posterior nose is sphenopalatine artery (terminal internal maxillary artery) and tends to be first target. Watch out for variant anatomy between ECA and ophthalmic artery.
Nasal septal perforation
Typically involves anterior septal cartilagenous area.
Surgery (Killian submucous resection) Cocaine use Too much nose picking Granulomatosis with polyangitis (Wegeners) which is renal masses, sinus mucosal thickening and nasal septal erosion and cavitatory lung nodules/fibrosis. cANCA positive. Syphillis
Sialolithiasis
Stones in salivary duct, most commonly submandibular gland duct (Whartons). Can lead to infected gland “sialoadenitis” and chronic obstruction which can lead to fatty atrophy.
Submandibular - Whartons duct
Parotid - Stensons duct
Sublingual - Rivinus duct
Odontogenic infection
Can be dental or periodontal in origin. More common from an extracted tooth than an abscess involving an intact tooth.
Attachment of mylohyoid muscle to mylohyoid ridge dictates spread of infection to sublingual and submandibular spaces. Above mylohyoid line (anterior mandibular teeth) goes to sublingual space. Below mylohyoid line (posterior mandibular teeth) goes to submandibular space.
Odontogenic abscess is most common masticator space mass in adult.
Ludwigs angina
Aggressive cellulitis in floor of mouth, will be shown with gas in tissues. Most cases start with odontogenic infection
Torus palatinus
Normal variant. Bony exostosis arising from hard palate in midline.
Osteonecrosis of Mandible
Related to prior radiation or bisphophanate treatment.
Ranula
Mucous retention cyst, typically lateral. Arise from sublingual space and are termed plunging if under mylohyoid muscle
