ENT Tests of function Flashcards
NARROW BAND IMAGING - procedure - patterns - exam outcomes
A biologic endoscopy technique focusing on vascularisation of the lesion
- Identifies neoangiogenic patterns inside and surrounding the target lesion
- Initially developed to improve diagnosis/localisation of Barrett’s oesophagus
Procedure: Narrow band spectrum filters reduce illumination in all wavelengths except blue 415nm and green 540nm (the peaks of haemoglobin absorption) - Enhances visualisation of mucosal and submucosal microvascular patterns
Patterns:
- Normal — green vessels, parallel to epithelium then branch obliquely and end as intra-epithelial papillary capillary loop (IPCL)
- Premalignant/malignant — well demarcated brown areas within blue/green background, scattered dark spots (speckled pattern), increased micovascular density, winding/’earthworm’ vessels with abnormal IPCLs
Characterised into 5 patterns: Ni et al n=104 — sens=89%, spec=93%, PPV=992%, NPV=90%
- Normal
- Laryngitis (enlarged diameter of vessels)
- Hyperplasia, mild dysplasia (IPCLs may be obscured by white plaque)
- Hyperplasia, mild-mod dysplasia (IPCLs recognisd as small dots)
- Severe dysplasia (Va)-invasive carcinoma (Vb, Vc) —> speckled pattern, tortuous, irregular distribution, scattered across tumour surface
NARROW BAND IMAGING - applications
Applications: - Early detection of abnormal microvascular changes - Distinguishes low grade vs high grade dysplasia vs SCC - Pre-operative — ‘optical biopsy’, evaluate 2nd primary, 20% gain (upstaging, change surgical resection) - Intra-operative — peripheral extension of lesion, refine laser technique - Post-operative — detect persistent/recurrent disease - Retains sensitivity and specificity post-RT as well
SALIVARY FLOW TESTING xxx
TESTS: Chorda Tympani
PROCEDURE: 6% citric acid on anterior tongue Wharton’s duct cannulated and salivary flow measured Compare the two sides
OUTCOME: Reduction of 25% = abnormal
ASSESSMENT OF SWALLOWING - clinical
History:
- Weight loss, haemoptysis etc
Examination:
- Oral cavity - dentures — poor sensation - CN function- IX, X, XII
- Neck - Masses
- FNE
Penetration = Saliva into trachea followed by clearance mechanisms
Aspiration = No clearance efforts observed
ASSESSMENT OF SWALLOWING - investigations
-
FEES - FNE then observe swallow of various consistencies and observe pharyngeal phase of swallowing, pooling, penetration/aspiration - Detects presence of: penetration, aspiration, pooling, retained secretions, effectiveness of cough
- Procedure: start with ice — water — pureed food — solids - Allows assessment of efficacy of compensatory strategies (e.g. head tuck, chin tuck) - Disadvantages: not good for oral phase, MBS better for quantifying pharyngeal movement - FEESST - FEES + sensory testing - Small puff of air in close proximity to laryngeal mucosa — elicits the Laryngeal Adductor Reflex (LAR) - Can be tested unilaterally - Grading of response, response elicited at: - 3mmHg = normal - 6mmHg = mild sensory impairment - 9mmHg = moderate impairment - Not elicited at 9mmHg = severe sensory impairment
- Modified Barium Swallow (MBS) - The gold-standard for swallowing complaints - Provides information regarding: - Anatomy - Function - safety of swallow, consistency of food, compensatory strategies
- Manometry - Assess for motility disorder e.g. achalasia
Management: - Diet modification, BioFEESback, swallowing exercises - Non-oral feeding (e.g. PEG)
LARYNGEAL EMG Def/technique/uses
Definition: A means of studying the electrical activity of the muscles of the larynx to provide diagnostic and prognostic information
Technique: Measure either spont activity or during phonation Monopolar needle into cricothyroid or thyroarytenoid muscle - T/A: percutaneous, midline through C/T membrane then head sup/lat - C/T: percutaneous, midline, then aim sup/lat along the cricoid to enter muscle
Uses:
- Diagnostic - Site of lesion: SLN vs RLN (i.e. high vs low vagal) based on C/T vs T/A - Neurologic vs mechanical limitation - Mechanical will have normal EMG with fixed cord - CA joint arthritis, arytenoid dislocation, posterior glottic scarring
- Prognostic - Predicting return of function after VC palsy
LARYNGEAL EMG Interpretations & treatment planning
Interpretation: - Spontaneous activity in normal muscle at rest is minimal - But not complete electrical silence (active with respiration) - Will have an initial negative deflection - Fibrillation potentials: presence of spontaneous, bizarre activity with initial positive deflection - Pathologic (denervation) - Polyphasic potentials: greater than 4 phases (N=2-3). - Hallmark of reinnervation
EMG findings after VC palsy: Timing is important - Initially: electrical silence (complete injury) vs reduced amplitude (incomplete, common in idiopathic lesions) - Fibrillation potentials occur by 3/52 (resting potential falls to near depol threshold) — perform 2-6/52 after injury - Then pattern is either reinnervation or no recovery - Reinnervation: polyphasic potentials. Motor unit weakness and asynchrony (can persist in long-term) - No recovery: spontaneous activity persists. muscle atrophies and replaced by CT Guiding treatment: Subjective, difficult to interpret. Rarely used - Normal EMG - acute: reduce arytenoid sublux, chronic: look for fixation - Polyphasic potentials: observe/speech therapy vs temporary injection (gel foam, fat, restylane) - Based on patient factors: aspiration, vocal demand, patient desire - Fibrillation potentials (persisting): complete nerve injury. Manage either: Radiesse injection, MT +/- AA or nerve anastomosis or reinnervation
Good prognosis = recruitment, near normal wave morphology, absence of spontaneous activity
Poor prognosis = spontaneous activity (fibrillation potentials), absent recruitment
STROBOSCOPY xxx
Enables the human eye to visualise the vibratory pattern of the vocal fold during phonation
-Pulsed light source creates an illusion of continuous slow motion mucosal oscillation
Theory: Fundamental frequency: M=100Hz, F=200Hz Talbot’s law = human retina can only appreciate 5 images/sec (stay on retina min 0.2s). Faster than that — seen as a continuous image Light pulses are slightly different to freq of glottal cycle - Pattern averaged over many successive non-identical cycles
Remeber ‘SAPMuC’ Synchrony of movement between the two vocal cords Amplitude Periodicity Mucosal wave Closure (glottic)
Features on Stroboscopy: Synchrony Amplitude - Normal = 1/3 of width of vocal fold Periodicity - Jitter = cycle-cycle variation in frequency - Shimmer = cycle-cycle variation in amplitude Mucosal wave Closure (glottic) - Incomplete — motion impairment, scar, MTD - Posterior gap — common in females - Anterior gap —deficit of anterior VC (surgery, sulcus, SLN palsy), may be normal in males - Spindle-shaped — presbylarynx - Hourglass — bilateral pathology e.g. vocal cord nodules - Irregular
VII FUNCTION - all types
- Topodiagnostic testing: Site of lesion - Schirmer’s test — GSPN - Stapedial reflex — N to Stapedius - Electrogustatometry — Chorda Tympani - Salivary Flow — Chorda Tympani
- Electrophysiology Prognosis - NET (acute test after 3-4 days) - MST (acute test after 3-4 days) - ENoG (acute test after 3-4 days) - EMG (chronic test - after 3 weeks and onward)
- Intra-operative monitoring - Active = electrical stimulation of nerve and measures CAPs - Passive = facial movement with direct stimulation
VII FUNCTION - techniques electrophysiology tests
- Nerve Excitation Test Subjective - Transcutaneous DC stimulation of VII at SMF - Minimum stimulation required to elicit a muscle contraction - >3.5mA difference between sides is significant
- Maximal Stimulation Test Subjective - Set-up as per NET - Maximal stimulation (patient tolerance or maximum level on machine) - Observe the 2 sides — equal, slightly reduced, markedly reduced, absent - Loss of response in 10 days assoc with incomplete recovery 3. Electroneuronography EnoG Objective - Evoked electromyography - Supramaximal stimulus to VII at SMF — bipolar electrode measures CAPs at nasolabial groove - Amplitude is proportional to number of intact axons (normal difference between sides = 3%) - 10% amplitude — 90% axonal loss — poor prognosis for spontaneous recovery - Timing: 1st 4 days = Wallerian degeneration, after 3 weeks = nerve desynchronisation 4. Electromyography Objective - Electrodes within muscle - Records active motor unit potentials: rest and voluntary contraction - Diphasic/triphasic potentials = normal - Fibrillation = 2-3 weeks post-injury —> LMN denervation, viable motor end plates — suitable for reinnervation/surgical exploration - Polyphasic potentials = regenerative process underway. Precede clinical recovery by 6-12 weeks - Electrical silence = long-standing denervation —> surgical exploration not indicated
ELECTROGUSTATOMETRY xxx
TESTS Chorda Tympani
PROCEDURE: Tongue is stimulated electrically to produce a metallic taste Two sides are compared
OUTCOME: Threshold compared between the two sides
SCHIRMER’S TEST xxx
Tests GSPN / VII Blotting paper inferior fornix 5 mins Compare length of moistened paper Outcome: > 75% unilateral decrease < 10mm both sides @ 5 mins = bilateral decrease
EUSTACHIAN TUBE FUNCTION xxx
- Valsalva - +ve when intact TM observed to be moving OR air heard thru perforation - Anatomically patent
- Toynbee test - Visual inspection of TM while patient swallows with nose closed manually - Significant portion of normal population can’t achieve this
- Politzer test - Visual inspection of TM whilst compressing one nostril with a finger and the other with a rubber tube which injects air into nasal cavity - Repeat the letter K or swallow - +ve when the over pressure that develops in NPx is transmitted to ME
- Frenzel manouevre - Opposite of Valsalva - Hard to learn but effective at inflating ET
- Imaging - CT vs MRI
Tympanometry
ALLERGY TESTING xxx
Broad categories:
- In vivo Skin prick (epidermal), intradermal - Time consuming, some discomfort, risk of anaphylaxis - May be difficult in children - Cheap, immediate result
- in vitro RAST, ELISA - Delayed result, expensive, less sensitive - Safe. Not affected by treatment (e.g. antihistamine) Skin prick testing - Epidermal injection of dilute antigen - 15-20mins observe for a wheal (qualitative)
Intradermal - Dermal injection of dilute antigen — more sensitive than skin prick testing - Can use a range of dilutions — quantitative
RAST Radioallergosorbent test - Attach test antigen to a surface then expose to patient’s serum - If patient has allergen-specific IgE it will remain bound to the antigen surface - Wash, then apply labeled anti-IgE IgG - Replaced by ImmunoCAP
Total IgE - 50% of AR patients have normal IgE - Doesn’t identify which allergens — can’t counsel re: allergen avoidance
SMELL ASSESSMENT xxx
History: most powerful tool - Nature, pattern, timing, onset, duration, degree - Improvement with vasoconstrictors suggests conductive cause - Antecedent events (URTI, trauma, AR, CRS) - Other sinonasal symptoms, PMHx, FHx, Medications, Occupation, Smoking
Examination: - Full ENT exam - FNE - Cranial Nerve exam Smell testing:
- Screening - alcohol pad used to test distance from nose it is detected
- Psychophysical - Threshold testing - Dilutional testing of butyl alcohol — lowest concentration of odourant that can be detected - Odour identification- UPSIT = University of Pennsylvania Smell Identification test - Commercially available, 40 micro encapsulated odorants scratch + sniff - Chance performance = 10/40. Very low UPSIT reflects avoidance — detect malingering
- Electrophysiological - Electro-Olfactogram (EOG) + Odour Event-Related Potentials (OERP) — research only
- Imaging - Unusual/ominous symptoms - Pattern doesn’t fit standard diagnosis - Expected resolution doesn’t occur - CT - CRS or post-head trauma - MRI - Tumours (assess integrity of dura/brain. Olfactory agenesis in Kallman’s syndrome)s
