Ultimate ENT Exam Guide

Lecture 1: Anatomy of the Ear

External Ear

• Auricle: Fibro-cartilaginous. Features: Helix, Antihelix, Tragus, Antitragus, Concha. Lobule has NO cartilage (fat & fibrous tissue only).
• Blood Supply: Superficial temporal & posterior auricular arteries.
• Nerve Supply: Greater auricular nerve (C2, C3) for lower parts. Lesser occipital (C2). Vagus nerve (Arnold's nerve) for posterior half of canal.
• External Auditory Canal (EAC): Outer 1/3 cartilaginous (contains hair/sebaceous glands), Inner 2/3 bony (no glands/hair). Narrowest part: Isthmus (0.5 cm from ear drum).

Middle Ear (Tympanic Cavity)

• 6 Walls:
  - Roof: Tegmen tympani.
  - Floor: Jugular bulb.
  - Anterior: Internal Carotid Artery, Eustachian tube.
  - Posterior: Mastoid aditus.
  - Medial: Oval window, round window, Promontory (basal turn of cochlea), Fallopian (Facial) canal.
  - Lateral: Tympanic Membrane (TM).
• Tympanic Membrane (TM): 3 layers. Outer squamous, middle fibrous (absent in pars flaccida), inner mucous. Has Cone of Light.
• Contents: Air, Muscles (Tensor tympani, Stapedius), Ossicles (Malleus, Incus, Stapes).
• Eustachian Tube: 36mm long. Outer 1/3 bony, inner 2/3 cartilaginous. Equalizes pressure.
• Mastoid Air Cells: 9 groups including Antrum, Mastoid tip, Zygomatic, Squamous, Petrous, Perisinus, Perilabyrinthine, Retrofacial, Subdural.

Inner Ear (Labyrinth)

• Osseous Labyrinth: Vestibule, 3 Semicircular Canals, Bony Cochlea (2.5 turns). Contains Perilymph (similar to extracellular fluid, high Na+).
• Membranous Labyrinth: Saccule, Utricle, Semicircular ducts, Cochlear Duct (Scala Media). Contains Endolymph (similar to intracellular fluid, high K+, low Na+).
• Organ of Corti: Situated on the basilar membrane inside Scala Media. Inner hair cells (1 row), Outer hair cells (3-4 rows). Overhung by Tectorial membrane. Reissner’s membrane separates it.

💡 Quick Exam Hints

• Lobule is the only part of the auricle devoid of cartilage.
• Isthmus is the narrowest part of the External Auditory Canal, located 0.5 cm from the eardrum.
• Arnold's nerve (branch of Vagus) supplies the posterior half of the canal (can cause cough reflex when examining).
• Tegmen Tympani forms the roof of the middle ear, separating it from the brain (temporal lobe).
• Endolymph is uniquely rich in Potassium (K+) unlike typical extracellular fluids.

Lecture 2: Physiology of Hearing & Balance

Physiology of Hearing

• Impedance Matching: Conversion of sound from air to fluid.
  - TM to Stapes footplate area ratio: 14:1.
  - Ossicular lever ratio: 1.3:1.
  - Total pressure increase: 18 times at the footplate.
• Cochlear Tonotopy: Basal portion responds to high frequencies. Apex responds to low frequencies.
• Protection: Stapedius and tensor tympani reflexively contract to stiffen ossicles during loud sounds.

Physiology of Balance (Vestibular System)

• Balance inputs: 70% vision, 15% proprioception, 15% vestibular.
• Semicircular Canals: Detect Angular acceleration (Dynamic equilibrium). Cupula deflection alters hair cells.
• Utricle & Saccule (Maculae): Detect Linear acceleration (Static equilibrium) and gravity via Otoconia (crystals). Utricle = horizontal, Saccule = vertical.
• Reflexes: Vestibulo-Ocular Reflex (VOR) stabilizes gaze. Vestibulocollic Reflex (VCR) stabilizes neck. Vestibulospinal Reflex (VSR) stabilizes trunk.

💡 Quick Exam Hints

• The middle ear acts as an impedance matcher increasing sound pressure by 18 times.
• High-frequency sounds are detected at the Base of the cochlea, low frequencies at the Apex.
• Vision provides the majority (70%) of balance information.
• Maculae (Utricle/Saccule) detect linear motion, while Semicircular Canals detect angular/rotational motion.
• VOR (Vestibulo-Ocular Reflex) allows you to read a sign while your head is moving.

Lecture 3: External Ear Conditions

Infections & Inflammations

• Erysipelas: Group A Strep. Well-demarcated superficial skin infection.
• Infectious Perichondritis: Painful red swelling sparing the lobule (no cartilage). Usually Pseudomonas/Staph.
• Acute Otitis Externa (Swimmer's Ear): Pseudomonas/Staph. Moisture alkalizes canal -> bacterial overgrowth. Pain on pressing tragus or pulling auricle. Tx: Aural toilet, topical antibiotics/steroids.
• Furunculosis: Staph aureus infection of a single hair follicle. Confined to lateral 1/3 (cartilaginous part) of EAC.
• Otomycosis: Fungal Otitis Externa. Aspergillus (80-90% - black dots), Candida (creamy). Extreme itching. Tx: Antifungal (clotrimazole, nystatin).
• Bullous Myringitis: Vesicles on Tympanic Membrane (TM). Sudden severe pain. Viral or Bacterial (same as Acute Otitis Media).

Necrotizing Otitis Externa (NOE)

• Definition: Skull base osteomyelitis. Highly mortal.
• Risk Group: Diabetics and Immunocompromised.
• Pathogen: Pseudomonas aeruginosa.
• Clinical Features: Severe deep nocturnal otalgia, granulations in EAC, Cranial nerve palsies (VII, VI, V, IX, X).
• Diagnosis: CT scan. Tc99 bone scan (osteoblast activity - diagnosis). Gallium 67 (WBC activity - follow up).
• Treatment: Strict diabetic control, long-term systemic antibiotics (Fluoroquinolones like ciprofloxacin for 6-8 weeks).

Other Conditions (Foreign Bodies, Neoplasms, Congenital)

• Foreign Body in Ear: Animated (insects/flies) MUST be killed with alcohol or olive oil before removal. Non-animated removed via Jobson horn probe, syringing, or suction.
• Neoplasms: BCC (mostly related to sun exposure) and SCC. Treated with wide local excision or radiotherapy.
• Congenital Anomalies: Preauricular sinus, Atresia of canal, Bat ear (prominent ear).
• Acquired Atresia & Stenosis: From trauma, burns, or recurrent OE. Treated with polythene tubes or meatoplasty.
• Wax (Cerumen): Wet (dominant trait), Dry (recessive). Bacteriostatic due to acidity.
• Keratosis Obturans: Large plug of desquamated keratin in EAC. Causes severe pain & deafness.
• Hematoma Auris: Subperichondrial blood collection (wrestlers/boxers). Tx: Evacuate and compress to prevent cauliflower ear.

💡 Quick Exam Hints

• Pain on moving the tragus is the hallmark of Acute Otitis Externa (Swimmer's Ear).
• Furunculosis is impossible in the bony part of the canal (no hair follicles there).
• Black dots (Wet newspaper appearance) in the ear canal strongly indicates Aspergillus Otomycosis.
• Necrotizing Otitis Externa is skull base osteomyelitis caused by Pseudomonas, almost exclusively in elderly diabetics.
• Always kill a live insect with alcohol or oil before attempting to remove it from the ear.

Lecture 4: Acute Otitis Media (AOM)

Definition & Aetiology

• Definition: Rapid onset inflammation of middle ear cleft + effusion. (<12 weeks).
• Subgroups:
  1. Sporadic: Infrequent.
  2. Resistant: Persists beyond 3-5 days of antibiotics.
  3. Persistent: Relapses within 6 days of finishing antibiotics.
  4. Recurrent: 3+ episodes in 6 months, or 4-6 in 12 months.
• Pathogens: Viral URTI usually precedes bacterial. Streptococcus pneumoniae (most common), Haemophilus influenzae, Moraxella catarrhalis. Common viruses: RSV.
• Risk Factors: Age <1 year, Daycare, bottle feeding (breastfeeding is protective), passive smoking.
• Routes of Spread: Eustachian tube (Most Common), through TM perforation, or Haematogenous.

Clinical Features & Treatment

• Symptoms: Rapid otalgia, fever, crying, ear pulling. Follows coryzal symptoms by 3-4 days.
• Signs: TM is opaque, yellow/red, bulging, and hypomobile.
• Treatment:
  1. Conservative: Analgesics (Paracetamol). Watchful waiting for 48 hours.
  2. Antibiotics (Amoxicillin, Macrolides, Ceftriaxone) indicated if: <6 months old, <2 years with recurrence, no improvement after 48h, severe symptoms, high-risk child (Down syndrome, cleft palate).
  3. Surgery (Myringotomy): Severe pain, recurrent, or complications present.
• Outcomes: Resolve, Resist, Persist, Recur, or Progress to TM Perforation/Complications.

💡 Quick Exam Hints

• Streptococcus pneumoniae is the most common bacterial cause of AOM.
• A bulging, red, and hypomobile tympanic membrane is the most reliable clinical sign of AOM.
• Most cases of AOM resolve spontaneously; Watchful Waiting is the initial step for uncomplicated cases.
• Amoxicillin is the first-line antibiotic when treatment is indicated.
• Decongestants and antihistamines are NOT recommended due to side effects.

Lecture 5: Secretory Otitis Media (SOM / OME)

Features & Pathophysiology

• Definition: Fluid accumulation behind intact TM without acute infection signs. Also called Glue Ear or Otitis Media with Effusion (OME).
• Pathophysiology: Eustachian tube dysfunction (due to adenoids, cleft palate, allergy) causes negative pressure -> fluid transudation.
• Symptoms: Conductive hearing loss, delayed speech. Otalgia is mild/intermittent.
• Signs: Opaque TM, loss of light reflex, retracted TM with decreased mobility.

Diagnosis, Treatment & Complications

• Diagnosis: Tympanometry shows a Flat Type B curve.
• Treatment: Watchful waiting (often resolves spontaneously). If persistent: Myringotomy with Tympanostomy tube (Grommet) +/- Adenoidectomy.
• Complications of SOM: Recurrent AOM, Chronic masked mastoiditis, Retraction pockets/Atelectatic ear, Cholesteatoma, TM Perforation, and Tympanosclerosis.

💡 Quick Exam Hints

• SOM is the most common cause of acquired hearing loss in childhood.
• Unlike AOM, SOM presents without acute signs of inflammation (no severe pain or fever).
• The classic tympanogram finding is a Flat Type B curve.
• Spontaneous resolution is common, making Watchful Waiting the primary management.
• Surgical treatment involves Ventilation tubes (Grommets) to aerate the middle ear.

Lecture 6: Chronic Suppurative Otitis Media (CSOM)

Classifications & Bacteriology

• Definition: Pars tensa/flaccida abnormality lasting > 3 months.
• Bacteriology: Pseudomonas, Proteus, E.coli, Staph aureus, Anaerobes.
• Types:
  1. Active Squamous (Cholesteatoma).
  2. Inactive Squamous (Retraction pocket/Atelectasis).
  3. Active Mucosal (Wet central perforation).
  4. Inactive Mucosal (Dry central perforation).

Cholesteatoma Types & Theories

• Definition (Active Squamous): Not a tumor, no cholesterol. It is keratinized squamous epithelium in the middle ear. Highly destructive (bone erosion). Scanty, foul-smelling discharge. Marginal or attic perforation.
• Types of Cholesteatoma:
  - Congenital: Embryonic rest cells behind an intact TM.
  - Acquired Primary: Results from a pre-existing retracted drum (no previous perforation).
  - Acquired Secondary: Secondary to recurrent otorrhea and attic perforation.
• Theories of Development: Migration, Invagination, Basal cell hyperplasia, Squamous metaplasia.

Diagnosis & Treatment

• Investigation: High Resolution CT (HRCT) Temporal bone is gold standard. Fistula test positive if SCC fistula present.
• Treatment: Aural toilet, Topical Quinolones. Surgery is definitive for Cholesteatoma (Tympanomastoidectomy: Canal wall up or down).

💡 Quick Exam Hints

• CSOM diagnosis requires symptoms lasting for more than 3 months.
• Pseudomonas is the most common bacteria isolated in CSOM.
• Cholesteatoma is a misnomer; it is simply misplaced squamous epithelium (skin in the wrong place).
• A marginal or attic perforation points to Cholesteatoma (unsafe), while a central perforation points to mucosal disease (safe).
• High-Resolution CT (HRCT) of the temporal bone is the gold standard investigation.

Lecture 7: CSOM Complications

Pathways of Spread & Warning Signs

• Pathways: Bone erosion (most common), Retrograde thrombophlebitis, Normal anatomical openings (Oval/Round windows).
• Warning Signs of Intracranial Spread: Deep boring ear pain in a chronic discharging ear, severe headache, foul creamy discharge, high fever, stiff neck / photophobia / altered consciousness (meningitis), visual field defects (brain abscess).

List of Complications

• Intratemporal: Mastoiditis, Facial paralysis, Labyrinthine fistula, Labyrinthitis.
• Extratemporal: Postauricular abscess, Bezold's abscess (neck), Citelli's abscess.
• Intracranial: Epidural/Subdural abscess (Subdural is most common), Meningitis, Brain abscess (Temporal lobe or Cerebellum), Lateral sinus thrombophlebitis, Otitic hydrocephalus.

💡 Quick Exam Hints

• The appearance of deep boring ear pain in chronic otorrhea is a major red flag for impending intracranial complications.
• Bone erosion is the most common pathway for the spread of infection.
• A stiff neck in a CSOM patient usually indicates meningitis.
• Visual field defects are one of the earliest signs of a brain abscess.
• Otitic brain abscesses almost exclusively occur in the Temporal lobe or Cerebellum.

Lecture 8: Hearing Loss (Deafness)

Definitions & Types

• Degrees: Mild (26-40 dB), Moderate (41-55 dB), Severe (71-90 dB), Profound (> 90 dB).
• Conductive Hearing Loss (CHL): Due to External issues (Wax, Foreign Body, Otitis Externa) or Middle Ear issues (AOM, CSOM, SOM, Otosclerosis, Ossicular discontinuity).
• Sensorineural Hearing Loss (SNHL):
  1. Congenital: Genetic 50% (Syndromic: Pendred/Usher vs Non-Syndromic) or Environmental 50% (CMV, Ototoxicity, Prematurity).
  2. Acquired: Aging (Presbycusis), Noise, Infections (Mumps/Syphilis), Vascular (CVA), Meniere's, Vestibular Schwannoma, Ototoxicity, Multiple Sclerosis.

Rehabilitation & Implants

• Hearing Aids: Behind the ear is the most common type. Components: Microphone, Amplifier, Receiver.
• Cochlear Implants: Captures sound and converts to electrical signals to directly stimulate the cochlear nerve fibers. Indicated for bilateral severe to profound SNHL with minimal benefit from hearing aids.
• Cochlear Implant Complications: Facial nerve palsy, Meningitis, CSF leakage, device migration/failure, wound infection.

💡 Quick Exam Hints

• A hearing loss of > 90 dB is classified as Profound.
• Presbycusis is the most common cause of acquired, age-related sensorineural hearing loss.
• Behind the ear is the most frequently prescribed type of hearing aid.
• Cochlear implants bypass damaged hair cells to directly stimulate the auditory nerve.
• Facial nerve palsy and Meningitis are serious complications of Cochlear Implantation.

Lecture 9: Tinnitus & Vertigo

Tinnitus & Its Management

• Definition: Perception of sound without external source. Subjective is more common than Objective. Non-pulsatile is always subjective.
• Objective (Pulsatile): Vascular (Glomus tumors, AVM, Atherosclerosis), Neuromuscular (Palatal myoclonus).
• Subjective: Meniere's, Noise exposure, Presbycusis, Ototoxicity (Aspirin, Aminoglycosides), Vestibular Schwannoma.
• Management:
  - Avoid exacerbators (Aspirin, NSAIDs, Caffeine, Smoking).
  - Broadband Masking at night.
  - Hearing aids (if HL is present).
  - Habituation/Retraining therapy and treating concurrent anxiety/depression (Tricyclics, Benzodiazepines).

Vertigo & Its Management

• Definition: Illusion of movement (rotation).
• Peripheral Causes:
  - Benign Paroxysmal Positional Vertigo (BPPV): Most common, lasts seconds, provoked by head movement.
  - Meniere's Disease: Fluctuating hearing loss, aural fullness, tinnitus, vertigo lasting minutes to hours.
  - Vestibular Neuritis: Acute severe vertigo lasting days, often post-URTI.
• Central Causes: Migraine, CVA, Multiple Sclerosis.
• Management: Vestibular rehabilitation (highly recommended), Medical (Labyrinthine sedatives: Betahistine, Cinnarizine, prochlorperazine), Surgery (Labyrinthectomy for Meniere's, posterior canal obliteration for BPPV).

💡 Quick Exam Hints

• If tinnitus is non-pulsatile, it is ALWAYS subjective.
• BPPV is triggered by head position changes and lasts only seconds.
• Meniere's disease attacks typically last for minutes to hours.
• Vestibular Neuritis causes severe vertigo that lasts for days.
• Betahistine and Cinnarizine are the mainstay labyrinthine sedatives for vertigo management.

Lecture 10: Nose Anatomy & Paranasal Sinuses

Nasal Anatomy & Mucosa

• Framework: Upper 1/3 is Bony (nasal bones). Lower 2/3 is Cartilaginous.
• Lateral Wall: Contains Superior, Middle, and Inferior turbinates/meati.
  - Middle Meatus: Most important. Receives maxillary, frontal, anterior ethmoid sinuses. Contains Bulla ethmoidalis & Hiatus semilunaris.
  - Inferior Meatus: Receives nasolacrimal duct.
  - Spheno-ethmoidal recess: Receives sphenoid sinus.
• Epithelium:
  1. Respiratory: Lower 2/3, ciliated pseudostratified columnar, pink.
  2. Olfactory: Upper 1/3, non-ciliated, yellow.

Vascular & Nerve Supply / Functions

• Blood Supply: Little's Area (Kiesselbach's plexus) at antero-inferior septum. Anastomosis of 4 arteries: Sphenopalatine, Greater palatine, Superior labial (from External Carotid) + Anterior ethmoidal (from Internal Carotid).
• Nerve Supply: Ophthalmic & Maxillary (Trigeminal - sensory). Vidian nerve (Secretory: Parasympathetic = rhinorrhea, Sympathetic = vasoconstriction). Olfactory Nerve (Smell).
• Functions of Paranasal Sinuses: Resonance of voice, Air conditioning of inspired air, Reduce weight of skull, Thermal insulation of skull base/orbit, and Protection of the eye from trauma.

💡 Quick Exam Hints

• The Middle Meatus is the most complex and important area, receiving drainage from the Maxillary, Frontal, and Anterior Ethmoid sinuses.
• The Inferior Meatus receives the nasolacrimal duct.
• Little's Area (antero-inferior septum) is the most common site for epistaxis (nosebleeds).
• Respiratory epithelium covers the lower 2/3, while Olfactory epithelium covers the upper 1/3.
• Parasympathetic stimulation via the Vidian nerve causes vasodilatation and rhinorrhea.

Lecture 11: Acute Rhinosinusitis (ARS) & Nasal Furunculosis

ARS Definition & Pathophysiology

• Definition: Symptoms lasting < 12 weeks. Requires 2+ symptoms (nasal blockage or discharge MUST be one) +/- facial pain +/- hyposmia.
• Pathophysiology: Preceding Viral URTI leads to stasis -> Secondary Bacterial Infection (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis).
• M/C Sinus Involved: Adults = Maxillary. Children = Ethmoidal.

Diagnosis, Complications & Furunculosis

• Diagnosis: Clinical. Plain X-ray is obsolete. CT without contrast is the first line screening study if needed (for complications).
• Treatment: Analgesia, Decongestants, Antibiotics (Amoxicillin, Cephalosporins).
• Complications: Periorbital/Orbital cellulitis (spread via lamina papyracea), Pott's puffy tumor (frontal bone osteomyelitis), Intracranial abscesses (Subdural is most common), Cavernous sinus thrombosis.
• Nasal Furunculosis: Acute Staph infection of a hair follicle. Patient presents with facial pain/tender nostril. Complication: Cellulitis of upper lip and Cavernous Sinus Thrombosis (due to retrograde venous drainage).

💡 Quick Exam Hints

• ARS is defined by symptoms lasting less than 12 weeks.
• The Maxillary sinus is most commonly affected in adults, while the Ethmoidal sinus is most common in children.
• Plain X-rays are obsolete; CT without contrast is the first-line radiological study if needed.
• Pott's Puffy Tumor is a subperiosteal abscess caused by osteomyelitis of the frontal bone.
• Nasal Furunculosis is very dangerous because it can lead to Cavernous Sinus Thrombosis.

Lecture 12: Chronic Rhinosinusitis (CRS)

Features & Pathophysiology

• Definition: Symptoms lasting > 12 weeks + Endoscopic signs (polyps, mucopus) OR CT changes (mucosal thickening).
• Symptoms: Local (Nasal obstruction, discharge, facial pain, anosmia). Distant (Cough, sore throat, dysphonia, fever, halitosis).
• Aetiology: Multifactorial. Staphylococcus aureus (superantigen hypothesis), Bacterial biofilms, Ciliary disorders (Cystic Fibrosis, Kartagener's syndrome).

Diagnosis & Treatment

• Diagnosis: Endoscopy. CT scanning is radiological investigation of choice (shows sinus opacity/thickening).
• Medical Treatment: Long-term Macrolides, Intranasal Corticosteroids (Beclomethasone/Fluticasone - safe long term), Saline irrigation.
• Surgical Treatment: Functional Endoscopic Sinus Surgery (FESS) if medical fails. FESS options: Antral puncture/Intranasal antrostomy/Caldwell-Luc (Maxillary), Trephination/Frontoethmoidectomy (Frontal).

💡 Quick Exam Hints

• CRS requires symptoms to be present for more than 12 weeks.
• Staphylococcus aureus and bacterial biofilms play a major role in CRS.
• CT scanning of the sinuses is the radiological investigation of choice before surgery.
• Intranasal Corticosteroids are the cornerstone of medical therapy and are safe for long-term use.
• Functional Endoscopic Sinus Surgery (FESS) is the primary surgical intervention for medical failures.

Lecture 13: Nasal Polyposis

Non-Neoplastic Polyps

• Pathology: Oedematous grapelike protrusions. Eosinophilic infiltration. Mostly arise from Middle Meatus (ethmoidal complex).
• Associated Conditions: Chronic Rhinosinusitis, Asthma, Samter's Triad (Nasal polyps + Asthma + Aspirin intolerance), Cystic Fibrosis, Allergic Fungal Sinusitis.
• Other Syndromic Causes: Young's syndrome (sinopulmonary disease + azoospermia), Churg-Strauss (asthma, fever, eosinophilia, vasculitis), Kartagener's (bronchiectasis, sinusitis, situs inversus, ciliary dyskinesia).
• Signs: Pale, smooth, insensitive to probing, do NOT bleed on touch. Usually bilateral.
• Treatment: Intranasal Corticosteroids (reduces recurrence). Surgical: FESS.

Antrochoanal Polyp

• Origin: Mucosa of the Maxillary Antrum, grows into choana/nasopharynx.
• Features: Mostly in Children/Young adults. Usually Single and Unilateral.
• Symptoms: Unilateral obstruction, hyponasality.
• Treatment: Surgical avulsion via FESS. Avoid Caldwell-Luc in children to prevent dental damage.

💡 Quick Exam Hints

• True nasal polyps are insensitive to probing and do not bleed on touch (unlike tumors).
• Samter's Triad = Nasal polyps + Asthma + Aspirin intolerance.
• Ordinary (ethmoidal) polyps are typically multiple and bilateral.
• Antrochoanal polyps originate in the maxillary sinus, and are typically single and unilateral (common in children).
• Young's, Churg-Strauss, and Kartagener's syndromes are high-yield systemic causes of nasal polyposis.

Lecture 14: Allergic & Non-Allergic Rhinitis

Allergic Rhinitis (AR)

• Definition: IgE mediated reaction.
• Classification:
  - Intermittent: < 4 days/week OR < 4 consecutive weeks/year.
  - Persistent: > 4 days/week AND > 4 consecutive weeks/year.
  - Severity: Mild (normal sleep/activity) vs Moderate-Severe (abnormal sleep, impaired activities).
• Signs & Symptoms: Watery rhinorrhea, sneezing, nasal obstruction, eye itching. Mucosa is pale or violet. Children show allergic salute (transverse nasal crease). Eosinophils in mucus.
• Investigations: Skin prick test, RAST (specific IgE).
• Pharmacology:
  - Intranasal Corticosteroids: Most effective overall.
  - H1 Antihistamines: Good for sneezing/itching, poor for congestion. 2nd gen (Cetirizine, Loratadine) has less sedation.
  - Anticholinergics (Ipratropium): Exclusively blocks rhinorrhea.
  - Immunotherapy: SC or sublingual administration for definitive treatment.

Non-Allergic Rhinitis

• Definition: Same symptoms as AR but Negative allergy tests.
• Types: Idiopathic (Vasomotor Rhinitis), Hormonal, Drug-induced, NARES (Non-Allergic Rhinitis with Eosinophilia Syndrome).
• Treatment: Avoid trigger. Medical: Similar to AR (Steroids, Antihistamines). Surgical: Turbinate cautery/ablation if medical fails (beware total turbinectomy -> risks atrophic rhinitis).

💡 Quick Exam Hints

• Allergic rhinitis is an IgE-mediated hypersensitivity reaction.
• Persistent AR is defined as symptoms lasting more than 4 days a week AND more than 4 weeks a year.
• The nasal mucosa in allergic rhinitis typically appears pale or violet (not red).
• Intranasal Corticosteroids are the most effective pharmacological treatment for AR.
• Ipratropium (Anticholinergic) is uniquely targeted to stop excessive rhinorrhea.

Section 15: High-Yield Clinical Comparisons

1. Endolymph vs. Perilymph

Feature	Endolymph	Perilymph
Location	Membranous Labyrinth (Scala Media, Saccule, Utricle)	Osseous Labyrinth (Scala Vestibuli, Scala Tympani)
Composition	Similar to intracellular fluid (High K+, Low Na+)	Similar to extracellular fluid (High Na+, Low K+)

2. Acute Otitis Media (AOM) vs. Secretory Otitis Media (SOM/OME)

Feature	Acute Otitis Media (AOM)	Secretory Otitis Media (SOM)
Inflammation Signs	Present (Severe pain, fever, toxicity)	Absent (No acute pain or fever)
Tympanic Membrane	Red, opaque, bulging	Opaque, retracted, loss of light reflex
Tympanometry	Not routinely used (clinical dx)	Flat Type B curve
Primary Treatment	Watchful waiting, then Amoxicillin	Watchful waiting, then Grommet tube

3. Active Squamous (Cholesteatoma) vs. Active Mucosal CSOM

Feature	Active Squamous CSOM (Cholesteatoma)	Active Mucosal CSOM
Nature of Disease	Unsafe (Bone destructive)	Safe (Confined to mucosa)
Perforation Site	Marginal or Attic	Central
Discharge	Scanty, purulent, foul-smelling	Copious, mucopurulent, odorless
Findings	Pearly white flakes of keratin	Edematous mucosa, central hole

4. Objective Tinnitus vs. Subjective Tinnitus

Feature	Objective Tinnitus	Subjective Tinnitus
Audibility	Heard by patient AND examiner	Heard ONLY by the patient
Prevalence	Rare	Most Common
Rhythm	Usually Pulsatile (synchronous with pulse)	Non-pulsatile
Common Causes	Glomus tumor, AVM, Palatal myoclonus	Meniere's, Presbycusis, Noise, Ototoxicity

5. Peripheral Vertigo vs. Central Vertigo

Feature	Peripheral Vertigo	Central Vertigo
Origin	Vestibular Labyrinth / Inner Ear	Brain stem, Cerebellum, Cortex
Common Causes	BPPV, Meniere's disease, Vestibular Neuritis	Migraine, CVA (Stroke), Multiple Sclerosis
Associated Symptoms	Hearing loss, tinnitus, aural fullness	Neurological deficits (weakness, diplopia)

6. Ethmoidal Nasal Polyps vs. Antrochoanal Polyp

Feature	Ethmoidal Nasal Polyps	Antrochoanal Polyp
Origin	Ethmoidal complex (Middle Meatus)	Mucosa of Maxillary Antrum
Patient Age	Adults	Children and Young Adults
Presentation	Multiple and Bilateral	Single and Unilateral
Associated with	Allergy, Asthma, Cystic Fibrosis	Unknown (allergy/infection suspected)

7. Allergic Rhinitis vs. Non-Allergic Rhinitis

Feature	Allergic Rhinitis	Non-Allergic Rhinitis
Pathophysiology	IgE-mediated hypersensitivity	Not IgE mediated (Idiopathic, drug, hormonal)
Allergy Tests (Skin/RAST)	Positive	Negative
Trigger Factors	Specific allergens (pollen, dust mites, pets)	Changes in temp, smells, smoke, stress