ENT Cheatsheet

Cheatsheet Content

### Lateral Wall of Nose - **Bony framework:** Maxilla, palatine, ethmoid, inferior concha. - **Conchae (Turbinates):** Superior, Middle, Inferior. Increase surface area, warm/humidify air. - **Meatuses:** Spaces below conchae. - **Inferior Meatus:** Nasolacrimal duct opens. - **Middle Meatus:** Frontal, Maxillary, Anterior Ethmoidal sinuses open. Contains bulla ethmoidalis & hiatus semilunaris. - **Superior Meatus:** Posterior Ethmoidal sinuses open. - **Ostia:** Openings of paranasal sinuses. - **Blood Supply:** Sphenopalatine artery (branch of maxillary a.), anterior/posterior ethmoidal arteries (branch of ophthalmic a.). ### Nasal Septum - **Components:** - **Bony:** Perpendicular plate of ethmoid (superior), Vomer (posteroinferior). - **Cartilaginous:** Quadrilateral cartilage (anterior). - **Membranous:** Smallest, most anterior part. - **Blood Supply:** - **Little's Area (Kiesselbach's Plexus):** Anterior part, rich anastomotic plexus. Formed by branches from anterior ethmoidal, posterior ethmoidal, sphenopalatine, greater palatine, and superior labial arteries. Common site of epistaxis. - Postero-superior: Sphenopalatine artery. - Antero-superior: Anterior ethmoidal artery. - **Nerve Supply:** Anterior ethmoidal nerve, Nasopalatine nerve. ### Epistaxis (Nosebleed) - **Causes:** - **Local:** Trauma (nose picking), septal deviation, dry mucosa, inflammation (rhinitis, sinusitis), foreign body, tumors (JNA, NPC). - **Systemic:** Hypertension, coagulopathies (hemophilia, Von Willebrand disease), anticoagulant meds, liver disease, Osler-Weber-Rendu syndrome. - **Types:** - **Anterior (90%):** From Little's area. Usually mild, self-limiting. - **Posterior (10%):** From Woodruff's plexus (postero-inferior part), sphenopalatine artery. More severe, often requires hospitalization. - **Management:** - **First Aid:** Lean forward, pinch soft part of nose for 10-15 min, cold compress. - **Medical:** Topical vasoconstrictors (oxymetazoline), nasal packing (anterior/posterior), cautery (chemical/electrical), ligation of vessels (sphenopalatine, anterior ethmoidal, external carotid). ### Chronic Rhinosinusitis (CRS) - **Definition:** Inflammation of nose and paranasal sinuses lasting >12 weeks. - **Symptoms:** Nasal obstruction, discharge (purulent/mucopurulent), facial pain/pressure, reduction/loss of smell. - **Types:** - **CRS without nasal polyps (CRSsNP):** More common, often associated with bacterial infection. - **CRS with nasal polyps (CRSwNP):** Often linked to allergic fungal rhinosinusitis, aspirin-exacerbated respiratory disease. - **Pathogenesis:** Multifactorial - ostial obstruction, mucociliary dysfunction, inflammation, bacterial biofilm, fungal sensitization. - **Diagnosis:** Clinical symptoms + endoscopy/CT scan confirms. - **Management:** - **Medical:** Nasal saline irrigation, topical nasal steroids (first line), oral steroids (short course), antibiotics (macrolides for anti-inflammatory effect), antifungals (controversial). - **Surgical:** Functional Endoscopic Sinus Surgery (FESS) - aims to restore ventilation and drainage of sinuses. ### Allergic Rhinitis - **Definition:** IgE-mediated inflammatory condition of nasal mucous membrane. - **Triggers:** Allergens (pollen, dust mites, pet dander, molds). - **Symptoms:** Sneezing, rhinorrhea (clear), nasal itching, nasal congestion. Often associated with allergic conjunctivitis, asthma. - **Classification:** - **Intermittent:** Symptoms 4 days/week AND >4 consecutive weeks. - **Mild/Moderate/Severe:** Based on impact on quality of life. - **Diagnosis:** Clinical history, skin prick test, specific IgE (RAST). - **Management:** - **Avoidance:** Identify and avoid triggers. - **Pharmacotherapy:** - **Antihistamines:** Oral (non-sedating), intranasal. - **Intranasal Corticosteroids (INCS):** Most effective for all symptoms. - **Leukotriene receptor antagonists:** (e.g., Montelukast) less effective than INCS. - **Decongestants:** Oral/topical (short-term only to avoid rhinitis medicamentosa). - **Immunotherapy:** Subcutaneous or sublingual for severe, persistent symptoms. ### Juvenile Nasopharyngeal Angiofibroma (JNA) - **Definition:** Benign, highly vascular tumor exclusively affecting adolescent males. - **Origin:** Sphenopalatine foramen. - **Symptoms:** Unilateral nasal obstruction, recurrent severe epistaxis (hallmark), facial swelling, proptosis (if orbital extension), conductive hearing loss (if Eustachian tube blocked). - **Diagnosis:** Endoscopy (smooth, reddish-blue mass), CT/MRI (to assess extension, classic "dumbbell" shape), angiography (pre-op embolization). **Biopsy is contraindicated due to severe bleeding risk.** - **Management:** - **Pre-operative embolization:** Essential to reduce intraoperative bleeding. - **Surgical excision:** Primary treatment. Approaches vary based on tumor size and extension (endoscopic, transpalatal, lateral rhinotomy). ### Nasopharyngeal Carcinoma (NPC) - **Definition:** Malignancy arising from the nasopharynx. - **Epidemiology:** Endemic in Southern China, Southeast Asia, North Africa. Associated with Epstein-Barr Virus (EBV), genetic factors, diet (salted fish). - **Symptoms:** - **Nasal:** Unilateral nasal obstruction, epistaxis, postnasal drip. - **Ear:** Unilateral conductive hearing loss (Eustachian tube obstruction), otitis media with effusion. - **Neck:** Painless neck mass (cervical lymphadenopathy - often first symptom). - **Neurological:** Cranial nerve palsies (esp. VI, V, IX, X, XI, XII) due to skull base invasion. - **Diagnosis:** Endoscopic guided biopsy of nasopharynx, MRI/CT for staging, EBV serology. - **Management:** Primarily **radiotherapy**, often combined with **chemotherapy**. Surgery has limited role. ### Squamous Cell Carcinoma (SCC) - **Definition:** Most common malignancy of head and neck region. - **Risk Factors:** Tobacco (smoking, chewing), alcohol, HPV (especially for oropharyngeal SCC), poor oral hygiene. - **Common Sites in ENT:** Larynx, oropharynx, oral cavity, hypopharynx, nasal cavity, paranasal sinuses. - **Symptoms:** Vary by site. - **Oral Cavity:** Non-healing ulcer, pain, mass. - **Oropharynx:** Sore throat, dysphagia, otalgia, neck lump. - **Larynx:** Hoarseness (early), dysphagia, dyspnea, stridor (late). - **Diagnosis:** Biopsy (definitive), endoscopy, CT/MRI (staging), PET scan. - **Management:** Surgery, radiotherapy, chemotherapy, or combined modalities depending on stage and site. ### Carcinoma of Larynx & Oropharynx #### Larynx - **Types:** Glottic (most common, best prognosis), Supraglottic, Subglottic. - **Symptoms:** - **Glottic:** Hoarseness (early symptom due to vocal cord involvement). - **Supraglottic:** Sore throat, dysphagia, otalgia (referred pain), neck mass (late). - **Subglottic:** Dyspnea, stridor (late). - **Diagnosis:** Laryngoscopy with biopsy, CT/MRI for staging. - **Management:** Early stage (T1/T2) - radiotherapy or partial laryngectomy. Advanced stage - total laryngectomy with neck dissection, often followed by chemoradiotherapy. #### Oropharynx - **Sites:** Tonsil, base of tongue, soft palate, posterior pharyngeal wall. - **Risk Factors:** HPV (esp. p16 positive), smoking, alcohol. - **Symptoms:** Sore throat, dysphagia, odynophagia, otalgia (referred), neck mass (lymph nodes). - **Diagnosis:** Oroscopy, direct laryngopharyngoscopy with biopsy, CT/MRI/PET for staging. - **Management:** Surgery (transoral robotic surgery, open), radiotherapy, chemotherapy, or combination. HPV-positive tumors often have better prognosis and may respond better to non-surgical treatment. ### Acoustic Neuroma (Vestibular Schwannoma) - **Definition:** Benign, slow-growing tumor arising from Schwann cells of the vestibular nerve (CN VIII), usually in the internal auditory canal (IAC) or cerebellopontine angle (CPA). - **Symptoms:** - **Unilateral progressive sensorineural hearing loss (SNHL):** Most common presenting symptom. - **Tinnitus:** Unilateral. - **Vertigo/Imbalance:** Less common early symptom than expected. - **Facial numbness/weakness:** Due to involvement of CN V, VII. - **Headache, hydrocephalus:** With large tumors. - **Diagnosis:** Audiometry (asymmetric SNHL, poor speech discrimination), Brainstem Auditory Evoked Potentials (BAEP), **MRI with gadolinium (gold standard)**. - **Management:** - **Observation (Watchful Waiting):** For small tumors, elderly, or those with comorbidities. - **Microsurgical Excision:** Via translabyrinthine, retrosigmoid, or middle fossa approach. - **Stereotactic Radiosurgery (Gamma Knife/CyberKnife):** For small to medium-sized tumors, or those unsuitable for surgery. ### Middle Ear Cleft - **Definition:** A continuous air-filled space comprising the Eustachian tube, middle ear cavity, mastoid antrum, and mastoid air cells. Lined by mucous membrane. - **Components:** - **Eustachian Tube:** Connects middle ear to nasopharynx. Equalizes pressure, drains secretions. - **Middle Ear (Tympanic Cavity):** Contains ossicles (malleus, incus, stapes). Transmits sound. - **Mastoid Antrum:** Air-filled cavity in mastoid process, connects to middle ear. - **Mastoid Air Cells:** Variable pneumatic spaces within the mastoid bone. - **Function:** Sound conduction, pressure equalization, protection. - **Clinical Relevance:** Pathway for spread of infection (e.g., otitis media to mastoiditis). ### Cholesteatoma - **Definition:** A destructive, expanding lesion of the middle ear and/or mastoid consisting of keratinizing squamous epithelium. It is not a tumor but a skin cyst that grows in the wrong place. - **Types:** - **Congenital:** Behind intact tympanic membrane, no history of otitis media or perforation. - **Acquired:** - **Primary Acquired:** Due to tympanic membrane retraction (e.g., pars flaccida retraction pocket) from chronic Eustachian tube dysfunction. - **Secondary Acquired:** Through a pre-existing tympanic membrane perforation. - **Pathology:** Accumulation of desquamated keratin, leading to bone erosion via pressure necrosis and enzymatic activity. - **Symptoms:** Chronic foul-smelling otorrhea, progressive conductive hearing loss, otalgia, vertigo, facial nerve palsy (complication). - **Complications:** Mastoiditis, labyrinthitis, facial nerve palsy, intracranial complications (meningitis, brain abscess). - **Diagnosis:** Otoscopy (retraction pocket, white cheesy material), CT scan (bone erosion, soft tissue mass). - **Management:** **Surgical excision** (mastoidectomy, tympanoplasty) is the only definitive treatment. Aims to remove all cholesteatoma, create a safe, dry ear, and preserve/improve hearing. ### Tonsillitis - **Definition:** Inflammation of the palatine tonsils. - **Causes:** - **Viral (most common):** Adenovirus, Rhinovirus, Influenza, EBV (infectious mononucleosis). - **Bacterial:** Group A Beta-Hemolytic Streptococcus (GABHS) - Strep throat. - **Symptoms:** Sore throat, dysphagia, fever, malaise, enlarged tender cervical lymph nodes, red and swollen tonsils (may have exudates/white spots). - **Complications:** Peritonsillar abscess (quinsy), rheumatic fever (GABHS), post-streptococcal glomerulonephritis. - **Diagnosis:** Clinical, rapid strep test, throat culture (for GABHS). - **Management:** - **Supportive:** Rest, fluids, analgesics (paracetamol, ibuprofen). - **Antibiotics:** For bacterial tonsillitis (e.g., Penicillin V). - **Tonsillectomy:** Indicated for recurrent infections (e.g., 7 episodes in 1 year, 5/year for 2 years, 3/year for 3 years), chronic tonsillitis, peritonsillar abscess, obstructive sleep apnea. ### Hypopharynx - **Definition:** The lowest part of the pharynx, extending from the level of the hyoid bone to the lower border of the cricoid cartilage (C6). - **Subsites:** - **Pyriform Sinus:** Lateral to the larynx. Most common site for hypopharyngeal carcinoma. - **Postcricoid Region:** Posterior wall of the cricoid cartilage. - **Posterior Pharyngeal Wall:** From the level of the hyoid bone to the cricoid. - **Function:** Directs food into the esophagus and air into the larynx. - **Clinical Relevance:** Common site for foreign body impaction, and malignancies (often aggressive). ### Laryngeal Inlet - **Definition:** The opening that connects the pharynx (specifically the hypopharynx) to the larynx. - **Boundaries:** - **Anteriorly:** Upper border of the epiglottis. - **Laterally:** Aryepiglottic folds (containing cuneiform and corniculate cartilages). - **Posteriorly:** Interarytenoid notch. - **Function:** Guards the entrance to the lower airway, preventing food and liquids from entering the trachea during swallowing. - **Clinical Relevance:** Swelling or obstruction (e.g., epiglottitis, trauma, tumors) can rapidly lead to airway compromise. ### Direct vs. Indirect Laryngoscopy #### Indirect Laryngoscopy - **Method:** Uses a laryngeal mirror or a rigid/flexible fiberoptic endoscope. - **View:** Provides a magnified, reversed (mirror) or direct (fiberoptic) view of the larynx. - **Anesthesia:** Usually topical anesthesia, sometimes no anesthesia for flexible. - **Indications:** Diagnostic evaluation of hoarseness, chronic cough, globus sensation, surveillance for malignancy. - **Advantages:** Outpatient procedure, less invasive. - **Disadvantages:** Limited view (especially posterior larynx), difficult in patients with strong gag reflex or anatomical variations, no access for biopsies/interventions. #### Direct Laryngoscopy - **Method:** Performed under general anesthesia using a rigid laryngoscope inserted into the mouth, directly visualizing the larynx. - **View:** Direct, magnified view of the entire larynx. - **Anesthesia:** General anesthesia. - **Indications:** Biopsy of lesions, removal of foreign bodies, laser surgery, laryngeal framework surgery, evaluation of subglottic/tracheal pathology. - **Advantages:** Provides excellent illumination and magnification, allows for bimanual palpation, permits biopsies and surgical interventions. - **Disadvantages:** Requires general anesthesia, more invasive, potential for dental/mucosal trauma.