ABOHNS Otolaryngology cheat sheet

Neck levels: I = submental/submandibular; II = upper jugular (skull base to hyoid); III = mid jugular (hyoid to cricothyroid membrane); IV = lower jugular (cricothyroid to clavicle); V = posterior triangle; VI = anterior/central compartment.

Levels I, II, and V are at highest risk for occult nodal metastasis from oral cavity primaries; the oral tongue drains first to levels I–II.

Nasopharyngeal carcinoma spreads to retropharyngeal nodes and level V before levels I–III, unlike most head and neck primaries.

Deep neck space infections: spaces include parapharyngeal, retropharyngeal, danger space, and prevertebral; the danger space extends from skull base to mediastinum and permits rapid spread.

Ludwig angina = bilateral submandibular/sublingual cellulitis with floor-of-mouth elevation; airway management precedes dental source control.

Lemierre syndrome = Fusobacterium necrophorum septic thrombophlebitis of the internal jugular vein after oropharyngeal infection.

Branchial cleft anomalies: first cleft near external auditory canal; second cleft most common, tract from anterior SCM border to tonsillar fossa; third/fourth tracts end near pyriform sinus.

Thyroglossal duct cyst: midline, moves with tongue protrusion; Sistrunk procedure removes cyst plus central hyoid body and tract to foramen cecum.

Rinne test: air > bone = positive (normal or sensorineural); bone > air = negative (conductive loss). Weber lateralizes to the conductive-loss ear or the better cochlea in sensorineural loss.

Pure-tone average = mean of thresholds at 500, 1000, and 2000 Hz; air-bone gap ≥10 dB suggests conductive component.

Acoustic neuroma (vestibular schwannoma) arises from vestibular (superior) division of CN VIII at the internal auditory canal; MRI with gadolinium is the study of choice.

Sudden sensorineural hearing loss: ≥30 dB across 3 contiguous frequencies in <72 hours; treat with high-dose corticosteroids, intratympanic steroids as salvage or adjunct.

Benign paroxysmal positional vertigo is caused by canalithiasis, most often posterior canal; Dix-Hallpike is diagnostic and canalith repositioning (Epley) is therapeutic.

Meniere disease = episodic vertigo, fluctuating sensorineural loss, tinnitus, aural fullness; endolymphatic hydrops is the histologic correlate.

Cholesteatoma: keratinizing squamous epithelium in the middle ear; epitympatic retraction pocket is common; treatment is surgical, with canal wall up or down mastoidectomy.

Otosclerosis: conductive loss with normal tympanic membrane, absent stapes reflex, Carhart notch at 2000 Hz; stapedotomy or amplification.

Ostiomeatal complex drains the maxillary, anterior ethmoid, and frontal sinuses; the sphenoid drains separately via the sphenoethmoid recess.

Sinus CT staging (Lund-Mackay): each sinus scored 0–2, plus ostiomeatal complex 0 or 2; total 0–24.

Functional endoscopic sinus surgery begins with uncinectomy and middle meatal antrostomy; the sphenoid ostium lies medial to the superior turbinate.

Frontal recess cells: agger nasi, frontal cell (Kuhn type I–IV), supraorbital ethmoid; Kuhn type III (frontal cell) and type IV (interfrontal septal cell) increase frontal sinus risk.

Cerebrospinal fluid leak: beta-2 transferrin is highly specific; beta-trace protein is an alternative marker.

Allergic fungal rhinosinusitis: nasal polyps, eosinophilic mucin, fungal hyphae on silver stain, and bone expansion/heterogeneous CT opacification.

Epistaxis: Kiesselbach plexus anteriorly (most common); posterior bleeding from sphenopalatine artery branches; sphenopalatine artery ligation or embolization for refractory posterior bleeding.

Nasal polyps are associated with aspirin-exacerbated respiratory disease (Samter triad: polyps, asthma, aspirin sensitivity) and with eosinophilic chronic rhinosinusitis.

Vocal fold vibration follows the myoelastic-aerodynamic theory; mucosal wave depends on the superficial lamina propria (Reinke space).

Vocal fold layers from superficial to deep: epithelium, superficial lamina propria, intermediate lamina propria, deep lamina propria, thyroarytenoid muscle.

Recurrent laryngeal nerve supplies all intrinsic laryngeal muscles except the cricothyroid (external branch of superior laryngeal nerve).

Left recurrent laryngeal nerve loops under the aortic arch; right loops under the right subclavian artery - left is longer and more often injured.

Spasmodic dysphonia: adductor type causes strained-strangled breaks; treatment is botulinum toxin injection into thyroarytenoid or posterior cricoarytenoid for abductor type.

Paradoxical vocal fold motion presents as inspiratory stridor with adducted folds on inspiration; treated with behavioral therapy and speech therapy.

Laryngeal electromyography helps distinguish vocal fold paralysis from fixation or cricoarytenoid arthritis.

Presbyphonia: age-related vocal fold atrophy with bowing and glottic gap; treatment includes voice therapy and injection augmentation.

TNM: T1 ≤2 cm, T2 >2–4 cm, T3 >4 cm or deep/extrinsic tongue muscle invasion, T4a moderately advanced local disease, T4b very advanced (unresectable).

Nodal staging: N1 single ipsilateral ≤3 cm; N2a single ipsilateral 3–6 cm; N2b multiple ipsilateral ≤6 cm; N2c bilateral/contralateral ≤6 cm; N3 >6 cm.

Tumor margins: 5 mm is the usual definition of a clear margin; close margins are typically 1–5 mm.

Sentinel lymph node biopsy is an option for early oral cavity squamous cell carcinoma with clinically N0 neck.

Human papillomavirus–positive oropharyngeal carcinoma has improved survival; p16 immunohistochemistry is the surrogate marker.

Radiotherapy dosing: 60–66 Gy for postoperative adjuvant; 70 Gy for definitive treatment of gross disease, typically 2 Gy per fraction.

Concurrent chemoradiation with cisplatin is standard for unresectable disease or positive margins/extranodal extension.

Salivary gland malignancy: mucoepidermoid carcinoma (MEC) is most common; adenoid cystic carcinoma has perineural spread and late distant metastasis.

Facial nerve branching: temporal (frontal), zygomatic, buccal, marginal mandibular, cervical; the marginal mandibular branch runs near the mandibular border and is at risk in neck dissection.

The facial nerve exits the stylomastoid foramen; the pes anserinus is the bifurcation into temporofacial and cervicofacial trunks.

Skin flap principles: random pattern flaps rely on subdermal plexus; axial flaps rely on named vessels; length-to-width ratio for random flaps usually ≤3:1.

Local flaps: advancement, rotation, transposition, and interpolation; the bilobed flap is useful for nasal tip defects.

Full-thickness skin grafts are best for defects with adequate vascular bed; composite grafts for nasal alar rim or helical rim.

Blepharoplasty: the orbital septum separates the preseptal from postseptal space; fat pads are medial, central, and lateral.

Rhinoplasty: the nasal valve is the narrowest point; spreader grafts widen the internal valve angle.

Cleft lip repair typically at 3–6 months (rule of 10s: weight ≥10 lb, hemoglobin ≥10 g/dL, age ≥10 weeks); palate repair at 9–18 months.

Acute otitis media: bulging tympanic membrane is the most specific finding; Streptococcus pneumoniae, nontypeable Haemophilus influenzae, and Moraxella catarrhalis are common pathogens.

Tympanostomy tube indications include recurrent AOM (≥3 episodes in 6 months or ≥4 in 12 months) and chronic otitis media with effusion ≥3 months with hearing loss.

Croup (laryngotracheobronchitis): barking cough, steeple sign on radiograph; treat with dexamethasone and nebulized epinephrine for severe cases.

Epiglottitis: drooling, tripod positioning, thumb sign; avoid agitating the child and secure the airway in the operating room.

Retropharyngeal abscess: neck stiffness, odynophagia, widened retropharyngeal space on CT; treatment is IV antibiotics with drainage for large collections.

Juvenile nasopharyngeal angiofibroma: adolescent males, epistaxis, nasal mass; treat with embolization and endoscopic resection; avoid biopsy.

Laryngomalacia: inspiratory stridor worse supine and with crying, improves with prone positioning; supraglottoplasty for severe cases.

Subglottic stenosis is graded by Cotton-Myer (I ≤50%, II 51–70%, III 71–99%, IV no lumen); treatment is dilation, laser, or laryngotracheal reconstruction.

Obstructive sleep apnea diagnosis: apnea-hypopnea index ≥5 with symptoms or ≥15 without symptoms on polysomnography.

Apnea = ≥90% airflow reduction for ≥10 seconds; hypopnea = ≥30% reduction with ≥3% desaturation or arousal.

Positive airway pressure is first-line therapy; adherence is commonly defined as ≥4 hours per night on ≥70% of nights.

Mallampati score, Friedman tongue position, and tonsil size help predict surgical candidacy for obstructive sleep apnea.

Drug-induced sleep endoscopy identifies levels of obstruction (palate, oropharynx, tongue base, epiglottis) to guide surgery.

Uvulopalatopharyngoplasty addresses retropalatal obstruction; success rates are modest and patient selection by DISE improves outcomes.

Hypoglossal nerve stimulation is indicated for CPAP-intolerant patients with BMI <32–35 kg/m² and favorable DISE findings.

Pediatric obstructive sleep apnea is most often adenotonsillar hypertrophy; adenotonsillectomy is first-line surgical treatment.

Recurrent laryngeal nerve injury causes hoarseness; bilateral injury causes airway obstruction; external branch of superior laryngeal nerve injury causes loss of pitch.

Superior parathyroid glands arise from the fourth pharyngeal pouch and are usually posterior; inferior glands arise from the third pouch and are more variable in location.

Hypocalcemia after total thyroidectomy: monitor calcium and parathyroid hormone; symptoms include perioral numbness and carpopedal spasm (Chvostek and Trousseau signs).

Papillary thyroid carcinoma spreads via lymphatics; follicular carcinoma spreads hematogenously to bone and lung.

Fine-needle aspiration with Bethesda categories guides management; Bethesda V/VI usually prompts surgery.

Medullary thyroid carcinoma arises from parafollicular C cells; calcitonin is the tumor marker; screen for RET mutation in MEN2.

Primary hyperparathyroidism: elevated calcium with inappropriately normal or high PTH; sestamibi and ultrasound guide focused parathyroidectomy.

Radioactive iodine is used for differentiated thyroid cancer after total thyroidectomy; it is not used for medullary or anaplastic carcinoma.

Type I hypersensitivity is IgE-mediated; type IV is T-cell mediated (delayed, e.g., contact dermatitis).

Allergic rhinitis is diagnosed by history plus skin prick testing or serum specific IgE; total IgE alone is not diagnostic.

Antihistamines block H1 receptors; intranasal corticosteroids are first-line for moderate-to-severe persistent allergic rhinitis.

Immunotherapy (subcutaneous or sublingual) modifies the disease course and is indicated for refractory symptoms or poor medication tolerance.

Anaphylaxis: epinephrine intramuscular 0.01 mg/kg (max 0.3–0.5 mg) into the lateral thigh is first-line; antihistamines and steroids are adjuncts.

Hereditary angioedema is bradykinin-mediated (C1 inhibitor deficiency); it does not respond to epinephrine or antihistamines; treat with C1 inhibitor, icatibant, or ecallantide.

Allergic fungal rhinosinusitis is a type I and type III hypersensitivity reaction; total IgE is often elevated.

Drug allergy: penicillin skin testing has high negative predictive value; desensitization is used when the drug is essential.