Respiratory — 5-min cram sheet

Respiratory — 5-min cram sheet

_Built from the pulmo disease index. Deck-faithful._

Buzzword → answer (the vignette reflex)

• Curschmann spirals + Charcot-Leyden crystals (mucous plugs) → bronchial asthma
• Eggshell calcification of hilar lymph nodes → silicosis (pathognomonic)
• Ferruginous bodies (barbell golden-brown rods, Prussian blue +) → asbestos / asbestosis
• Comet tail sign (round opacity, irregular outline) → rounded atelectasis (asbestos)
• Signet ring sign (airway > artery) on HRCT → bronchiectasis
• Lupus pernio (facial lesion) → sarcoidosis (pathognomonic); non-caseating granuloma → sarcoidosis
• Caseating granuloma + Langhans giant cells + central caseous necrosis → TB tubercle
• Bulging fissure sign (RUL, DM/alcoholic) → Klebsiella / Friedlander's pneumonia
• Lady Windermere (RML + lingula nodular bronchiectasis, elderly woman) → NTM / MAC
• Fungus ball in a pre-existing (old TB) cavity → aspergilloma
• "Cannonball" nodules (multiple round nodules) → lung metastases
• Pleural rind encasing lung + Calretinin⁺ / TTF-1⁻ → malignant mesothelioma
• Hampton's hump (peripheral wedge infarct) / S1Q3T3 → pulmonary embolism
• Hyaline membranes (histological hallmark) → ARDS
• Crazy paving + milky BAL with foamy macrophages → PAP; headcheese sign → hypersensitivity pneumonitis
• Sail sign → LLL collapse; Luftsichel sign (air crescent) → LUL collapse
• Salt-and-pepper chromatin + nuclear molding → SCLC; keratin pearls + intercellular bridges → squamous cell carcinoma
• Pancoast (apical) tumour → Horner's syndrome
• "Angel wings" (massive upper-lobe PMF) → complicated coal worker's pneumoconiosis

Imaging / spirometry / histology → diagnosis

Criteria / staging / scores at a glance

• GINA 2025 asthma = chronic airway inflammation + variable symptoms + variable expiratory airflow limitation (asthma = variable, COPD = persistent).
• Asthma dx: pre-BD FEV1/FVC <80%, FEV1 <80% pred; reversibility ↑≥200 mL AND ≥12% post-salbutamol; PEF diurnal variability >10%; bronchial challenge fall in FEV1 ≥20%.
• Life-threatening asthma: confusion, hypotension, RR >30, SpO₂ <90%, silent chest.
• GINA discharge: SpO₂ >94% RA, PFT >60–80% predicted, step-up + review 1–2 wk.
• COPD (GOLD 2025) = post-BD FEV1/FVC <70%.
• GOLD severity (post-BD FEV1 %pred): 1 ≥80% · 2 50–<80% · 3 30–<50% · 4 <30% (FEV1 <50% = Roflumilast threshold).
• GOLD ABE: A = 0–1 exac (no hosp) + mMRC 0–1 or CAT <10 → single BD; B = 0–1 exac + mMRC ≥2 or CAT ≥10 → LABA+LAMA; E = ≥2 moderate exac or ≥1 hosp → LABA+LAMA (+ICS if eos ≥300).
• mMRC 0–4; ≥2 = highly symptomatic. CAT <10 = Group A, ≥10 = Group B.
• COPD exacerbation = worsening symptoms over <14 days, usually infection.
• IDSA/ATS severe pneumonia = 1 major (septic shock needing vasopressors / resp failure needing MV) OR 3 minor (RR ≥30, IV-fluid-corrected hypotension, hypothermia, confusion, leukopenia <4,000, thrombocytopenia <100,000, BUN ≥20, P:F ≤250, multilobar).
• CURB-65: Confusion (new) · Urea >7 mmol/L (20 mg/dL) · RR >30 · SBP <90 or DBP <60 · age >65. Score 0–1 home, 2 ward, 3–5 ICU.
• MAFIA PCC (anti-Pseudomonal): Meropenem, Aminoglycosides, Fluoroquinolones (NOT Moxifloxacin), Imipenem, Aztreonam, Piperacillin-tazobactam, Ceftazidime, Cefepime.
• Responsive pneumonia 72h (all 7): T ≤37.8°C, HR ≤100, RR ≤24, SBP ≥90, SpO₂ ≥90% RA, normal mental status, normal oral intake.
• CAP treatment duration: 3–4 d non-severe stable; ≥5 d severe/deteriorating; 7+ d Egypt.
• Corticosteroid in CAP: severe CAP + (septic shock OR P:F <300 OR rapid progression ≤3 d).
• Lobar pneumonia stages: congestion 1–2 d → red hepatization 3–4 d → grey hepatization 1 wk → resolution 1–2 wk.
• TST positivity (induration): ≥5 mm = HIV / recent contact / old TB on CXR / immunosuppressed; ≥10 mm = recent arrival <5 yr / IVDU / high-risk settings / DM, silicosis, CKD, steroids, malignancy; ≥15 mm = no risk factor.
• ADA cut-offs: CSF >8 U/L (TB meningitis) · ascitic >36 U/L · pleural >70 IU/L highly suggestive TB, <40 excludes, >40 + fluid/serum ratio ≥2 = TB effusion.
• QFT-G (IGRA) vs TST: IGRA = ESAT-6 + CFP-10, no BCG cross-react, higher specificity, 1 visit, 24 h (blood processed within 12 h); TST = PPD single, BCG false-positive, 2 visits, 48–72 h.
• TB regimen (new): 2 mo HRZE → 4 mo HR. Daily/daily optimal; intermittent 3×/wk only with DOT and NOT HIV.
• HRZES daily doses (mg/kg): H 5 (max 300) · R 10 (max 600) · Z 25 · E 15 · S 15. Streptomycin = only injectable first-line.
• TB monitoring: sputum at 2 mo + completion; LFTs (AST/ALT/bili/CBC) twice weekly first 2 wk then monthly.
• MDR-TB = resistance to both Isoniazid + Rifampicin.
• Light's criteria (exudate if any one): pleural/serum protein >0.5; pleural/serum LDH >0.6; pleural LDH >2/3 ULN serum.
• Scadding CXR staging (NOT progressive): I bilateral hilar adenopathy · II hilar + infiltrates · III infiltrates only · IV fibrosis/honeycombing.
• BAL CD4/CD8: sarcoidosis ≥2.5 · hypersensitivity pneumonitis <1 (neutrophilia → worse prognosis).
• Reid classification (mildest → severest): cylindrical → varicose → cystic (saccular).
• Runyon (NTM): 1 slow photochromogen (kansasii, marinum) · 2 slow scotochromogen (scrofulaceum) · 3 slow non-photochromogen (avium/MAC) · 4 fast growers <7 d (fortuitum, chelonae, abscessus).
• NTM pulmonary dx = ALL radiological (symptoms + cavitary/nodular lesion + exclude other) + ONE microbiological (2 positive sputum cultures OR 1 bronchial wash OR biopsy + histology).
• Lung cancer %: 95% of lung tumours are primary; NSCLC 85% (squamous 30%, non-squamous 70% → adeno 90% / large-cell 10%); SCLC 15%. Smoking = 80% of cases, 60× in heavy smokers.
• NSCLC TNM: T1–T4 (size + local invasion), N0–N3, M0/M1. Mets: liver, brain, bone, adrenal.
• SCLC: limited (one hemithorax, single radiation port) vs extensive.
• Berlin ARDS: acute ≤1 wk, bilateral opacities, not cardiac, P:F with PEEP ≥5. Severity by P:F — mild >200, moderate 100–200, severe ≤100.
• Revised Geneva (PE): clinical probability → PE-unlikely = D-dimer, PE-likely = CTPA.
• Simplified PESI (each 1 pt): age >80, chronic cardiopulmonary disease, cancer, HR ≥110, SBP <100, SaO₂ <90%. sPESI ≥1 = higher 30-day mortality risk.
• PE risk strat: low = sPESI 0 + no RV strain · intermediate = sPESI ≥1 or RV strain · high = haemodynamic instability → systemic thrombolysis.
• Pneumoconiosis latency: asbestosis 20–30 yr (<10 yr if very heavy) · mesothelioma up to 40 yr · chronic silicosis >15 yr · acute silicosis within months.

Discriminators that decide questions

1. Obstructive vs restrictive (spirometry step 1 = FEV1/FVC): obstructive = FEV1/FVC <0.7 (or <LLN), ↓FEV1, ↓FEF25–75, FVC normal/↓, TLC normal/↑; restrictive = normal/↑ FEV1/FVC, ↓FVC, ↓TLC.
2. Asthma vs COPD: asthma = variable + reversible (FEV1 ↑ ≥200 mL AND ≥12%), DLCO normal/high; COPD = persistent, post-BD FEV1/FVC <70%, low DLCO if emphysema.
3. Transudate vs exudate: exudate if any Light's criterion met (protein ratio >0.5 / LDH ratio >0.6 / LDH >2/3 ULN); transudate = heart failure, cirrhosis, hypoalbuminaemia, nephrotic; exudate = infection, malignancy, TB, PE, autoimmune.
4. Mediastinal shift AWAY vs TOWARD: away = tension pneumothorax / massive effusion (fluid/air pushes); toward = atelectasis / lobar collapse / fibrosis / lobectomy (volume loss pulls).
5. Mesothelioma vs adenocarcinoma (IHC): Calretinin⁺ / TTF-1⁻ = mesothelioma; TTF-1⁺ / Napsin-A⁺ = primary lung adenocarcinoma. (BAL CD4/CD8 ≥2.5 sarcoid vs <1 HP is the parallel ILD discriminator.)