15. lung cancer

review obstruction/restrictive lung patterns **

upper, middle, lower

lobes of the right lung

(2 lobes): upper, lower + lingula

lobes of the left lung

horizontal and oblique

fissures in the right lung

oblique only

fissures in the left lung

Right mainstem

= wider, shorter, more vertical

{RIGHT/LEFT} mainstem bronchus has a higher aspiration risk?

Pulmonary artery

Right: Anterior

Left: Superior

what is the RALS mnemonic?

type I pneumocytes

squamous, lines the aveoli

used for GAS EXCHANGE

pores of kohn = small openings between alveoli that allow air and macrophage movement. (& bac in pneumo)

type II pneumocytes

cuboidal and clustered on aveoli

2 functions:

• SURFACTANT (DDPC)

• STEM CELL PRECURSOR (makes pneumocytes/repair)

LUNG VOLUMES

know this

Ventilation → PaCO₂ / ETCO₂
Oxygenation → PaO₂ / SpO₂
Airflow/volumes → PFTs
Gas diffusion → DLCO

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Test	What it evaluates	High-yield interpretation
Spirometry ⭐	Airflow	Measures FEV₁, FVC, FEV₁/FVC
FEV₁	Volume exhaled in first second	↓ especially in obstructive disease
FVC	Total amount forcibly exhaled	↓ especially in restrictive disease
FEV₁/FVC	Obstruction	↓ = obstructive ⭐
TLC	Total lung capacity	↓ = restrictive ⭐; ↑ may occur with hyperinflation
RV	Air remaining after maximal expiration	↑ = air trapping
DLCO ⭐	Alveolar-capillary gas diffusion	↓ in emphysema, ILD, pulmonary vascular disease
Pulse oximetry	Oxygenation	Measures SpO₂
ABG ⭐	Oxygenation + ventilation + acid-base	PaO₂ = oxygenation; PaCO₂ = ventilation
Capnography	Ventilation	Measures ETCO₂; especially important during anesthesia
Exercise testing / 6-min walk	Functional cardiopulmonary reserve	Assesses exertional limitation/desaturation

	Obstructive	Restrictive
FEV₁	↓↓↓	↓
FVC	Normal/↓	↓↓
FEV₁/FVC	↓ ⭐	Normal/↑
TLC	Normal/↑	↓ ⭐
RV	↑	↓/normal

 physiologic evaluation of the lung.

“Can the lungs move air, exchange gas, and oxygenate the patient?”

USPSTF: ALL 3 required ⭐⭐⭐

Criteria	Requirement
Age	50–80 years
Smoking history	≥20 pack-years
Smoking status	Currently smokes OR quit within past 15 years

criteria for annual low dose chest CT screening

Quit smoking ≥15 years ago,

OR

Health status substantially limits life expectancy or ability/willingness to undergo curative lung cancer treatment.

when to stop screening with low dose CT?

lung cancer

number one cause of cancer death worldwide

Adenocarcinoma

(non-small cell)

most common primary lung tumor: females / nonsmokers

associated with digital clubbing & loc’d peripheral

histo: glandular pattern & +mucin

KRAS / EGFR / ALK

Adenocarcinoma (non-small cell) — most common markers

peripheral

(adeno = away)

loc of Adenocarcinoma (non-small cell)

Bronchioloalveolar subtype (Adenocarcinoma in situ)

CXR looks hazy similar to pneumonia;

aveolar “thickening” , tall columnar walls +mucus

*does NOT invade aveoli (more like a hug)

better prognosis 🙂

squamous cells carcinoma

Hilar mass arising from bronchus (centrally loc’d)

cavitation, cigs, hyperCa (due to PTHrP)

+keratin pearls, desmosomes (intracellular bridges)

Lab	Finding
Ca²⁺	↑
PTHrP	↑
PTH	↓
Phosphate	↓

seen in what cancer?

small cell (oat cell) carcinoma

central lung cancer

may cause neuro-paraneoplastic/endocrine syndromes: LEMS + SIADH + ectopic ACTH + Anti-Hu neurologic syndromes

MYC — very aggressive

small cell (oat cell) carcinoma is associated with what oncogene?

small cell (oat cell) carcinoma

kulchitchy’s cells —> small dark blue cells

+chromogranin A

neuro-specific: +enolase , +synpatophysin

History: Smoking history ⭐⭐⭐, age >50, secondhand smoke, radon, asbestos, occupational exposures, family history

PE: Persistent/new or changing cough ⭐, dyspnea, hemoptysis, chest pain, wheezing +/- constitunial symptoms

• Older smoker + new/change in chronic cough ± hemoptysis + weight loss → suspect lung cancer.

• Apical mass + shoulder pain + Horner syndrome → Pancoast tumor

• Central lung mass + facial swelling/distended neck veins → SVC syndrome

• Recurrent pneumonia in the SAME lobe → think obstructing lung tumor

P&E of lung cancer

sus CXR

—> CT chest

—> biopsy

• Central mass → Bronchoscopy/EBUS

• Peripheral mass → CT-guided transthoracic biopsy

• Enlarged mediastinal nodes → EBUS-guided biopsy

  • _{^{determine hitso-path}}

—> PET/CT ± brain MRI for staging

→ molecular testing when indicated

→ treatment

diagnostic work up lung cancer?

 PNEUMOTHORAX

 _{^{Patient develops acute dyspnea + pleuritic chest pain + decreased breath sounds shortly after CT-guided lung biopsy → iatrogenic pneumothorax}}

Most common complication of transthoracic lung biopsy →

uncorrectable coagulopathy.

Major contraindication for transthoracic lung biopsy →

Pneumothorax — Upright CXR

_{^{Air in pleural space → partial/complete lung collapse}}

• Visible visceral pleural line ⭐

 • No lung markings peripheral to pleural line

• Hyperlucent affected side

 • Collapsed lung toward hilum

Small + stable → observe ± O₂

Large/symptomatic → needle/catheter aspiration or chest tube

how to tx pneumothorax?

Pneumothorax — Supine CXR

Air travels anteriorly/basally when patient is supine

Deep sulcus sign ⭐⭐⭐

• Abnormally deep, hyperlucent costophrenic angle

 • May NOT see classic apical pleural line

Tension Pneumothorax 🚨

Pneumothorax + mediastinal/tracheal shift AWAY from affected side

• Depressed ipsilateral diaphragm

• Widened intercostal spaces

obstructive shock

↑ intrathoracic pressure → compresses vena cava (+JVP)→ ↓ venous return → ↓ preload → ↓ CO → obstructive shock (hypotensive,tachycardia) → cardiac arrest

what type of shock is associated with tension pneumothorax

TENSION PNEUMOTHORAX

_{^{Clinical dx— DO NOT wait for CXR}}

⭐ Immediate decompression → chest tube

pt presents with:

Hypotension + tachycardia + severe respiratory distress + unilateral absent breath sounds + tracheal deviation AWAY

 positive-pressure ventilation

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_^Why?

_{^{PPV → pushes air into lungs → air can enter pleural space → ↑ pleural pressure → tension pneumothorax → ↓ venous return → obstructive shock.}}

_{^{⭐ Board pearl: Pneumothorax + mechanical ventilation = higher risk of tension pneumothorax.}}

_{^{If the patient is crashing and needs ventilation, don't withhold life-saving ventilation—simultaneously recognize and decompress a suspected tension pneumothorax.}}

Simple traumatic PTX can progress to tension pneumothorax by?

Open Pneumothorax

-Chest-wall defect communicating with pleural space

tx: Vented occlusive dressing + chest tube away from wound → definitive wound closure

“sucking chest wound”

TOWARD = volume LOSS → Atelectasis / pneumonectomy

AWAY = volume GAIN → Pleural effusion / large mass

NO SHIFT = volume preserved → Pneumonia

White hemithorax → look at the mediastinum

• TOWARD = volume ____

• AWAY = volume ____

• NO SHIFT = volume ___