# Pleura, Pulmonary Embolism and Interstitial Lung Disease for NEET PG Medicine: Light's Criteria, Pneumothorax, PE, IPF, Sarcoidosis

Source: https://tracknation.in/story/pleura-pulmonary-embolism-and-interstitial-lung-disease-for-neet-pg-medicine-light-s-criteria-pneumothorax-pe-ipf-sarcoidosis (TrackNation — free UPSC notes with PYQs)

> NEET PG Medicine: transudate vs exudate and Light's criteria, chylothorax and empyema, primary and tension pneumothorax, pulmonary embolism work-up, signs and risk classes, idiopathic pulmonary fibrosis, sarcoidosis with Löfgren and Heerfordt syndromes, pulmonary hypertension and bronchiectasis imaging, with a diagram, hooks, vignette MCQs and cards.

## Start Here

🎯 **Exam priority: Medium–high.** *Expect: Light's criteria numbers, causes of transudates vs exudates, empyema drainage
triggers, tension pneumothorax first step, PE investigations and ECG/X-ray signs, IPF crackles and treatment, Löfgren vs Heerfordt, and the
pulmonary hypertension cut-off.*

CBME mapping: respiratory competencies in **GM 3 and GM 28**. Tuberculous effusion is in article 7; PE pathology (Virchow triad) in
Pathology article 3.

*Pleural effusion, pneumothorax, PE, IPF, sarcoidosis. Drawn by TrackNation.*

## Pleural Effusion

- **Signs**: reduced breath sounds, dullness to percussion, absent tactile fremitus on the affected side.

- **Transudates**: heart failure, cirrhosis with ascites, nephrotic syndrome. **Exudates**: pneumonia, cancer, pulmonary
embolism, tuberculosis.

- **Chylothorax**: milky fluid high in triglycerides (trauma, surgery, tumours). **Empyema**: frank pus; drain completely
if pH < 7.20, glucose < 60 mg/dL, positive Gram stain or culture, or loculations.

| **Light's criteria — exudate if ≥ 1**

 | **Cut-off**

 |
| Pleural fluid : serum protein

 | ≥ 0.5

 |
| Pleural fluid : serum LDH

 | ≥ 0.6

 |
| Pleural fluid LDH

 | ≥ 2/3 of the upper limit of serum LDH

 |

## Pneumothorax

- **Primary spontaneous**: no lung disease; classically tall, thin men in their teens and 20s; rupture of apical blebs (smoking).
Signs: absent fremitus, **hyper-resonance**, reduced breath sounds.

- **Tension pneumothorax**: positive intrapleural pressure throughout breathing collapses the lung, shifts the mediastinum and
impairs venous return → shock. **Immediate needle decompression.**

- Asymptomatic primary spontaneous pneumothorax: observe with a repeat X-ray regardless of size; symptomatic: aspiration or drain devices.

## Pulmonary Embolism and Pulmonary Hypertension

- **Work-up**: clinical scores (Wells, revised Geneva, PERC); a negative D-dimer makes PE very unlikely in low-probability
patients; **CT angiography** is the usual test (V/Q scan sometimes).

- **Signs**: ECG often sinus tachycardia; **S1Q3T3** or new RBBB suggests RV strain. X-ray classics: Westermark sign
(focal oligaemia) and Hampton hump (peripheral wedge).

- **Treatment**: anticoagulation; thrombolysis (some reserve it for high-risk PE) or catheter/surgical clot removal; IVC filter if
anticoagulation is contraindicated.

- **Pulmonary hypertension**: mean pulmonary arterial pressure > 20 mm Hg; signs include a loud P2 and RV heave.

| **PE risk class (MSD)**

 | **Definition**

 |
| High risk (massive)

 | RV dysfunction with hypotension: SBP < 90 or fall ≥ 40 mm Hg for 15 minutes

 |
| Intermediate (submassive)

 | RV dysfunction without hypotension (imaging, biomarkers)

 |
| Low risk

 | No RV dysfunction, normotensive

 |

## Interstitial Lung Disease, Sarcoidosis, Bronchiectasis

- **Idiopathic pulmonary fibrosis** = usual interstitial pneumonia: exertional breathlessness, cough, fine bibasal
**Velcro crackles**, clubbing in about half; honeycombing; restrictive spirometry with low diffusing capacity. Treat with
**pirfenidone or nintedanib**, oxygen, rehabilitation, transplant.

- **Sarcoidosis**: non-caseating granulomas, mostly lungs and thoracic nodes (hilar/mediastinal in 90%); uveitis is the commonest
eye lesion; hypercalcaemia from macrophage activation of vitamin D. A normal chest X-ray (stage 0) does not exclude it. First-line treatment:
corticosteroids. **Löfgren syndrome** (arthritis, erythema nodosum, hilar nodes) is self-limited — NSAIDs. **Heerfordt syndrome**
(uveoparotid fever): uveitis, parotid swelling, facial palsy, fever.

- **Bronchiectasis**: cystic fibrosis, immune defects, recurrent infection; imaging shows tram-track lines and the signet-ring sign.

## Traps the Examiner Sets

- Effusion = dull; pneumothorax = hyper-resonant.

- Tension pneumothorax: decompress before the X-ray.

- Light's: 0.5 protein, 0.6 LDH, 2/3 LDH — any one = exudate.

- S1Q3T3 is suggestive, not common; sinus tachycardia is commoner.

- Löfgren resolves on its own; Heerfordt = uveoparotid fever.

## Memory Hooks & Shortcuts

*Shortcuts to lock in this article's numbers and lists. Each one only re-packages facts proven above.*

- 🧠 **Light's: 'Point five, point six, two-thirds'** — Light's criteria

- 🧠 **Dull = Drink (fluid); Drum = air (hyper-resonant)** — effusion vs pneumothorax

- 🧠 **Tension: Treat before the Test (needle first)** — tension pneumothorax

- 🧠 **Löfgren = 'LEgs, Joints, Hilum' — Leaves by itself** — Löfgren

- 🧠 **Heerfordt = 'Eyes, Ears (parotid), Face, Fever'** — Heerfordt

- 🧠 **Velcro crackles, Velcro lungs (IPF)** — IPF

## Rapid-Revision Cards

- Heart failure, cirrhosis, nephrotic syndrome.

- Pneumonia, cancer, PE, TB.

- Protein ratio ≥ 0.5; LDH ratio ≥ 0.6; LDH ≥ 2/3 ULN.

- Milky; high triglycerides.

- pH < 7.2, glucose < 60, Gram+, loculated.

- Dull, ↓ breath sounds, ↓ fremitus.

- Tall thin young men; apical blebs.

- Hyper-resonant, ↓ breath sounds.

- Needle decompression first.

- CT pulmonary angiography.

- Negative rules out in low probability.

- Sinus tachycardia; S1Q3T3; new RBBB.

- Oligaemia / peripheral wedge.

- SBP < 90 or fall ≥ 40 mm Hg.

- If anticoagulation contraindicated.

- UIP, honeycomb, Velcro crackles, clubbing 50%.

- Pirfenidone, nintedanib.

- Non-caseating granulomas; hilar nodes 90%.

- Arthritis + erythema nodosum + hilar nodes; NSAIDs.

- Uveitis, parotids, facial palsy, fever.

- Macrophage 1α-hydroxylation of vitamin D.

- Mean PAP > 20 mm Hg.

- Tram tracks, signet ring.

## Sources

*Facts in this article were checked against these documents.*

- MSD Manual Professional: Pleural Effusion; Pneumothorax; Pulmonary Embolism; Idiopathic Pulmonary Fibrosis; Sarcoidosis; Pulmonary Hypertension; Bronchiectasis — Merck & Co. (MSD Manuals), reviewed 2025–26 (link)

- Competency Based Undergraduate Curriculum, General Medicine (GM 3, GM 28) — National Medical Commission, 2024

## Test Yourself: Practice Questions

Thirty questions in NEET PG style, most of them clinical vignettes.

## Practice Questions (NEET PG pattern)

*Original questions written in the style of the exam: +4 for a correct answer, −1 for a wrong one. Every answer
was checked against the sources listed above. NEET PG papers are not published by NBEMS, so these are not past-paper questions.*

**Q1.** Pleural fluid protein 4.2 g/dL with serum protein 6.5 g/dL (ratio 0.65). By Light's criteria the effusion is

- (a) indeterminate

- (b) a transudate

- (c) an exudate

- (d) chylous

**Answer: (c)** — Protein ratio ≥ 0.5 is enough.

**Q2.** Which is NOT one of Light's criteria for an exudate?

- (a) fluid:serum LDH ≥ 0.6

- (b) pleural fluid glucose < 60 mg/dL

- (c) fluid:serum protein ≥ 0.5

- (d) fluid LDH ≥ 2/3 upper limit of serum

**Answer: (b)** — Low glucose is an empyema/drainage marker.

**Q3.** The commonest causes of a transudative pleural effusion are

- (a) heart failure, cirrhosis and nephrotic syndrome

- (b) pneumonia, cancer and TB

- (c) trauma and surgery

- (d) pancreatitis and SLE

**Answer: (a)** — Exudates: pneumonia, cancer, PE, TB.

**Q4.** After a thoracic duct injury, pleural fluid is milky white. The fluid will be high in

- (a) glucose

- (b) amylase

- (c) triglycerides

- (d) red cells only

**Answer: (c)** — Chylothorax.

**Q5.** A parapneumonic effusion should be completely drained when the fluid shows

- (a) pH < 7.20 or glucose < 60 mg/dL

- (b) pH 7.45

- (c) clear straw colour

- (d) protein ratio 0.3

**Answer: (a)** — Also positive Gram stain/culture or loculations.

**Q6.** Examination shows reduced breath sounds, dullness to percussion and absent tactile fremitus at the right base. The likely finding is

- (a) pleural effusion

- (b) pneumothorax

- (c) emphysema

- (d) consolidation with patent bronchus

**Answer: (a)** — Pleural thickening can mimic it.

**Q7.** A tall, thin 20-year-old smoker has sudden pleuritic chest pain and breathlessness; the left chest is hyper-resonant with reduced breath sounds. The diagnosis is

- (a) pleural effusion

- (b) pneumonia

- (c) primary spontaneous pneumothorax

- (d) pulmonary embolism

**Answer: (c)** — Rupture of apical blebs.

**Q8.** A patient becomes hypotensive; the mediastinum is shifted away from a hyper-resonant hemithorax with absent breath sounds. Immediate management is

- (a) needle decompression

- (b) intubation only

- (c) CT chest

- (d) chest X-ray first

**Answer: (a)** — Tension pneumothorax impairs venous return.

**Q9.** Tension pneumothorax causes shock mainly by

- (a) bleeding into the pleura

- (b) impairing venous return to the heart

- (c) sepsis

- (d) direct myocardial injury

**Answer: (b)** — Positive intrapleural pressure throughout the cycle.

**Q10.** An asymptomatic young man has a primary spontaneous pneumothorax on X-ray. Per MSD, management is

- (a) immediate surgery

- (b) intercostal drain in all

- (c) thrombolysis

- (d) observation with a follow-up radiograph regardless of size

**Answer: (d)** — Symptomatic: aspiration or ambulatory devices.

**Q11.** The investigation most commonly used to diagnose pulmonary embolism is

- (a) echocardiography

- (b) D-dimer alone

- (c) CT pulmonary angiography

- (d) chest X-ray

**Answer: (c)** — V/Q scan sometimes.

**Q12.** In an outpatient with low clinical probability of PE, a negative D-dimer

- (a) makes PE very unlikely

- (b) requires immediate thrombolysis

- (c) confirms PE

- (d) is meaningless

**Answer: (a)** — Use with Wells/Geneva scores.

**Q13.** An ECG pattern suggesting pulmonary embolism is

- (a) S wave in I, Q wave and inverted T in III

- (b) delta wave

- (c) U waves

- (d) ST elevation in II, III, aVF

**Answer: (a)** — Or a new RBBB.

**Q14.** A peripheral wedge-shaped pleural-based opacity on chest X-ray after PE is the

- (a) golden S sign

- (b) Kerley B line

- (c) Hampton hump

- (d) Westermark sign

**Answer: (c)** — Westermark = focal loss of vascular markings.

**Q15.** A PE patient has RV dysfunction and systolic BP 82 mm Hg. The risk class is

- (a) not PE

- (b) high risk (massive)

- (c) intermediate (submassive)

- (d) low risk

**Answer: (b)** — Thrombolysis is considered.

**Q16.** A patient with acute PE has a recent intracranial haemorrhage, so anticoagulation is contraindicated. An option is

- (a) an inferior vena cava filter

- (b) aspirin alone

- (c) high-dose thrombolysis

- (d) no treatment

**Answer: (a)** — Until anticoagulation can resume.

**Q17.** A 68-year-old has progressive exertional breathlessness, dry cough, fine bibasal 'Velcro' crackles and clubbing; HRCT shows honeycombing. The diagnosis is

- (a) bronchiectasis

- (b) idiopathic pulmonary fibrosis

- (c) sarcoidosis

- (d) COPD

**Answer: (b)** — Histology: usual interstitial pneumonia.

**Q18.** Antifibrotic drugs used in idiopathic pulmonary fibrosis are

- (a) salbutamol and tiotropium

- (b) pirfenidone and nintedanib

- (c) methotrexate

- (d) prednisolone and azathioprine as first line

**Answer: (b)** — With oxygen, rehabilitation, transplant.

**Q19.** Spirometry in idiopathic pulmonary fibrosis shows

- (a) a restrictive pattern with reduced diffusing capacity

- (b) reversible obstruction

- (c) obstruction with FEV1/FVC < 0.7

- (d) normal values always

**Answer: (a)** — Fibrosis stiffens the lungs.

**Q20.** A young woman has fever, painful ankles, red tender shin nodules and bilateral hilar lymphadenopathy. The likely diagnosis and treatment are

- (a) rheumatic fever — penicillin

- (b) Löfgren syndrome — usually NSAIDs; self-limited

- (c) TB — start ATT

- (d) lymphoma — chemotherapy

**Answer: (b)** — Arthritis, erythema nodosum, hilar nodes.

**Q21.** A patient has uveitis, bilateral parotid swelling, facial nerve palsy and fever. This is

- (a) mumps

- (b) Heerfordt syndrome (uveoparotid fever) of sarcoidosis

- (c) Sjögren syndrome

- (d) Bell palsy only

**Answer: (b)** — A sarcoid variant.

**Q22.** Hypercalcaemia in sarcoidosis results from

- (a) increased activation of vitamin D by granuloma macrophages

- (b) parathyroid adenoma

- (c) bone metastases

- (d) milk-alkali syndrome

**Answer: (a)** — 1,25-dihydroxyvitamin D production.

**Q23.** The histological hallmark of sarcoidosis is

- (a) Reed-Sternberg cells

- (b) non-caseating granulomas

- (c) Schaumann bodies only

- (d) caseating granulomas

**Answer: (b)** — Lungs and lymphatic system most often affected.

**Q24.** First-line treatment for symptomatic pulmonary sarcoidosis is

- (a) corticosteroids

- (b) antitubercular drugs

- (c) antifibrotics

- (d) antibiotics

**Answer: (a)** — Löfgren syndrome usually needs only NSAIDs.

**Q25.** The commonest ocular manifestation of sarcoidosis is

- (a) retinal detachment

- (b) uveitis

- (c) cataract

- (d) glaucoma

**Answer: (b)** — Blurred vision, photophobia, tearing.

**Q26.** A normal chest X-ray in suspected cardiac sarcoidosis

- (a) confirms TB

- (b) does not exclude sarcoidosis

- (c) means stage 4

- (d) excludes sarcoidosis

**Answer: (b)** — Stage 0; HRCT is more sensitive.

**Q27.** Pulmonary hypertension is defined haemodynamically by a mean pulmonary arterial pressure above

- (a) 40 mm Hg

- (b) 20 mm Hg

- (c) 60 mm Hg

- (d) 10 mm Hg

**Answer: (b)** — Wedge ≤ 15 mm Hg in pre-capillary disease.

**Q28.** A thickened, dilated airway seen next to its adjacent artery on CT is the

- (a) halo sign

- (b) signet-ring sign of bronchiectasis

- (c) tree-in-bud

- (d) crazy paving

**Answer: (b)** — Tram-track lines are the other classic sign.

**Q29.** Bronchiectasis is commonly caused by all EXCEPT

- (a) sarcoid hypercalcaemia

- (b) immune defects

- (c) cystic fibrosis

- (d) recurrent infections

**Answer: (a)** — Some cases are idiopathic.

**Q30.** Clubbing in idiopathic pulmonary fibrosis is present in about

- (a) 50% of cases

- (b) never

- (c) all cases

- (d) 5%

**Answer: (a)** — Velcro crackles are the classic sign.

### Active Recall

From memory: list causes of transudates and exudates and Light's criteria; describe chylothorax and empyema drainage; describe primary and tension pneumothorax and their management; outline PE work-up, signs, risk classes and treatment; and describe IPF, sarcoidosis syndromes and the pulmonary hypertension cut-off.