Pulmonology

Lights Criteria

If at least one of the following three criteria is present, the fluid is exudate; if none is present

The ratio of pleural fluid protein to serum protein is greater than 0.5

The ratio of pleural fluid lactate dehydrogenase (LDH) to serum LDH is greater than 0.6

The pleural fluid LDH level is greater than two thirds of the upper limit of normal for serum LDH

Cyanide Toxicity

Synthetic product combustion (burning of plastics), amygdalin ingestion (apricot seeds)

Headache, dyspnea, drowsiness, cherry red skin, venules in retina may appear red, breath may smell of bitter almonds

Normal PaO2

Venous PaO2 high

Methemoglobin level zero

Elevated lactate (greater than 8)

Treatment: Decontamination, hydroxocobalamin (first line), sodium thiosulfate, or sodium nitrite

Carbon Monoxide Poisoning

Motor Exhaust, gas heater, fire victims

Headache, vomiting, confusion, visual changes, cherry red skin with possible bulla

Normal PaO2 on ABG

Elevated carboxyhemoglobin

Elevated lactate

Bilateral globus pallidus lesions on MRI

Treatment: High flow oxygen, hyperbaric oxygenation if severe

Methemoglobinemia

Iron in hemoglobin it can become oxidized → Decreased oxygen saturation and oxygen content

Caused by congenital defect or drug induced (anesthetics, dapsone, etc)

Shortness of breath

Cyanosis that is resistant to oxygen

Venous blood may look chocolate brown

Elevated methemoglobin level on ABG/VBG

Treatment is methylene blue

Hb Concentration, SaO2, PaO2, Total O2 in CO, Methemoglobinemia, and Cyanide

Acute Mountain Sickness (AMS)

Symptoms start 6 to 12 hours after altitude change

Diagnosis is subjective – headache, GI symptoms, fatigue, weakness, dizziness

Treatment:

DESCENT

Take an extra day to acclimatize to altitude

Acetazolamide

Supplemental oxygen

High Altitude Pulmonary Edema (HAPE)

Usually occurs 2 to 4 days after arrival at altitude

Need two of the four symptoms:

Chest pain

Cough (usually pink frothy sputum)

Dyspnea at rest

Dyspnea at exertion

And two of the four signs:

Central cyanosis

Rales/wheeze

Tachycardia

Tachypnea

CXR shows patchy infiltrates with NORMAL heart size

POCUS may show B lines

ECG with right axis deviation or ischemia

Treatment:

DESCENT

Hyperbaric oxygen chamber

Nifedipine

Phosphodiesterase inhibitors (sildenafil)

NEVER DIURETICS

High Altitude Cerebral Edema (HACE)

Severe AMS with new neurologic findings

Ataxia, altered mental status, visual changes, seizure

Appear to be intoxicated, dysarthric, unable to walk in a straight line

Ocular POCUS may show increased optic nerve diameter

Treatment:

IMMEDIATE DESECENT

Supplemental oxygen

Portable hyperbaric oxygen bag

Dexamethasone and acetazolamide

Prevention

Graded ascent:

Maximum daily sleeping elevation gain of 500 meters per day

Acclamation day every 1000 meter gain in elevation

Pharmacologic prophylaxis:

Acetazolamide starting 24 hours prior to ascent

Dexamethasone

Ibuprofen

Nifedipine if a history of HAPE

Adequate hydration

Asbestos Pneumoconioses

Shipbuilding, roofing, plumbing, construction

White calcified supradiaphragmatic and pleural plaques

Linear opacities at the lung bases

Affects the LOWER lobes

Golden brown fusiform rods found in alveolar sputum using PRUSSIAN BLUE stain

Increase risk of bronchogenic carcinoma

Increased risk of Caplan syndrome

Berylliosis Pneumoconioses

Exposure to beryllium in aerospace, electronic, and nuclear industries

Histology shows non-caseating granulomas

Hilar adenopathy

Carries an increased risk of cancer and cor-pulmonae

Affects the UPPER lobes

Coal Worker’s Pneumoconioses

Long term exposure to coal dust

Affects the UPPER lobes

Small round nodular opacities

Increased risk of Caplan syndrome

Leads to progressive massive fibrosis

Silicosis Pneumoconioses

Sandblasting, foundries (glass and pottery)

Carries and increased risk of TB

Increased risk of lung cancer, cor-pulmonale and Caplan syndrome

Affects the UPPER lobes

“Eggshell” calcification of hilar lymph nodes on chest radiograph

Sarcoidosis

African American females and Northern Europeans

Third and fourth decade of life

Usually asymptomatic

Cough, malaise, weight loss, dyspnea, and arthritis

Uveitis

Erythmea nodosum: Painful red and tender nodules on the shins

CXR/CT shows hilar lymphadenopathy and nodules

Biopsy of lymph nodes reveals non-caseating granulomas

PFTs: restrictive / obstructive pattern with decreased diffusion capacity

Increase ACE level, increased IL-2 levels, hypercalcemia, hypercalciuria, increased alkaline phosphatase

Treatment: systemic corticosteroids

Pulmonary Edema

Cardiogenic: High pulmonary capillary pressure (pulmonary artery wedge pressure)

Non-Cardiogenic: Radiographic evidence of alveolar fluid accumulation without hemodynamic evidence to suggest a cardiogenic etiology

Cardiogenic: Dyspnea, Dyspnea on exertion, Orthopnea, PND, Past Medical History of Myocardial Infarction and CHG

Non-Cardiogenic: Infection, Blood transfusion, Overdose, Hiking, Drowning, Sepsis, Pneumonia

S3 gallop

JVD

Peripheral edema

Enlarged liver

Crackles / Rales

Ascites

Warm Extremities – Non-Cardiogenic

Cool Extremities – Cardiogenic

Acute Respiratory Distress Syndrome (ARDS)

Subsequent inflammatory response to underlying injury leads to damage to epithelial barriers (exacerbated by mechanical stretch) and accumulation of protein-rich edema fluid in alveoli

Alveolar damage results in ventilation-perfusion mismatch (V/Q mismatch) → Increased shunting (alveoli unable to exchange oxygen) and dead space (microvascular injury leading to lack of perfusion)

Acute Respiratory Distress Syndrome (ARDS) Diagnosis

A – Abnormal Chest radiograph (bilateral lung opacities)

R – respiratory failure within one week of insult

D – decreased PA02/Fio2 (ratio less than 300)

S – symptoms not due to Heart Failure

Transudative Pleural Effusion

Exudative Pleural Effusion