Pulmonary Pathology PDF

Obstructive Lung Disease Jason Ryan, MD, MPH Obstructive Lung Diseases Key points: Air trapping, slow flow out, less air out Reduced FEV1 (slow flow out) Reduced FVC (less air out) Reduced FEV1/FVC (hallmark) Residual & Total Lung Volume Both go up in obstructive disease From...

Obstructive Lung Disease Jason Ryan, MD, MPH Obstructive Lung Diseases Key points: Air trapping, slow flow out, less air out Reduced FEV1 (slow flow out) Reduced FVC (less air out) Reduced FEV1/FVC (hallmark) Residual & Total Lung Volume Both go up in obstructive disease From air trapping Both fall in restrictive disease Less air fills the lungs due to restriction Obstructive Lung Diseases Chronic bronchitis Emphysema Asthma Bronchiectasis Chronic Bronchitis Chronic cough Productive of sputum At least 3 months over two years No other cause of cough present Strongly associated with smoking Chronic Bronchitis Hypertrophy of mucous secreting glands Reid Index Thickness of glands/total wall >50% in chronic bronchitis Lungs can plug with mucous “mucous plugging” Increased risk of infection Chronic Bronchitis Poor ventilation of lungs Increased CO2 Decreased O2 Hypoxic vasoconstriction Pulmonary hypertension Right heart failure (cor pulmonale) Chronic Bronchitis Cough Wheezing Crackles Dyspnea Cyanosis (shunting) Shunting 80%) FEV1/FVC (hallmark) Causes #1: Poor breathing mechanics #2: Interstitial lung diseases Poor Breathing Mechanics Not a primary pulmonary issue Under-ventilation of lungs Alveoli working: A-a gradient normal Neuromuscular ALS, Polio, myasthenia gravis Structural Scoliosis Morbid obesity Interstitial Lung Disease Bilateral, diffuse pattern Small, irregular opacities (reticulonodular) “Honeycomb” lung appearance. Image courtesy of Drriad Image courtesy of James Heilman, MD DLCO Diffusing capacity in lung of carbon monoxide DLCO separates cases restrictive disease Restriction with normal DLCO Extra-pulmonary cause: obesity Restriction with low DLCO Interstitial lung disease DLCO DLCO = diffusing capacity of carbon monoxide Measures ability of lungs to transfer gas to RBCs Patient inhales small amount (not dangerous) CO CO uptake is diffusion limited Amount taken up ≈ diffusion function lungs Machine measures CO exhaled Normal = 75 – 140% predicted Severe disease 10 seconds Multiple episodes per night are typical Sleep Apnea Symptoms Unrestful sleep Daytime somnolence Loud snoring Sleep Apnea Types Central sleep apnea No effort to breathe Obstructive sleep apnea Decreased air flow despite effort to breathe Central Sleep Apnea Patients with marginal ventilation when awake Hypoventilate when awake Fall asleep  apnea periods Central nervous system disease (encephalitis) Neuromuscular diseases (polio, ALS) Severe kyphoscoliosis Narcotics Central Sleep Apnea Cheyne-Stokes breathing Cyclic breathing Delayed detection/response to changes in PaCO2 Common in heart failure and stroke patients Normal Breathing Cheyne-Stokes Images courtesy of Aleksa Lukic Obstructive Sleep Apnea Recurrent soft tissue collapse in the pharynx Strongest risk factor is obesity Sleep Apnea Complications HTN Pulmonary HTN Arrhythmias Sudden death Erythropoiesis Chronic hypoxia EPO release Sleep Apnea Diagnosis Polysomnography “Sleep study” Patient sleeps in monitored setting EEG, eye movements O2 level, HR, respiratory rate Number of apnea episodes recorded Sleep Apnea Treatments Weight loss Takes time; not best option for exhausted patients CPAP First line for symptomatic patients Upper airway surgery Severe disease CPAP Image courtesy of Aslam Calicut Cystic Fibrosis Jason Ryan, MD, MPH Cystic Fibrosis Inherited genetic disease Autosomal recessive pattern Both parents must be carriers Results in thick, sticky mucus in lungs/GI tract Common cause chronic lung disease in children CFTR Cystic Fibrosis Transmembrane Regulator CFTR protein is abnormal in CF CFTR gene encodes for the abnormal protein CFTR Cystic Fibrosis Transmembrane Regulator ATP ion transporter Epithelial Cell Functions Pumps Cl- out of epithelial cells Against concentration gradient (uses ATP) Creates a membrane potential that draws out Na/H2O Hydrates mucosal surfaces (lungs, GI tract) Sweat gland functions Removes NaCl from sweat (makes sweat hypotonic) CF patients have high NaCl in sweat CFTR Mutations Many mutations identified Most common mutation: delta F508 Deletion of 3 DNA bases Codes for 508th AA acid: phenylalanine Most common consequence: abnormal processing Abnormal protein folding Prevents protein trafficking to correct cellular location CF Pathophysiology Thick mucous in lungs Recurrent pulmonary infections (Pseudomonas, S. Aureus) Chronic bronchitis Bronchiectasis Thick mucous in GI tract Impaired flow of bile and pancreatic secretions Malabsorption especially fats Loss of fat soluble vitamins (A, D, E, K) Steatorrhea CF Presentation Usually diagnosed other 1 Pitting edema 1 Superficial veins visible 1 Alternative diagnosis likely -2 Score >=3 High Probability 1-2 Mod Probability 0 Low Probability D-dimer Degradation product of fibrin Sensitive but not specific (unidirectional) Levels elevated in DVT/PE Levels also elevated in many, many other conditions Useful when normal in setting of low-mod Wells score Pulmonary Embolism Diagnosis CT angiogram VQ Scan Westgate EJ, FitzGerald GA Pulmonary Embolism in a Woman Taking Oral Contraceptives and Valdecoxib. PLoS Medicine Vol. 2, No. 7, e197. doi:10.1371/journal.pmed.0020197 Treatment DVT/PE Initial treatment with heparin or LMWH Transition to warfarin (oral) Massive PE: thrombolysis (tPA) Patent Foramen Ovale Found in ~25% adults Failure of foramen ovale to close after birth Can allow venous clot to reach arterial system (brain) Rarely causes stroke in patients with DVT/PE Fat Embolism Often occurs after a long bone facture Fat may cross lungs  small artery infarctions Fat embolism syndrome: pulmonary, neuro, skin Hellerhoff /Wikipedia Fat Embolism Lung Dyspnea, hypoxemia Diffuse capillary leak (ARDS) Often requires mechanical ventilation Neurological Usually confusion May develop focal deficits Petechiae James Heilman, MD/Wikipedia Amniotic Fluid Embolism During labor or shortly after Amniotic fluid, fetal cells, fetal debris enter maternal circulation Inflammatory reaction Often fatal Wikipedia/Public Domain Amniotic Fluid Embolism Phase I Pulmonary artery vasospasm  pulmonary hypertension Right heart failure Hypoxia Myocardial capillary damage  left heart failure Pulmonary capillary damage  ARDS Acute respiratory distress syndrome Key features: respiratory distress, ↓O2, hypotension Amniotic Fluid Embolism Phase II (hemorrhagic phase) Massive hemorrhage DIC Key feature: bleeding Seizures also often occur Chest X-rays Jason Ryan, MD, MPH Chest X-ray Difficult to see different structures Many, many normal variants Many, many pathologic findings Reasonable goals: Basic chest anatomy Classic examples of pathology Chest Anatomy Aortic Knob Pulmonary Artery SVC Left Right Atrium Atrium Left Ventricle IVC Right Ventricle Pulmonary Edema Pulmonary Edema Image courtesy of Radiology Assistant Pleural Effusion Image courtesy of James Heilman, MD Pneumothorax Lobar Pneumonia Interstitial Fibrosis Hilar Lymphadenopathy Pulmonary Nodule Image courtesy of Lange123