USMLE - Respiratory Part 2

Montelukast, Zafirlukast

--/ leukotriene receptor.

Especially good in aspirin induced asthma

Zileuton --/ 5 lipoxygenase pathway.

Blocks arachidonic acid --> leukotrienes

Both used to treat Asthma

Beclomethasone, Fluticasone

-/ cytokine production

-/ NFkB (NFkB --> TNF alpha)

Ipratropium (short), Tiotropium (long)

--/ muscarinic receptors thereby preventing bronchoconstriction

Asthma and COPD

Theophylline--/ PDE leading to increased cAMP

Asthma treatment

Narrow therapeutic index --> cardiotoxic, neurotoxic

P450 metabolism

Blocks actions of Adenosine

PTHORAX

Pleuritic pain, Tracheal deviation, Hyperresounant, sudden Onset, Reduced breath sounds, Absent Fremitus, XR --> Collapse

Short: Albuterol --> Beta2 --> SM relaxation

Long: Salmeterol, Formoterol.

Used for prophylaxis.

Can cause tremors and arrhythmias

Antiinflammation + Anti parasympathetic tone

First Line Therapy: Corticosteroids

Beta 2 agonists, Methylxanthines, Anti Muscarinic, Antileukotrienes, Abs

Loratadine, Fexofenadine, Desloratadine (adine)

Allergy

Much less sedating because do not enter CNS

Diphenhydramine, dimenhydrinate, chlorpheniramine (en/ine, en/ate)

Allergy, motion sickness, sleep aid

Sedation, antimuscarinic, anti alpha adrenergic

H1 blockers

Chylothorax. Due to thoracic duct injury from trauma or malignancy.

Appears milky with high triglyceride content

High Protein content, appears cloudy

"CAPTAIN"

Due to Collagen Vascular Disease, Abdominal pathology, Pneumonia, TB, Trauma (occurs in states of increased vascular permeability), Asbestos, Infection (Pneumonia), Malignancy

Must be drained to prevent infection

Low protein content

"CHEMN"

Due to CHF, Hepatic cirrhosis (Hypoalbuminia), Embolism, Meig Syndrome, Nephrotic syndrome

Mixed Type III/IV hypersensitivity rxn to environmental antigen

"Holding Down Tough Cows on a Farm"

Presents with headache, dyspnea, tight chest, cough

Seen in farmers and bird owners

Viruses (influenza, RSV, adenovirus), Mycoplasma, Legionella, Chlamydia

Diffuse, patchy inflammation in interstitial areas

Involves ≥ 1 lobe.

Indolent course

S pneumoniae, S aureus, H influenzae, Klebsiella

Acute inflammatory infiltrates from bronchioles into adjacent alveoli

Neutrophils in alveolar spaces

Patchy distribution involving ≥ 1 lobe

S. pneumoniae, KlebsiellaIntra

alveolar exudate --> consolidation

May involve entire lung

Obstruction of SVC impairs blood drainage from Head (Facial Plethora) Neck (JVD) and Arms (Edema)

Caused by malignancy, thrombosis (from indwelling catheters)

Can lead to Increased ICP --> headache, dizziness, aneurysm, cranial artery rupture

Carcinomas in apex of lung affect cervical sympathetic plexus resulting in Horner's Syndrome (Ipsilateral Miosis, Anhidrosis, Ptosis)

Pleural. Associated with asbestosis.

Results in Hemorrhagic pleural effusions and pleural thickening.

Psommoma bodies

Excellent Prognosis.

Metastasis: rare.

Symptoms due to mass effect

Can lead to CARCinoid syndrome (5HT release --> Cutaneous flushing, Asthmatic wheezing, Right valve lesions, Cramps, Diarrhea, Salivation)

Nests of neuroendocrine cells. Chromogranin +

Peripheral, highly anaplastic undifferentiated tumor

Poor Prognosis

Surgery.

Poor response to chemo

Pleomorphic giant cells

Central, undifferentiated, aggressive

May produce ACTH, ADH, Abs against presynaptic Ca channels (Lambert Eaton)

Genetics: amplification of myc oncogenes

Chemotherapy.

Inoperable

Kulchitsky cells (small dark blue cells). Salt and Pepper neuroendocrine chromatin

Central

Hilar mass arises from bronchus

Cavitation, Cigarettes, hyperCa (produces PTH)

Dysplastic squamous cells with Keratin Pearls and Intracellular Bridges

Localized collection of pus within parenchyma

Caused by bronchial obstruction (cancer), aspiration of oropharyngeal contents (pts predisposed to LOC i.e. alcoholics), infection of S aureus or anaerobes (Bacteroides, Fusobacterium, Peptostretococcus)

Air-Fluid levels often seen on CXR

Derived from Clara Cells

Hazy infiltrates similar to pneumonia

Grows along alveolar septa --> apparent thickening of alveolar walls

Excellent prognosis

Can present as pneumonia

Peripheral.

Develops in scars (old Tuberculous Granulomas)

Most common lung cancer in nonsmokers and females

Activating k-ras mutation

Osteoarthropathy (clubbing)

Brain, Liver (jaundice, hepatomegaly), Adrenals, Bone (pathologic fracture)

Metastasis from Breast, Bladder, Colon, or Prostate

Bronchioloalveolar and bronchial carcinoid

SPHERE

SVC syndrome, Pancoast tumor, Hornerns, Endocrine (paraneoplastic), Recurrent laryngeal symptoms (hoarseness), Effusions (pleural or pericardial)

ABCDE

Avalanche, Bloody cough, Cough, Coin Lesions on XR, nonCalcified nodules on CT, Disrupted bronchi (bronchial obstruction), whEezing

Breath sounds: Bronchial, Late inspiratory Crackles

Percussion: dull

Fremitus: increased

Tracheal deviation: none

Unilateral chest pain, dyspnea, unilateral chest expansion

Air enters pleural space but cannot exit

Breath sounds: decreased

Percussion: hyperresonant

Fremitus: decreased

Tracheal deviation away from lesion

Trauma or lung infection

Unilateral chest pain, dyspnea, unilateral chest expansion

Rupture of apical bleb --> accumulation of air in pleural space

Breath sounds: decreased

Percussion: hyperresonant

Fremitus: decreased

Tracheal deviation towards side of lesion

Tall thin young male

Breath sounds: decreased

Percussion: dull

Fremitus: decreased

Tracheal deviation toward side of lesion

Breath sounds: decreased

Percussion: dull

Fremitus: decreased

Tracheal deviation: none

Respiratory effort against airway obstruction. Associated with obesity, snoring, HTN, PHTN, Arrhythmias, Sudden Death

Cessation of breathing for >10 sec

Central (no respiratory effort) vs Obstructive

Results in Hypoxia --> EPO release --> Erythropoiesis

Wt loss, CPAP, Surgery

Caused by Aspiration, Acute pancreatitis, Air or Amnionic emboli, Radiation, DIC, Drugs, Dialysis, Diffuse Infection, Sepsis, Shock, Trauma, Uremia

Diffuse alveolar damage --> Increased capillary permeability --> protein rich exudate into alveoli --> Intraalviolar hyaline membane

Initial damage caused by release of substances toxic to alveolar wall by neutrophils, activation of coagulation cascade, ROS

Histo: Alveolar fluid and hylaline membranes

Surfactant deficiency --> Increased Surface Tension --> alveolar collapse

L/S < 1.5 predictive Because of low O2 tension --> risk of PDA

Therapeutic O2 --> ROP and Bronchopulmonary Dysplasia

Risk factors: Prematurity, Maternal Diabetes, Cesarean delivery (decreased release of glucocorticoids)

Treatment: maternal steroids before birth. Artificial surfactant for the infant

Associated with shipbuilding, roofing, plumbing

Associated with Bronchogenic Carcinoma and Mesothelioma

Asbestos bodies are golden brown fusiform rods (dumbbells) in Macs Ivory White calcified pleural plaques are pathognomonic but not precancerous

Associated with foundries, sandplansting, mines

Si --> Macs --> release fibrogenic factors

Increased risk for TB because Si --/ phagolysosomes thereby --/ macs.

Also increased risk for Bronchogenic Carcinoma

Affects Upper Lobes

Eggshell calcifications on hilar lymph nodes

Coal Miners Lung. Affects Upper Lobes

Anthracosis, Silicosis, Asbestosis

Caplan Syndrome which can lead to Cor Pulmonale

Bleomycin, Busulfan, Amiodarone, Methotrexate

Decreased Diffusion Capacity and Increased A-a Gradient

"A Good Physician Would Never Speak Hateful, Disgusting Epithets Intentionally"

ARDS, Goodpasture, Pneumoconioses, Wegeners (granulomatosis with polyangiitis), NRDS (hyaline membrane disease), Sarcoidosis (bilateral hilar lymphadenopathy, noncaseating granulomas, Increased ACE and Ca), Hypersensitivity pneumonitis, Drugs, Eosinophilic Granulomas (Langerhans cell histiocytosis), Idiopathic (repeat injury with collagen deposition)

Muscles: Polio, MG.

Structural: Scoliosis, Morbid Obesity

FVC: decreased, TLC: decreased, FEV1/FVC > 80%

"No Hot Days Post September, Onto KA"

chronic Necrotizing infection of bronchi, Hemoptasis, permanently Dilated airways, Purulent Sputum, Smoking (poor ciliary motility), bronchial Obstruction, Kartageners's (Dynein arm), Allergic bronchopulmonary Aspergillosis, CF

"His Majesty Coughed and Wheezed In Excruciating Pain 'Till Dawn"

Hypoxia, Mucus plugging, Cough, Wheeze, I/E ratio decreased, Pulsus Paradoxus (decrease in Systolic Pressure), Tachypnea, Dyspnea

Methacholine challenge. Muscarinic agonist

Bronchial hyper-responsiveness causes reversible Bronchoconstriction + Smooth Muscle hypertrophy

Antigen --> IgE on mast cell. Mast cell releases inflammatory mediators (leukotrienes, histamine, etc.)

Early response to inflammation = bronchoconstriction

Late response to inflammation = Bronchial hyper-reactivity

URI, stress, allergens

Cushmann's Spirals (shed epithelium from mucus plugging). Charcot-Leyden Crystals (Formed from breakdown of eosinophils in sputum)