Pulmonology List of Most Commons for Physician Assistant Students

This topic deserves an introduction. Why? Because it is Lung Cancer Awareness Month. How many of you have ever heard of Lung Cancer Awareness Month? Exactly. That’s probably because Breast Cancer Awareness Month probably stole its light in October. Unfortunately, breast cancer does not cause the most mortality in the United States, lung cancer does; that goes for men and for women. Why is this? Probably because there is not a unified and inexpensive diagnostic screening method for lung cancer as there is for breast cancer. Lung cancer causes almost double the number of deaths per year as breast, colon/rectal, and prostate cancers. Nonsmokers living with smokers have more than a 30% increased risk for developing lung cancer, regardless of whether or not the smoker is physically smoking around the nonsmoker or not. A diet rich in fruits and vegetables may protect against the development of lung cancer in smokers. However, high dose supplements of beta-carotene (also found in carrots) has been shown to increase the risk for lung cancer and is not recommended. So there you go. I have increased your knowledge about lung cancer in a matter of a few minutes. Hopefully now you will remember that every november is Lung Cancer Awareness Month and that you will remember to include lung cancer in your differential and to screen folks for it when necessary.

Most Commons in Pulmonology

• Cough - Most common complaint seen in outpatient setting
• Dyspnea (difficulty breathing) - common complain at emergency department
• COPD - most common respiratory disease; 3rd leading cause of death in US
• More prevalent in males
• Most common cause of COPD - cigarette smoking
• Most common bacterial pathogens in COPD are: Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis
• Asthma - most common in children
• More common in male children
• Prevalence changes to adult women after puberty
• Most common in Caucasians
• Most are categorized as moderate persistent
• More common in obese individuals
• Most common Interstitial Lung Diseases
• (1) Usual Interstitial Pneumonia (idiopathic pulmonary fibrosis) - idiopathic interstitial pneumonia (IIP)
• (2) Sarcoidosis - idiopathic, granulomatous
• (3) Hypersensitivity Pneumonitis (HP) - known cause, granulomatous
• Idiopathic Interstitial Lung Disease - Most common type of Interstitial Lung Disease (ILD) or Diffuse Parenchymal Lung Disease
• Usual Interstitial Pneumonia (UIP) - most common Idiopathic Interstitial Pneumonia (IIP) and most common interstitial lung disease (ILD) overall
• Worse prognosis than other IIP: 3 year survival after diagnosis
• Smoking increases risk for development
• More common in men 50+ (middle aged or elderly)
• Anti-inflammatories worsen mortality
• When truly idiopathic, also known as idiopathic pulmonary fibrosis (PF): guidelines state that if you have a pathologic pattern of usual interstitial pneumonia and no known cause, you may use this term
• Note: recent treatment approved
• Sarcoidosis - most commonly presents in young African American women ages 10-40
• Reactivation mTB - most common in males 30-50 y/o
• Apical (hilar) infection most common
• Most common route of acquiring pneumonia is by aspiration of oropharyngeal secretions
• Community Acquired Pneumonia - most common causative agent is Streptococcus pneumoniae
• Twice as frequently during the winter in ages <5 and >65
• Nosocomial Pneumonia - most common infection in the intensive care unit
• Coccidiodomycosis - most commonly acquired in the summer/late fall during outdoor activities
• Allergic bronchopulmonary aspergillosis, pulmonary aspergilloma, angio-invasive aspergillosis - most common forms of Aspergillosis
• Aspergillosis - leading cause of death in acute leukemia, hematopoietic stem cell transplantation
• Most common species is aspergillus fumigatus
• Transudate - most common cause of a transudative effusion is congestive heart failure
• Pneumonia - most infectious disease in US
• Most common cause of death in pediatric population
• Most common cause of pneumonia in children: viral (RSV)
• Most common bacterial cause in children: S. pneumoniae
• Most common pathogen causing CAP: streptococcal pneumoniae
• Mycoplasma Pneumoniae - most common in 50 y/o
• Streptococcal Pneumoniae - most common in elderly and patients with comorbidities
• Haemophilus influenzae - most common in patients with comorbidities (COPD)
• Lung cancer - most prominent in African American men
• Most common cause of cancer death for men and women in US
• Most common cause of lung cancer among non-smokers: radon
• Non-Small Cell Carcinoma (NSCLC) - most common type of bronchogenic carcinoma
• Most common lung cancer subtype: adenocarcinoma (45-50%)
• Most commonly found in female non-smokers
• Leading cause of lung cancer: smoking
• Pulmonary Arterial Hypertension - most common in women 40-50 y/o
• Respiratory tract infections are the leading cause of mortality worldwide causing 3.9 million deaths in 2004 (WHO)
• Rhinovirus and Coronavirus - 2 most common viruses associated with common cold
• The “common cold” - the most frequent acute respiratory illness in the US
• Respiratory Syncytial Virus (RSV) - most common viral pathogen causing acute lower respiratory tract infection in young children (bronchiolitis)
• Most common cause of infant hospitalization in US
• Most children infected by age 3
• HCAP/HAP/VAP - most common MDR pathogen is Pseudomonas Aeruginosa
• Acute bronchitis - most commonly viral
• If longer than 3 weeks, considered chronic
• Pertussis - most common in children under the age of 1 (previously 1-5 y/o)

Other Helpful Hints

• Light’s Criteria - diagnostically differentiates between a transudative and exudative pleural effusion; not enough to formulate a diagnosis by itself
• Pleural fluid protein/serum protein ratio greater than 0.5
• Pleural fluid LDH/serum LDH ratio greater than 0.6
• Pleural fluid greater than ⅔ upper limit of normal serum LDH
• Exudate if any 1 of the above criteria is met, otherwise usually transudate
  

Disease	FVC	FEV1	FEV1/FVC	FEF25-75	FET
Obstructive	Normal <80%	Decreased <80%	Decreased < 0.7	Decreased <60%	Increased
Restrictive	Decreased <80%	Normal or Decreased <80%	Normal or Increased 0.7	Normal >60%	Normal
Mixed	Decreased <80%	Decreased <80%	Decreased < 0.7	Decreased or Normal <60%	Increased or Normal

• Tiffeneau index (FEV1/FVC x 100): % of FVC expired in one second
• FET = Forced Expiratory Time
• Pay Attention Here: The important thing to know about how to differentiate an obstructive vs. restrictive lung disease is based on their TLC, not the vital capacity, which will be decreased in obstructive lung diseases (this can be misleading).

Disease	TLC	FRC	TV	RV	VC
Obstructive	Increased	Increased	N	Increased	Decreased
Restrictive	Decreased	Decreased	N	Decreased	Decreased

• Obstructive vs. Restrictive Lung Diseases
• Obstructive Lung Diseases - chronic obstructive pulmonary disease, asthma, cystic fibrosis, bronchiectasis, and bronchiolar diseases (constrictive bronchiolitis, bronchiolitis obliterans syndrome)
• Restrictive Lung Diseases - interstitial lung diseases (ILD): sarcoidosis, chronic beryllium disease, hypersensitivity pneumonitis, pneumoconiosis, asbestos

Plethysmography Pattern	Feature	DLCO	Likely Dx
Obstructive	Hyperinflation (TLC >120%)	Decreased	Emphysema
Obstructive	Hyperinflation	Normal or Increased	Asthma
Obstructive	Normal lung volume	Normal	Chronic Bronchitis
Restrictive	Low RV	Decreased	Scar (Sarcoid or fibrosis)
Restrictive	Normal RV	Normal	Neuromuscular disease

• COPD Staging - Global initiative for chronic Obstructive Lung Disease Criteria

GOLD I	Mild	No symptoms Cough, sputum Limited exercise capacity Infrequent exacerbations	FEV1 > 80% predicted
GOLD II	Moderate	Significant limitation in exertional capacity Limited ADLs	50% < FEV1 < 80%
GOLD III	Severe	SOB, even at rest	30% < FEV1 <  50%
GOLD IV	Very Severe	Frequent, severe exacerbations	FEV1 < 30% predicted

• Alpha-1 Antitrypsin Deficiency - autosomal co-dominant inheritance
• Most common PI*ZZ allele
• Suspect if
• COPD onset before age 45
• Basilar emphysema (also known as panlobular emphysema)
• Unexplained liver disease, cirrhosis
• Absence of COPD risk factors
• Necrotizing panniculitis
• Unexplained bronchiectasis
• FH of any of above
• Caseating granulomas - hallmark lesion of tuberculosis
• Latent TB Infection - patients with latent tuberculosis are not infectious
• The main risk is reactivation mTB, also known as secondary TB
• PPD Skin Testing - “Never shake hands with TB on your Left”
• i.e. PPD tests are always performed on the patient’s right arm
• Quantiferon-TB Testing
• Cannot distinguish between active disease and latent infection
• CT Chest Findings: Aspergillosis
• Early: halo sign (i.e. an area of ground-glass infiltrate surrounding nodular densities)
• Late: crescent sign (i.e. air surrounding nodules, indicative of developing cavitation)
• Pulmonary Embolism Chest X-ray Findings
• Westermark Sign (oligemia): an abrupt cutoff of pulmonary vessels or dilation of pulmonary arteries proximal to embolus
• Hampton’s Hump: wedge shaped consolidation in the periphery against the pleural surface or a pleural based area of increased opacity
• Lung Cancer High Risk Factors - US Preventative Services Task Force
• 55-80 y/o
• 30 pack-year history of smoking
• Not quit within last 15 years
• Surgical candidate
• MRSA Risk Factors for Pneumonia
• Pleural effusion
• Recent Illness (including influenza infection)
• IVDA
• Multifocal infiltration (cavitations) on CXR
• ESRD
• Recent prior antibiotics (last 3 months)

Resources:

Pleural Diseases

Approach to the Patient with Pulmonary Disease, Dr. Orcutt

Pulmonary Function Tests, Dr. Dekat

Asthma, Dr. Dekat

Cecil’s Essentials of Medicine, 8th Edition, Thomas E. Andreoli

https://meded.ucsd.edu/isp/1998/asthma/html/spirexp.html

http://www.cdc.gov/TB/topic/testing/default.htm