pulmonary pathology: restrictive lung disease

Question 1

restrictive lung disease

Answer 1

• lung diseases that cause reduced expansion of lung and/or chest wall
• decreased compliance of lung and/or chest wall
  
  • MSK disorders: chest wall disorders (scoliosis, flail chest), neuromuscular disorders (SCI, GB, MG)
  • lung disorders: PF, sarcoidosis, pneumonia, atelectasis, pneumothorax, pleural effusion
• FEV1/FVC > 80%, but FVC is very small

Question 2

normal vs restrictive lung volume and pressure

Answer 2

• elimination of surface tension allows for more uniform expansion, less pressure for inflation and prevents derecruitment during deflation
• surface tension due to attractive forces between molecules
  
  • molecules on the surface are attracted to each other and resist expansion, working to minimize surface area
  • surface tension can be thought of as the work required to expand surface area
• surfactant reduces surface tension at air-liquid interface, due to amphipathic phsopholipids
  
  • surfactant forms a thin film at the air-liquid interface

more work has to be done

Question 3

interstitial lung disease caused by

Answer 3

• known and unknown causes
  
  • known:
    
    • chemo/radiation therapy
    • toxins (asbestosis, silicosis, coal dust
    • abnormal immune reactions
    • hypersensitivity reactions (farmer’s lung, bird fancier lung)
    • sarcoidosis
  • unknown
    
    • idiopathic pulmonary fibrosis (IPF)

Question 4

restrictive lung clinical presentation

Answer 4

• PFT
  
  • reduction in lung volumes and capacities (V_T and VC)
    
    • tidal volume, vital capacity
  • airflow usually maintained (FEV1/FVC ratio) but overall volume is smaller
• chest radiograph
  
  • small lungs
  • diffuse infiltration often characterized as small nodules, irregular lines or ground glass opacities
• common signs/symptoms
  
  • dyspnea, tachypnea, hypoxemia/cyanosis, wheezing/crackles

Question 5

restrictive disease and PFT - lung volume

Answer 5

• overall TLC and FRC reduced

Question 6

restrictive disease and PFT - flow rates

Answer 6

• flow rates are similar but volumes are smaller with restricitve lung disease

Question 7

pulmonary interstitium

Answer 7

• collection of support tissues within lung that include alveolar epitherlium, pulmonary capilarry endothelium, basement membrane, perivascular and perilymphatic tissues
• lace-like network of tissue that goes throughout both lungs and supports the alveoli

Question 8

idiopathic pulmonary fibrosis (pathogenesis)

Answer 8

• earliest manifestation is “alveolitis”
  
  • accumulation of inflammatory (immune) cells in interstitium and alveolar spaces
  • immune/inflammatory cells
    
    • release inflammatory mediators and stimulate fibrosis -> progressive lung destruction
• end-stage: fibrotic lung with useless airspaces, characterized as cystic spaces separated by thick bands of connective tissue with inflammatory cells

Question 9

atelectasis

Answer 9

• lung (alveolar) collapse due to loss of air volume
  
  • failure of lungs to inflate
• sidelying: affected up for treatment

Question 10

pneumonia

Answer 10

• an acute inflection of the lower respiratory tract typically involving the lung parenchyma (part involved in gas exchange - alveoli, alveolar ducts, respiratory bronchioles)
  
  • thickened and irritated alveolar walls (inflammation) and accumulation of mucus and inflammatory cells
• within the lung itself, so you can’t just drain it

Question 11

pneumonia

Answer 11

• origin of infection
  
  • community-acquired pneumonia (CAP): contracted outside hospital
  • hospital-acquired pneumonia (HAP): nonsocial pneumonia
• infectious agent: bacterial, viral, aspiration, fungal, opportunistic

Question 12

pneumonia clinical presentation

Answer 12

• fever/chills - hyperthermia or hypothermia
• tachypnea > 18 breaths/minute
  
  • pediatrics
• tachycardia (>100 bpm)
• cough with or without sputum
  
  • color of sputum can tell you about infectious agent
• mental status change: especially in elderly patient
  
  • confusion, delirium
• pleurisy (chest wall pain)
• adventitious breath sounds (wheeze/crackles, pleural friction rub)

Question 13

covid-19 transmission

Answer 13

• respiratory droplet (primary) versus airborn
• contact
• estimated reproduction number
  
  • R0 (how transmissible a pathogen is in population): 2-2.5
    
    • 1 person affects 2-2.5
• asymptomatic infection rate ~ 40%
  
  • time from exposure to symptom onset ~ 6 days

Question 14

SARS CoV 2

Answer 14

• has a “spike protein” that attaches to ACE 2 receptor that is distributed widely throughout body
• injects RNA into “host” cell
  
  • host produces new virus and triggers severe inflammation

Question 15

covid impacts multiple organ symptoms

Answer 15

• lung impacts mimic restrictive diseases

Question 16

covid CT findings

Answer 16

• early findings are ground glass opacities
  
  • normal CT
• later findings include bilateral and peripheral disease indicative of fibrotic lung changes

Question 17

poast acute sequelae COVID symptoms (PASC)

Answer 17

• brain fog, inattention, dizziness, anxiety/depression, insomnia, headaches
• anosmia
• odynophag
• chest pain/pressure, palpitations, arrhythmias
• dyspnea, coughing
• abdominal cramping, diarrhea
• generalized weakness
• arthralgia
• severity not correlated with intesnity of inital infection
  
  • about 20 percent of those infected
• also myalgic encephalitis/chronic fatique syndrome (ME/CFS)

Question 18

post-exertional malaise (PEM)

Answer 18

• characteristic of ME/CFS
• includes feeling bad, sick, tired as well as fatigue
• described as “crash/relapse” of illness
  
  • all symptoms worsen, not just fatigue
• exertion can be physical or mental
• persists more than 24 hours
• leads to additional limitation in activities
• take rehab low and slow

Question 19

hypoxemia/silent hypoxemia

Answer 19

• SpO2 < 93% (clinically < 88%)
• below normal level of oxygen in the blood
• silent: individual ahs lower oxygen saturation level than anticipated, but individual does not experience any breathing difficulty
  
  • they feel ok

Question 20

pulse oximetry

Answer 20

• inaccruate if weak or non-pulsatile (poor perfusion to digit) or irregular pulse
• palpate patient’s pulse to confirm
• review pulse waveform
  
  • SpO2 - See Pleth before O2

Question 21

postural orthostatic tachycardia syndrome (POTS)

Answer 21

• lightheadedness, palpitations, headaches, nausea/vomiting, fatigue
• increase risk in those with prior concussion history, autoimmune disorders (RA, celiac)
• sustained HR increment > 30 beats/minute within 10 minutes of standing
• education:
  
  • avoid hot baths/showers, Valsalva, large meals, dehydration, HOB elevation, sodium intake, compression garments, progressive exercise
    
    • 2-3L water per day, 10-12 grams/day of sodium, lower limb compression stockings and regular and progressive exercise
  • counter pressure maneuvers: isometrics, crossing and uncrossing LE/UE, squatting
  • referral