17 - Subacute and Chronic Lung Disease

Lung Abscess definition

Lung parenchyma dead via liquefactive necrosis, walled off by granulation tissue, forming a cavity filled with pus

What is the difference between primary and secondary lung abscesses?

Primary is in a lung w/o any underlying lesion/abnormalities, while secondary is in a lung that has congenital malformation, foreign body obstruction, etc.

What material is the one that causes lung abscesses, and why?

Saliva, since it carries bacteria(needed for an abscess to happen)

What are 2 factors that can increase abscess chance, and why?

1. Alcoholism: Impairs consciousness and gag reflex, allowing aspiration to happen more

2. Gingivitis: Location for the bacteria to stay

Most vulnerable lobes of the right lung to abscess:

• Posterior segment of upper lobe

• Superior segment of lower lobe

Lowest points when laying supine

Most vulnerable lobes of the left lung to abscess:

• Apicoposterior segment of upper lobe

• Superior segment of lower lobe

Lowest points when laying supine

Where is this abscess located?

Lower lobe, since the upper/anterior part is the upper lobe

A putrid smell in sputum indicates

Anaerobic bacteria activity

Investigation to find causative organism in lung abscess

1. Sputum gram stain/culture

2. Hemoculture

3. Needle aspiration (Less common than first 2)

A cough, along with other symptoms like fever for a month rules out…

• URI

• LRI

• Asthma exacerbation

Post-TB, hemoptysis for three days, think:

1. Post-TB Bronchiectasis

2. Aspergilloma

3. Reactivation TB

Post-TB Bronchiectasis mechanism

Inflammation from TB → Dilation and damage of airways and impaired mucociliary function → more bacteria colonize and grow → more inflammation and repeat

What do these supine and prone CTs tell us?

The lump in the cavity is mobile and when pt. lies supine in drops, then falls forward when they lay prone → aspergilloma

Aspergilloma

• What does it require to happen

• Symptoms

• Requires some structural hole/cavity like TB or bulla

• Asymptomatic until hemoptysis

Pneumoconiosis meaning

Lung injury from inhaling mineral dust like asbestos, coal dust, and silica

Patient with years of concrete cutting/drilling → think of ___?

Silicosis

Silicosis pathology and symptoms

• Over many years of drilling concrete, silica crystals enter the alveoli where macrophages engulf them, but can’t kill them. This instead kills the macrophage, causing inflammation and releases the silica again. That continues the cycle of inflammation

• The inflammation leads to fibrosis that forms nodules that impair respiration, and the thickened walls makes diffusion into blood harder → chronic progressive dyspnea, and the fibrotic tissue causes irritation but there’s no pus → dry cough

Silicosis on CXR and CT

เส้นๆ on CXR but nodules on CT

Pneumonia vs atypical pneumonia

• Visibility on gram stain: Atypical pneumonia organisms won’t show up

• Symptoms: Typical pneumonia causes sudden high fever with purulent sputum while atypical pneumonia has low fever with dry cough

• Location: Consolidation of one lobe vs patchy changes in both lungs and multiple lobes

• Response to antibiotics: Atypical pneumonia doesn’t respond to beta-lactams

EVALI

• Stands for

• What is it?

• Clinical clues

• E-cigarette or vaping associated lung injury

• An acute injury of alveoli caused by inhaled vaping aerosols, leading to damage to alveolar epithelium and inflammatory exudate leaking into alveoli

• History of heavy vaping, failure of antibiotics, GI symptoms, foamy macrophages in BAL

Associate this with one of the conditions we learned today

Silicosis

Associate this with one of the conditions we learned today

EVALI

Associate this with one of the conditions we learned today

Lung abscess

Associate this with one of the conditions we learned today

Aspergilloma