---

Metered Dose Inhaler (MDI)

What Is an MDI?

• Short-acting beta-2 agonists (e.g., albuterol/salbutamol) - for quick relief
• Inhaled corticosteroids (e.g., beclomethasone, fluticasone) - for long-term control
• Antimuscarinics (e.g., ipratropium bromide) - for COPD

---

Parts of an MDI

• Metal canister - holds the pressurized medicine
• Plastic actuator (boot/mouthpiece) - the part you put in your mouth
• Dose counter (on most modern inhalers) - shows remaining doses
• Cap - protects the mouthpiece

---

Step-by-Step: How to Use an MDI

Before Your First Use (Priming)

1. Remove the cap and check the mouthpiece is clean.
2. Shake the inhaler for about 10 seconds.
3. Point it away from your face and spray 2-4 puffs into the air (check your medicine instructions for exact number).
4. Re-prime if you haven't used the inhaler for 1-2 weeks or if you drop it.

Taking a Dose

• Check the dose counter. If it reads zero, the inhaler is empty - replace it.
• Remove the mouthpiece cap. Check inside for any debris.
• Shake the inhaler well.

• Stand or sit up straight.
• Tilt your head back slightly.
• Breathe out fully and completely, away from the device - empty your lungs as much as possible.

• Place the mouthpiece in your mouth, above your tongue.
• Close your lips tightly around it to form a seal.
• As you start to breathe in, press down firmly on the canister once to release one puff.
• Breathe in slowly and deeply for 3 to 5 seconds - this draws the medicine deep into the lungs.

• Remove the inhaler from your mouth.
• Hold your breath and count to 10 seconds - this allows medicine to settle in the airways.
• Then breathe out slowly through your mouth.

• If prescribed more than one puff, wait 1 minute between puffs, then repeat steps 2-4.

• Replace the cap and store in a cool, dry place.
• If you used an inhaled corticosteroid, rinse your mouth with water and spit it out - this prevents oral thrush (fungal infection).

---

Using a Spacer (Valved Holding Chamber)

• Slows down the aerosol so you don't need perfect timing
• More medicine reaches the lungs (less deposited in mouth/throat)
• Reduces risk of oral thrush with steroid inhalers

1. Attach the MDI to the spacer's rubber ring.
2. Shake the inhaler.
3. Press down once to release the puff into the spacer.
4. Breathe in slowly and steadily through the spacer mouthpiece.
5. Hold your breath for 10 seconds, then breathe out.
6. Do NOT fire multiple puffs into the spacer at once - one puff at a time.

---

Common Mistakes to Avoid

---

Cleaning Your MDI

• Remove the canister and rinse the plastic actuator (boot) with warm water once a week.
• Let it air dry completely before reassembling.
• Never put the metal canister in water.
• Never brush or wipe the inside of a spacer.

---

When to Replace Your Inhaler

• When the dose counter reaches zero
• If more than 1-2 weeks have passed since last use (re-prime before using)
• If the inhaler has been dropped or damaged

---

---

Available Vaccine Types for Pneumonia

---

Type 1 - Pneumococcal Conjugate Vaccines (PCVs)

• Effective in infants, children, and adults
• Trigger immunological memory (long-lasting protection)
• The current standard for childhood immunization worldwide
• PCV15, PCV20, and PCV21 are the current recommended options for adults in the US (CDC, updated Feb 2026)

---

Type 2 - Pneumococcal Polysaccharide Vaccine (PPSV)

• Each 0.5 ml dose contains 25 micrograms of capsular polysaccharide from each of the 23 serotypes
• Given as a single intramuscular or subcutaneous dose (preferably deltoid muscle)
• Protective antibody levels develop by week 3 after vaccination
• Does NOT work well in children under 2 years or immunocompromised individuals (no T-cell response)
• 30-50% of recipients get mild local reactions (redness, pain at injection site)

---

Comparison: PCV vs PPSV23

---

Current US CDC Recommendations (2025-2026)

• Receive PCV15, PCV20, or PCV21
• If PCV15 is used, follow with PPSV23

• Same options: PCV15, PCV20, or PCV21

• Age 65+: May optionally receive PCV20 or PCV21 (discuss with provider)

• WHO recommends either a 3-dose primary series (3p+0) or 2 primary doses + 1 booster (2p+1) starting from 6 weeks of age
• PCV20 is now also an option for children in some scenarios

---

Risk Groups Who Especially Need Pneumococcal Vaccination

• Age 50 years and older (US: 50+; many countries: 65+)
• Post-splenectomy patients
• Sickle cell disease
• Chronic heart, lung, liver, or kidney disease
• Diabetes mellitus
• Alcoholism
• Organ transplant recipients
• HIV/AIDS and other immunocompromising conditions
• Cochlear implant recipients or those with CSF leaks
• Children under 5 (routine program)

---

Important Notes

• PCV21 (Capvaxive) is the newest addition, FDA approved June 2024, covering 21 serotypes - it is now an ACIP-recommended option for all adults 18 and older
• Never mix PPV23 in the same syringe as influenza vaccine - give separately in different arms (safe to give on the same day)
• Interrupted PCV schedules in infants should be resumed without repeating prior doses
• Interchangeability between PCV10 and PCV13 in infant schedules has not been documented; try to complete the series with the same product

---

Recurrent Pneumonia - Differential Diagnosis

Definition

• 2 or more episodes within a 6-month period, OR
• 3 or more episodes in a lifetime
• With radiographic clearing between episodes (distinguishes it from non-resolving/persistent pneumonia)

Key clinical clue: Recurrent pneumonia in the same lobe/segment suggests a local structural/obstructive cause. Recurrent pneumonia in different lung regions suggests a systemic cause (immune, mucociliary, aspiration).

---

DD Organized by Category

1. Structural / Anatomical Causes

---

2. Airway Obstruction (Local)

---

3. Aspiration-Related Causes

---

4. Immunodeficiency (Primary)

---

5. Immunodeficiency (Secondary)

---

6. Impaired Mucociliary Clearance

---

7. Underlying Lung Disease

---

8. Mimics of Recurrent Pneumonia (Non-infectious)

---

Age-Based Approach

---

Diagnostic Workup Clues

• Same lobe repeatedly → bronchoscopy to exclude obstruction (tumor, foreign body)
• Different lobes → systemic workup (immune, mucociliary, aspiration)
• Low serum immunoglobulins → primary immunodeficiency
• Sweat chloride / CFTR gene → CF
• Nasal NO + ciliary biopsy → PCD
• Modified barium swallow / pH probe → aspiration/GERD
• HRCT chest → bronchiectasis, sequestration, structural anomalies
• Bronchoscopy + BAL → obstruction, lipid-laden macrophages (aspiration), eosinophilia, infection

---

---

Persistent / Non-Resolving Pneumonia - Differential Diagnosis

Definition

• Clinical non-response: No improvement in fever, symptoms within 72-96 hours of antibiotics
• Radiological non-resolution: Infiltrate persists beyond 4-6 weeks (longer in elderly, COPD)
• Distinct from recurrent pneumonia (which clears between episodes) - here the same infiltrate persists without clearing

---

Mnemonic: C H A O S

---

Detailed DD by Category

1. Complications of Pneumonia (C)

---

2. Host (Patient) Factors (H)

---

3. Antibiotic Issues (A)

---

4. Organism Factors (O)

Resistant / Unusual Bacteria

Atypical / Intracellular Organisms

Mycobacteria

Fungi

Viruses

Parasites

---

5. Second (Alternative Non-Infectious) Diagnosis (S)

Malignancy

Inflammatory / Autoimmune Lung Disease

Vascular

Drug-Induced Pneumonitis

Other

---

Timeline for Normal Radiological Resolution

---

Diagnostic Approach

1. Reassess diagnosis - Was it really pneumonia? Review CXR, microbiology
2. CT chest (HRCT) - Detects abscess, empyema, masses, bronchiectasis, structural anomaly
3. Bronchoscopy + BAL - Essential if CT non-diagnostic; BAL for cultures (including AFB, fungal), cytology, lipid-laden macrophages
4. Sputum - AFB smear/culture, fungal cultures, Gram stain
5. Serology - Legionella urinary antigen, atypical serology, fungal antigens (galactomannan, beta-D-glucan)
6. HIV test - Mandatory in any non-resolving pneumonia without another clear cause
7. Immunoglobulins - If recurrent or persistent in younger patient
8. Autoimmune screen - ANA, ANCA, anti-GBM if vasculitis/CTD suspected
9. CT-guided biopsy / VATS biopsy - If all else fails and malignancy/ILD suspected

---

---

Percussion Notes - Types and Causes

What is Percussion?

---

The 5 Percussion Notes

1. RESONANT

• Normal lung parenchyma (healthy adult)

---

2. HYPERRESONANT (Hyper-resonance / Tympanitic)

Tympany = extreme form of hyperresonance, heard normally over stomach/bowel (gas-filled); abnormally over a large pneumothorax (described as tympanitic) or a large pulmonary cyst/cavity.

---

3. DULL

---

4. STONY DULL (Stony Dullness)

Key distinction: Stony dullness is denser/flatter than plain dullness - it cannot be made less dull by changing posture or by deep breathing. Associated with absent tactile fremitus (unlike consolidation which increases fremitus).

---

5. FLAT (Absolute Flatness)

---

Summary Comparison Table

---

Clinical Correlation: Percussion + Other Signs

---

Special Percussion Signs

• Traube's space (gastric tympany): Tympanitic area over left lower chest - obliterated (dull) in splenomegaly or left-sided pleural effusion
• Kronig's isthmus: Band of resonance over each shoulder - narrowed in upper lobe TB or fibrosis
• Shifting dullness: Dullness that shifts with posture - classic for pleural effusion or ascites
• Coin test: Resonance heard when a coin is placed on chest and tapped - used to confirm pneumothorax (metallic bell-like tone)

---