Respiratory Infection Assessment: Determining Severity Without a Clinic

Upper vs. Lower Respiratory Tract

The dividing line is the larynx (voice box). Above it: nose, sinuses, throat, upper larynx. Below it: trachea, bronchi, lungs.

This distinction matters because:

• Upper respiratory infections are almost always viral, do not respond to antibiotics, and rarely cause serious illness in otherwise healthy adults
• Lower respiratory infections (bronchitis, pneumonia) can be bacterial, may respond to antibiotics, and carry significantly higher mortality risk without treatment

Clues pointing to upper tract:

• Runny nose, nasal congestion
• Sore throat
• Ear pain
• Normal or near-normal breathing rate
• Mild fever or none

Clues pointing to lower tract:

• Chest tightness, chest pain that worsens with breathing or coughing
• Shortness of breath at rest
• Elevated breathing rate
• Wheezing or abnormal breath sounds
• Higher fever
• Productive cough with thick colored sputum

Vital Signs as Severity Indicators

Breathing Rate

Count chest rises for 60 seconds. Do not announce that you are counting — patients alter their breathing when aware. The most accurate way is to hold the patient's wrist as if checking pulse, then observe the chest.

Normal breathing rates:

• Adults: 12-20 breaths per minute
• Children 6-12: 18-25 per minute
• Children 2-6: 20-30 per minute
• Infants under 2: 25-50 per minute

Elevated rate significance:

• Adults 20-25: mild concern, monitor closely
• Adults 25-30: significant concern, likely lower tract involvement
• Adults above 30: severe, possible pneumonia or respiratory failure
• Children any age with rate consistently above 50: danger sign

WHO defines "fast breathing" in children under 5 as a key indicator for community-acquired pneumonia requiring treatment.

Temperature

Under 38°C (100.4°F): May still be infection, but lower concern for serious bacterial illness.

38-38.5°C (100.4-101.3°F): Febrile illness; viral vs. bacterial indeterminate without other signs.

Above 38.5°C (101.3°F): Higher concern for bacterial cause, particularly with productive cough and elevated breathing rate.

Above 40°C (104°F): Significant systemic illness. Aggressive fever management warranted.

Oxygen Saturation (Pulse Oximetry)

A pulse oximeter is one of the highest-value medical devices per dollar for a prep kit. It measures peripheral oxygen saturation (SpO2) non-invasively via a sensor on the fingertip.

Normal: SpO2 95-100% Mild concern: 92-94% Significant concern: 88-92% Emergency: Below 88%

In a patient with respiratory infection, SpO2 below 94% at rest indicates impaired gas exchange — the infection is significantly affecting lung function. Below 90% warrants urgent evaluation and supplemental oxygen if available.

Heart Rate

Tachycardia (elevated heart rate) accompanies fever and respiratory distress. It alone is not diagnostic but adds to the clinical picture.

The PSI/PORT score (Pneumonia Severity Index) used in emergency departments incorporates age, comorbidities, vital signs, mental status, and exam findings. At its simplest: the combination of elevated breathing rate + elevated heart rate + fever + productive cough + abnormal chest exam = pneumonia until proven otherwise.

Chest Assessment in the Field

Without a stethoscope, chest assessment is limited but possible:

Look:

• Is the chest wall expanding symmetrically?
• Are accessory muscles being used? (Neck muscles pulling up, or intercostal muscles between ribs visibly contracting)
• Is the patient leaning forward on outstretched arms to breathe? (Tripod position — indicates respiratory distress)
• Cyanosis: bluish color of lips, fingertips, or tongue

Feel:

• Place hands flat on the chest wall. Is there equal movement both sides with each breath?
• Decreased movement on one side suggests pneumonia, pleural effusion, or collapsed lung (pneumothorax)

With a stethoscope:

• Normal breath sounds: clear rush of air heard in all fields
• Crackles (rales): popping, crackling sounds like hair being rubbed between fingers — heard in pneumonia and pulmonary edema
• Wheezing: musical, high-pitched sound — indicates bronchospasm
• Absent or significantly reduced breath sounds in one area: possible pneumonia, effusion, or pneumothorax
• Pleural friction rub: a grating, creaking sound — suggests pleuritis (inflammation of lung lining)

Pneumonia Assessment

Pneumonia should be suspected when:

• Productive cough with thick yellow/green/rusty sputum
• Fever above 38.5°C
• Breathing rate above 20-25 in adults
• Chest pain that worsens with breathing (pleuritic chest pain)
• Systemic illness: fatigue, malaise, reduced appetite
• Crackles on auscultation of affected lung fields

Atypical Pneumonia ("Walking Pneumonia")

Caused by organisms like Mycoplasma pneumoniae or Chlamydophila pneumoniae. Presents differently:

• Often gradual onset
• Dry, non-productive cough
• Low-grade fever
• Patient may feel unwell but not dramatically ill
• Often young adults, previously healthy

Atypical pneumonia responds to macrolides (azithromycin, doxycycline) but not to beta-lactam antibiotics (amoxicillin, cephalexin). If a patient is not improving on amoxicillin, consider atypical organisms.

Antibiotic Decisions

Upper respiratory infections (cold, most sore throats, most sinus infections, viral bronchitis):

No antibiotics. Antibiotics do not shorten the course of viral illness. They cause side effects (diarrhea, yeast infections) and promote antibiotic resistance. The expectation that respiratory infections always need antibiotics is wrong and harmful.

Symptomatic treatment:

• Fever and discomfort: ibuprofen or acetaminophen
• Nasal congestion: nasal saline irrigation, decongestants (pseudoephedrine)
• Sore throat: throat lozenges, salt water gargles, analgesics
• Cough: honey has modest evidence for cough suppression (adults and children over 1 year), dextromethorphan for dry cough

Bacterial pneumonia:

Community-acquired pneumonia antibiotic choices:

• Azithromycin (Z-Pack) 500mg day 1, then 250mg days 2-5: Covers typical and atypical organisms. Excellent for outpatient treatment.
• Doxycycline 100mg twice daily × 5-7 days: Good coverage for typical and atypical including Mycoplasma.
• Amoxicillin-clavulanate (Augmentin) 875mg twice daily × 5-7 days: Covers typical bacterial pneumonia. Does not cover atypical.
• Levofloxacin or moxifloxacin: Respiratory fluoroquinolones with excellent coverage. Reserve for when first-line fails.

Duration: 5 days is adequate for most mild-moderate pneumonias with good clinical response. Extend to 7 days for incomplete response.

Pneumonia with Concerning Signs:

If any of the following: breathing rate above 30, SpO2 below 94%, altered mental status, inability to take oral medications, systolic BP below 90 — the patient needs IV antibiotics and hospitalization-level care. Oral antibiotics and field management are inadequate.

Danger Signs That Require Evacuation

Any patient with respiratory infection who develops these signs needs evacuation:

• Breathing rate above 30 per minute at rest
• SpO2 below 90% (or below 94% with respiratory distress symptoms)
• Cyanosis: Blue discoloration of lips, tongue, or fingertips
• Altered mental status: Confusion, difficulty staying awake, inability to give coherent history
• Unable to maintain upright position to breathe (must lie flat but cannot breathe lying flat = orthopnea — indicates heart failure or severe respiratory compromise)
• No improvement or worsening after 48-72 hours of appropriate antibiotics
• Any child under 2 years with significant respiratory symptoms

The time from uncomplicated community pneumonia to respiratory failure can be rapid — particularly in elderly patients, those with diabetes, or immunocompromised individuals. When doubt exists, err toward evacuation.