MD Notes

creation date: 2024-12-29 14:12
tags: Pathologies

Upper Respiratory Tract Infection

Background

Definitions

Upper respiratory tract infections (URTIs) are infections at or above the vocal cords, including the nasal cavity, sinuses, pharynx, and larynx.

URTIs include the common cold, influenza, sinusitis, pharyngitis, laryngitis, and epiglottitis.

This page will cover URTIs with a focus on viral causes. See specific conditions for more details.

Etiology

Most URTIs are caused by viruses. Some are caused by bacteria.

Viruses include rhinovirus, coronavirus, influenza virus, respiratory syncytial virus (RSV), adenovirus, parainfluenza virus, human metapneumovirus, Epstein-Barr virus, and enterovirus.

Bacterias include streptococcus pneumoniae, streptococcus pyogenes, haemophilus influenzae, mycoplasma pneumoniae, moraxella catarrhalis.

Pathogenesis

Manifestation of infection typically occur from innate immune response.

Clinical Presentation

Signs & Symptoms

Symptoms of infection typically are self-limiting and last ≤14 days.

Common features of URTI include:

  • Sore throat
  • Nasal congestion
  • Rhinorrhea (with or without purulence)
  • Cough
  • Fever

Features may vary slightly depending on the type of URTI. For example, a loss of taste/smell with COVID-19 or facial tenderness to palpation with rhinosinusitis.

Bacterial etiology may be considered with the following signs:

  • High-grade fever
  • Double worsening
  • Persisting symptoms >10 days

Additionally, consider group A streptococcal pharyngitis based on the Centor score criterions:

  • Sans cough
  • Tender lymph nodes
  • Right age (3-14 years old)
  • Exudate on tonsils
  • Pyrexia

Bacterial etiology of sinusitis can be considered based on the presence of:

  • Pressure
  • Obstruction
  • Discharge/drip
  • Smell (hyposmia or anomia)

History & Physical Exam

History:

  • Recent travel history
  • Sick contacts
  • Vaccination status (eg. COVID-19, Hib vaccination, influenza vaccination)
  • Review of systems - HEENT, pulmonary

Physical exam:

  • HEENT exam
  • Pulmonary exam

Risk factors

URTIs are more common in the fall and winter. They also occur more in children than in adults.

Diagnosis

Criteria

Diagnosis is made clinically.

Work-up

If clinically suspicious of bacterial infection, a nasal swab may be used for confirmation.

  • Rapid strep test
  • Heterophile antibody test (infectious mononucleosis)
  • PCR swabs (eg. flu, COVID-19, pertussis, RSV)
    Availability and indications for swabs may vary.

In cases of more severe disease, blood studies may aid in determining severity. Infection may manifest as lymphopenia/lymphocytosis, elevation of ESR and CRP, and other panels may show signs of end-organ damage.

Blood cultures can evaluate for bacteremia and ABG for patients with signs of respiratory distress.

Imaging studies may be indicated if suspicion of specific diagnosis:

  • Chest x-ray for pneumonia
  • Neck imaging for croup, epiglottitis
  • CT maxillofacial for rhinosinusitis red flags

Differential

Diagnoses include other infectious causes:

  • Lower respiratory tract infections (eg. pneumonia)
  • Acute HIV infection
  • Measles

Noninfectious causes include:

Red Flags / Complications

Complications are rare with URTIs.

Possible complications include progression of infection beyond the upper respiratory tract (eg. to the lower respiratory tract or to the ear as otitis media).

Specific etiology/condition may also have their own complications.

Management

Lifestyle / Social

As most URTIs are viral in origin and self-limiting. Management is largely non-pharmaceutical and symptom based.

General advice includes:

  • Rest and hydration
  • Avoid smoking and alcohol use
  • Isolation if necessary

For pain and/or fever:

  • Ibuprofen 400mg PO q4-6h
  • Acetaminophen 650mg PO q4h or 1000mg PO q6h

For rhinorrhea or sinus congestion:

  • Elevate head
  • Warm compress for facial pain
  • Nasal saline irrigation
  • Intranasal decongestants

Pharmacological / Interventional

Antibiotics are not typically prescribed due to the viral etiology. See bacterial specific conditions for antibiotic treatment:

  • Group A Streptococcal pharyngitis
  • Bacterial sinusitis

Return precautions

Patients should be counselled to return should the following symptoms occur:

  • Dyspnea
  • Chest pain
  • Productive cough
  • High grade fever
  • Severe headache or facial pain
  • Dizziness or confusion
  • Symptom duration exceeding 2 weeks (with exception to cough)

References

Tools / Guidelines

Additional Reading

Backlinks