How is it Diagnosed?
Acute Respiratory Infections (ARIs) affect the upper or lower respiratory tract and are
among the most common causes of morbidity. Diagnosis starts with clinical history
including sudden onset of cough, sore throat, nasal congestion, fever, and breathing
difficulty. Duration (typically <14 days), symptom severity, and exposure history (travel,
sick contacts) are noted.
Physical examination includes auscultation for wheezes, rales, or decreased breath
sounds. Vital signs may reveal fever, tachypnea, or hypoxia.
For upper respiratory tract infections (e.g., viral pharyngitis, common cold), diagnosis is
clinical. For suspected lower respiratory infections like pneumonia or bronchitis, further
evaluation is needed. A chest X-ray is crucial for detecting lung infiltrates, consolidation,
or pleural effusion.
Pulse oximetry assesses oxygen saturation; arterial blood gas (ABG) may be used in
severe cases. CBC can show leukocytosis in bacterial infections or lymphocytosis in
viral infections. In select cases, sputum culture, nasopharyngeal swabs for viral PCR
(e.g., influenza, RSV, SARS-CoV-2), and blood cultures are indicated.
Special tests like CRP or procalcitonin levels may assist in distinguishing bacterial from
viral causes. Prompt diagnosis enables appropriate antimicrobial therapy, supportive
care, and isolation measures when needed.