Pneumonia is a significant respiratory condition involving acute inflammation of the lung parenchyma, which can result from bacterial, viral, or fungal infections. Two main types are crucial to distinguish for effective treatment: nosocomial (hospital-acquired) pneumonia and community-acquired pneumonia (CAP). Nosocomial pneumonia commonly involves pathogens such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Haemophilus influenzae. In these cases, alveoli fill with fluid leading to impaired gas exchange. The clinical presentation often includes subjective symptoms like fever, productive cough with rust-colored or purulent sputum, chills, pleuritic chest pain, myalgia, and signs like crackles or pleural rub detected on auscultation. Objective findings may reveal decreased breath sounds or dullness to percussion, and decreased oxygen saturation (SaO2 <90%) or hypoxemia (PaO2 <60 mmHg). Community-acquired pneumonia, on the other hand, frequently presents with bacterial lobar infiltrates on chest X-ray, often caused by pathogens like Streptococcus pneumoniae and Haemophilus influenzae. Viral pneumonia accounts for about 5-15% of CAP cases and typically shows diffuse infiltrates. Diagnostics involve chest radiography, complete blood counts with differential to assess white blood cell elevation (WBC >15,000 suggestive of bacterial infection), sputum Gram stain, culture, and urinary antigen testing. Blood cultures and arterial blood gases help evaluate severity and guide treatment. Treatment depends on pneumonia type and severity. Uncomplicated CAP can be managed with antibiotics such as amoxicillin, azithromycin, clarithromycin, or doxycycline. For patients with recent antibiotic use or comorbidities, broader-spectrum agents like amoxicillin-clavulanate (Augmentin) or levofloxacin are used. Nosocomial pneumonia often requires tailored antibiotic approaches to cover resistant organisms, considering local hospital antibiograms. Follow-up is key in outpatient management: patients should be monitored at 48 hours to assess response and again at 1 and 4 weeks after initial visit, including repeat chest X-rays to confirm resolution. Preventative measures such as pneumococcal and influenza vaccinations are strongly recommended to reduce pneumonia incidence. Understanding the detailed clinical and imaging features of pneumonia supports timely diagnosis and appropriate therapy, which is vital for improving patient outcomes in both community and hospital settings.