From the Guidelines

A small right pleural effusion associated with right lung pneumonia is likely to resolve on its own with antibiotic therapy alone.

The presence of a small pleural effusion in a patient with pneumonia is a common finding and does not necessarily require drainage, as it is likely to be a simple parapneumonic effusion that will resolve with antibiotic treatment 1.
The size of the effusion is an important factor in determining the management plan, with small effusions (less than 10mm rim of fluid on lateral decubitus or less than one-fourth of the hemithorax opacified on an upright chest radiograph) being less likely to require drainage 1.
The patient's clinical response to treatment, including the resolution of symptoms and the reduction in size of the effusion, should be closely monitored, and reassessing the effusion size is crucial in determining the need for further intervention 1.
Chest ultrasound is a useful imaging modality for assessing the size and characteristics of the effusion, and can help guide the decision to drain the effusion 1.
Antibiotic therapy should be continued for 2-4 weeks, depending on the adequacy of drainage and the patient's clinical response 1.

The presence of loculated or organizing fluid may influence treatment decisions, as drainage by chest tube alone may not be effective, and adjunctive therapy may be required 1.
The choice of imaging modality should be based on the clinical presentation and the need for further evaluation, with CT chest with IV contrast being recommended for suspected parapneumonic effusion or empyema 1.

From the Research

A small right pleural effusion associated with right lung pneumonia can be a clinically significant finding, as it may indicate the presence of a parapneumonic effusion or empyema 2.
Parapneumonic effusions are a common complication of pneumonia, and their presence can be associated with a higher risk of mortality and longer hospital stays 3.
The assessment of a pleural effusion requires a careful history, physical examination, imaging techniques, and clinical workup to determine the nature of the exudate and the stage of the pleural space infection 2.

Diagnostic thoracentesis and withdrawal of liquid for microbiological, cytological, and biochemical analysis is urgently recommended in all cases to assess the severity of the disease and the likelihood of a complicated or uncomplicated course 2.
Pleural fluid analysis can help differentiate between different types of pleural effusions, such as parapneumonic effusions, empyema, and tuberculous pleural effusion 4.
Imaging techniques, such as chest x-rays and ultrasound, can be used to detect small pleural effusions, but may not always be able to distinguish between physiologic pleural fluid and pleural effusion 5.

The treatment of parapneumonic effusions and empyema depends on the stage of the disease and the presence of any underlying conditions, and may range from conservative medical management to invasive surgical interventions 2.
The selection of adequate anti-mycoplasma antibiotics with or without corticosteroid is the mainstay of treatment for Mycoplasma pneumoniae pleural effusion, based on local epidemiologic data on macrolide resistance 4.
Patients with pneumonia and pleural effusions at ED presentation may require more aggressive management and closer monitoring, as they are at higher risk of adverse outcomes 3.