DISCUSSION
The pleural sac is a compartment typically filled with a thin layer of fluid known as pleural fluid, which acts as a lubricant and helps reduce friction between the parietal and visceral pleural lining surfaces during respiration.4 An accumulation of fluid occurs because of an imbalance in the rate of production and drainage of fluid due to changes in many local factors.4
The typical presentation of a case of PE may include the pleuritic type of chest pain, which indicates inflammation of the pleura, with the pain increasing on movement and respiration with some associated shortness of breath and dry cough. In contrast, the patient presented with only left-sided shoulder pain with no respiratory symptoms in this case. As a clinician, the underlying PE may present with these atypical symptoms and should not be simply mistaken for musculoskeletal pain. PE should be on the top of the list of differentials. An underlying undiagnosed rapidly accumulating PE can, in turn, lead to rapid deterioration of the patient.
The first step in determining the cause of a PE in cases where clinical history does not correlate, but PE is evident on clinical imaging is to perform a diagnostic thoracocentesis; this will help a clinician to differentiate if the PE is transudative or exudative. However, diagnostic thoracentesis is not required in patients with a small quantity of PF (<500 cc) and a definite diagnosis (e.g., viral pleurisy) or in patients with heart failure (HF), obvious on clinical examination but no unusual findings.5
In patients with an exudative PE, like the case we are discussing here, Further evaluation is needed to determine the underlying pathology affecting the pleura leading to the PE. Lactic Acid Dehydrogenase (LDH) and serum protein levels in the PF and serum are used to confirm an exudative effusion diagnosis. The Light’s criteria are the most widely used criterion for distinguishing between exudative and transudative effusions.6,7
According to the lights criteria; the following can be calculated:
When one of the three conditions is satisfied, the effusion is exudative, as in this example. A variety of conditions can cause exudative effusions, and their care can be difficult since they frequently necessitate surgical interventions in addition to the medical management.8
What strikes the most, in this case, is that how the patient initially on presentation had mild PE and needed only medical treatment for his underlying asymptomatic pneumonia. However, within the next 24 hours, the patient started to reaccumulate fluid in his pleural space, which leads to his sudden clinical deterioration, which required the urgent need for chest tube placement and drainage under interventional radiology guidance.
Massive pleural effusions are a common manifestation of pulmonary tuberculosis, 9 or an underlying malignancy. It has been reported in malignancies of different origins, the most frequent being ovarian carcinoma, sarcomas, mesotheliomas, and pancreatic adenocarcinomas. Some cases of massive PE, although rare are reported even in patients with pancreatic pleural fistulas, alcohol-induced pancreatitis and sarcoidosis.10
In our patient, the rapidly developing and reaccumulating PF raised the suspicion for any underlying malignancy or TB as statistics prove it to be the most common pathological cause, but the diagnostic pleural tapping in this patient ruled out these causes and the workup for any other potential cause was not supported by further investigations that were done.
Therefore, the diagnosis of massive parapneumonic effusion was made do the neutrophilic predominant picture of the thoracocentesis, which was complicated with drainage via a chest tube, although this is rare in literature to accumulate within a short period of time rapidly.