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:
- Ratio between PF protein and serum protein > 0.5;
- Ratio between PF LDH and serum LDH > 0.6;
- LDH in PF is more than two-third of the upper limit of serum LDH.
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.