In simple words: This code is for fluid buildup in the lining of the lungs (pleural effusion) that doesn't have a more specific cause listed in medical codes. This can include various types of pleural fluid.

This code encompasses pleural effusions that don't fit into other, more specific categories within the ICD-10-CM classification system.It includes conditions such as encysted pleurisy and pleural effusion not otherwise specified (NOS).It specifically excludes chylous pleural effusion (J94.0), malignant pleural effusion (J91.0), pleurisy NOS (R09.1), and tuberculous pleural effusion (A15.6).

Example 1: A 65-year-old male presents with shortness of breath and chest pain. Chest X-ray reveals a right-sided pleural effusion.Thoracentesis is performed to analyze the fluid and rule out malignancy.Code J90 is used for the pleural effusion if the fluid analysis doesn't reveal a specific etiology., A 70-year-old female with a history of heart failure is admitted with worsening dyspnea.Physical examination reveals diminished breath sounds on the left side, and an X-ray shows a left pleural effusion.After diuresis, the effusion resolves. Code J90 is utilized due to the non-specific nature of the effusion's cause., A 40-year-old male presents with chronic cough and low-grade fever.CT scan shows a small encapsulated pleural effusion.The etiology is unknown after extensive workup.J90 is appropriate for this chronic effusion with unspecified cause.

Detailed history and physical examination findings; Chest X-ray or other imaging reports (CT scan, ultrasound) showing pleural effusion;Thoracentesis reports if performed (including fluid analysis results);Treatment notes documenting any interventions to manage the pleural effusion;Physician's assessment and diagnosis.

** Always carefully consider other potential codes before applying J90. If the cause of the pleural effusion is identified, a more specific code should be used. This code is a catch-all and should be used only when no other code better fits the clinical situation.