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Case 18
Published in Andrew Solomon, Julia Anstey, Liora Wittner, Priti Dutta, Clinical Cases, 2021
Andrew Solomon, Julia Anstey, Liora Wittner, Priti Dutta
Transudates are caused by decreased oncotic pressure or increased hydrostatic pressure. Common causes of transudates are left ventricular failure, nephrotic syndrome and liver cirrhosis. Exudates are caused by increased capillary permeability. Common causes of exudates are infections, malignancy and connective tissue disease.
The respiratory system
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
This is a common problem and is detected clinically when approximately 0.5 L is present. It appears first in the costophrenic angle. The effusion is categorized as a transudate or exudate. Normal pleural fluid has a protein concentration of 0.4 g/dL. A transudate has a protein concentration <30 g/L and is usually due to haemodynamic disorders, such as cardiac failure or severe hypoalbuminaemia. Exudates are due to inflammatory or neoplastic processes, where vascular permeability is increased, and have a protein content >30 g/L. The causes of pleural effusions are given in Table 8.5.
Answers
Published in Andrew Schofield, Paul Schofield, The Complete SAQ Study Guide, 2019
Andrew Schofield, Paul Schofield
Fluid in the pleural space is known as a pleural effusion. The fluid may be a transudate or an exudate. Transudates are commonly caused by cardiac failure, cirrhosis or renal failure. Exudates have high protein content and are commonly due to infection, inflammation or malignancy. Examination of the chest classically reveals reduced chest expansion on that side, a ‘stony dull’ percussion note and reduced breath sounds. Small effusions may be seen on a chest X-ray as blunting of the costophrenic angle. Larger effusions are seen more clearly as a fluid level/meniscus in the lung fields. A diagnostic aspiration is performed to determine the nature of the effusion. Drainage may be required if the effusion is causing symptoms. If pleural effusions are recurrent, pleurodesis may be necessary. This involves the installation of an irritant, such as talc, into the pleural space to cause local inflammation and fusion of the pleura to the chest wall. Persistent collections may require surgical intervention.
Advances in pleural effusion diagnostics
Published in Expert Review of Respiratory Medicine, 2020
Lucía Ferreiro, María E. Toubes, María E. San José, Juan Suárez-Antelo, Antonio Golpe, Luis Valdés
The first step to determine whether further testing is needed is establishing if PE is a transudate (increase of hydrostatic pressure in the pleural capillaries, or negative pressure in the pleural space, or reduction of oncotic pressure in pulmonary capillaries) or an exudate (increased permeability in the capillaries or obstruction of lymphatic drainage from the lung) [10]. The diagnosis, prognosis, and therapy for a PE will depend on the transudate or exudates nature of PE. Exudative pleural effusions occur when the pleura is damaged, whereas in transudates the pleura is not affected. This differentiation will be made in accordance with Light’s Criteria: pleural fluid protein/serum protein >0.5; pleural fluid LDH/serum LDH >0.6; or pleural fluid LDH >2/3 serum LDH in the upper limit of normal. Meeting just one of these criteria will be enough for identifying a PF as an exudate [11]. Other criteria include cholesterol levels (exudate if >55 mg/dL) [12] or the association of cholesterol and LDH [13], but none of these parameters have proven to be superior to the other [14]. In Figure 2, an algorithm is proposed for identifying the etiology of a PE.
Congenital Cystic Diaphragm with Diaphragmatic Eventration in a Fetus: A Case Presentation
Published in Fetal and Pediatric Pathology, 2019
Li Zhen, Cong-Min Gu, Lv-Yin Huang, Dong-Zhi Li
After counseling, the parents opted to terminate the pregnancy. A male fetus weighing 530 g was delivered vaginally at 22 weeks after induction of labor. Autopsy revealed a right diaphragmatic eventration containing herniated liver and pulmonary hypoplasia (Fig. 1F). The fetal lung to body weight ratio (FLB ratio) was 0.008 (normal range 0.013–0.045). The size of the elevated area accounted for 60% of the total area of the right diaphragm, with the posterior inferior muscle at the crux unaffected. Microscopically, the right diaphragm showed no muscle fibers and was thinner than the left normal diaphragm (Fig. 1G). A shriveled cystic structure was attached to the lower surface of the right diaphragm at the center of the eventration portion (Fig. 1F). A small amount of clear yellowish fluid was present within the cystic cavity, which appeared similar to a transudate. Histological studies demonstrated that the cystic wall was composed of homogeneous fibroelastic tissue with mesothelial cells (Fig. 1H), like that of the eventration membrane to which the cyst was attached. These findings suggested that it was a diaphragmatic mesothelial cyst originating from the eventration membrane. Genomic array analysis of the aborted fetus using CytoScan 750K Array (Affymetrix, Santa Clara, CA, USA) found no unbalanced chromosomal abnormality.
Optimal diagnostic strategies for pleural diseases and identifying high-risk patients
Published in Expert Review of Respiratory Medicine, 2023
D N Addala, P Denniston, A Sundaralingam, N M Rahman
Despite being devised half a century prior, light’s criteria for differentiating exudates from transudates is the first step in interpreting pleural fluid biochemistry. Light’s criteria defines exudates as pleural effusions with any of: pleural fluid (PF) protein to serum ratio as >0.5, PF LDH to serum ratio >0.6 or PF LDH as two-thirds the upper limit of the reference range for normal serum LDH[47–49]. The identification of exudates are clinically important as the typical exudative conditions (listed in Table 1) include malignancy and infection, with distinct treatment paradigms, in contrast to transudates, which broadly reflect systemic fluid overloaded states.