Hepatic pleural fluid is defined as cirrhosis with pleural effusion in the decompensated phase, and exclude pleural fluid due to other diseases. The incidence is 0.4-30%.
1.The mechanism of hepatic pleural fluid
(1) Portal hypertension and hypoproteinemia: In cirrhosis, portal blood flow is obstructed, resulting in lymphatic stasis, lymphatic fluid overflow and pleural fluid. Albumin synthesis is impaired and plasma colloid osmotic pressure decreases, prompting plasma to enter the thoracic cavity from within the blood vessels.
(2) Diaphragmatic fissure: It has been reported that by intraperitoneal injection of 99mTc sulfated colloid, a significant increase was found in the thoracic cavity, confirming the existence of diaphragmatic fissure, and thoracoscopic examination of hepatic pleural fluid revealed the presence of diaphragmatic vesicles.
(3) Increased lymphatic reflux: excessive hepatic lymphatic fluid production in cirrhosis leads to lymphatic vessel pressure close to portal vein pressure, increased pressure in the thoracic duct plus its own negative intrathoracic pressure, prompting pleural lymphatic duct expansion, stasis, lymphatic fluid overflow and formation of pleural fluid.
(4) Mechanism of generation of hepatic pleural fluid without ascites: one-way fissure flow hypothesis A few patients with hepatic pleural fluid are seen clinically without ascites, which is now also considered to be related to the presence of a transverse septal fissure. Rubinstein et al. showed by intraperitoneal injection of 99m Tc-labeled sulfated colloid that in patients with clinical ascites deficiency, the abdominal cavity leads to the thoracic cavity with one-way fluid accumulation through the transverse septal fluid flow and the thoracic cavity effect, and further radioisotope scans and ultrasound confirmed the presence of such channels.
(5) Lymphatic absorption: the lymphatic network on both sides of the diaphragm is well developed, and ascites is absorbed and transferred to the thoracic cavity for accumulation through the diaphragmatic lymphatic vessels, and since the lymphatic network is much more developed on the right side than on the left, this is thought to be one of the reasons why the incidence of pleural fluid is greater on the right side than on the left.
(6) Pulmonary edema and small pulmonary vasodilatation: Studies have shown that reduced plasma colloid osmotic pressure, increased capillary permeability due to endocrine disorders, high power pulmonary circulation and portal-pulmonary venous shunts in the decompensated phase of cirrhosis all contribute to the formation of pleural effusion.
2.Treatment of hepatic pleural effusion
(1) General treatment: The basic treatment of hepatic pleural fluid, that is, the treatment of ascites, including bed rest, liver protection, correction of hypoproteinemia, restriction of water intake, in the use of diuretics at the same time do not need to strictly limit sodium and affect the effect of diuretics.
(2) Drug treatment
Diuretics: Ampicillin, aminoglutethimide, tachyphylaxis and butylamine can also be used, and generally potassium-preserving diuretics are combined with potassium-eliminating diuretics.
The domestic scholars have used the domestic synthetic atrial peptide III (HA P-III) to treat thoracic and ascitic fluid in cirrhosis, which shows obvious diuretic and natriuretic effects, accompanied by mild potassium and chloride effects, and seems to be better than diuretics. However, because of its short duration of action, the synthesis of long-acting ANP and its analogues is still needed for formal clinical application.
Posterior pituitary hormone: Some scholars in China applied posterior pituitary hormone to treat 16 cases of refractory hepatic hydrothorax and achieved good results. The mechanism may be that posterior pituitary hormone can contract the small visceral arteries and pre-capillary dilators to reduce portal blood flow, and can contract the hepatic artery to reduce the pressure in the hepatic sinusoids, so that the portal pressure decreases and the hydrothorax gradually subsides.
Octreotide: Octreotide successfully treats hepatic pleural fluid, and it is considered that controlling ascites formation is the purpose of treatment. For patients who are difficult to treat with diuretics and sodium control and develop hepatorenal syndrome, thoracic catheter is inserted to drain pleural fluid and octreotide is given intravenously for 5 days, and the urine volume and sodium excretion increase after treatment, along with the improvement of renal function, the symptoms of pleural fluid disappear.
(3) Other treatments
Direct return of pleural fluid:Direct return of pleural fluid is used to treat intractable hepatic pleural fluid, but this therapy cannot be used when pleural fluid is secondary to infection.
Pleural adhesions or discharge of pleural fluid followed by pleural adhesions, pleural adhesions, i.e. intrathoracic injection of sclerosing agent to induce aseptic pleurisy between two layers of pleura, so that the adhesions between the two layers of pleura can be blocked, thus blocking the reaccumulation of pleural fluid, and tetracycline is currently considered more desirable. Talc is one of the most effective sclerosing agents for pleural adhesions, it is a fine powdered magnesium trisilicate that stimulates the pleura causing pleural fibrosis and making granulomatous changes, resulting in permanent and firm pleural adhesions.
Air compensation method for hepatic pleural fluid: for every 250~500ml of pleural fluid, 50~100ml of filtered air is injected at the same time to keep the pleural cavity pressure between 1/5~1/10 of the original, and 1% lidocaine and tetracycline are injected into the pleural adhesions after the pleural fluid is pumped, and the pumped pleural fluid is concentrated 5~10 times back to the vein.
In recent years, TIPSS has been applied to treat upper gastrointestinal bleeding in China, and the recent efficacy is obvious, but because of the complication of reobstruction of the shunt and encephalopathy after portal shunt, it is considered that TIPSS is the most effective method to treat hepatic pleural fluid.
Rubin Stein D treated two cases of hepatic pleural fluid with thoracotomy diaphragm repair, and the pleural fluid disappeared, but it should not be widely used because of the surgical trauma and the difficulty of diaphragm repair.