Pleural effusion

Pleural effusion

• Abnormal fluid collection in the pleural space
• Maybe transudate or exudate
• Presents with dyspnea, cough, chest pain.
• Dullness to percussion, decreased breath sounds, decreased tactile fremitus, mediastinal shift to opposite side in large effusions, egophony
• Common causes of transudative effusions are CCF, cirrhosis, nephrotic syndrome, hypoproteinemia.
• Common causes of exudative effusions are pneumonia, malignancy, TB, PE, Meigs syndrome, collagen vascular diseases like SLE, RA, uremia
• CxR shows blunting of costophrenic angle, radio-opaque density, lateral decubitus film more sensitive for small effusions

Empyema: Empyema is pus in the pleural space. Commonly caused by Pneumococci, S.milleri, S.aureus, anaerobic bacteria. It may result from direct spread of lung infections, liver abscess, hematogenous seeding or from penetrating injuries to the chest. Long-standing empyema may heal with fibrosis and calcification causing breathing difficulties. Presents with fever, chest pain, cough with expectoration, malaise, poor appetite, weight loss etc. CxR shows radio-opaque shadows with blunting of the costophrenic angles; ultrasound and CT will show, in addition, loculated lesions and septations. “Split pleura sign” is seen on CT scan, due to separation of the visceral from the parietal pleura by pus. Apart from antibiotics, chest tube drainage is needed for cure.

Chylothorax: It is the accumulation of chyle in the pleural cavity. Trauma to the thoracic duct from thoracic surgery, cirrhosis, venous thrombosis in the neck veins or mediastinal lymphadenopathy causing obstruction to drainage of chyle can cause chylothorax. Infectious causes include tuberculosis, filariasis and histoplasmosis. Genetic defects such as Down’s and Noonan’s syndrome or developmental anomalies of lymphatics can also cause chylothorax. It presents with dyspnea, cough, chest discomfort etc. Rapid accumulation of large quantities of chyle may cause hypotension. Chronic cases lead to nutritional imbalances such as weight loss, muscle wasting, immunodeficiency, metabolic acidosis, hyponatremia and hypocalcemia. On examination, pleural fluid in chylothorax is typically milky white, chylomicrons are present, pleural fluid triglycerides > 110 mg/dl and pleural fluid/ serum cholesterol ratio <1. Chylomicrons can be detected quantitatively or stained with Sudan III.

Pulmonary hypertension (PAH): It is defined as systolic blood pressure in the pulmonary artery greater than 30 mmHg. PAH is more common in females aged 30-60 years. It may be idiopathic or secondary. Increased resistance in pulmonary vessels is seen due to proliferation of pulmonary endothelial and smooth vessel cells, pulmonary vasoconstriction, chronic inflammation and increased local thromboxane and endothelin-1. Platelet dysfunction, decreased activity of tissue plasminogen activator and pro-thrombotic tendency is seen. Familial cases are associated with defects in BMPR2 gene (AD), ALK 1, ENG, SMAD9, CAV1 and KCNK3. Appetite suppressants like fenfluramine and dexfenfluramine, methamphetamines and dasatinib are known to cause PAH. Estrogen is associated with higher risk of PAH. Secondary causes of PAH include HIV/AIDS, scleroderma, cirrhosis, congenital heart disease, Pickwickian disease, pneumoconiosis, COPD, sickle cell disease, recurrent pulmonary emboli, chronic left ventricular failure and living at high-altitude. Pulmonary arteries and arterioles show medial hypertrophy, thickening of elastic laminae and concentric intimal thickening. PAH is a diagnosis of exclusion. It presents with nonspecific symptoms such as dyspnea especially on exertion, fatigue, chest pain, fainting, cough and cyanosis. Symptoms of right heart failure are seen in advanced cases. Physical examination shows loud P2, right parasternal lift, pansystolic murmur from TR, diastolic murmur from PR, S3, edema, raised JVP, hepatomegaly and ascites. ECG may show right ventricular hypertrophy and right axis deviation; CxR may show RVH, prominent pulmonary artery shadow; echo may show right heart hypertrophy and valvular regurgitation. Confirmation is done by right heart catheterization which shows increased pressure in the pulmonary artery. Treatment is with prostacyclin or epoprostenol, bosentan (endothelin receptor antagonist) and PDE5 inhibitors sildenafil and tadalafil. Rarely, patients may benefit from calcium channel blockers like nifedipine and diltiazem. Lung transplantation may be required.

Barotrauma: It is damage to the lungs caused by pressure changes. Barotrauma occurring due to mechanical ventilation is called ventilator associated lung injury (VALI) or ventilator induced lung injury. Clinical manifestations of barotrauma include pneumothorax, pulmonary interstitial emphysema , subcutaneous emphysema, pneumoperitoneum, pneumomediastinum or pneumopericardium, air embolisation and tension cysts. Positive pressure ventilation and high volume ventilation carries a high risk of barotrauma. Hyperinflated alveoli rupture, leaking air into surrounding tissues. End-inspiratory volume and intrinsic PEEP are good predictors of barotrauma risk. Symptoms can vary from mild hypoxemia, hypotension, and tachycardia to extremely severe signs, such as profound hypoxemia, cardiovascular collapse and low cardiac output. Subcutaneous emphysema will present with crepitus. CxR will show air in the surrounding chest tissues, perivascular air halos, linear streaks of air radiating toward the hilum, pneumatoceles and large sub pleural air collections. Keeping the end-inspiratory plateau pressure <30 cmH2O, tidal volume 6-8 ml/kg and carefully titrating PEEP can protect from developing barotrauma.

Barotrauma is also seen in diving and breathing compressed air. Decompression Sickness or Caisson disease is seen during rapid ascent from a dive, leading to formation of nitrogen bubbles which block local and systemic circulation and DIC. Symptoms include headache, malaise,dyspnea, joint pains (bends), paresthesias, paresis, incontinence, dizziness, seizures, coma etc. Some cases present with osteonecrosis a few weeks later. It is treated with 100% oxygen and recompression therapy.

Foreign body aspiration: Most common in young children < 4 year old. Peanuts, marbles, popcorn, coins, button batteries are most commonly aspirated objects in children while fish and meat pieces are most common in adults. Typically foreign bodies get lodged in the larynx, trachea, glottis or bronchi. It presents with sudden onset of choking, coughing, dyspnea, stridor, wheezing. Some cases may be asymptomatic. CxR may show foreign body if radiopaque, atelectasis, pneumothorax or pneumonia in older cases. Lateral decubitus films are more sensitive. CT, MRI and endoscopy can be done on a case-to-case basis. Rigid bronchoscopy can be done to remove the obstructing object.

Button battery ingestion

• More common in children due to easy access to electronics
• Typically ingested rather than aspirated
• Once in the gut, generates electrical current, generation of hydroxide radicals and caustic necrosis of mucosa
• Esophageal perforation can occur
• Catastrophic hemorrhage may occur
• Essential to remove by endoscopy or surgery, even though patients may be asymptomatic