Disorders of the pulmonary circulation and the respiratory regulation

Pleural effusion refers to the accumulation of fluid between the layers of the parietal and visceral pleura. Common causes of this condition include infection, malignancy, autoimmune disorders, or volume overload. Clinical manifestations include chest pain, cough, and dyspnea. Imaging can confirm the presence of a pleural effusion, and pleural fluid analysis can help in the evaluation of an etiology. Management is dependent on the underlying condition and whether the effusion is causing respiratory distress. Drainage of the effusion may provide symptomatic relief.

Hypersensitivity pneumonitis (HP), previously called extrinsic allergic alveolitis, is an immunologically induced inflammatory disease affecting the alveoli, bronchioles, and lung parenchyma. It is caused by repeated inhalation of an inciting agent in a susceptible host that triggers first a type III (complement-mediated) hypersensitivity reaction in the acute phase and then a type IV (delayed) reaction in the subacute and chronic phases. The clinical presentation of acute HP includes cough, fever, and malaise, while subacute and chronic forms present as insidious onset of a cough and dyspnea over weeks to months. Diagnosis is aided by high-resolution CT scans and bronchoalveolar lavage. Management includes avoiding the inciting agent and administration of steroids in subacute and chronic cases. Early treatment has a good prognosis, but long-term exposure can cause permanent scarring and fibrosis.

Pulmonary embolism (PE) is a potentially fatal condition that occurs as a result of intraluminal obstruction of the main pulmonary artery or its branches. The causative factors include thrombi, air, amniotic fluid, and fat. In PE, gas exchange is impaired due to the decreased return of deoxygenated blood to the lungs. Deep vein thrombosis (DVT) is diagnosed in > 50% of patients presenting with symptoms, in whom the lower-extremity deep-venous system is the most common source of thrombus. Some individuals are asymptomatic, but the most common presenting symptom is dyspnea. The symptoms can be acute or chronic, and diagnosis is usually based on radiographic findings. Initial management is supportive and focuses on restoring oxygenation and hemodynamic stability. Both medical (systemic anticoagulants) and interventional therapies (catheter-based approach, surgery) are used to reestablish vessel patency.

Blunt chest trauma is a non-penetrating traumatic injury to the thoracic cavity. Thoracic traumatic injuries are classified according to the mechanism of injury as blunt or penetrating injuries. Different structures can be injured including the chest wall (ribs, sternum), lungs, heart, major blood vessels, and the esophagus. The extent and specific type of thoracic traumatic injury can be identified by a proper history and physical examination supported by adequate imaging studies. Management depends on the specific type of injury.

A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Symptom severity depends on the degree of the collapsed lung. A large or tension pneumothorax can result in cardiopulmonary collapse. A diagnosis is made with imaging, though tension pneumothorax is a clinical diagnosis. Management is based on the size and stability of the patient, and can include needle decompression and chest tube (thoracostomy) placement.

Obstructive sleep apnea (OSA) is a disorder characterized by recurrent obstruction of the upper airway during sleep, causing hypoxia and fragmented sleep. Obstructive sleep apnea is due to a partial or complete collapse of the upper airway and is associated with snoring, restlessness, sleep interruption, and daytime somnolence. The diagnosis relies on medical history, and polysomnography can confirm the diagnosis. Management includes lifestyle changes, methods of positive airway pressure, and surgical intervention.

COVID-19, also known as Coronavirus disease, is a respiratory infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV 2). Transmission mainly occurs via direct contact or aerosol droplets. The disease may present asymptomatically or with fever and dry cough.

Permanent sleepless nights are torture: Sleep disorders are accompanied by much suffering for affected individuals. Which of the disorders that mostly occur nocturnally should you know about for your practice routine and the medical exam? The following article will introduce you to the fundamentals of sleep disorders, diagnostics as well as therapeutic remedies in cases of REM sleep behavior disorders and sleep myoclonus. Particular focus is laid on narcolepsy and restless legs syndrome. This article is concisely prepared with focus on the exam and will leave no questions concerning sleep disorders in neurology unanswered.

Acute Respiratory Distress Syndrome (ARDS) is a severe inflammatory reaction of the lung that is characterized by presence of pulmonary infiltrates due to alveolar fluid accumulation, without evidence suggestive of a cardiogenic etiology. SIRS and sepsis are the major causes of ARDS. The main finding of ARD is respiratory failure. Chest x-ray usually shows diffuse bilateral lung infiltrates described as " (“butterfly opacity”). Management depends mainly on treating the underlying etiology, and maintaining adequate oxygenation, which may requires intubation and mechanical ventilation.

Respiratory Distress Syndrome (RDS), also known as "Hyaline membrane disease", is caused by the deficiency of lung surfactant in a pre-term infant due to the immaturity of the lungs. The risk of RDS is inversely related to the gestational age, and, most commonly occurs in infants less than 28 weeks of gestational age. Neonatal respiratory distress syndrome is associated with high morbidity and mortality in pre-term infants and considered one of the most common causes of neonatal death. Respiratory distress syndrome should be differentiated from the other causes of respiratory distress after birth, which will be discussed in details in this article.

Pulmonary hypertension (PH) is a clinical condition that is characterized by elevated pulmonary arterial pressure. It can lead to serious clinical consequences, thus early detection and treatment is important before it becomes advanced and less responsive to therapy. PH is a feature of advanced underlying disease that are usually caused by cardiac, pulmonary, or intrinsic vascular diseases. Therefore, suspected cases will undergo diagnostic testing to confirm the condition and identify the underlying cause. The definition, epidemiology, classification and etiologies, pathophysiology, clinical features, diagnostic evaluation and treatment all will be discussed in this article.