Respiratory disease

Respiratory disease is a medical term that encompasses pathological conditions affecting the organs and tissues that make gas exchange possible in higher organisms, and includes conditions of the upper respiratory tract, trachea, bronchi, bronchioles, alveoli, pleura and pleural cavity, and the nerves and muscles of breathing. Respiratory diseases range from mild and self-limiting, such as the common cold, to life-threatening entities like bacterial pneumonia, pulmonary embolism, and lung cancer.

The study of respiratory disease is known as pulmonology. A doctor who specializes in respiratory disease is known as a pulmonologist, a chest medicine specialist, a respiratory medicine specialist, a respirologist or a thoracic medicine specialist.

UBET Respiratory diseases can be classified in many different ways, including by the organ or tissue involved, by the type and pattern of associated signs and symptoms, or by the cause (aetiology) of the disease.

Characterized by a high neutrophil count, e.g. asthma, cystic fibrosis, emphysema, chronic obstructive pulmonary disorder or acute respiratory distress syndrome. Asthma is one of the deadly lung diseases. Asthma is a disease that infects the airways leading to the loss of the control over the smooth muscles that line the bronchi and bronchioles. When exposed to an irritant such as dust or smoke, the smooth muscles that line airways of the asthmatic patient start to contract faster and stronger leading to difficulty breathing.

Restrictive lung diseases are a category of respiratory disease characterized by a loss of lung compliance, causing incomplete lung expansion and increased lung stiffness, such as in infants with respiratory distress syndrome.

Infections can affect any part of the respiratory system. They are traditionally divided into upper respiratory tract infections and lower respiratory tract infections.

The most common upper respiratory tract infection is the common cold. However, infections of specific organs of the upper respiratory tract such as sinusitis, tonsillitis, otitis media, pharyngitis and laryngitis are also considered upper respiratory tract infections.

The most common lower respiratory tract infection is pneumonia, an infection of the lungs which is usually caused by bacteria, particularly Streptococcus pneumoniae in Western countries. Worldwide, tuberculosis is an important cause of pneumonia. Other pathogens such as viruses and fungi can cause pneumonia for example severe acute respiratory syndrome and pneumocystis pneumonia. A pneumonia may develop complications such as a lung abscess, a round cavity in the lung caused by the infection, or may spread to the pleural cavity.

Poor oral care may be a contributing factor to lower respiratory disease. New research suggests bacteria from gum disease travel through airways and into the lungs.

Malignant tumors of the respiratory system, particularly primary carcinomas of the lung, are a major health problem responsible for 15% of all cancer diagnoses and 30% of all cancer deaths. The majority of respiratory system cancers are attributable to smoking tobacco.

The major histological types of respiratory system cancer are:

Small cell lung cancer

Non-small cell lung cancer

Adenocarcinoma of the lung

Squamous cell carcinoma of the lung

Large cell lung carcinoma

Other lung cancers (carcinoid, Kaposi’s sarcoma, melanoma)

Lymphoma

Head and neck cancer

Pleural mesothelioma, almost always caused by exposure to asbestos dust.

In addition, since many cancers spread via the bloodstream and the entire cardiac output passes through the lungs, it is common for cancer metastases to occur within the lung. Breast cancer may invade directly through local spread, and through lymph node metastases. After metastasis to the liver, colon cancer frequently metastasizes to the lung. Prostate cancer, germ cell cancer and renal cell carcinoma may also metastasize to the lung.

Treatment of respiratory system cancer depends on the type of cancer. Surgical removal of part of a lung (lobectomy, segmentectomy, or wedge resection) or of an entire lung pneumonectomy), along with chemotherapy and radiotherapy, are all used. The chance of surviving lung cancer depends on the cancer stage at the time the cancer is diagnosed, and to some extent on the histology, and is only about 14-17% overall. In the case of metastases to the lung, treatment can occasionally be curative but only in certain, rare circumstances.