Respiratory disease

Respiratory disease
Micrograph of an emphysematous lung; emphysema is a rare respiratory disease, strongly associated with smoking. H&E stain.
Specialty	Pulmonology

Respiratory diseases, or lung diseases,

The study of respiratory disease is known as pulmonology. A physician 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.

Obstructive lung disease

The latest evidence suggests that primary pulmonary rehabilitation and maintenance rehabilitation delivered through telerehabilitation for people with chronic respiratory disease reaches outcomes similar to centre-based rehabilitation.[8] While there are no safety issues identified, the findings are based on evidence limited by a small number of studies.^[8]

Respiratory tract infections

Infections can affect any part of the respiratory system. They are traditionally divided into upper respiratory tract infections and lower respiratory tract infections.^{[citation needed]}

Upper respiratory tract infection

The upper airway is defined as all the structures connecting the glottis to the mouth and nose.^[9] 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.

Epiglottitis is a bacterial infection of the larynx which causes life-threatening swelling of the epiglottis with a mortality rate of 7% in adults and 1% in children.^[10] Haemophilus influenzae is still the primary cause even with vaccinations. Also Streptococcus pyogenes can cause epiglottitis. Symptoms include drooling, stridor, difficulty breathing and swallowing, and a hoarse voice.^[11]

Croup (Laryngotracheobronchitis) is a viral infection of the vocal cords typically lasting five to six days. The main symptom is a barking cough and low-grade fever. On an X-ray, croup can be recognized by the "steeple sign", which is a narrowing of the trachea. It most commonly occurs in winter months in children between the ages of 3 months and 5 years. A severe form caused by bacteria is called bacterial tracheitis.^[12]

Poor oral care may be a contributing factor to lower respiratory disease, as bacteria from gum disease may travel through airways and into the lungs.[14]^[15]

Upper and lower respiratory tract infection

Primary ciliary dyskinesia is a genetic disorder causing the cilia to not move in a coordinated manner. This causes chronic respiratory infections, cough, and nasal congestion. This can lead to bronchiectasis, which can cause life-threatening breathing issues.^[16]

Tumors

Malignant tumors

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.^{[citation needed]}

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.

• Pulmonary hamartoma
• Congenital malformations such as
  congenital cystic adenomatoid malformation
  (CCAM).

Pleural cavity diseases

Pleural cavity diseases include

A collection of fluid in the pleural cavity is known as a

Pulmonary vascular diseases are conditions that affect the pulmonary circulation. Examples are:^{[18][citation needed]}

• iatrogenic
  – caused by invasive medical procedures).
• cor pulmonale
  .
• Pulmonary edema, leakage of fluid from capillaries of the lung into the alveoli (or air spaces). It is usually due to congestive heart failure.
• Pulmonary hemorrhage, inflammation and damage to capillaries in the lung resulting in blood leaking into the alveoli. This may cause blood to be coughed up. Pulmonary hemorrhage can be due to auto-immune disorders such as
  Goodpasture's syndrome
  .

Neonatal diseases

Pulmonary diseases also impact newborns and the disorders are often unique from those that affect adults.

Infant respiratory distress syndrome most commonly occurs in less than six hours after birth in about 1% of all births in the United States.^[9] The main risk factor is prematurity with the likelihood of it occurring going up to 71% in infants under 750g.^[19] Other risk factors include infant of a diabetic mother (IDM), method of delivery, fetal asphyxia, genetics, prolonged rupture of membranes (PROM), maternal toxemia, chorioamnionitis, and male sex. The widely accepted pathophysiology of respiratory distress syndrome is it caused by insufficient surfactant production and immature lung and vascular development. The lack of surfactant makes the lungs atelectatic causing a ventilation to perfusion mismatch, lowered compliance, and increased air resistance. This causes hypoxia and respiratory acidosis which can lead to pulmonary hypertension. It has a ground glass appearance on an x-ray. Symptoms can include tachypnea, nasal flaring, paradoxical chest movement, grunting, and subcostal retractions.^[9]

Bronchopulmonary Dysplasia is a condition that occurs after birth usually from mechanical ventilation and oxygen use. It happens almost exclusively in pre-mature infants and is characterized by the alveoli, and lung vasculature becoming inflamed and damaged. Complications from BPD can follow a patient into adulthood. As a child they may experience learning disabilities, pulmonary hypertension, and hearing problems. As an adult, there is an increased likelihood for asthma and exercise intolerance.^[20]

Meconium Aspiration Syndrome occurs in full term or post-term infants who aspirate meconium. Risk factors include a diabetic mother, fetal hypoxia, precipitous delivery, and maternal high blood pressure.^[21] Its diagnosis is based on meconium stained amniotic fluid at delivery and staining on the skin, nails, and umbilical cord. Aspiration can cause airway obstruction, air-trapping, pneumonia, lung inflammation, and inactivated surfactant. It presents as patchy atelectasis and hyperinflation on an x-ray with a pneumothorax of pneumomediastinum also possible.^[9]

Persistent Pulmonary Hypertension of the Newborn (PPHN) is a syndrome that occurs from an abnormal transition to extra-uterine life. It is marked by an elevated pulmonary vascular resistance and vasoconstriction causing a right-to-left shunt of the blood through the foramen ovale or ductus arteriosus.^[9] There are three main causes of PPHN are parenchymal diseases such as meconium aspiration syndrome, idiopathic, and hypoplastic vasculature like in a diaphragmatic hernia. It will eventually resolve in most infants.^[22] This is the only syndrome that inhaled nitric oxide is approved for by the FDA.^[23]

Transient Tachypnea of the Newborn is caused by the retention of alveolar fluid in the lungs. It commonly occurs in infants who are delivered via caesarean section without the onset of labor because absorption of amniotic fluid in the lungs has not yet commenced. Other risk factors are male sex, macrosomia, multiple gestations, and maternal asthma. It usually presents with tachypnea and increased work of breathing. On an x-ray diffuse infiltrates, interlobar fissures, and sometimes pleural effusions can be seen. It is a diagnosis of exclusion because of its similarity to other diseases and frequently CPAP is used to help push the lung fluid into the pulmonary vasculature.^[9][24]

Pulmonary interstitial emphysema is the condition of air escaping overdistended alveoli into the pulmonary interstitium. It is a rare disease that occurs most often in premature infants, even though it is possible to appear in adults.^[25] It often presents as a slow deterioration with the need for increased ventilatory support. Chest x-ray is the standard for diagnosis where it is seen as linear or cystic translucencies extending to the edges of the lungs.^[9]

Bronchiolitis is the swelling and buildup of mucus in the bronchioles. It is usually caused by respiratory syncytial virus (RSV), which is spread when an infant touches the nose or throat fluids of someone infected.^[26] The virus infects the cells causing ciliary dysfunction and death. The debris, edema, and inflammation eventually leads to the symptoms.^[27] It is the most common reason for admission of children under the age of one year. It can present widely from a mild respiratory infection to respiratory failure. Since there is no medication to treat the disease, it is only managed supportively with fluids and oxygen.^[28]

Diagnosis

Respiratory diseases may be investigated by performing one or more of the following tests:

• Biopsy of the lung or pleura
• Blood test
• Bronchoscopy
• Chest X-ray
• CT scan, including high-resolution computed tomography
• Culture of microorganisms from secretions such as sputum
• Ultrasound scanning can be useful to detect fluid such as pleural effusion
• Pulmonary function test
• Ventilation–perfusion scan

Epidemiology

Respiratory disease is a common and significant cause of illness and death around the world. In the US, approximately one billion

In the UK, approximately 1 in 7 individuals are affected by some form of chronic lung disease, most commonly chronic obstructive pulmonary disease, which includes asthma, chronic bronchitis and emphysema.^[32] Respiratory diseases (including lung cancer) are responsible for over 10% of hospitalizations and over 16% of deaths in Canada.^[33]

In 2011, respiratory disease with ventilator support accounted for 93.3% of ICU utilization in the United States.^[34]

References

External links

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