Neuroendocrine hyperplasia is rare and poorly understood lung condition which is characterized by an abnormal growth pulmonary neuroendocrine cells in the lungs. It is a non-progressive disease of the interstitial tissues of the lungs. Prior to the findings of the hyperplasia of neuroendocrine cells it was known as tachypnea of infancy, as most children outgrow the need for oxygen supplementation within two to seven years. It is characterized by

tachypnea Tachypnea, also spelt tachypnoea, is a respiratory rate greater than normal, resulting in abnormally rapid and shallow breathing. In adult humans at rest, any respiratory rate of 1220 per minute is considered clinically normal, with tachypnea be ...

hypoxemia Hypoxemia is an abnormally low level of oxygen in the blood. More specifically, it is oxygen deficiency in arterial blood. Hypoxemia has many causes, and often causes hypoxia as the blood is not supplying enough oxygen to the tissues of the body ...

, and retractions. It is typically diagnosed in infants and children younger than one year of age. There is no currently recognized treatment, infants and children are given oxygen supplementation until they outgrow the need; since neuroendocrine cells do not multiply or get larger in size while the lungs continue to grow. This allows the lung disease to have less effect on lung function with age, although they will always have the same amount of neuroendocrine cells as they were born with.

Signs and symptoms

People with this diagnosis may have no obvious symptoms, they may present with

shortness of breath Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing disc ...

wheezing A wheeze is a continuous, coarse, whistling sound produced in the respiratory airways during breathing. For wheezes to occur, some part of the respiratory tree must be narrowed or obstructed (for example narrowing of the lower respiratory tract ...

. Infants and children present with symptoms of heavy breathing at a rate greater than 20 breath/min. Oxygen levels are lower due to hypoxia, and chest x-rays show signs of

pneumonia Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity ...

. NEHI typically presents in otherwise healthy infants during the first months to year of life. Severe cases may risk permanent damage to the lungs and death from severe tachypnea. * Tachypnea * Hypoxemia * retractions * crackles (in lungs) *

exercise intolerance Exercise intolerance is a condition of inability or decreased ability to perform physical exercise at the normally expected level or duration for people of that age, size, sex, and muscle mass. It also includes experiences of unusually severe post ...

Causes

There is not cause of Neuroendocrine hyperplasia, however some known causes are a rapid increase of pulmonary endocrine cells in the lungs in children under the age of 2. An increase in pulmonary endocrine cells is usually seen in adults with a history of

smoking Smoking is a practice in which a substance is burned and the resulting smoke is typically breathed in to be tasted and absorbed into the bloodstream. Most commonly, the substance used is the dried leaves of the tobacco plant, which have bee ...

, COPD, or

cystic fibrosis Cystic fibrosis (CF) is a rare genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine. Long-term issues include difficulty breathing and coughing up mucus as a result of frequent lung infections. O ...

. Children under the age of 2 may present with signs of

interstitial lung disease Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of respiratory diseases affecting the interstitium (the tissue and space around the alveoli (air sacs)) of the lungs. It concerns alveolar epithelium, pulmo ...

and be diagnosed with NEH following severe progression.

Mechanism

Neuroendocrine hyperplasia is a rare condition amongst

chILD A child ( : children) is a human being between the stages of birth and puberty, or between the developmental period of infancy and puberty. The legal definition of ''child'' generally refers to a minor, otherwise known as a person younger ...

. This condition is characterized as an overgrowth of pulmonary endocrine cells in the lungs. These cells receive signals from

neurons A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. N ...

to produce

hormones A hormone (from the Ancient Greek, Greek participle , "setting in motion") is a class of cell signaling, signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and beh ...

. With this rapid increase of PNC (pulmonary endocrine cells), this can affect the airways of children. Furthermore, this increase can be a precursor of pulmonary carcinoid tumors.

Diagnosis

To diagnose neuroendocrine hyperplasia after a referral is made for fast breathing (tachypnea) or need for extra oxygen. There are several tests that are commonly performed to confirm the diagnosis.

Chest CT A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...

gives a better look at the lungs to see signs of pneumonia. With a bronchoscopy, a scope (small camera) is passed from the mouth or nose, through the windpipe, and into the lungs to check for other causes of breathing problems. A

lung biopsy A lung biopsy is an interventional procedure performed to diagnose lung pathology by obtaining a small piece of lung which is examined under a microscope. Beyond microscopic examination for cellular morphology and architecture, special stains and ...

may be the only way to diagnose the disease if the chest CT does not show the characteristic findings. In a biopsy, a small portion of lung tissue is removed to determine if lung disease is present.

Treatment

There is no consensus on the therapy for NEHI, and management generally consists of supportive care: supplemental oxygen for chronic hypoxemia, adequate nutrition, proper immunization, avoidance of environmental pollutants, and treatment of recurrent

infections An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmiss ...

. To relieve symptoms of NEH, there are not any methods yet proven effective in infants. Supportive care and adequate nutrition may be considerate in improve quality of life as NEH in most cases is not treatable.

Prognosis

Most outcomes in neuroendocrine hyperplasia leads to failure to thrive due to the restrictions of oxygen flow in lungs. The long-term outcome of NEHI is generally favourable with most patients gradually improving over time, although persistent airway obstruction mimicking severe asthma and relapse with respiratory infection.

Epidemiology

The incidence and prevalence of NEHI are unknown, but it is clearly rare. Available data derive from small to moderate sized case series. The original report of this disorder in 2005 included 15 cases. A study from a large referral center identified 19 cases (14 percent) from among 138 lung biopsy cases accrued over a 10-year perio

Twenty-three NEH cases were included in a separate study testing chest CAT scan. The largest report to date includes 37 cases in a manuscript focusing on infant pulmonary function testing (PFT)

Current research

The research being done on neuroendocrine hyperplasia consists of a criterion to distinguish its characteristics from similar cHILD cases. A recent study in November, 2020 helped identify pathologic features of NEH, and used clinical patients to support their data. Another study reviewed the various supplemental oxygen use in NEH patients. They identified factors in NEH to help in clinical course. As well as, reviewed failure to thrive patients who would have an increased use of supplemental oxygen. Other than its associations with chILD, researchers do not know much about this condition.

References

External links

{{DEFAULTSORT:Neuroendocrine Hyperplasia Congenital disorders of respiratory system