Choking is the fourth most common cause of unintentional injury-related death in the US. Many episodes are not reported because they are brief and resolve without seeking medical attention. Among reported events, the majority of episodes (80%) occur among children younger than age 15, with fewer episodes (20%) among age 15 and older. The death rate from choking is low at most ages but increases starting around age 74. Choking due to a foreign object resulted in 162,000 deaths (2.5 per 100,000) in 2013, compared to 140,000 deaths (2.9 per 100,000) in 1990.

Conditions which commonly involve hemoptysis include bronchitis and pneumonia, lung cancers and tuberculosis. Other possible underlying causes include aspergilloma, bronchiectasis, coccidioidomycosis, pulmonary embolism, pneumonic plague, and cystic fibrosis. Rarer causes include hereditary hemorrhagic telangiectasia (HHT or Rendu-Osler-Weber syndrome), Goodpasture's syndrome, and granulomatosis with polyangiitis. In children, hemoptysis is commonly caused by the presence of a foreign body in the airway. The condition can also result from over-anticoagulation from treatment by drugs such as warfarin.

Blood-laced mucus from the sinus or nose area can sometimes be misidentified as symptomatic of hemoptysis (such secretions can be a sign of nasal or sinus cancer, but also a sinus infection). Extensive non-respiratory injury can also cause one to cough up blood. Cardiac causes like congestive heart failure and mitral stenosis should be ruled out.

The origin of blood can be identified by observing its color. Bright-red, foamy blood comes from the respiratory tract, whereas dark-red, coffee-colored blood comes from the gastrointestinal tract. Sometimes hemoptysis may be rust-colored.

The most common cause of minor hemoptysis is bronchitis.

- Lung cancer, including both non-small cell lung carcinoma and small cell lung carcinoma.

- Sarcoidosis

- Aspergilloma

- Tuberculosis

- Histoplasmosis

- Pneumonia

- Pulmonary edema

- Pulmonary embolism

- Foreign body aspiration and aspiration pneumonia

- Goodpasture's syndrome

- Granulomatosis with polyangiitis

- Eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)

- Bronchitis

- Bronchiectasis

- Pulmonary embolism

- Anticoagulant use

- Trauma

- Lung abscess

- Mitral stenosis

- Tropical eosinophilia

- Bleeding disorders

- Hughes-Stovin Syndrome and other variants of Behçet's disease

- Squamous Cell Carcinoma Of Esophagus

In one study, peanuts were the most common obstruction. In addition to peanuts, hot dogs, and grapes, latex balloons are also a serious choking hazard in children that can result in death. A latex balloon will conform to the shape of the trachea, blocking the airway and making it difficult to expel with the Heimlich maneuver.

Hemoptysis is the coughing up of blood or blood-stained mucus from the bronchi, larynx, trachea, or lungs. This can occur with lung cancer, infections such as tuberculosis, bronchitis, or pneumonia, and certain cardiovascular conditions. Hemoptysis is considered massive at . In such cases, there are always severe injuries. The primary danger comes from choking, rather than blood loss.

If the person is awake and able to breathe often all that is requires is providing extra oxygen while the operating room is prepared for bronchoscopy.

If a children less than one and is unable to breathe at all then five back blows followed by five chest thrusts should be done. In children over the age of one abdominal thrusts are recommended.

If this is not effective than bag mask ventilation is recommended. Next laryngoscopy can be tried to look and see if the foreign body can be removed. If the above is not effective than intubation or cricothyrotomy can be tried.

The American Heart Association recommends chest thrusts rather than abdominal thrusts for pregnant or obese persons who are choking.

Chest thrusts are performed in a similar to the abdominal thrusts, but with a change in hand placement of the rescuer. The hands are placed on the lower part of the choking victim's chest, at the base of the breastbone or sternum, rather than over the middle of the abdomen, as in traditional abdominal thrusts. Strong inward thrusts are then applied.

Perinatal asphyxia is the medical condition resulting from deprivation of oxygen (hypoxia) to a newborn infant long enough to cause apparent harm. It results most commonly from a drop in maternal blood pressure or interference during delivery with blood flow to the infant's brain. This can occur as a result of inadequate circulation or perfusion, impaired respiratory effort, or inadequate ventilation. There has long been a scientific debate over whether newborn infants with asphyxia should be resuscitated with 100% oxygen or normal air. It has been demonstrated that high concentrations of oxygen lead to generation of oxygen free radicals, which have a role in reperfusion injury after asphyxia. Research by Ola Didrik Saugstad and others led to new international guidelines on newborn resuscitation in 2010, recommending the use of normal air instead of 100% oxygen.

Breastfeeding is associated with a lower risk of SIDS. It is not clear if co-sleeping among mothers who breastfeed without any other risk factors increased SIDS risk.

Situations that can cause asphyxia include but are not limited to: the constriction or obstruction of airways, such as from asthma, laryngospasm, or simple blockage from the presence of foreign materials; from being in environments where oxygen is not readily accessible: such as underwater, in a low oxygen atmosphere, or in a vacuum; environments where sufficiently oxygenated air is present, but cannot be adequately breathed because of air contamination such as excessive smoke.

Other causes of oxygen deficiency include

but are not limited to:

- Acute respiratory distress syndrome

- Carbon monoxide inhalation, such as that from a car exhaust and the smoke's emission from a lighted cigarette: carbon monoxide has a higher affinity than oxygen to the hemoglobin in the blood's red blood corpuscles, bonding with it tenaciously, and, in the process, displacing oxygen and preventing the blood from transporting oxygen around the body

- Contact with certain chemicals, including pulmonary agents (such as phosgene) and blood agents (such as hydrogen cyanide)

- Drowning

- Drug overdose

- Exposure to extreme low pressure or vacuum to the pattern (see space exposure)

- Hanging, specifically suspension or short drop hanging

- Self-induced hypocapnia by hyperventilation, as in shallow water or deep water blackout and the choking game

- Inert gas asphyxiation

- Congenital central hypoventilation syndrome, or primary alveolar hypoventilation, a disorder of the autonomic nervous system in which a patient must consciously breathe; although it is often said that persons with this disease will die if they fall asleep, this is not usually the case

- Respiratory diseases

- Sleep apnea

- A seizure which stops breathing activity

- Strangling

- Breaking the wind pipe.

- Prolonged exposure to chlorine gas

SIDS rates decrease with increasing maternal age, with teenage mothers at greatest risk. Delayed or inadequate prenatal care also increases risk. Low birth weight is a significant risk factor. In the United States from 1995 to 1998, the SIDS death rate for infants weighing 1000–1499 g was 2.89/1000, while for a birth weight of 3500–3999 g, it was only 0.51/1000. Premature birth increases the risk of SIDS death roughly fourfold. From 1995 to 1998, the U.S. SIDS rate for births at 37–39 weeks of gestation was 0.73/1000, while the SIDS rate for births at 28–31 weeks of gestation was 2.39/1000.

Anemia has also been linked to SIDS (note, however, that per item 6 in the list of epidemiologic characteristics below, extent of anemia cannot be evaluated at autopsy because an infant's total hemoglobin can only be measured during life.). SIDS incidence rises from zero at birth, is highest from two to four months of age, and declines toward zero after the infant's first year. Baby boys have a ~50% higher risk of SIDS than girls.

Among the causes of hypopnea are:

- anatomical defects such as nasal septum deformation or congenital narrowness of nasal meatus and the gullet

- acute tonsillitis and/or adenoiditis

- obesity or being overweight

- neuromuscular disease or any condition that entails weakened respiratory muscles

- hypoventilation syndromes involving compromised or failed respiratory drive

- use of sedatives e.g. sleeping pills

- alcohol abuse

- smoking

- aging

- others, most of which are also typical causes of airway obstruction, snoring and sleep apnea

When laryngospasm is coincident with a cold or flu, it may be helpful for some sufferers to take acid reflux medication to limit the irritants in the area. If a cough is present, then treat a wet cough; but limit coughing whenever possible, as it is only likely to trigger a spasm. Drink water or tea to keep the area from drying up. Saline drops also help to keep the area moist. Pseudoephederine may also help to clear any mucus that may cause coughing and thereby triggering more spasms.

Chewing: Horses may develop choke if they do not chew their food properly. Therefore, horses with dental problems (e.g. acquired or congenital malocclusion, loose or missing teeth, or excessively sharp dental ridges) that do not allow them to completely grind their food are particularly at risk. In addition, horses that bolt their feed and do not take the time to chew properly are more likely to suffer from choke.

Dry Food: Dry foods may cause choke, especially if the horse does not have free access to water, or if the horse has other risk factors linked to choking. While pelleted or cubed feeds in general fall in this category, horse owners sometimes express particular concerns about beet pulp. However, while horses have choked on beet pulp, a university study did not document that beet pulp is a particular problem. It is believed that choke related to beet pulp is linked to the particle size and the horse's aggressive feeding behaviour, rather than the actual feed itself. Research suggests that horses that bolt their feed without sufficient chewing, or who do not have adequate access to water, are far more likely to choke, regardless of the type of feed, compared to horses that eat at a more leisurely rate. The risk of choke associated with any dry feed can be reduced by soaking the ration prior to feeding.

Foreign Objects: Horse may ingest non-edible materials such as pieces of wood. Cribbers may be more prone to this type of choke, if they happen to swallow a piece of wood or other material while cribbing.

Minor laryngospasm will generally resolve spontaneously in the majority of cases.

Laryngospasm in the operating room is treated by hyperextending the patient's neck and administering assisted ventilation with 100% oxygen. In more severe cases it may require the administration of an intravenous muscle relaxant, such as Succinylcholine, and reintubation.

When Gastroesophageal Reflux Disease (GERD) is the trigger, treatment of GERD can help manage laryngospasm. Proton pump inhibitors such as Dexlansoprazole (Dexilant), Esomeprazole (Nexium), and Lansoprazole (Prevacid) reduce the production of stomach acids, making reflux fluids less irritant. Prokinetic agents reduce the amount of acid available by stimulating movement in the digestive tract.

Spontaneous laryngospasm can be treated by staying calm and breathing slowly, instead of gasping for air. Drinking (tiny sips) of ice water to wash away any irritants that may be the cause of the spasm can also help greatly.

Patients who are prone to laryngospasm during illness can take measures to prevent irritation such as antacids to avoid acid reflux, and constantly drinking water or tea keep the area clear of irritants.

Additionally, laryngospasms can result from hypocalcemia, causing muscle spasms and/or tetany. Na+ channels remain open even if there is very little increase in the membrane potential. This affects the small muscles of the vocal folds.

Choking horses should be deprived of food and drink pending veterinary attention, so as not to increase the obstructive load within the esophagus. The veterinarian will often sedate the horse and administer spasmolytics, such as butylscopolamine, to help the esophagus to relax. Once the muscles of the esophagus no longer force the food down the throat (active peristalsis), it may slip down on its own accord. If spasmolytics do not solve the problem, the veterinarian will usually pass a stomach tube through one of the nostrils and direct it into the esophagus until the material is reached, at which point "gentle" pressure is applied to manually push the material down. Gentle warm water lavage (water sent through the stomach tube, to soften the food material) may be required to help the obstructing matter pass more easily, but caution should be exercised to prevent further aspiration of fluid into the trachea.

Refractory cases are sometimes anesthetised, with an orotracheal tube placed to prevent further aspiration and to allow for more vigorous lavage. Disruption of the impacted material can sometimes be achieved via endoscopy. If these methods still do not lead to results, the horse may require surgery to remove the material.

Some workers have advocated the use of oxytocin in choke, on the grounds that it decreases the esophageal muscular tone. However, this technique is not suitable in pregnant mares, as it may lead to abortion.

Hypopnea is a disorder that may result in excessive daytime sleepiness and compromised quality of life, including traffic accidents, diminished productivity in the workplace, and emotional problems.

Cardiovascular consequences of hypopnea may include myocardial infarction, stroke, psychiatric problems, impotence, cognitive dysfunction, hypertension, coronary heart disease, and memory loss.

Strangling involves one or several mechanisms that interfere with the normal flow of oxygen into the brain:

- Compression of the carotid arteries or jugular veins—causing cerebral ischemia.

- Compression of the laryngopharynx, larynx, or trachea—causing asphyxia.

- Stimulation of the carotid sinus reflex—causing bradycardia, hypotension, or both.

Depending on the particular method of strangulation, one or several of these typically occur in combination; vascular obstruction is usually the main mechanism. Complete obstruction of blood flow to the brain is associated with irreversible neurological damage and death, but during strangulation there is still unimpeded blood flow in the vertebral arteries. Estimates have been made that significant occlusion of the carotid arteries and jugular veins occurs with a pressure of around , while the trachea demands six times more at approximately .

As in all cases of strangulation, the rapidity of death can be affected by the susceptibility to carotid sinus stimulation. Carotid sinus reflex death is sometimes considered a mechanism of death in cases of strangulation, but it remains highly disputed. The reported time from application to unconsciousness varies from 7–14 seconds if effectively applied to one minute in other cases, with death occurring minutes after unconsciousness.

Bacterial infections of the orbit have long been associated with a risk of catastrophic local

sequelae and intracranial spread.

The natural course of the disease, as documented by Gamble (1933), in the pre-antibiotic era,

resulted in death in 17% of patients and permanent blindness in 20%.

The Wisconsin Sleep Cohort Study estimated in 1993 that roughly one in every 15 Americans was affected by at least moderate sleep apnea. It also estimated that in middle-age as many as nine percent of women and 24 percent of men were affected, undiagnosed and untreated.

The costs of untreated sleep apnea reach further than just health issues. It is estimated that in the U.S. the average untreated sleep apnea patient's annual health care costs $1,336 more than an individual without sleep apnea. This may cause $3.4 billion/year in additional medical costs. Whether medical cost savings occur with treatment of sleep apnea remains to be determined.

Anti-ligature is the "prevention" of tying or binding. Anti-ligature devices are used to prevent vulnerable people from accidentally or intentionally self harming, (typically hanging). Anti-ligature devices and equipment are primarily used where people are considered to be 'at risk' such as hospitals, prisons and nursing homes, but can also be found in some offices and schools.

They are designed to withstand high levels of abuse and as a result are constructed from solid stainless steel and have minimal moving parts. They typically feature sloped or curved corners to which nothing can be attached and are proportioned at specific critical angles and distances with no protruding parts to prevent ligature points.

Examples of anti-ligature devices can include electronically controlled tap-less wash basins and seat-less WC pans with concealed WC cisterns and anti-ligature shower controls and shower heads.

A 2012 study has shown that hypoxia (an inadequate supply of oxygen) that characterizes sleep apnea promotes angiogenesis which increase vascular and tumor growth, which in turn results in a higher incidence of cancer mortality.

Complications include hearing loss, blood infection, meningitis, cavernous sinus thrombosis, and optic nerve damage (which could lead to blindness).

Pseudodysphagia is the irrational fear of swallowing or choking. The symptoms are psychosomatic. The act of swallowing becomes mentally linked with choking or with undercapacity of the esophageal opening. This can induce panic reactions before or during the act of swallowing. The sensation of difficult swallowing feels authentic to the affected individual, although it is based on nothing in reality. It is important that dysphagia (difficult or painful swallowing) be ruled out before a diagnosis of pseudodysphagia is made.

Fear of choking is associated with anxiety, depression, panic attacks, hypochondriasis, and weight loss. The condition can occur in children and adults; it is equally common among males and females. Quality of life can be severely affected. Avoidance of restaurants or social settings is common, since sometimes food can only be taken in small bites or with liquid.

Characterization of idiopathic dysphagia as psychosomatic has recently been challenged by published case reports documenting instances of "pseudodysphagia" patients suffering from the little-known entity Omohyoid muscle syndrome. Should this syndrome be found to have a spectrum of severity (particularly if mild cases of OMS do not demonstrate the typical transient soft neck mass), the medical community may need to consider ruling out this subtle, truly somatic etiology before arriving at true pseudodysphagia, the latter being essentially a diagnosis of exclusion.

Substance abuse is the second most common risk factor for suicide after major depression and bipolar disorder. Both chronic substance misuse as well as acute intoxication are associated. When combined with personal grief, such as bereavement, the risk is further increased. Substance misuse is also associated with mental health disorders.

Most people are under the influence of sedative-hypnotic drugs (such as alcohol or benzodiazepines) when they die by suicide with alcoholism present in between 15% and 61% of cases. Use of prescribed benzodiazepines is asscociated with an increased rate of attempted and completed suicide. The prosuicidal effects of benzodiazepines are suspected to be due to a psychiatric disturbance caused by side effects or withdrawal symptoms. Countries that have higher rates of alcohol use and a greater density of bars generally also have higher rates of suicide. About 2.2–3.4% of those who have been treated for alcoholism at some point in their life die by suicide. Alcoholics who attempt suicide are usually male, older, and have tried to take their own lives in the past. Between 3 and 35% of deaths among those who use heroin are due to suicide (approximately fourteenfold greater than those who do not use). In adolescents who misuse alcohol, neurological and psychological dysfunctions may contribute to the increased risk of suicide.

The misuse of cocaine and methamphetamine has a high correlation with suicide. In those who use cocaine the risk is greatest during the withdrawal phase. Those who used inhalants are also at significant risk with around 20% attempting suicide at some point and more than 65% considering it. Smoking cigarettes is associated with risk of suicide. There is little evidence as to why this association exists; however it has been hypothesized that those who are predisposed to smoking are also predisposed to suicide, that smoking causes health problems which subsequently make people want to end their life, and that smoking affects brain chemistry causing a propensity for suicide. Cannabis however does not appear to independently increase the risk.

Problem gambling is associated with increased suicidal ideation and attempts compared to the general population. Between 12 and 24% pathological gamblers attempt suicide. The rate of suicide among their spouses is three times greater than that of the general population. Other factors that increase the risk in problem gamblers include mental illness, alcohol and drug misuse.