Hamman's syndrome, also known as Macklin's syndrome, is a syndrome of spontaneous subcutaneous emphysema (air in the subcutaneous tissues of the skin) and pneumomediastinum (air in the mediastinum, the center of the chest cavity), sometimes associated with pain and, less commonly, dyspnea (difficulty breathing), dysphonia, and a low-grade fever.

Hamman's syndrome can cause Hamman's sign, an unusual combination of sounds that can be heard with a stethoscope.

The cause of Hamman's syndrome is most commonly unknown (idiopathic).

Excessive duration and/or intensity of activities that mimic valsalva manoeuvres, "i.e." that increase intrathoracic pressure, can cause barotrauma, and hence pregnancy (and constipation and other causes of excessive straining) can be a precipitating cause of Hamman's syndrome. Indeed, it is estimated to occur in approximately 1 in 100,000 live births and is associated with prolonged labour times

Additionally, vomiting and coughing have also been noted as occasional precipitating factors. Hamman's is thus unsurprisingly occasionally known to be associated with asthma ("i.e." frequent coughing), alcohol abuse ("i.e." frequent vomiting) and inhalational illicit drug use (such as cocaine use).

Despite these associations, often, no precipitating cause is found.

The main symptom is usually severe central chest pain. Other symptoms include laboured breathing, voice distortion (as with helium) and subcutaneous emphysema, specifically affecting the face, neck, and chest. Pneumomediastinum can also be characterized by the shortness of breath that is typical of a respiratory system problem. It is often recognized on auscultation by a "crunching" sound timed with the cardiac cycle (Hamman's crunch).

Pnemomediastinum may also present with symptoms mimicking cardiac tamponade as a result of the increased intrapulmonary pressure on venous flow to the heart.

Pneumomediastinum (from Greek "pneuma" – "air", also known as mediastinal emphysema) is (abnormal presence of air or other gas) in the mediastinum. First described in 1819 by René Laennec, the condition can result from physical trauma or other situations that lead to air escaping from the lungs, airways, or bowel into the chest cavity.

The symptomatic patient may present with dyspnea, cyanosis, chest pain, pulsus paradoxus, bradycardia or tachycardia. On physical examination, the patient may have the classic “Beck’s triad” – hypotension, raised JVP and distant heart sounds, when complicated by cardiac tamponade. Extension of the mediastinal air to the subcutaneous tissues via the fascial planes may lead to subcutaneous emphysema. When air and fluid mix together in the pericardial sac, a tinkling sound superimposed over a succussion splash is heard. This is known as a “Bruit de Moulin”, which is French for “Mill–wheel” murmur. Air between the anterior parietal pericardium and the thoracic cage may also give rise to the “Hamman’s Sign” – which is a crunching sound typically heard on auscultation of the chest, but may sometimes be heard even with the unaided ear.

The ‘Harlequin Sign’ is unilateral flushing and sweating of the face, neck, and upper chest usually after exposure to heat or strenuous exertion. Horner syndrome, another problem associated with the sympathetic nervous system, is often seen in conjunction with harlequin syndrome.

Since Harlequin syndrome is associated with a dysfunction in the autonomic nervous system, main symptoms of this dysfunction are in the following: Absence of sweat(anhidrosis) and flushing on one side of the face, neck, or upper thoracic area. In addition, other symptoms include cluster headaches, tearing of the eyes, nasal discharge, abnormal contraction of the pupils, weakness in neck muscles, and drooping of on side of the upper eyelid.

Harlequin syndrome is a condition characterized by asymmetric sweating and flushing on the upper thoracic region of the chest, neck, and face. Harlequin syndrome is considered an injury to the autonomic nervous system (ANS). The ANS controls some of the body's natural processes such as sweating, skin flushing, and pupil response to stimuli. Such individuals with this syndrome have an absence of sweat skin flushing unilaterally; usually on the one side of the face, arms, and chest. It is an autonomic disorder that may occur at any age. Harlequin syndrome affects fewer than 200,000 people in the United States.

Symptoms associated with Harlequin syndrome are more likely to appear when a person has been in the following conditions: exercising, warm environment, and intense emotional situation. Since one side of the body sweats and flushes appropriately to the condition, the other side of the body will have an absence of such symptoms. This syndrome has also been called the "Harlequin sign," and thought to be one of the spectrum of diseases that may cause Harlequin syndrome.

It can also be the outcome of a one sided endoscopic thoracic sympathectomy (ETS) or endoscopic sympathetic blockade (ESB) surgery.

Harlequin syndrome can also be seen as a complication of VA (veno-arterial) extracorporeal membrane oxygenation (ECMO). This involves differential hypoxemia (low oxygen levels in the blood) of the upper body in comparison to the lower body.

The classic history of esophageal rupture is one of severe retching and vomiting followed by excruciating retrosternal chest and upper abdominal pain. Odynophagia, tachypnea, dyspnea, cyanosis, fever, and shock develop rapidly thereafter.

Physical examination is usually not helpful, particularly early in the course. Subcutaneous emphysema (crepitation) is an important diagnostic finding but is not very sensitive, being present in only 9 of 34 patients (27 percent) in one series. A pleural effusion may be detected.

Mackler's triad includes chest pain, vomiting, and subcutaneous emphysema, and while it is a classical presentation, it is only present in 14% of people.

Pain can occasionally radiate to the left shoulder, causing physicians to confuse an esophageal perforation with a myocardial infarction.

It may also be audibly recognized as Hamman's sign.

The syndrome is a rare clinical disorder.

- Physical

- Overgrowth

- Accelerated skeletal maturation

- Dysmorphic facial features

- Prominent eyes

- Bluish sclerae

- Coarse eyebrows

- Upturned nose

- Radiologic examination

- Accelerated osseous maturation

- Phalangeal abnormalities

- Tubular thinning of the long bones

- Skull abnormalities

- Mental

- Often associated with intellectual disability (of variable degree)

Signs and symptoms of spontaneous subcutaneous emphysema vary based on the cause, but it is often associated with swelling of the neck and chest pain, and may also involve sore throat, neck pain, difficulty swallowing, wheezing and difficulty breathing. Chest X-rays may show air in the mediastinum, the middle of the chest cavity. A significant case of subcutaneous emphysema is easy to detect by touching the overlying skin; it feels like tissue paper or Rice Krispies. Touching the bubbles causes them to move and sometimes make a crackling noise. The air bubbles, which are painless and feel like small nodules to the touch, may burst when the skin above them is palpated. The tissues surrounding SCE are usually swollen. When large amounts of air leak into the tissues, the face can swell considerably. In cases of subcutaneous emphysema around the neck, there may be a feeling of fullness in the neck, and the sound of the voice may change. If SCE is particularly extreme around the neck and chest, the swelling can interfere with breathing. The air can travel to many parts of the body, including the abdomen and limbs, because there are no separations in the fatty tissue in the skin to prevent the air from moving.

Common misdiagnoses include myocardial infarction, pancreatitis, lung abscess, pericarditis, and spontaneous pneumothorax. If esophageal perforation is suspected, even in the absence of physical findings,chest xray, water soluble contrast radiographic studies of the esophagus and a CT scan should be promptly obtained. In most cases, non-operative management is administered based on radiological evidence contained in mediastinal collection.

In patients that have already been diagnosed with sarcoidosis, Heerfordt syndrome can be inferred from the major symptoms of the syndrome, which include parotitis, fever, and facial nerve palsy. In cases of parotitis, ultrasound-guided biopsy is used to exclude the possibility of lymphoma. There are many possible causes of facial nerve palsy, including Lyme disease, HIV, Melkersson–Rosenthal syndrome, schwannoma, and Bell's palsy. Heerfordt syndrome exhibits spontaneous remission. Treatments for sarcoidosis include corticosteroids and immunosuppressive drugs.

Signs and symptoms vary depending on what part of the tracheobronchial tree is injured and how severely it is damaged. There are no direct signs of TBI, but certain signs suggest the injury and raise a clinician's suspicion that it has occurred. Many of the signs and symptoms are also present in injuries with similar injury mechanisms such as pneumothorax. Dyspnea and respiratory distress are found in 76–100% of people with TBI, and coughing up blood has been found in up to 25%. However, isolated TBI does not usually cause profuse bleeding; if such bleeding is observed it is likely to be due to another injury such as a ruptured large blood vessel. The patient may exhibit dysphonia or have diminished breath sounds, and rapid breathing is common. Coughing may be present, and stridor, an abnormal, high-pitched breath sound indicating obstruction of the upper airway can also occur.

Damage to the airways can cause subcutaneous emphysema (air trapped in the subcutaneous tissue of the skin) in the abdomen, chest, neck, and head. Subcutaneous emphysema, present in up to 85% of people with TBI, is particularly indicative of the injury when it is only in the neck. Air is trapped in the chest cavity outside the lungs (pneumothorax) in about 70% of TBI. Especially strong evidence that TBI has occurred is failure of a pneumothorax to resolve even when a chest tube is placed to rid the chest cavity of the air; it shows that air is continually leaking into the chest cavity from the site of the tear. Air can also be trapped in the mediastinum, the center of the chest cavity (pneumomediastinum). If air escapes from a penetrating injury to the neck, a definite diagnosis of TBI can be made. Hamman's sign, a sound of crackling that occurs in time with the heartbeat, may also accompany TBI.

Pneumopericardium is a medical condition where air enters the pericardial cavity. This condition has been recognized in preterm neonates, in which it is associated with severe lung pathology, after vigorous resuscitation, or in the presence of assisted ventilation. This is a serious complication, which if untreated may lead to cardiac tamponade and death. Pneumomediastinum, which is the presence of air in the mediastinum, may mimic and also coexist with pneumopericardium.

It can be congenital, or introduced by a wound.

Tracheobronchial injury (TBI) is damage to the tracheobronchial tree (the airway structure involving the trachea and bronchi). It can result from blunt or penetrating trauma to the neck or chest, inhalation of harmful fumes or smoke, or aspiration of liquids or objects.

Though rare, TBI is a serious condition; it may cause obstruction of the airway with resulting life-threatening respiratory insufficiency. Other injuries accompany TBI in about half of cases. Of those people with TBI who die, most do so before receiving emergency care, either from airway obstruction, exsanguination, or from injuries to other vital organs. Of those who do reach a hospital, the mortality rate may be as high as 30%.

TBI is frequently difficult to diagnose and treat. Early diagnosis is important to prevent complications, which include stenosis (narrowing) of the airway, respiratory tract infection, and damage to the lung tissue. Diagnosis involves procedures such as bronchoscopy, radiography, and x-ray computed tomography to visualize the tracheobronchial tree. Signs and symptoms vary based on the location and severity of the injury; they commonly include dyspnea (difficulty breathing), dysphonia (a condition where the voice can be hoarse, weak, or excessively breathy), coughing, and abnormal breath sounds. In the emergency setting, tracheal intubation can be used to ensure that the airway remains open. In severe cases, surgery may be necessary to repair a TBI.

Marshall-Smith Syndrome, discovered in 1971 (Marshall, Graham, Scott, Boner, & Smith), is characterized by unusual accelerated skeletal maturation (usually starting before birth) and symptoms like conspicuous physical characteristics, respiratory difficulties, and mental retardation. Cases described in the literature show a clinical variability regarding related symptoms. For instance, respiratory difficulties are ranging from absent to severe difficulties.

The key affected features of this condition are described in its name.

Scalp: There are raised nodules over the posterior aspect of the scalp, covered by scarred non-hair bearing skin.

Ears: The shape of the pinnae is abnormal, with the superior edge of the pinna being turned over more than usual. The size of the tragus, antitragus and lobule may be small.

Nipples: The nipples are absent or rudimentary. The breasts may be small or virtually absent.

Other features of the condition include:

Dental abnormalities: missing or widely spaced teeth

Syndactyly: toes or fingers may be partially joined proximally

Renal abnormalities: renal hypoplasia, pyeloureteral duplication

Eye abnormalities: Cataract, coloboma of the iris and asymmetric pupils.

Subcutaneous emphysema is a common result of certain types of surgery; for example it is not unusual in chest surgery. It may also occur from surgery around the esophagus, and is particularly likely in prolonged surgery. Other potential causes are positive pressure ventilation for any reason and by any technique, in which its occurrence is frequently unexpected. It may also occur as a result of oral surgery, laparoscopy, and cricothyrotomy. In a pneumonectomy, in which an entire lung is removed, the remaining bronchial stump may leak air, a rare but very serious condition that leads to progressive subcutaneous emphysema. Air can leak out of the pleural space through an incision made for a thoracotomy to cause subcutaneous emphysema. On infrequent occasions, the condition can result from dental surgery, usually due to use of high-speed tools that are air driven. These cases result in usually painless swelling of the face and neck, with an immediate onset, the crepitus (crunching sound) typical of subcutaneous emphysema, and often with subcutaneous air visible on X-ray.

One of the main causes of subcutaneous emphysema, along with pneumothorax, is an improperly functioning chest tube. Thus subcutaneous emphysema is often a sign that something is wrong with a chest tube; it may be clogged, clamped, or out of place. The tube may need to be replaced, or, when large amounts of air are leaking, a new tube may be added.

Since mechanical ventilation can worsen a pneumothorax, it can force air into the tissues; when subcutaneous emphysema occurs in a ventilated patient, it is an indication that the ventilation may have caused a pneumothorax. It is not unusual for subcutaneous emphysema to result from positive pressure ventilation. Another possible cause is a ruptured trachea. The trachea may be injured by tracheostomy or tracheal intubation; in cases of tracheal injury, large amounts of air can enter the subcutaneous space. An endotracheal tube can puncture the trachea or bronchi and cause subcutaneous emphysema.

The Kocher–Debré–Semelaigne syndrome is hypothyroidism in infancy or childhood characterised by lower extremity or generalized muscular hypertrophy, myxoedema, short stature and cretinism. The absence of painful spasms and pseudomyotonia differentiates this syndrome from its adult form, which is Hoffmann syndrome.

The syndrome is named after Emil Theodor Kocher, Robert Debré and Georges Semelaigne.

Also known as Debre–Semelaigne syndrome or cretinism-muscular hypertrophy, hypothyroid myopathy, hypothyroidism-large muscle syndrome, hypothyreotic muscular hypertrophy in children, infantile myxoedema-muscular hypertrophy, myopathy-myxoedema syndrome, myxoedema-muscular hypertrophy syndrome, myxoedema-myotonic dystrophy syndrome.

Kocher-Debre-Semelaigne syndrome gives infant a Hercules appearance.

Pashayan syndrome also known as Pashayan–Prozansky Syndrome, and blepharo-naso-facial syndrome is a rare syndrome. Facial abnormalities characterise this syndrome as well as malformation of extremities. Specific characteristics would be a bulky, flattened nose, where the face has a mask like appearance and the ears are also malformed.

A subset of Pashayan syndrome has also been described, known as "cerebrofacioarticular syndrome", "Van Maldergem syndrome'" or "Van Maldergem–Wetzburger–Verloes syndrome". Similar symptoms are noted in these cases as in Pashayan syndrome.

The exact cause of Heerfordt syndrome has not yet been definitively determined. Of those patients who have been diagnosed with Heerfordt syndrome, 15% have a close relative who also has the syndrome. One possible explanation is that the syndrome results from a combination of an environmental agent and a hereditary predisposition. "Mycobacterium" and "Propionibacteria" species have both been suggested as the environmental agent, though the evidence for this is inconclusive.

There is a range of signs and symptoms including cleft lip or palate, mental retardation and various forms of ectodermal dysplasia. Additional symptoms may include fused eyelids, absent nails, delayed bone growth and dry skin. It is believed that this syndrome follows an autosomal dominant pattern of inheritance with incomplete penetrance, and caused by a mutation affecting the TP63 gene. It has been suggested that this syndrome, AEC syndrome and Rapp–Hodgkin syndrome may be variations of the same disease.

There is no specific treatment or cure for individuals affected with this type of syndrome, though some of the abnormal physical features may be surgically correctable.

Reye syndrome progresses through five stages:

- Stage I

- Rash on palms of hands and feet

- Persistent, heavy vomiting that is not relieved by not eating

- Generalized lethargy

- Confusion

- Nightmares

- No fever usually present

- Headaches

- Stage II

- Stupor

- Hyperventilation

- Fatty liver (found by biopsy)

- Hyperactive reflexes

- Stage III

- Continuation of Stage I and II symptoms

- Possible coma

- Possible cerebral edema

- Rarely, respiratory arrest

- Stage IV

- Deepening coma

- Dilated pupils with minimal response to light

- Minimal but still present liver dysfunction

- Stage V

- Very rapid onset following stage IV

- Deep coma

- Seizures

- Multiple organ failure

- Flaccidity

- Hyperammonemia (above 300 mg/dL of blood)

- Death

Psychiatric syndromes often called "psychopathological syndromes" (psychopathology is a psychic dysfunction occurring in mental disorder, also it's the study of the origin, diagnosis, development, and treatment of mental disorders).

In Russia those psychopathological syndromes are used in modern clinical practice and described in psychiatric literature in the details: asthenic syndrome, obsessive syndrome, emotional syndromes (for example, manic syndrome, depressive syndrome), Cotard's syndrome, catatonic syndrome, hebephrenic syndrome, delusional and hallucinatory syndromes (for example, paranoid syndrome, paranoid-hallucinatory syndrome, Kandinsky-Clérambault's syndrome also known as syndrome of psychic automatism, hallucinosis), paraphrenic syndrome, psychopathic syndromes (includes all personality disorders), clouding of consciousness syndromes (for example, twilight clouding of consciousness, amential syndrome also known as amentia, delirious syndrome, stunned consciousness syndrome, oneiroid syndrome), hysteric syndrome, neurotic syndrome, Korsakoff's syndrome, hypochondriacal syndrome, paranoiac syndrome, senestopathic syndrome, encephalopathic syndrome.

There are some examples of the psychopathological syndromes used in modern Germany: psychoorganic syndrome, depressive syndrome, paranoid-hallucinatory syndrome, obsessive-compulsive syndrome, autonomic syndrome, hostility syndrome, manic syndrome, apathy syndrome.

Also well known Münchausen syndrom, Ganser syndrome, neuroleptic-induced deficit syndrome, olfactory reference syndrome.