pathology hypoxia

Acute hypoxia is characterized by a rapid onset, occurring in less than 6 hours.

Cyanosis is a bluish discoloration of the skin and mucous membranes due to insufficient oxygen in the blood.

A condition where the oxygen pressure (SpO2) in the blood is too low to saturate hemoglobin.

Hypoxia is a low level of oxygen in body tissues.

A type of hypoxia where the tissues are unable to utilize oxygen effectively, often due to the presence of toxins or metabolic poisons.

Hypercapnia is an increased partial pressure of CO2 in arterial blood.

Hypocapnia is a decreased level of CO2 in arterial blood.

A condition where alveoli are perfused with blood but not ventilated, leading to inadequate gas exchange.

Pneumonia, pulmonary edema, tissue trauma, atelectasis, mucous plugging, and pulmonary arteriovenous fistula can all cause a pulmonary shunt.

The target organs affected by hypoxia include the brain, heart, lungs, kidneys, liver, and skeletal muscle.

The severity of hypoxia is determined by onset (sudden or gradual), duration, severity, type of hypoxia, and tissue sensitivity to hypoxia.

Examples of acute hypoxia include mountain sickness, suffocation, airway obstruction with a foreign body, sudden suppression of the respiratory center, acute cardiac failure, and shock (acute circulatory failure).

Consequences include severe fatal barotrauma, rapid confusion, drowsiness, and death due to respiratory center failure.

Hyperventilation is an increase in the rate and depth of breathing (tachypnoea, hyperpnea) that occurs in response to hypoxic stimulation, aiming to correct hypoxia while causing a loss of CO2.

A compensatory response that leads to secondary polycythemia, which can be beneficial in hypoxia due to blood loss but may increase blood viscosity and risk for thrombosis.

Hyperventilation is a compensatory mechanism that occurs in circumstances when CO2 in the air is elevated, which can lower hypoxia but may lead to hypercapnia (higher blood levels of CO2).

Tachycardia is a condition that develops in hypoxic, respiratory, and hemic hypoxia, characterized by an increased heart rate that raises the myocardial need for oxygen, potentially leading to myocardial hypoxic injury.

Hypotension is abnormally low blood pressure, which can occur as a symptom of hypoxia.

Chronic hypoxia refers to a condition that lasts more than 90 days.

The Oxyhemoglobin dissociation curve describes the relationship between the saturation of hemoglobin and the partial pressure of arterial oxygen.

Hyperventilation can lead to respiratory alkalosis due to the excessive loss of CO2.

A condition characterized by inadequate ventilation leading to increased carbon dioxide levels and decreased oxygen levels in the blood.

The pathogenesis involves hypobaric hypoxic hypoxia.

A condition where the muscles responsible for breathing are unable to function properly, leading to respiratory failure.

Skeletal deformations can restrict lung expansion and impair effective breathing, leading to reduced oxygen intake.

Factors such as decreased temperature, decreased carbon dioxide levels, and increased pH can cause a leftward shift in the Oxyhemoglobin Dissociation Curve, indicating increased affinity of hemoglobin for oxygen.

Sickle cell hemoglobin (HbSS) has a low affinity for oxygen, resulting in a rightward shift of the oxyhemoglobin dissociation curve, which impairs its ability to bind oxygen effectively.

Cyanosis is characterized by a blueish discoloration of the skin or mucous membranes.

Fulminant hypoxia is defined as a lightning-fast onset of hypoxia.

Hypoxemia is a low level of O2 in arterial blood.

A condition where normal ventilation occurs without adequate blood supply, leading to increased 'dead space' in the lungs.

Conditions such as pulmonary embolism, lung emphysema, and cardiovascular shock can lead to increased dead space due to normal ventilation without blood supply.

It can rapidly progress to mixed hypoxia, which includes combinations of circulatory + hemic and circulatory + respiratory hypoxia.

Factors that can affect the Oxyhemoglobin Dissociation Curve include pH levels, carbon dioxide concentration, temperature, and the presence of 2,3-bisphosphoglycerate (2,3-BPG).

Hypoxia contributes to a rightward shift of the oxyhemoglobin dissociation curve, which helps hemoglobin to unload oxygen more readily to starved tissues.

Chronic hypoxia is a prolonged state of insufficient oxygen supply to the tissues, often resulting from conditions such as chronic heart failure, chronic respiratory failure, or chronic anemia.

A type of hypoxia caused by insufficient oxygen in the environment or reduced oxygen availability in the air.

Central cyanosis occurs when the level of deoxygenated hemoglobin in the arteries is above 50 g/L with oxygen saturation below 85%.

A PO2 of ~27 mmHg corresponds to ~50% hemoglobin saturation, known as the P50 of hemoglobin.

A condition characterized by decreased cardiac output leading to prolonged systemic transit time, which can result in inadequate oxygen delivery to tissues.

Cardiovascular failure and shock of any etiology can lead to circulatory hypoxia.

A low count of erythrocytes in blood leads to low hemoglobin levels.

A leftward shift in the Oxyhemoglobin Dissociation Curve signifies an increased affinity of hemoglobin for oxygen, which can occur in conditions such as decreased carbon dioxide levels, increased pH, or lower temperatures.

The Oxyhemoglobin Dissociation Curve (ODC) is a graphical representation that illustrates the relationship between the partial pressure of oxygen (pO2) and the saturation of hemoglobin with oxygen.

Conditions like thalassemia and inherited hemoglobinopathies can increase hemoglobin's affinity to oxygen, impairing oxygen delivery to tissues.

Secondary polycythemia is a compensatory response where the body increases red blood cell production in response to chronic hypoxia, enhancing oxygen transport.

The Oxyhemoglobin Dissociation Curve is significant in clinical settings as it helps in understanding how various physiological and pathological conditions affect oxygen delivery to tissues.

Anesthetic substance overdose leads to dehydrogenase blockage, which disrupts normal cellular respiration and contributes to Histotoxic hypoxia.

CO intoxication refers to carbon monoxide poisoning, where carboxyhemoglobin, the compound formed when carbon monoxide binds to hemoglobin, appears lightly red.

A type of hypoxia that occurs when there is inadequate blood flow to tissues, leading to insufficient oxygen delivery.

The Oxyhemoglobin Dissociation Curve is a graphical representation that illustrates the relationship between the partial pressure of oxygen (pO2) and the saturation of hemoglobin with oxygen (SaO2).

Hyperventilation is the fastest compensatory mechanism for respiratory acidosis, helping to increase oxygen levels in the body.

Cyanosis is a bluish discoloration of the skin and mucous membranes due to insufficient oxygen in the blood.

Tachycardia raises the myocardial need for oxygen, which can lead to myocardial hypoxic injury.

Cyanosis is a bluish discoloration of the skin and mucous membranes due to insufficient oxygenation of the blood.

Hemic hypoxia is a type of hypoxia caused by anemia, characterized by a total hemoglobin level of 60 to 90 g/L, which is below the normal range of 120 to 150 g/L.

A pulse oximeter measures the absorption of light at two wavelengths corresponding to oxyhemoglobin and deoxyhemoglobin.

A type of hypoxic hypoxia that occurs when a person stays in an inadequately ventilated room or a place with high CO2 levels.

These functions deteriorate, leading to reduced awareness of the current situation, coordination difficulties, and decreased muscle function.

A rightward shift in the Oxyhemoglobin Dissociation Curve indicates a decreased affinity of hemoglobin for oxygen, which can occur in conditions such as increased carbon dioxide levels, increased temperature, or decreased pH (Bohr effect).

A leftward shift in the Oxyhemoglobin Dissociation Curve signifies an increased affinity of hemoglobin for oxygen, which can occur in conditions such as decreased carbon dioxide levels, decreased temperature, or increased pH.

Hypercapnia refers to an increased level of CO2 in the blood, which can result from hyperventilation and may lead to respiratory acidosis, causing a decrease in blood pH.

Hypercapnia increases the activity of the respiratory center, prompting the body to attempt to restore normal CO2 levels.

Tachycardia can result in circulatory hypoxia due to the increased demand for oxygen by the heart.

A rightward shift of the oxyhemoglobin dissociation curve (ODC) indicates that hemoglobin has a decreased affinity for oxygen, facilitating oxygen unloading to tissues, especially under conditions like increased temperature, increased CO2 production, decreased pH, increased 2,3-diphosphoglycerate (DPG), hypoxia, and anemia.

An increase in breathing rate that can lower hypoxia but may also lead to hypocapnia, which is a decreased level of CO2 in the blood.

Monobromides and tetrachloromethane block Krebs cycle enzymes, leading to impaired cellular respiration.

Lung emphysema leads to a reduction of surface area for gas exchange, which can result in respiratory hypoxia.

Hypercapnia is the condition of elevated CO2 in the blood, which occurs when CO2 cannot be exchanged via the lungs.

A type of hypoxia caused by a reduction in the oxygen-carrying capacity of the blood, often due to anemia or carbon monoxide poisoning.

Histotoxic hypoxia is a type of hypoxia that occurs when the tissues are unable to utilize oxygen effectively, despite adequate oxygen delivery.

The Oxyhemoglobin Dissociation Curve is a graphical representation that illustrates the relationship between the partial pressure of oxygen (pO2) and the saturation of hemoglobin with oxygen (SaO2).

Compensatory mechanisms in hypoxia include the cardiovascular system, respiratory system, erythrocytes, and tissue metabolism, which work to maintain adequate oxygen levels in the body.

The organ systems responsible for blood oxygenation include the cardiovascular system and the respiratory system.

Dyspnea is the subjective and objective difficulty of breathing, commonly referred to as shortness of breath or breathlessness.

Tissue metabolism can adapt to lower oxygen levels by increasing anaerobic processes, thereby allowing cells to generate energy even when oxygen is scarce.

Symptoms caused by compensatory mechanisms in hypoxia may include increased heart rate, rapid breathing, and other physiological responses to improve oxygen delivery.

Histotoxic hypoxia refers to a reduction in ATP production by the mitochondria due to a defect in the cellular usage of oxygen.

Factors that create left shifts are generally the opposite of those that create right shifts, including conditions like methemoglobinemia and carbon monoxide binding.

Hypoxia may be classified as either generalized, affecting the whole body, or local, affecting a region of the body.

Fulminant hypoxia is a rare condition that occurs mostly in catastrophe medicine, characterized by a rapid onset of hypoxia, often due to explosive decompression at high altitudes.

During explosive decompression, oxygen is forced out from the lungs due to the rapid expansion of gas, leading to severe hypoxia.

Physiologic stressors can shift the Oxyhemoglobin dissociation curve rightward or leftward, changing hemoglobin’s P50.

The PaO2 in blood can be initially normal despite the presence of circulatory hypoxia.

Conditions that lead to the inability to transport oxygen molecules, such as CO intoxication and methemoglobinemia.

A condition caused by the oxidation of Fe 2+ to Fe 3+, leading to a reduced ability to transport oxygen.

A rightward shift in the Oxyhemoglobin Dissociation Curve indicates a decreased affinity of hemoglobin for oxygen, facilitating oxygen release to tissues.

A rightward shift is caused by increased temperature, increased CO2 production (leading to decreased pH and acidosis), increased 2,3-diphosphoglycerate (DPG), hypoxia, and anemia.

Fetal hemoglobin is structurally different from adult hemoglobin and is adapted to have a high affinity for oxygen, which is necessary due to the relatively low partial pressures of oxygen in the uteroplacental circulation.

Hypoxia is often a pathological condition, but variations in arterial oxygen concentrations can be part of normal physiology.

Acute hypoxia is characterized by a rapid onset and is less frequent compared to chronic hypoxia.

A type of hypoxia resulting from inadequate oxygenation of the blood due to respiratory failure or impaired gas exchange.

A type of hypoxic hypoxia induced by low atmospheric pressure, which can lead to altitude sickness.

A compensatory mechanism that prioritizes blood flow to vital organs during hypoxia.

A rightward shift in the Oxyhemoglobin Dissociation Curve indicates a decreased affinity of hemoglobin for oxygen, which can occur in conditions such as increased carbon dioxide levels, decreased pH, or increased temperature.

Erythrocytes, or red blood cells, are crucial for transporting oxygen throughout the body and can increase in number or efficiency in response to hypoxia.

Other symptoms of hypoxia include fatigue, malaise, anxiety, confusion, and insomnia.

Peripheral / acral / venous cyanosis is observed in the upper and lower extremities where blood flow is slower, often due to low cardiac output, venous stasis, or exposure to extreme cold.

A leftward shift indicates that less PO2 can achieve a higher hemoglobin saturation compared to the baseline, meaning hemoglobin has a higher affinity for oxygen and is less willing to release it to peripheral tissues.

Carbon monoxide binds hemoglobin approximately 250 times more rapidly than oxygen, reducing available binding spots and causing a leftward shift in the curve.

Respiratory hypoxia is caused by a decline in respiratory functions at any level, including hypoventilation, impairment of gas diffusion via the alveolo-capillary membrane, and ventilation-perfusion mismatch.

Arterial blood gas measures the partial pressure of dissolved oxygen in the blood as well as the saturation of hemoglobin.

Cyanosis might not be clinically evident in a patient with severe anemia due to the inability to obtain a high enough level of reduced hemoglobin.

A state of heightened mood and poor judgement of one's capacity that can occur at high altitudes due to diminished cerebral cortical inhibitory functions, similar to alcohol intoxication.

Lack of oxygen in the blood flowing to the tissues because of decreased haemoglobin level.

During hypoxia, cerebral cortical inhibitory functions are diminished, which affects judgement and can mimic the effects of alcohol intoxication.

Severe depression and apathy occur following the initial euphoria experienced at high altitudes.

Factors that can affect the Oxyhemoglobin Dissociation Curve include pH, temperature, carbon dioxide levels, and the presence of 2,3-bisphosphoglycerate (2,3-BPG).

Superficial breathing, often caused by pain from conditions like thoracic trauma, pleuritis, or intercostal neuralgia, can lead to inadequate ventilation and hypoxia.

A condition where blood pH deviates to alkalinity due to low levels of CO2, often caused by hypocapnia.

Methemoglobinemia (metHb) is unable to accept oxygen like the typical 2+ oxidation state, which creates a leftward shift in the ODC.

Lung edema leads to fluid accumulation in the alveoli, impairing gas exchange and contributing to respiratory hypoxia.

Examples of conditions that can lead to chronic hypoxia include chronic heart failure, congestive heart failure, chronic respiratory failure, and chronic anemia.

Hypercapnia can lead to respiratory acidosis, which is characterized by a decrease in blood pH.

A hormonal response activated by hypovolemia, which can have positive effects in hypoxia due to blood loss but negative effects in circulatory hypoxia related to heart pathology.

Symptoms include headache, nausea, vomiting, dyspnoea, and sleeping disorders.

Common causes include foreign bodies, tumors, inflammatory edema (such as bronchitis), and bronchospasms during asthma attacks.

Altitude sickness typically begins at around 2500 m elevation.

At 3500 m elevation, cerebral oedema may occur due to dilated cerebral arteries.

Pneumonia causes a decline in functioning alveoli, which reduces the efficiency of gas exchange and can lead to respiratory hypoxia.

At 3000 m elevation, pulmonary oedema is possible due to constricted pulmonary arteries.

Central / arterial cyanosis occurs when arterial blood is not sufficiently oxygenated and contains reduced hemoglobin, often associated with conditions like Tetralogy of Fallot and lung diseases.

Physiological responses that the body employs to counteract the effects of hypoxia, such as hyperventilation and circulatory responses.

A condition characterized by decreased levels of carbon dioxide in the blood, often resulting from hyperventilation.

A condition where the brain's respiratory centers are inhibited, often due to medications, narcotic abuse, or hypocapnia, leading to decreased breathing effort.

A type of hypoxia that occurs when there is insufficient oxygen available in the environment, leading to reduced oxygen levels in the blood.

Cyanide poisoning causes cessation of aerobic cell metabolism by binding to the enzyme cytochrome C oxidase and blocking the mitochondrial transport chain.

An increase in red blood cell mass that occurs as a compensatory response to chronic hypoxia, enhancing oxygen transport in the blood.

Impairment of gas diffusion occurs when the alveolo-capillary membrane is damaged or thickened, hindering the exchange of oxygen and carbon dioxide.

Pneumofibrosis is characterized by increased thickness of connective tissue in the alveolar septum, which can hinder gas exchange and lead to respiratory hypoxia.

Cryptogenic fibrosing alveolitis is a type of pneumofibrosis that results in thickening of the alveolar walls, impairing gas exchange and contributing to respiratory hypoxia.

Compensatory capacity is lower if hypoxia develops abruptly, lasts longer, and is severe.