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Pathology - Chronic Respiratory Acidemia
Pathophysiology
Acidemia (pH <7.35) caused by persistent respiratory acidosis is a representation of chronic respiratory acidosis.
It may also be presented with hypoxemia (Sao2 <90%) . Both stem from long-term lung illness. Inadequate CO2 excretion is caused by decreased alveolar ventilation. The ensuing hypercarbia lowers arterial pH and causes a respiratory acidosis (Paco2 >45 mm Hg). Renal compensation has occurred because this is a chronic disease, limiting the drop in arterial pH. Increased renal bicarbonate production and increased urine acid excretion, mostly by ammoniagenesis, are components of renal compensation. HCO3- >28 mEq/L is the secondary (compensatory) metabolic alkalosis that arises from compensating for the underlying respiratory acidosis. The patient's hypoxemia is caused by a combination of high CO2 levels, which displace oxygen from alveoli, and ventilation-perfusion mismatch, which is brought on by the breakdown of the lung architecture in emphysema. An elevated hematocrit level results from chronic hypoxia, which also raises red blood cell synthesis and boosts renal erythropoietin secretion. The patient's PaO2 (less than 55 mm Hg) or SaO2 (less than 88% at rest) meet the requirements for home oxygen therapy.
Pathophysiology
Acidemia (pH <7.35) caused by persistent respiratory acidosis is a representation of chronic respiratory acidosis.
It may also be presented with hypoxemia (Sao2 <90%) . Both stem from long-term lung illness. Inadequate CO2 excretion is caused by decreased alveolar ventilation. The ensuing hypercarbia lowers arterial pH and causes a respiratory acidosis (Paco2 >45 mm Hg). Renal compensation has occurred because this is a chronic disease, limiting the drop in arterial pH. Increased renal bicarbonate production and increased urine acid excretion, mostly by ammoniagenesis, are components of renal compensation. HCO3- >28 mEq/L is the secondary (compensatory) metabolic alkalosis that arises from compensating for the underlying respiratory acidosis. The patient's hypoxemia is caused by a combination of high CO2 levels, which displace oxygen from alveoli, and ventilation-perfusion mismatch, which is brought on by the breakdown of the lung architecture in emphysema. An elevated hematocrit level results from chronic hypoxia, which also raises red blood cell synthesis and boosts renal erythropoietin secretion. The patient's PaO2 (less than 55 mm Hg) or SaO2 (less than 88% at rest) meet the requirements for home oxygen therapy.
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Pathology - Metabolic Acidosis
Pathophysiology
The most likely cause of type 1 diabetes mellitus is a shortage of insulin. Severe hyperglycemia and ketoacidosis are caused by the inability of insulin-dependent organs to absorb and metabolize glucose and by the persistent synthesis of glucose and ketone by the liver. The osmotic diuresis that ensues from this leads to hypovolemia, which explains the hypotension, tachycardia, and hemoconcentration that have been noted. A metabolic acidosis (HCO3 - <22) is caused by excess ketoacids because the excess acid is buffered by serum bicarbonate ions. The observed tachypnea is caused by peripheral chemoreceptors being stimulated by low arterial blood pH. A secondary respiratory alkalosis (Paco2 <33) is caused by this hyperventilation, and it helps to partially offset the initial metabolic acidosis. The cause of hyponatremia is the replacement of serum sodium with glucose, an alternative osmolyte.
Due to potassium shifting out of cells as a result of low insulin and cellular buffering of H+ ions in exchange for K+ ions, hyperkalemia is the result. Here, urinary potassium losses are causing wholebody potassium depletion, which is being concealed by hyperkalemia. Intravenous saline/insulin infusion is the first line of treatment, and serum electrolytes, acid-base balance, hyperglycemia, and hemodynamics are all closely monitored.
Pathophysiology
The most likely cause of type 1 diabetes mellitus is a shortage of insulin. Severe hyperglycemia and ketoacidosis are caused by the inability of insulin-dependent organs to absorb and metabolize glucose and by the persistent synthesis of glucose and ketone by the liver. The osmotic diuresis that ensues from this leads to hypovolemia, which explains the hypotension, tachycardia, and hemoconcentration that have been noted. A metabolic acidosis (HCO3 - <22) is caused by excess ketoacids because the excess acid is buffered by serum bicarbonate ions. The observed tachypnea is caused by peripheral chemoreceptors being stimulated by low arterial blood pH. A secondary respiratory alkalosis (Paco2 <33) is caused by this hyperventilation, and it helps to partially offset the initial metabolic acidosis. The cause of hyponatremia is the replacement of serum sodium with glucose, an alternative osmolyte.
Due to potassium shifting out of cells as a result of low insulin and cellular buffering of H+ ions in exchange for K+ ions, hyperkalemia is the result. Here, urinary potassium losses are causing wholebody potassium depletion, which is being concealed by hyperkalemia. Intravenous saline/insulin infusion is the first line of treatment, and serum electrolytes, acid-base balance, hyperglycemia, and hemodynamics are all closely monitored.
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Pathology- Pre Renal Azotemia
Pathophysiology
Acute kidney injury (AKI) is characterized by decreased glomerular filtration rate (GFR) and oliguria, or urine flow less than 0.5 mL/kg/h, as well as a recent doubling of serum creatinine. In this instance, decreased renal arterial perfusion is the source of renal dysfunction, which is known as pre-renal etiology of AKI. Reduced cardiac output from aortic stenosis results in decreased LV stroke volume (notice the lower pulse pressure), which lowers renal perfusion. Arterial constriction and tachycardia have been caused by baroreceptor activation. When pre-renal azotemia occurs, the BUN:creatinine ratio rises to more than 20:1, which is higher than normal.
When there is a low effective circulating volume, there is a rise in tubular urea reabsorption, which results in a high BUN. This is caused by high levels of ADH.
A pre-renal etiology is further suggested by fractional sodium excretion of less than 1%, which is indicative of avid tubular sodium reabsorption. When there is a low effective circulation volume, the renin-angiotensin-aldosterone system is active, and the renal tubules are responding appropriately to this high level of activity. In this scenario, renal function should be corrected as soon as renal perfusion is restored. The patient's dyspnea necessitates a careful assessment of his aortic stenosis in order to decide whether surgery is necessary.
Pathophysiology
Acute kidney injury (AKI) is characterized by decreased glomerular filtration rate (GFR) and oliguria, or urine flow less than 0.5 mL/kg/h, as well as a recent doubling of serum creatinine. In this instance, decreased renal arterial perfusion is the source of renal dysfunction, which is known as pre-renal etiology of AKI. Reduced cardiac output from aortic stenosis results in decreased LV stroke volume (notice the lower pulse pressure), which lowers renal perfusion. Arterial constriction and tachycardia have been caused by baroreceptor activation. When pre-renal azotemia occurs, the BUN:creatinine ratio rises to more than 20:1, which is higher than normal.
When there is a low effective circulating volume, there is a rise in tubular urea reabsorption, which results in a high BUN. This is caused by high levels of ADH.
A pre-renal etiology is further suggested by fractional sodium excretion of less than 1%, which is indicative of avid tubular sodium reabsorption. When there is a low effective circulation volume, the renin-angiotensin-aldosterone system is active, and the renal tubules are responding appropriately to this high level of activity. In this scenario, renal function should be corrected as soon as renal perfusion is restored. The patient's dyspnea necessitates a careful assessment of his aortic stenosis in order to decide whether surgery is necessary.
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Pathology - Acute Tubular Necrosis
Pathophysiology
A femur fracture has caused hemorrhage and hypovolemia, which went untreated for several hours. This has resulted in renal ischemia, a protracted reduction in renal perfusion, and tubular cell damage, also known as ATN. In the most active tubules of the proximal tubules and thick ascending limb, ischemic damage first results in ATP depletion. Damage to endothelial cells results in the release of local vasoconstrictors. By compressing capillaries, vascular permeability increases and interstitial pressure rises, further limiting local blood flow.
As a result, even after reperfusion starts, the initial ischemia injury persists. The high fractional sodium excretion (usually only 1-2% of filtered sodium is expelled) is indicative of a tubular damage diagnosis.
Additionally, muddy-brown casts made of tubular epithelial cells can be found in urine sediment. Certain nephrotoxins, such as aminoglycoside antibiotics, radiocontrast medium, and NSAIDs, are other causes of ATN. ATN falls under the category of "intrinsic" AKI, which denotes that damage to a kidney's structural component is the cause of the issue.
Pathophysiology
A femur fracture has caused hemorrhage and hypovolemia, which went untreated for several hours. This has resulted in renal ischemia, a protracted reduction in renal perfusion, and tubular cell damage, also known as ATN. In the most active tubules of the proximal tubules and thick ascending limb, ischemic damage first results in ATP depletion. Damage to endothelial cells results in the release of local vasoconstrictors. By compressing capillaries, vascular permeability increases and interstitial pressure rises, further limiting local blood flow.
As a result, even after reperfusion starts, the initial ischemia injury persists. The high fractional sodium excretion (usually only 1-2% of filtered sodium is expelled) is indicative of a tubular damage diagnosis.
Additionally, muddy-brown casts made of tubular epithelial cells can be found in urine sediment. Certain nephrotoxins, such as aminoglycoside antibiotics, radiocontrast medium, and NSAIDs, are other causes of ATN. ATN falls under the category of "intrinsic" AKI, which denotes that damage to a kidney's structural component is the cause of the issue.
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Pathology - Idiopathic Pulmonary Fibrosis
Pathophysiology
Chronic inflammation of the alveolar walls causes diffuse, progressive fibrosis and the breakdown of the normal architecture of the lung in idiopathic pulmonary fibrosis. This process gradually deteriorates terminal respiratory units' ability to perform normal gas exchange and pulmonary perfusion. There is an increased elastic work of breathing with extra inspiratory effort as a result of this restrictive lung illness. The frequent presentation symptoms include dry cough, dyspnea, and clubbing of the fingers and toes. The sequential opening of collapsing respiratory units is reflected in the respiratory crackles. Breathing at low lung volumes, loss of pulmonary surfactant, and deformed architecture all contribute to this collapse. Tests for pulmonary function often reveal a decline in all lung volumes; on expiration, greater lung recoil forces retain the FEV1:FVC ratio. As lung fibrosis advances and there is a ventilation-perfusion mismatch when breathing at reduced lung capacities, gas exchange becomes inefficient.
Pathophysiology
Chronic inflammation of the alveolar walls causes diffuse, progressive fibrosis and the breakdown of the normal architecture of the lung in idiopathic pulmonary fibrosis. This process gradually deteriorates terminal respiratory units' ability to perform normal gas exchange and pulmonary perfusion. There is an increased elastic work of breathing with extra inspiratory effort as a result of this restrictive lung illness. The frequent presentation symptoms include dry cough, dyspnea, and clubbing of the fingers and toes. The sequential opening of collapsing respiratory units is reflected in the respiratory crackles. Breathing at low lung volumes, loss of pulmonary surfactant, and deformed architecture all contribute to this collapse. Tests for pulmonary function often reveal a decline in all lung volumes; on expiration, greater lung recoil forces retain the FEV1:FVC ratio. As lung fibrosis advances and there is a ventilation-perfusion mismatch when breathing at reduced lung capacities, gas exchange becomes inefficient.
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Pathology - Hypersensitivity Pneumonitis
Pathophysiology
This illness may present as acute, subacute, or chronic. An heightened alveolar immune response to an external environmental allergen—most frequently, organic dusts or molds—causes HP. The immunological response eventually results in the infiltration of mononuclear cells and the progressive formation of noncaseating granulomas. Some people with chronic illnesses who have decreased diffusion ability on pulmonary function tests may develop interstitial lung fibrosis. All patients desaturate during exercise, and the majority of patients suffer hypoxemia at rest. Although the symptoms may resemble occupational asthma, HP affects alveoli rather than bronchi. Animal excrement, other occupational compounds (such paints and resins), plant materials, or proteins can all be allergens. Finding the problematic allergen or allergens and avoiding them are essential to halting the deterioration of alveoli and lung tissue fibrosis.
Pathophysiology
This illness may present as acute, subacute, or chronic. An heightened alveolar immune response to an external environmental allergen—most frequently, organic dusts or molds—causes HP. The immunological response eventually results in the infiltration of mononuclear cells and the progressive formation of noncaseating granulomas. Some people with chronic illnesses who have decreased diffusion ability on pulmonary function tests may develop interstitial lung fibrosis. All patients desaturate during exercise, and the majority of patients suffer hypoxemia at rest. Although the symptoms may resemble occupational asthma, HP affects alveoli rather than bronchi. Animal excrement, other occupational compounds (such paints and resins), plant materials, or proteins can all be allergens. Finding the problematic allergen or allergens and avoiding them are essential to halting the deterioration of alveoli and lung tissue fibrosis.
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Pathology - Mitral Stenosis
Pathophysiology
The most frequent reason is rheumatoid arthritis, which causes the valve leaflets to calcify and stiffen fibrously. The distinctive opening snap of the calcified mitral valve is caused by vigorous opening early in diastole, and the diastolic rumble is caused by turbulent blood flow through the narrow valve. The atrial kick, which forces blood through the narrow valve, is what generates the presystolic accentuation of the murmur. Increased left atrial pressure and left atrial distention (see the huge P waves in this example) are the results of restricting blood flow from the left atrium. Pulmonary edema is the result of subsequent rises in the pulmonary venous and capillary pressures (notice the rales and crackles). Exertion and lying down at night both increase venous return, which in turn raises left atrial pressure and exacerbates pulmonary edema. Right ventricular overload is frequently the result of pulmonary hypertension, which is a long-term rise in pulmonary venous pressure. Peripheral edema and jugular vein dilatation are signs of right sided heart failure and right heart enlargement (notice the right axis deviation).
Pathophysiology
The most frequent reason is rheumatoid arthritis, which causes the valve leaflets to calcify and stiffen fibrously. The distinctive opening snap of the calcified mitral valve is caused by vigorous opening early in diastole, and the diastolic rumble is caused by turbulent blood flow through the narrow valve. The atrial kick, which forces blood through the narrow valve, is what generates the presystolic accentuation of the murmur. Increased left atrial pressure and left atrial distention (see the huge P waves in this example) are the results of restricting blood flow from the left atrium. Pulmonary edema is the result of subsequent rises in the pulmonary venous and capillary pressures (notice the rales and crackles). Exertion and lying down at night both increase venous return, which in turn raises left atrial pressure and exacerbates pulmonary edema. Right ventricular overload is frequently the result of pulmonary hypertension, which is a long-term rise in pulmonary venous pressure. Peripheral edema and jugular vein dilatation are signs of right sided heart failure and right heart enlargement (notice the right axis deviation).
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Pathology - Mitral Regurgitation
Pathophysiology
The holosystolic murmur is caused by regurgitant blood flowing from the left ventricle to the left atrium through the mitral valve. When the patient clenches her fists during the handgrip, the murmur gets louder. This action increases systemic vascular resistance, which in turn causes the mitral valve to regurgitate more during systole and reduces the left ventricle's forward flow into the aorta. Rapid ventricular filling from an enlarged left atrium at the beginning of diastole causes the S3 sound. In line with ECG findings, a chest radiograph reveals left atrial and LV enlargement.
Regurgitation of left ventricle blood flow is accompanied by a rise in left atrial and pulmonary pressures, which are regulated by the left atrium's gradual expansion and greater compliance. LV enlargement is a compensatory mechanism to keep the heart pumping blood. Fatigue and weakness upon exertion are signs that the heart is not working hard enough to raise its output when exercising. PND may be a sign of declining left atrial pressure and maybe the beginning of heart failure.
Pathophysiology
The holosystolic murmur is caused by regurgitant blood flowing from the left ventricle to the left atrium through the mitral valve. When the patient clenches her fists during the handgrip, the murmur gets louder. This action increases systemic vascular resistance, which in turn causes the mitral valve to regurgitate more during systole and reduces the left ventricle's forward flow into the aorta. Rapid ventricular filling from an enlarged left atrium at the beginning of diastole causes the S3 sound. In line with ECG findings, a chest radiograph reveals left atrial and LV enlargement.
Regurgitation of left ventricle blood flow is accompanied by a rise in left atrial and pulmonary pressures, which are regulated by the left atrium's gradual expansion and greater compliance. LV enlargement is a compensatory mechanism to keep the heart pumping blood. Fatigue and weakness upon exertion are signs that the heart is not working hard enough to raise its output when exercising. PND may be a sign of declining left atrial pressure and maybe the beginning of heart failure.
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Pathology - Acute Mitral Regurgitation
Pathophysiology
The rupture of the chordae tendinae, which connects the papillary muscles to the valve leaflets, results in acute mitral valve regurgitation. The holosystolic murmur is caused by regurgitant blood flowing from the left ventricle to the left atrium through the mitral valve. The murmur's decrescendo character indicates how quickly the left ventricle and left atrium's pressures equilibrated as a result of the significant blood regurgitation. The issue does not appear to be connected to a recent myocardial ischemia episode if there are no new ECG findings or changes in cardiac enzyme levels. Breathlessness is primarily caused by pulmonary edema, which is seen on the chest radiograph. Acute elevation of left atrial pressure results from regurgitation of blood into the left atrium. Pulmonary edema is the consequence of elevated pulmonary venous and capillary pressures brought on by elevated left atrial pressure. Pulmonary edema is far less common when chronic mitral valve regurgitation is present because left atrial compliance progressively rises with time.
Pathophysiology
The rupture of the chordae tendinae, which connects the papillary muscles to the valve leaflets, results in acute mitral valve regurgitation. The holosystolic murmur is caused by regurgitant blood flowing from the left ventricle to the left atrium through the mitral valve. The murmur's decrescendo character indicates how quickly the left ventricle and left atrium's pressures equilibrated as a result of the significant blood regurgitation. The issue does not appear to be connected to a recent myocardial ischemia episode if there are no new ECG findings or changes in cardiac enzyme levels. Breathlessness is primarily caused by pulmonary edema, which is seen on the chest radiograph. Acute elevation of left atrial pressure results from regurgitation of blood into the left atrium. Pulmonary edema is the consequence of elevated pulmonary venous and capillary pressures brought on by elevated left atrial pressure. Pulmonary edema is far less common when chronic mitral valve regurgitation is present because left atrial compliance progressively rises with time.
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Pathology - Aortic Stenosis
Pathophysiology
The most common cause of this in people over 65 is calcification and age-related deterioration of the valve. Because of the blood flow impedance during systole caused by valve stenosis, there is an increase in left ventricular afterload. Since the left ventricle must create a high pressure in order to expel blood through the narrow valve, the murmur's crescendo-decrescendo pattern reflects the nature of the pressure differential across the stenotic valve.
The inadequate stroke volume supplied to the aorta during systole is the cause of the weakening and delay of the carotid pulse. The onset of angina is a reflection of the stenosis getting worse and is brought on by the hypertrophied left ventricle's increased cardiac oxygen demand. A more concerning symptom is syncope, which is caused by a failure to sustain the brain's oxygen supply and an inability to increase cardiac output during exertion. Atrial contraction at the end of diastole pushes blood into a hypertrophied and rigid left ventricle, which results in the S4 sound. Although the patient does not already exhibit symptoms of heart failure, if therapy is not received, the circumstances in his left ventricle will probably cause this situation to worsen.
Pathophysiology
The most common cause of this in people over 65 is calcification and age-related deterioration of the valve. Because of the blood flow impedance during systole caused by valve stenosis, there is an increase in left ventricular afterload. Since the left ventricle must create a high pressure in order to expel blood through the narrow valve, the murmur's crescendo-decrescendo pattern reflects the nature of the pressure differential across the stenotic valve.
The inadequate stroke volume supplied to the aorta during systole is the cause of the weakening and delay of the carotid pulse. The onset of angina is a reflection of the stenosis getting worse and is brought on by the hypertrophied left ventricle's increased cardiac oxygen demand. A more concerning symptom is syncope, which is caused by a failure to sustain the brain's oxygen supply and an inability to increase cardiac output during exertion. Atrial contraction at the end of diastole pushes blood into a hypertrophied and rigid left ventricle, which results in the S4 sound. Although the patient does not already exhibit symptoms of heart failure, if therapy is not received, the circumstances in his left ventricle will probably cause this situation to worsen.
