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Pathology - Pituitary adenoma
Definition • A benign epithelial neoplasm of the anterior pituitary gland. • The majority are functioning tumors that excessively secrete prolactin, growth hormone (GH), or adrenocorticotropic hormone (ACTH), in that order of prevalence. • Functional adenomas that produce thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), or luteinizing hormone (LH) are exceedingly rare.
Epidemiology: Rare, having an incidence of 1 in 100,000 annually. • Predominantly occur in middle-aged individuals. • Women are more frequently afflicted than males.
Aetiology • Predominantly unknown in most instances. A minor percentage is observed in conjunction with hereditary tumor disorders, such as MEN. 1. Genetics • The two most well-characterized genetic anomalies are MEN 1 and gsp, a mutation in the G-protein alpha subunit.
Presentation • Characteristics of endocrine hyperfunction vary according to the hormone produced, such as galactorrhea and sexual dysfunction in prolactin-secreting cases, acromegaly in growth hormone-secreting instances, or Cushing's syndrome in adrenocorticotropic hormone-secreting scenarios. • Large adenomas can induce mass effect symptoms, including headache, nausea, and visual field disturbances, due to compression of the optic chiasm. • Numerous people may exhibit symptoms and indications of hypopituitarism, but it is infrequently the presenting complaint.
Macroscopy: Pituitary adenomas are soft tumors that can be classified as small microadenomas (less than 10 mm in size) or bigger macroadenomas (greater than 10 mm in size). Histopathology The tumors consist of solid nests or trabeculae of neoplastic cells characterized by homogeneous round nuclei, stippled chromatin, and subtle nucleoli. Immunohistochemistry employing antibodies targeting prolactin, growth hormone, and adrenocorticotropic hormone can be utilized to ascertain the hormone synthesized by the tumor. Prognosis: Generally favorable after suitable medicinal or surgical intervention, although some patients may experience recurrences. 2 The endocrine repercussions of these tumors may, however, yield significant consequences, such as cardiovascular disease in acromegaly.
Definition • A benign epithelial neoplasm of the anterior pituitary gland. • The majority are functioning tumors that excessively secrete prolactin, growth hormone (GH), or adrenocorticotropic hormone (ACTH), in that order of prevalence. • Functional adenomas that produce thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), or luteinizing hormone (LH) are exceedingly rare.
Epidemiology: Rare, having an incidence of 1 in 100,000 annually. • Predominantly occur in middle-aged individuals. • Women are more frequently afflicted than males.
Aetiology • Predominantly unknown in most instances. A minor percentage is observed in conjunction with hereditary tumor disorders, such as MEN. 1. Genetics • The two most well-characterized genetic anomalies are MEN 1 and gsp, a mutation in the G-protein alpha subunit.
Presentation • Characteristics of endocrine hyperfunction vary according to the hormone produced, such as galactorrhea and sexual dysfunction in prolactin-secreting cases, acromegaly in growth hormone-secreting instances, or Cushing's syndrome in adrenocorticotropic hormone-secreting scenarios. • Large adenomas can induce mass effect symptoms, including headache, nausea, and visual field disturbances, due to compression of the optic chiasm. • Numerous people may exhibit symptoms and indications of hypopituitarism, but it is infrequently the presenting complaint.
Macroscopy: Pituitary adenomas are soft tumors that can be classified as small microadenomas (less than 10 mm in size) or bigger macroadenomas (greater than 10 mm in size). Histopathology The tumors consist of solid nests or trabeculae of neoplastic cells characterized by homogeneous round nuclei, stippled chromatin, and subtle nucleoli. Immunohistochemistry employing antibodies targeting prolactin, growth hormone, and adrenocorticotropic hormone can be utilized to ascertain the hormone synthesized by the tumor. Prognosis: Generally favorable after suitable medicinal or surgical intervention, although some patients may experience recurrences. 2 The endocrine repercussions of these tumors may, however, yield significant consequences, such as cardiovascular disease in acromegaly.
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Pathology - Thalassemias
Definition • A collection of hereditary erythrocyte diseases resulting from the insufficient synthesis of alpha or beta globin chains. Pathogenesis • Insufficient production of either A- or B-globin chains results in the accumulation of surplus unpaired chains. • This culminates in the destruction of developing erythrocytes and the premature elimination of circulating erythrocytes in the spleen. The anemia in thalassaemia results from a combination of inadequate erythropoiesis and splenic haemolysis. Beta-thalassemia major • Resulting from mutations in both B-globin genes.
• Complications arise within the initial months of life as HbF levels diminish and surplus A-chains start to build in erythrocytes. • Deteriorating anaemia results in heightened erythropoietic stimulation, causing an increase in the bone marrow volume and the reactivation of extramedullary haematopoiesis.
• Manifestations in infancy include pallor, inadequate feeding, and growth failure. • The complete blood count indicates hypochromic, microcytic anemia. • The diagnosis is corroborated by the nearly absent HbA on hemoglobin electrophoresis. Beta-thalassemia minor • Resulting from mutations in a single B-globin gene.
• Asymptomatic silent carriers exhibit moderate microcytic anemia. • An elevated HbA2 level on hemoglobin electrophoresis is a critical diagnostic indicator. Alpha-thalassemia • A-chains are essential for both adult and fetal hemoglobin. • In the fetus, surplus G-chains aggregate to form tetramers referred to as Hb Bart's. In adulthood, surplus B-chains aggregate to form tetramers referred to as HbH. The deletion of all four A-globin genes results in severe fetal anemia, widespread edema, major hepatosplenomegaly, and fetal demise between 28 and 40 weeks of gestation. The deletion of three alpha-globin genes results in HbH illness, characterized by varying degrees of persistent hemolysis. The majority of individuals experience moderate chronic hemolytic anemia throughout their lives (Hb 7–10 g/dL) accompanied by splenomegaly. Deletion of one or two alpha-globin genes results in alpha-thalassemia minor, which is typically asymptomatic. A minor case of microcytic anemia may be present.
Definition • A collection of hereditary erythrocyte diseases resulting from the insufficient synthesis of alpha or beta globin chains. Pathogenesis • Insufficient production of either A- or B-globin chains results in the accumulation of surplus unpaired chains. • This culminates in the destruction of developing erythrocytes and the premature elimination of circulating erythrocytes in the spleen. The anemia in thalassaemia results from a combination of inadequate erythropoiesis and splenic haemolysis. Beta-thalassemia major • Resulting from mutations in both B-globin genes.
• Complications arise within the initial months of life as HbF levels diminish and surplus A-chains start to build in erythrocytes. • Deteriorating anaemia results in heightened erythropoietic stimulation, causing an increase in the bone marrow volume and the reactivation of extramedullary haematopoiesis.
• Manifestations in infancy include pallor, inadequate feeding, and growth failure. • The complete blood count indicates hypochromic, microcytic anemia. • The diagnosis is corroborated by the nearly absent HbA on hemoglobin electrophoresis. Beta-thalassemia minor • Resulting from mutations in a single B-globin gene.
• Asymptomatic silent carriers exhibit moderate microcytic anemia. • An elevated HbA2 level on hemoglobin electrophoresis is a critical diagnostic indicator. Alpha-thalassemia • A-chains are essential for both adult and fetal hemoglobin. • In the fetus, surplus G-chains aggregate to form tetramers referred to as Hb Bart's. In adulthood, surplus B-chains aggregate to form tetramers referred to as HbH. The deletion of all four A-globin genes results in severe fetal anemia, widespread edema, major hepatosplenomegaly, and fetal demise between 28 and 40 weeks of gestation. The deletion of three alpha-globin genes results in HbH illness, characterized by varying degrees of persistent hemolysis. The majority of individuals experience moderate chronic hemolytic anemia throughout their lives (Hb 7–10 g/dL) accompanied by splenomegaly. Deletion of one or two alpha-globin genes results in alpha-thalassemia minor, which is typically asymptomatic. A minor case of microcytic anemia may be present.
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Pathology - Haemophilia
Definition • An inherited predisposition to bleeding resulting from a deficiency of either factor VIII (haemophilia A) or factor IX (haemophilia B).
Epidemiology Haemophilia A manifests in around 1 in 5,000 to 10,000 male births. Haemophilia B is rarer, with an incidence of about 1 in 20,000 to 30,000 male births. Genetics • The genes for factor VIII and factor IX are situated on the X chromosome, resulting in haemophilia exhibiting sex-linked inheritance, mostly affecting males. • A multitude of mutations have been documented, resulting in significant variability in the severity of haemophilia.
Pathogenesis Factors VIII and IX collectively constitute the factor VIII-factor IX complex, which activates factor X in the coagulation cascade. The absence of these factors hinders coagulation.
Presentation: • Susceptibility to bruising and significant hemorrhage following trauma or surgical procedures. • Spontaneous hemorrhages into major weight-bearing joints, including the knee, elbow, and ankles (hemarthroses), are prevalent. Coagulation assays • Both types of haemophilia result in an extended APTT and a normal PT. • The two can only be differentiated by assessing the levels of each factor.
Prognosis: The primary treatment intervention is the replacement of the deficient component. • Factor concentrates are aggregated from numerous donors and present a significantly elevated risk of infection transmission. • While rigorous donor screening and viral inactivation processes mitigate this danger, there is a trend towards the adoption of synthetic factors.
Definition • An inherited predisposition to bleeding resulting from a deficiency of either factor VIII (haemophilia A) or factor IX (haemophilia B).
Epidemiology Haemophilia A manifests in around 1 in 5,000 to 10,000 male births. Haemophilia B is rarer, with an incidence of about 1 in 20,000 to 30,000 male births. Genetics • The genes for factor VIII and factor IX are situated on the X chromosome, resulting in haemophilia exhibiting sex-linked inheritance, mostly affecting males. • A multitude of mutations have been documented, resulting in significant variability in the severity of haemophilia.
Pathogenesis Factors VIII and IX collectively constitute the factor VIII-factor IX complex, which activates factor X in the coagulation cascade. The absence of these factors hinders coagulation.
Presentation: • Susceptibility to bruising and significant hemorrhage following trauma or surgical procedures. • Spontaneous hemorrhages into major weight-bearing joints, including the knee, elbow, and ankles (hemarthroses), are prevalent. Coagulation assays • Both types of haemophilia result in an extended APTT and a normal PT. • The two can only be differentiated by assessing the levels of each factor.
Prognosis: The primary treatment intervention is the replacement of the deficient component. • Factor concentrates are aggregated from numerous donors and present a significantly elevated risk of infection transmission. • While rigorous donor screening and viral inactivation processes mitigate this danger, there is a trend towards the adoption of synthetic factors.
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Pathology - von Willebrand disease
Definition: An inherent predisposition to bleeding resulting from a quantitative or qualitative deficiency of von Willebrand factor (vWF).
Epidemiology The most prevalent hereditary coagulopathy. Type 1 (75%) constitutes a quantitative deficiency. Type 2 (20%) constitutes a qualitative flaw. Type 3, albeit less common, represents the most severe manifestation of the disease. The vWF gene resides on chromosome 12. Types 1 and 2 are transmitted in an autosomal dominant manner. Type 3 is an autosomal recessive characteristic.
Pathogenesis • von Willebrand factor (vWF) functions as an adhesion molecule, facilitating platelet attachment to subendothelial structures, and serves as a carrier for factor VIII. • Insufficient vWF activity results in a propensity for bleeding, attributable to impaired platelet adhesion and factor VIII deficiency. Presentation • The primary signs include mucosal hemorrhaging, especially epistaxis, and bleeding subsequent to trauma or surgical procedures.
Joint and muscle hemorrhages are infrequent and manifest solely in type 3 illness. Coagulation assessments • Extended activated partial thromboplastin time (APTT). • Extended hemorrhagic duration. • Normal prothrombin time (PT). Formal diagnosis necessitates the quantification of plasma von Willebrand factor (vWF) and the assessment of vWF functionality, such as through the ristocetin-induced platelet agglutination assay.
Prognosis: Most patients necessitate no further treatment. • Prophylactic therapy is used prior to surgery
Definition: An inherent predisposition to bleeding resulting from a quantitative or qualitative deficiency of von Willebrand factor (vWF).
Epidemiology The most prevalent hereditary coagulopathy. Type 1 (75%) constitutes a quantitative deficiency. Type 2 (20%) constitutes a qualitative flaw. Type 3, albeit less common, represents the most severe manifestation of the disease. The vWF gene resides on chromosome 12. Types 1 and 2 are transmitted in an autosomal dominant manner. Type 3 is an autosomal recessive characteristic.
Pathogenesis • von Willebrand factor (vWF) functions as an adhesion molecule, facilitating platelet attachment to subendothelial structures, and serves as a carrier for factor VIII. • Insufficient vWF activity results in a propensity for bleeding, attributable to impaired platelet adhesion and factor VIII deficiency. Presentation • The primary signs include mucosal hemorrhaging, especially epistaxis, and bleeding subsequent to trauma or surgical procedures.
Joint and muscle hemorrhages are infrequent and manifest solely in type 3 illness. Coagulation assessments • Extended activated partial thromboplastin time (APTT). • Extended hemorrhagic duration. • Normal prothrombin time (PT). Formal diagnosis necessitates the quantification of plasma von Willebrand factor (vWF) and the assessment of vWF functionality, such as through the ristocetin-induced platelet agglutination assay.
Prognosis: Most patients necessitate no further treatment. • Prophylactic therapy is used prior to surgery
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Pathology - Thrombotic thrombocytopenic purpura
Definition: A thrombotic microangiopathy resulting from a deficiency of ADAMTS13.
Epidemiology • Uncommon.
Aetiology
Inherited instances result from genetic mutations in ADAMTS13. Sporadic cases result from autoantibodies targeting ADAMTS13.
Pathogenesis ADAMTS13 is a metalloproteinase that cleaves von Willebrand factor (vWF) into smaller fragments.
Deficiency of ADAMTS13 results in the accumulation of ultra-high molecular weight variants of vWF, which adhere to endothelial cells and promote microthrombus development in tiny arteries.
Microthrombi induce organ dysfunction, particularly impacting the brain and kidneys. • Platelets are swiftly depleted in the microthrombi, resulting in thrombocytopenia. Red blood cells traversing the microthrombi are fragmented, resulting in anemia.
Clinical Manifestation • Pyrexia, petechial rash, and hemorrhage. • Neurological manifestations are generally pronounced. • Acute renal failure may also manifest. Hematology • Decreased hemoglobin with normal mean corpuscular volume. •
Reticulocyte count. • Platelet count. • Standard coagulation. Blood film • Anisocytosis of red blood cells. • Notable schistocytes (fragmented erythrocytes).
Prognosis: Survival rates range from 80% to 90% with prompt diagnosis and plasma exchange. Approximately one-third of individuals experience relapses within two years.
Definition: A thrombotic microangiopathy resulting from a deficiency of ADAMTS13.
Epidemiology • Uncommon.
Aetiology
Inherited instances result from genetic mutations in ADAMTS13. Sporadic cases result from autoantibodies targeting ADAMTS13.
Pathogenesis ADAMTS13 is a metalloproteinase that cleaves von Willebrand factor (vWF) into smaller fragments.
Deficiency of ADAMTS13 results in the accumulation of ultra-high molecular weight variants of vWF, which adhere to endothelial cells and promote microthrombus development in tiny arteries.
Microthrombi induce organ dysfunction, particularly impacting the brain and kidneys. • Platelets are swiftly depleted in the microthrombi, resulting in thrombocytopenia. Red blood cells traversing the microthrombi are fragmented, resulting in anemia.
Clinical Manifestation • Pyrexia, petechial rash, and hemorrhage. • Neurological manifestations are generally pronounced. • Acute renal failure may also manifest. Hematology • Decreased hemoglobin with normal mean corpuscular volume. •
Reticulocyte count. • Platelet count. • Standard coagulation. Blood film • Anisocytosis of red blood cells. • Notable schistocytes (fragmented erythrocytes).
Prognosis: Survival rates range from 80% to 90% with prompt diagnosis and plasma exchange. Approximately one-third of individuals experience relapses within two years.
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Pathology - Idiopathic thrombocytopenic purpura
Definition: A decrease in platelet count resulting from autoimmune damage.
Epidemiology • Rare, with an occurrence of 1 in 100,000. • Affects both adults and children. • Adult idiopathic thrombocytopenic purpura (ITP) exhibits a higher prevalence in women, with a ratio of 3:1. Childhood ITP exhibits a peak incidence between the ages of 2 and 4, with no gender preference.
Aetiology • The formation of platelet autoantibodies occurs for unidentified reasons.
Pathogenesis: Platelets are coated with autoantibodies and subsequently destroyed in the spleen.
Presentation • Abrupt emergence of cutaneous petechiae, epistaxis, and gingival hemorrhage. • A prior viral infection is frequently observed in pediatric cases. Complete blood count • Profound thrombocytopenia. • Normal hemoglobin and leukocyte count.
Peripheral blood smear
A combination of normal and enlarged platelets is observed. Bone marrow findings • Normal or elevated quantities of megakaryocytes.
• Typical megakaryocyte
morphology. • Typical haematopoiesis. 2 ITP is a diagnosis of exclusion when other causes of thrombocytopenia have been eliminated.
Prognosis: Childhood instances often resolve within one to two months. Adult instances are more prone to exhibit a chronic mild-to-moderate bleeding tendency.
Definition: A decrease in platelet count resulting from autoimmune damage.
Epidemiology • Rare, with an occurrence of 1 in 100,000. • Affects both adults and children. • Adult idiopathic thrombocytopenic purpura (ITP) exhibits a higher prevalence in women, with a ratio of 3:1. Childhood ITP exhibits a peak incidence between the ages of 2 and 4, with no gender preference.
Aetiology • The formation of platelet autoantibodies occurs for unidentified reasons.
Pathogenesis: Platelets are coated with autoantibodies and subsequently destroyed in the spleen.
Presentation • Abrupt emergence of cutaneous petechiae, epistaxis, and gingival hemorrhage. • A prior viral infection is frequently observed in pediatric cases. Complete blood count • Profound thrombocytopenia. • Normal hemoglobin and leukocyte count.
Peripheral blood smear
A combination of normal and enlarged platelets is observed. Bone marrow findings • Normal or elevated quantities of megakaryocytes.
• Typical megakaryocyte
morphology. • Typical haematopoiesis. 2 ITP is a diagnosis of exclusion when other causes of thrombocytopenia have been eliminated.
Prognosis: Childhood instances often resolve within one to two months. Adult instances are more prone to exhibit a chronic mild-to-moderate bleeding tendency.
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Pathology - Sickle cell disorders
Definition: A collection of hereditary red blood cell diseases resulting from HbS.
Epidemiology • Most commonly observed in individuals of African heritage and regions with current or historical malaria endemicity. The mutant gene persists as heterozygote carriers are safeguarded against the severe effects of Plasmodium falciparum malaria.
Genetics: HbS results from a point mutation in the β-globin gene located on chromosome 11, leading to a substitution of glutamic acid with valine. Heterozygotes are characterized by possessing sickle cell trait. • Homozygotes experience sickle cell disease or sickle cell anemia. Pathogenesis HbS exhibits a solubility that is 50 times inferior to that of HbA. Under low oxygen tension, HbS polymerizes into rod-like aggregates, resulting in the red blood cell adopting a sickled morphology.
Presentation • Individuals possessing sickle cell trait do not experience sickling due to the presence of normal HbA protein, which diminishes the aggregation of HbS. Patients are typically asymptomatic and exhibit normal hemoglobin levels. They are, nonetheless, genetically significant as carriers of the sickle cell allele. Individuals with sickle cell disease typically manifest symptoms at the age of two, after depleting most of their HbF, resulting in nearly all hemoglobin being HbS. Their red blood cells undergo sickling in venous blood, resulting in chronic hemolysis and episodes of vascular crises.
Complete blood count: Decreased hemoglobin, often ranging from 7 to 9 g/dL.
Peripheral blood smear • Sickle-shaped erythrocytes and their variations are present. • In adults, evidence of hyposplenism is present, shown by target cells, Howell–Jolly bodies, and Pappenheimer bodies. Diagnosis • The sickle cell solubility test serves as an effective screening method wherein a reducing agent is included into hemoglobin recovered from erythrocytes. HbS rapidly precipitates, resulting in a turbid solution. Definitive diagnosis necessitates Hb electrophoresis, which reveals a singular predominant HbS band and the absence of normal HbA.
Prognosis: Patients with sickle cell disease exhibit a markedly reduced lifetime. The median age of death is approximately 42 years for males and 48 years for women.
Complications associated with sickle cell disease Childhood: Hand-foot syndrome. • Splenic sequestration crisis. • Cerebrovascular accident. Subsequent years • Bacterial infections. • End-stage renal disease. • Priapism. • Ulceration of the lower extremities. • Pigmentary gallstones. • Avascular necrosis of the femoral head. • Pulmonary syndrome.
Definition: A collection of hereditary red blood cell diseases resulting from HbS.
Epidemiology • Most commonly observed in individuals of African heritage and regions with current or historical malaria endemicity. The mutant gene persists as heterozygote carriers are safeguarded against the severe effects of Plasmodium falciparum malaria.
Genetics: HbS results from a point mutation in the β-globin gene located on chromosome 11, leading to a substitution of glutamic acid with valine. Heterozygotes are characterized by possessing sickle cell trait. • Homozygotes experience sickle cell disease or sickle cell anemia. Pathogenesis HbS exhibits a solubility that is 50 times inferior to that of HbA. Under low oxygen tension, HbS polymerizes into rod-like aggregates, resulting in the red blood cell adopting a sickled morphology.
Presentation • Individuals possessing sickle cell trait do not experience sickling due to the presence of normal HbA protein, which diminishes the aggregation of HbS. Patients are typically asymptomatic and exhibit normal hemoglobin levels. They are, nonetheless, genetically significant as carriers of the sickle cell allele. Individuals with sickle cell disease typically manifest symptoms at the age of two, after depleting most of their HbF, resulting in nearly all hemoglobin being HbS. Their red blood cells undergo sickling in venous blood, resulting in chronic hemolysis and episodes of vascular crises.
Complete blood count: Decreased hemoglobin, often ranging from 7 to 9 g/dL.
Peripheral blood smear • Sickle-shaped erythrocytes and their variations are present. • In adults, evidence of hyposplenism is present, shown by target cells, Howell–Jolly bodies, and Pappenheimer bodies. Diagnosis • The sickle cell solubility test serves as an effective screening method wherein a reducing agent is included into hemoglobin recovered from erythrocytes. HbS rapidly precipitates, resulting in a turbid solution. Definitive diagnosis necessitates Hb electrophoresis, which reveals a singular predominant HbS band and the absence of normal HbA.
Prognosis: Patients with sickle cell disease exhibit a markedly reduced lifetime. The median age of death is approximately 42 years for males and 48 years for women.
Complications associated with sickle cell disease Childhood: Hand-foot syndrome. • Splenic sequestration crisis. • Cerebrovascular accident. Subsequent years • Bacterial infections. • End-stage renal disease. • Priapism. • Ulceration of the lower extremities. • Pigmentary gallstones. • Avascular necrosis of the femoral head. • Pulmonary syndrome.
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Pathology -Glucose-6-phosphate dehydrogenase deficiency
Definition: An hereditary hemolytic disorder resulting from a mutation in the glucose-6-phosphate dehydrogenase (G6PD) gene.
Epidemiology • Prevalent, impacting up to 10% of the global population. • There is significant geographical heterogeneity, with the highest rates observed among Africans, Asians, Italians, and Greeks. The G6PD gene is on the X chromosome. • A solitary mutant allele, consequently, induces G6PD deficiency in males.
Homozygous women are similarly impacted, although such people are rarely observed. Heterozygous women exhibit no clinical signs, as the normal allele generates sufficient enzyme activity.
Pathogenesis • G6PD is an enzyme involved in the hexose monophosphate pathway, a metabolic process essential for the production of reduced glutathione. • Reduced glutathione safeguards the red blood cell membrane from oxidative damage. • Individuals with G6PD deficiency experience episodes of hemolysis in response to oxidative stress.
Presentation • The majority of individuals remain asymptomatic with normal hemoglobin levels. • Upon exposure to oxidants, they may experience an acute hemolytic episode characterized by fever, jaundice, and dark urine resulting from hemoglobinuria. • Frequent precipitants include medications (notably anti-malarials) and fava beans, a prevalent food in Mediterranean regions. Complete blood count • decreased hemoglobin during an acute hemolytic event.
Peripheral blood smear • Alteration in erythrocyte morphology (poikilocytosis). • Erythrocytes exhibiting indentations in their peripheries, known as 'bite cells,' are distinctive. Spherocytes may also be observed. Supplementary examinations Screening assays for G6PD deficiency are available that indirectly evaluate G6PD activity by assessing the capacity of red blood cells to decrease dyes. • A definitive diagnosis necessitates direct enzyme assay.
Definition: An hereditary hemolytic disorder resulting from a mutation in the glucose-6-phosphate dehydrogenase (G6PD) gene.
Epidemiology • Prevalent, impacting up to 10% of the global population. • There is significant geographical heterogeneity, with the highest rates observed among Africans, Asians, Italians, and Greeks. The G6PD gene is on the X chromosome. • A solitary mutant allele, consequently, induces G6PD deficiency in males.
Homozygous women are similarly impacted, although such people are rarely observed. Heterozygous women exhibit no clinical signs, as the normal allele generates sufficient enzyme activity.
Pathogenesis • G6PD is an enzyme involved in the hexose monophosphate pathway, a metabolic process essential for the production of reduced glutathione. • Reduced glutathione safeguards the red blood cell membrane from oxidative damage. • Individuals with G6PD deficiency experience episodes of hemolysis in response to oxidative stress.
Presentation • The majority of individuals remain asymptomatic with normal hemoglobin levels. • Upon exposure to oxidants, they may experience an acute hemolytic episode characterized by fever, jaundice, and dark urine resulting from hemoglobinuria. • Frequent precipitants include medications (notably anti-malarials) and fava beans, a prevalent food in Mediterranean regions. Complete blood count • decreased hemoglobin during an acute hemolytic event.
Peripheral blood smear • Alteration in erythrocyte morphology (poikilocytosis). • Erythrocytes exhibiting indentations in their peripheries, known as 'bite cells,' are distinctive. Spherocytes may also be observed. Supplementary examinations Screening assays for G6PD deficiency are available that indirectly evaluate G6PD activity by assessing the capacity of red blood cells to decrease dyes. • A definitive diagnosis necessitates direct enzyme assay.
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Pathology - Anemia of chronic illness
Definition: A decrease in hemoglobin concentration associated with chronic inflammatory diseases, persistent infections, and malignancies. Epidemiology: The second most prevalent etiology of anemia.
Aetiology: Any chronic inflammatory condition, persistent infection, or neoplasm. Pathogenesis The underlying mechanisms are intricate and multifaceted. Current evidence indicates that inflammatory cytokines (e.g., IL-6) diminish the sensitivity of the marrow to erythropoietin and hinder the incorporation of iron into developing red blood cells. Consequently, there is a reduction in erythropoiesis, which is frequently ineffective.
Presentation: Fatigue and dyspnea. Complete blood count: Decreased hemoglobin, typically mild to moderate in severity. • MCV is often within the normal range, although it may be diminished.
Peripheral blood film • Red blood cells are typically normal in size, however some may be diminutive. • There is no significant variation in size or morphology. Bone marrow • The marrow typically exhibits normal cellularity. • Stainable iron is present.
Definition: A decrease in hemoglobin concentration associated with chronic inflammatory diseases, persistent infections, and malignancies. Epidemiology: The second most prevalent etiology of anemia.
Aetiology: Any chronic inflammatory condition, persistent infection, or neoplasm. Pathogenesis The underlying mechanisms are intricate and multifaceted. Current evidence indicates that inflammatory cytokines (e.g., IL-6) diminish the sensitivity of the marrow to erythropoietin and hinder the incorporation of iron into developing red blood cells. Consequently, there is a reduction in erythropoiesis, which is frequently ineffective.
Presentation: Fatigue and dyspnea. Complete blood count: Decreased hemoglobin, typically mild to moderate in severity. • MCV is often within the normal range, although it may be diminished.
Peripheral blood film • Red blood cells are typically normal in size, however some may be diminutive. • There is no significant variation in size or morphology. Bone marrow • The marrow typically exhibits normal cellularity. • Stainable iron is present.
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Pathology - Megaloblastic anemias
Definition: A decrease in hemoglobin concentration resulting from compromised erythroid DNA synthesis. The majority of instances pertain to deficiencies in either vitamin B12 or folate.
Aetiology
Autoimmune gastritis is the predominant cause of vitamin B12 deficiency. Megaloblastic anemia resulting from autoimmune gastritis is referred to as pernicious anemia. This impacts around 1 in 1000 individuals, with a feminine predisposition
. • An inadequate diet is the predominant cause of folate deficiency. The primary dietary sources of folate are leafy green vegetables. Deficiency is commonly observed in the elderly and individuals with alcohol dependence.
Pathogenesis Vitamin B12 and folate are essential for the conversion of deoxyuridine monophosphate into deoxythymidine monophosphate, a chemical necessary for DNA synthesis. • Developing red blood cells are unable of division due to insufficient DNA synthesis required for the formation of two nuclei. • Consequently, they become stalled in their maturation as giant immature cells (megaloblasts), a significant number of which perish in the bone marrow. •
Certain megaloblasts persist and differentiate into unusually large erythrocytes (macrocytes), which are subsequently discharged into the bloodstream.
Presentation • Symptoms associated with severe anemia. Mild jaundice may occur as a result of hemolysis. Vitamin B12 deficiency may lead to neurological manifestations, such as cognitive impairment, peripheral neuropathy, and subacute combined degeneration of the spinal cord.
Complete blood count • Hemoglobin concentration is generally exceedingly low, nearing only 2 g/dL. • MCV is generally elevated. Peripheral blood smear • Notable anisocytosis and poikilocytosis characterized by big oval macrocytes. Nucleated red blood cells may be observed. • Hypersegmented neutrophils. The bone marrow is hypercellular, with numerous immature big erythroid blasts (megaloblasts) and massive metamyelocytes.
Definition: A decrease in hemoglobin concentration resulting from compromised erythroid DNA synthesis. The majority of instances pertain to deficiencies in either vitamin B12 or folate.
Aetiology
Autoimmune gastritis is the predominant cause of vitamin B12 deficiency. Megaloblastic anemia resulting from autoimmune gastritis is referred to as pernicious anemia. This impacts around 1 in 1000 individuals, with a feminine predisposition
. • An inadequate diet is the predominant cause of folate deficiency. The primary dietary sources of folate are leafy green vegetables. Deficiency is commonly observed in the elderly and individuals with alcohol dependence.
Pathogenesis Vitamin B12 and folate are essential for the conversion of deoxyuridine monophosphate into deoxythymidine monophosphate, a chemical necessary for DNA synthesis. • Developing red blood cells are unable of division due to insufficient DNA synthesis required for the formation of two nuclei. • Consequently, they become stalled in their maturation as giant immature cells (megaloblasts), a significant number of which perish in the bone marrow. •
Certain megaloblasts persist and differentiate into unusually large erythrocytes (macrocytes), which are subsequently discharged into the bloodstream.
Presentation • Symptoms associated with severe anemia. Mild jaundice may occur as a result of hemolysis. Vitamin B12 deficiency may lead to neurological manifestations, such as cognitive impairment, peripheral neuropathy, and subacute combined degeneration of the spinal cord.
Complete blood count • Hemoglobin concentration is generally exceedingly low, nearing only 2 g/dL. • MCV is generally elevated. Peripheral blood smear • Notable anisocytosis and poikilocytosis characterized by big oval macrocytes. Nucleated red blood cells may be observed. • Hypersegmented neutrophils. The bone marrow is hypercellular, with numerous immature big erythroid blasts (megaloblasts) and massive metamyelocytes.
