Asplenia
Overview Definition The spleen is one of the secondary lymphatic organs central to immune function that plays a role in filtering the blood and removing old or damaged erythrocytes. Asplenia is defined as the lack of a spleen or splenic function. Etiology Epidemiology Epidemiology differs based on etiology. Pathophysiology Table: Causes of asplenia by category […]
Lymphocytes: Histology
Overview Definitions and description Lymphocytes are blood cells involved in immune response, which arise from the common lymphoid progenitor (CLP). Description: 30% of circulating WBCs Spherical and/or ovoid cells Diameter: 6–15 μm Lifespan: weeks to years Belong to a heterogeneous group of cells called leukocytes (WBCs), which are divided as follows: Granulocytes: derived from the […]
Hepatitis E Virus
Classification General Characteristics Structure Basic features Epidemiology Pathogenesis Transmission Host risk factors Pathophysiology Primary replication: Clinical Presentation Diagnosis and Management Diagnosis Management Prevention Comparison of Hepatitis Viruses Table: Comparison of hepatitis viruses A–E Differential Diagnosis References
Arrhythmogenic Right Ventricular Cardiomyopathy
Overview Definition Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disease of the heart muscle characterized by the fibrofatty replacement of the right ventricular myocardium. Epidemiology The prevalence is 1:2000 to 1:5000. In 11% of cases: sudden cardiac death (SCD) Mean age at presentation is 30 years. Men-to-women predominance is almost 3:1. Presentation is most […]
Hypertrophic and Keloid Scars
Overview Definitions A hypertrophic scar (HS) is a benign exuberant overgrowth of fibro-collagenous tissue. An HS occurs in an area of injury and grows rapidly, but does not go beyond the boundaries of the wound and tends to regress. Keloids are defined as a benign overgrowth of fibro-collagenous tissue, occurring in an area of dermal […]
Iron Deficiency Anemia
Overview Definition Anemia is defined as a hemoglobin level that is 2 standard deviations below the mean for age, sex, and ethnicity. Because iron is a fundamental building block of hemoglobin, a deficiency in this mineral can result in decreased hemoglobin production and anemia. Epidemiology Most common cause of anemia worldwide (50% of all anemias) […]
White Myeloid Cells: Histology
Overview Definition White myeloid cells are leukocytes developed from the common myeloid progenitor (CMP), which is derived from hematopoietic stem cells (HSCs) of the bone marrow. Cell description Table: Cell description of agranulocytes Type Nucleus Granules Characteristics and functions Monocyte (3%–7% of differential count) Kidney shaped (indented or C shaped) None Characteristics: Lifespan: hours to […]
Erythrocytes: Histology
Overview Definition and description Erythrocytes, also called red blood cells (RBCs), are terminally differentiated structures lacking nuclei but filled with oxygen-carrying hemoglobin. Erythrocytes are the most abundant cells in the blood. Diameter: 7.5 μm Biconcave shape: Gives RBCs high surface-to-volume ratio Sets up most hemoglobin within a short distance from the cell surface, facilitating efficient […]
Edema
Body Fluid Compartments Intracellular fluid compartment Accounts for ⅔ of total body water The total volume contained by all cells in the body Calculated by subtracting the total body water from extracellular fluid volume Extracellular fluid compartment Accounts for ⅓ of total body water Can be measured using: Inulin Mannitol Radioactive sodium Subdivided into: Interstitial […]
Genu Varum
Overview Definition Classification Epidemiology Etiology Pathophysiology Clinical Presentation History Parents describe a bow-legged appearance and abnormal gait. Physical examination Diagnosis Diagnosis is primarily based on clinical examination. It is critical to differentiate between normal physiologic genu varum and a pathologic process. Diagnostic evaluation Imaging X-ray: Management The majority of cases of genu varum are physiologic […]