NEET MDS Lessons
General Pathology
Lupus erythematosus
- chronic discoid lupus is primarily limited to the skin, while SLE can involve the skin and other systems.
- pathogenesis: light and other external agents plus deposition of DNA (planted antigen) and immune complexes in the basement membrane.
Histology:
- basal cells along the dermal-epidermal junction and hair shafts (reason for alopecia) are vacuolated (liquefactive degeneration)
- thickening of lamina densa as a reaction to injury.
- immunofluorescent studies reveal a band of immunofluorescence (band test) in involved skin of chronic discoid lupus or involved/uninvolved skin of SLE.
- lymphocytic infiltrate at the dermal-epidermal junction and papillary dermis.
Chronic lymphocytic leukaemia
Commoner in middle age. It starts insidiously and often runs a long chronic course
Features:
- Lymphnode enlargement.
- Anaemia (with haemolytic element).
- Moderate splenomegaly.
- Haemorrhagic tendency in late stages.
- Infection.
Blood picture:
- Anaemia with features of haemolytic anaemia
- Total leucocytic count of 50-100,OOO/cu.mm.
- Upto 90-95% cells are lymphocytes and prolymphocytes.
- Thrombocytopenia may be seen.
Bone marrow. Lymphocytic series cells-are seen. Cells of other series are reduced,
Biochemical examination
This is a method by which the metabolic disturbances of disease are investigated by assay of various normal and abnormal compounds in the blood, urine, etc.
Monocytosis:
Causes
-Infections causing lymphocytosis, especialy tuberculosis and typhoid.
-Monocytic leukaemia.
-Some auto immune diseases.
Neutropenia: Neutropenia is an abnormally low number of neutrophils
Causes
-Typhoid, paratyphoid. .
-Viral and ricketseal infections.
-Malaria, Kala azar.
-Hypersplenism.
-Aplastic and megaloblastic anaemia.
-Marrow infiltration by malignancies, lymphomas etc.
-SLE.
Adult Respiratory Distress Syndrome
A constellation of pathologic and clinical findings initiated by diffuse injury to alveolar capillaries. This syndrome is associated with a multitude of clinical conditions which primarily damage the lung or secondarily as part of a systemic disorder.
Pathogenesis
There are many types of injuries which lead to the ultimate, common pathway, i.e., damage to the alveolar capillary unit. The initial injury most frequently affects the endothelium, less frequently the alveolar epithelium. Injury produces increased vascular permeability, edema, fibrin-exudation (hyaline membranes). Leukocytes (primarily neutrophils) plays a key role in endothelial damage.
Pathology
Heavy, red lungs showing congestion and edema. The alveoli contain fluid and are lined by hyaline membranes.
Pathophysiology
Severe respiratory insufficiency with dyspnea, cyanosis and hypoxemia refractory to oxygen therapy.
Congestive heart failure (CHF)
A. Left-sided CHF
1. May result from nearly any heart disease affecting the left ventricle (e.g., ischemic heart disease, hypertension, valvular disease).
2. Common signs and symptoms include:
a. Dyspnea (shortness of breath) exacerbated by exertion.
b. Paroxysmal nocturnal dyspnea.
c. Orthopnea.
d. Tachypnea.
e. Pleural effusion.
f. Consequences include pulmonary edema.
B. Right-sided CHF
1. The most common cause of right heart failure is left heart failure. It uncommonly occurs in isolation. Other causes include left-sided lesions (mitral stenosis), pulmonary hypertension, cardiomyopathy, and tricuspid or pulmonary valvular disease.
2. Frequently presents with peripheral edema, especially in the ankles and feet (i.e., dependent edema), enlarged liver or spleen, and distention of the neck veins.