NEET MDS Lessons
General Pathology
OEDEMA
Excessive accumulation of fluid in the extra vascular compartment (intersttitial tissues). This includes ascites (peritoneal sac), hydrothorax (pleural cavity) hydropericardium (pericardial space) and anasarca (generalised)
Factors which tend to accumulate interstitial fluid are:
- Intravascular hydrostatic pressure
- Interstitial osmotic pressure.
- Defective lymphatic drainage.
- Increased capillary permeability.
Factors that draw fluid into circulation are:
- Tissue hydrostatic-pressure (tissue tension).
- Plasma osmotic pressure,
Oedema fluid can be of 2 types:
A. Exudate.
It is formed due to increased capillary permeability as in inflammation.
B. Transudate
Caused by alterations of hydrostatic and osmotic pressures.
|
Exudate |
Transudate |
Specific Gravity |
>1.018 |
1.012 |
Protein Content |
High |
Low |
Nature of Protein |
All Plasma Protein |
Albumin mostly |
Spontaneous Clotting |
High(Inflammatory Cells) |
Low |
Local Oedema
1. Inflammatory oedema. Mechanisms are.
- Increased capillary permeability.
- Increased vascular hydrostatic pressure.
- Increased tissue osmotic pressure.
2.Hypersensitivity reactions especially types I and III
3. Venous obstruction :
- Thrombosis.
- Pressure from outside as in pregnancy, tourniquets.
4. Lymphatic obstruction:
- Elephantiasis in fillariasis
- Malignancies (Peau de orange in breast cancer).
Generalized Oedema
1. Cardiac oedema
Factors :Venous pressure increased.
2. Renal oedema
- Acute glomerulonephritis
- Nephrotic syndrome
3. Nutritional (hypoproteinaemic) oedema. it is seen in
- Starvation and Kwashiorkor
- Protein losing enteropathy
4. Hepatic oedema (predominantly ascites)
Factors:
- Fall in plasma protein synthesis
- Raised regional lymphatic and portal venous pressure
5. Oedema due to adrenal corticoids
As in Cushing's Syndrome
Pulmonary oedema
- Left heart failure and mitral stenosis.
- Rapid flv infusion specially in a patient of heart failure.
HERPES ZOSTER (Shingles)
An infection with varicella-zoster virus primarily involving the dorsal root ganglia and characterized by vesicular eruption and neuralgic pain in the dermatome of the affected root ganglia.
caused by varicella-zoster virus
Symptoms and Signs
Pain along the site of the future eruption usually precedes the rash by 2 to 3 days. Characteristic crops of vesicles on an erythematous base then appear, following the cutaneous distribution of one or more adjacent dermatomes
Eruptions occur most often in the thoracic or lumbar region and are unilateral. Lesions usually continue to form for about 3 to 5 days
Geniculate zoster (Ramsay Hunt's syndrome) results from involvement of the geniculate ganglion. Pain in the ear and facial paralysis occur on the involved side. A vesicular eruption occurs in the external auditory canal, and taste may be lost in the anterior two thirds of the tongue
Pathology
The branch of medicine dealing with the essential nature of disease, especially changes in body tissues aorgans that cause or are caused by disease. Pathology is the structural and functional manifestations of disease.
Anatomic pathology the anatomical study of changes in the function, structure, or appearance of organs or tissues,including postmortem examinations and the study of biopsy specimens.
Cellular pathology - Cytopathology is a diagnostic technique that examines cells from various body sites to determine the cause or the nature of disease.
Clinical pathology pathology applied to the solution of clinical problems, especially the use of laboratory
methods inclinical diagnosis.
Comparative pathology that which considers human disease processes in comparison with those of other
animals.
Oral pathology that treating of conditions causing or resulting from morbid anatomic or functional changes in thestructures of the mouth.
Surgical pathology the pathology of disease processes that are surgically accessible for diagnosis or treatment.
Wilson’s disease
Caused by a decrease in ceruloplasmin, a serum protein that binds copper, resulting in metastatic copper deposits.
Common organs affected include:
(1) Liver, leading to cirrhosis.
(2) Basal ganglia.
(3) Cornea, where Kayser-Fleischer rings (greenish rings around the cornea) are observed.
Cor pulmonale
a failure of the right side of the heart. It is caused by prolonged high blood pressure in the right ventricle of the heart, which in turn is most often caused by pulmonary hypertension - prolonged high blood pressure in the arteries or veins of the lungs. People with heart disease, or lung diseases such as cystic fibrosis, are at greater risk.
Pathophysiology
There are several mechanisms leading to pulmonary hypertension and cor pulmonale:
Pulmonary vasoconstriction
Anatomic changes in vascularisation
Increased blood viscosity
Primary pulmonary hypertension
Causes
Acute:
• Massive pulmonary embolization
• Exacerbation of chronic cor pulmonale
Chronic:
• COPD
• Loss of lung tissue following trauma or surgery
Verruca vulgaris
1. Commonly known as warts.
2. Caused by the human papillomavirus (HPV).
3. Warts can be seen on skin or as an oral lesion (vermilion border, oral mucosa, or tongue).
4. Transmitted by contact or autoinoculation.
5. A benign lesion.
Psoriasis is a chronic disorder characterized by scaly, erythematous plaques, which histologically are secondary to epidermal proliferation.
- genetic factors (HLA relationships), environmental (physical injury, infection, drugs, photosensitivity), abnormal cellular proliferation (deregulation of epidermal proliferation) and microcirculatory changes in the papillary dermis (diapedesis of neutrophils into the epidermis) are all interrelated.
- the plaques of psoriasis are characteristically well-demarcated pink or salmon colored lesions covered by a loosely-adherent silver-white scale which, when picked off, reveals pinpoint bleeding sites (Auspitz sign).
- the nail changes in psoriasis include pitting, dimpling, thickening and crumbling with a yellowish-brown discoloration of the nail plate.
- the characteristic histologic features of psoriasis include:
- hyperkeratosis
- absence of the granulosa cells (present in lichen planus).
- parakeratosis
- regular, club-shaped elongation of the rete pegs (irregular and saw toothed in lichen planus) with vessel proliferation in the papillary dermis (reason for the bleeding associated with Auspitz sign).
- characteristic subcorneal collection of neutrophils called a Munro's microabscess (diapedesis from vessels in papillary dermi).
- 7% develop HLA B27 positive psoriatic arthritis