Blastomycosis (North American Blastomycosis; Gilchrist's Disease)

A disease caused by inhalation of mold conidia (spores) of Blastomyces dermatitidis, which convert to yeasts and invade the lungs, occasionally spreading hematogenously to the skin or focal sites in other tissues.

Pulmonary blastomycosis tends to occur as individual cases of progressive infection

Symptoms are nonspecific and may include a productive or dry hacking cough, chest pain, dyspnea, fever, chills, and drenching sweats. Pleural effusion occurs occasionally. Some patients have rapidly progressive infections, and adult respiratory distress syndrome may develop.

Metastatic Tumors 

These are the most common malignant tumor of bone. Certain tumors exhibit a distinct skeletal prediliction. In adults more than 75% of skeletal metastases originate from cancers of the prostate, breast, kidney, and lung. In children, neuroblastoma, Wilms' tumor, osteosarcoma, Ewing sarcoma, and rhabdomyosarcoma are the common sources of bony metastases. Most metastases involve the axial skeleton (vertebral column, pelvis, ribs, skull, sternum), proximal femur, and humerus. The radiologic appearance of metastases can be purely osteolytic, purely osteoblastic, or mixed osteolytic-osteoblastic (majority of cases). In lytic lesions (e.g., kidney& lung), the metastatic cells secrete substances such as prostaglandins, interleukins, etc. that stimulate osteoclastic bone resorption; the tumor cells themselves do not directly resorb bone. Similarly, metastases that elicit a blastic response (e.g., prostate adenocarcinoma) do so by stimulating osteoblastic bone formation.

Iron deficiency anaemia.

Absorption of iron is affected by :
- Iron stores.
- Rate of erythropoiesis
- Acid pH aids absorption.
- Phosphates and phytates in diet impair absorption.

Causes  of deficiency:

- Increased demand:
o    Growth (in children)
o    Menstruation, Pregnancy, lactation.
- Inadequate intake and absorption.
o    Dietary deficiency.
o    Achlorhydria or gastrectomy.
o    Malabsorption states.

- Chronic blood loss
o    Peptic ulcer, bleeding piles
o    Menorrhagia.
o    Hook worm infestation

Features:
- Anaemia.
- Koilonychia.
- Atrophic glossitis and angular stomatitis.
- Dysphagia-Plummer Vinson syndrome.

Blood findings:

- Microcytjc_hypochromic cells, ring cells and pessary cells.
- Anisocytosis and poikilocytosis.
- Low MCV. MCH and MCHC.
- Serum iron is low but iron binding capacity is increased

Bone marrow

Erythroid hyperplasia with imcronormoblasts. Iron stains reveal depleted stores

Differential  diagnosis .-

- Sideroblastic anaemia which is also microcytic hypochromic  but there is excess iron in the erythroid cells .Some are pyridoxine responsive.
- (ii) Thalassaemia
 

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.

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.

Nevus
1. Commonly known as moles.
2. A benign, pigmented tumor of melanocytes, found deep within connective tissue.
3. Types of skin nevi:
a. Junctional nevus—found in the epidermis.
It is the only type of nevus that may be considered to be premalignant.
b. Compound nevus—found in both the epidermis and underlying dermis.
c. Intraepidermal nevus—found in the dermis.

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