Haemolytic anaemia 

Anemia due to increased red cell destruction (shortened life span)

Causes:

A. Corpuscular defects:

1.Membrane defects:

    - Spherocytosis.
    - Elliptocytosis.

2. Haemoglobinopathies:

    - Sickle cell anaemia.
    - Thalassaemia
    - Hb-C, HBD, HbE.
    
3. Enzyme defects .deficiency of:

    - GIucose -6 phosphate dehydrogenase (G6-PD)
    - Pyruvate kinase
    
4. Paroxysmal nocturnal haemoglobinuria.

B. Extracorpusular mechanisms 

1. Immune based:
    - Autoimmune haemolytic anaemia.
    - Haemolytic disease of new born.
    - Incompatible transfusion.
    - Drug induced haemolysis
    
2. Mechanical haemolytic anaemia.
3. Miscellaneous due to :

    - Drugs and chemicals.
    - Infections.
    - Burns.

features of haemolytic anaemia

- Evidence of increased Hb breakdown:

    -> Unconjugated hyperbilirubinaemia.
    -> Decreased plasma haptoglobin.
    -> Increased urobilinogen and stercobilinogen.
    -> Haemoglobinaemia, haemoglobinuria and haemosiderinuria if Intravascular haemolysis occurs.

- Evidence or compensatory erythroid hyperplasia:

    -> Reticulocytosis and nucleated RBC in peripheral smear.
    -> Polychromasia and macrocytes 
    -> Marrow erythroid hyperplasia
    -> Skull and other bone changes.

- Evidences of damage to RBC:

    -> Spherocytes and increased osmotic fragility
    -> Shortened life span.
    -> Fragmented RBC.
    -> Heinz bodies.
 

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,
 

Liver cirrhosis

It is a chronic, progressive diffuse process characterized by 
a. Hepatocellular necrosis           
b. Replacement by fibrosis and inflammation 
c. Hyperplasia of surviving liver cells forming regenerating nodules 
d. Vascular derangement. 

All these changes lead to loss of the normal liver architecture. 

Pathology of cirrhosis
At first the liver is enlarged or of normal size. Late in the disease, it is reduced in size and weight. 
Consistency- Firm. 
Colour -May be yellow (fatty change), red (congestion), green (cholestaisis), or pale gray (recent nodules due to absence of pigment). 

Morphologically  According to the size of these nodules, cirrhosis can be classified
    
    Micronodular (regular) cirrhosis. Small nodules 2-3 mm.in diameter.
    Macronodular (irregular) cirrhosis, nodules up to one cm in diameter.
    Mixed cirrhosis is the end stage of all types of cirrhosis
    
Microscopic picture 

1 Regenerating nodulesn- Proliferated hepatocytes arranged in thick plates and separated by blood sinusoids.  Central vein in abnormal sites (eccentric) - Hepatocytes may be small , large , or binucleated 

2- Fibrosis- It replaces damaged hepatocytes. It develops at certain sites:-
a-perivenular    b -perisinusoidal    c -pericellular  and d -in relation to portal tracts.

- It may be young, cellular and highly vascular or mature with diminished vasculsarity. It encloses groups of hepatocytes, lobules or regenerating nodules.

-As a result of hepatocyte injury and fibrosis, there’s loss of normal liver architecture including the lobular and acinar pattern as well as the liver cell plates 

3- Bile ductular proliferation:- Occurs in the fibrous septa.Focal choestaisis with feathery degeneration of hepatocytes occur at the margins of regenerating nodules. It becomes diffuse terminally.  

4- Inflammatory cells:-   Lymphocytes, macrophages and plasma cells infiltrate the fibrous septa and regenerating nodules 

Etiological classification of cirrhosis

Congenital Occurs at childhood
- congenital syphilis   
  
Hereditary diseases:- 
a. Primary idiopathic haemochromatosis      b. Thalassemia      c. Wilson’s disease      d.α 1-antitrypsin deficien e. glycogen storage disease

Acquired

-Cryptogenic (10-50%).             
-Alcoholic (30-70%)
-Post viral  (15-20%)                
- Biliary cirrhosis (16%) primary or secondary. 

Pneumoconioses—are environmentally related lung diseases that result from chronic inhalation of various substances.

1. Silicosis (stone mason’s disease) 
a. Inhalant: silica dust.
b. Associated with extensive fibrosis of the lungs.
c. Patients have a higher susceptibility to tuberculosis infections.

2. Asbestosis
a. Inhalant: asbestos fibers.
b. Associated with the presence of pleural plaques.
c. Consequences include:
(1) Mesothelioma (malignant mesothelial tumor).
(2) Bronchogenic carcinoma.

3. Anthracosis
a. Inhalant: carbon dust.
b. Usually not as harmful as silicosis or asbestosis.
c. Associated with the presence of macrophages containing carbon.

Bacterial meningitis (pyogenic, suppurative infections)

1. Common causes include:
a. Escherichia coli in newborns.
b. Haemophilus influenzae in infants and children.
c. Neisseria meningitides in young adults.
d. Streptococcus pneumoniae and Listeria monocytogenes in older adults.

Clinical findings include severe headache, irritability, fever, and a stiff neck.
a. A spinal tap shows CSF fluid that is cloudy or purulent and is under increased pressure. There is also an increase in protein and a decrease in glucose levels.
3. Can be fatal if left untreated.

Paroxysmal nocturnal haemoglobinuria (PNH).

Feature:

• Acquired RBC rnembrane defect rendering it susceptible  to complement lysis.
• Features of intravascular haemolysis.
• Blood picture of haemolysis anemais with pancytopenia.
• Ham’s acid serum test (lysis at 37COin acid pH) + ve