Splenomegaly

Causes of Splenomegaly
Sequestration
Proliferation
Lipid deposition disorders
Endowment
Engorgement
iNvasion

Sequestration
Haemolytic anaemia: anaemia and jaundice (not that in haemolytic anemia, splenomegaly is more prominent than hepatomegaly)
1. Congenital - Intracorpuscupar problems
(i) RBC membrane disorders
- Hereditary Spherocytosis (more in Caucasians)
- Hereditary Elliptocytosis (more in Asians, usually asymptomatic)
(ii) RBC metabolism (enzyme) disorders
- G6PD: clinical presentation: episodes of Jaundice with appropriate triggers
- Pyruvate Kinase deficiency: RBCs are dependent on glycolysis for ATP to maintan Na+/K+ ATPase.
(iii) RBC haemoglobinopathies
- Sickle Cell Anaemia
- Thalassemia (Alpha, Beta, HbE (more in Malays). Do note that Thalassemia may be divided into Thal Minor (Thal B minor, Thal a type 1), Thal intermedia (Prof Ivy ng says: more severe than Thal minor, less severe than Thal B major. An example will be HbH disease), Thal Major (Thal B)

2. Acquired
(i) immune mediated
a. Autoimmune haemolytic anaemia
- Warm antibodies: idiopathic, SLE, Evan's syndrome
- Cold Antibodies: Idiopathic cold haemagluttinin syndrome, infectious mononucleosis, mycoplasma, paroxysmal cold haemoglobinuria (Donath Landsteiner Syndrome)
b. Alloimmune haemolytic anaemia

- Rhesus Disease

- ABO hemolytic disease of the newborn

- Anti-Kell

- RhC, RhE

- Blood transfusion

c. Drug induced: high dose penicillin (Hapten and type I hypersensitivity?), Methyldopa

(ii) Non immune mediated
a. drugs e.g. Ribavirin
b. Toxins
c. Trauma: heart valves (i think this is due to a form of microangiopathic haemolytic anaemia)
d. microngiopathic haemolytic anaemia: TTP, HUS, DIVC, HELLP syndrome
e. Infection: malaria, septicaemia
f. membrane diseases?

Proliferation:
2* to
(i) INFECTION
- Bacteria: sepsis, mycoplasma, clostridium
- Viral: EBV, CMV, HIV (w/ MAC: mycobacterium avium complex)
- Parasitic: malaria, Kala-Azar (leishmaniasis ==> RARE)

(ii) INFLAMMATION
Chronic inflammation
- SLE
- Rheumatoid Arthritis
- Infective endocarditis

Lipid Deposition Disorders
Lysosomal storage diseases/Mucopolysaccharidosis
Dont need to know so much. if you want, read up on
1. Gauchers
2. Niemann Pick's
3. Hunter's syndrome
4. Hur;er's disease
5. the glycogen storage diseases

Endowment
Congenital:
- haemangioma (of the spleen)
- Harmatoma (of the spleen)
- Cyst (of the spleen)

Engorgement
(i) Extrahepatic portal vein thrombosis
(ii) Liver Cirrhosis (e.g. 2* to Biliary Atresia, alcoholic liver disease, viral hepatitis)
(iii) Congestive heart failure (results in a firm, enlarged liver)

Invasion
(i) Lymphoma (the spleen is part of your reticuloendothelial system)
(ii) Leukaemia