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PA19.4 | Splenomegaly — Causes & Differentiation — Part 3
Category 4 — Infiltrative and Storage Splenomegaly
Abnormal material accumulates within splenic macrophages or the reticuloendothelial system, expanding the organ.
- Gaucher disease — deficiency of glucocerebrosidase → glucocerebroside accumulates in macrophages (Gaucher cells: crumpled tissue paper cytoplasm). Massive splenomegaly; bone marrow replacement; Erlenmeyer flask deformity of femur on X-ray. Enzyme replacement therapy available.
- Niemann-Pick disease — sphingomyelinase deficiency → sphingomyelin in macrophages (foam cells); moderate splenomegaly; neurological features.
- Amyloidosis — AA or AL amyloid deposits in splenic sinusoids and follicles; sago spleen (follicular deposits, gross: tapioca-like nodules) or lardaceous spleen (diffuse red pulp deposits, gross: large, waxy, pale).
- Sarcoidosis — non-caseating granulomas in white pulp; moderate splenomegaly; associated hilar lymphadenopathy.
Category 5 — Immune/Inflammatory Splenomegaly
Chronic autoimmune activation drives follicular hyperplasia and macrophage expansion.
- Rheumatoid arthritis + splenomegaly + neutropenia = Felty syndrome — a triad to memorise. IgG-coated neutrophils are sequestered in spleen; the neutropenia increases infection risk. Splenomegaly here is moderate.
- Systemic lupus erythematosus (SLE) — periarterial fibrosis ("onion-skin" lesion) of central arterioles is the pathognomonic splenic finding. Moderate splenomegaly; thrombocytopenia from anti-platelet antibodies + splenic sequestration.
- Chronic immune stimulation — e.g., chronic haemolytic states produce secondary white pulp hyperplasia in addition to red pulp work hypertrophy.
CLINICAL PEARL
Massive splenomegaly — the high-yield short list (commit to memory):
| Disease | Category | Key pointer |
|---|---|---|
| CML | Haematological (infiltration) | Leukocytosis, basophilia, BCR-ABL |
| Myelofibrosis | Haematological (EMH) | Leukoerythroblastic film, dry tap |
| Kala-azar (VL) | Infective | Bihar/Jharkhand, pancytopenia, rK39 |
| Malaria (chronic/tropical) | Infective | Haemozoin, tropical splenomegaly syndrome |
| Gaucher disease | Infiltrative/storage | Gaucher cells, Erlenmeyer flask |
| Thalassaemia major | Haematological (EMH) | Childhood onset, target cells, HbF ↑ |
Mnemonic: "Come Meet Kala-azar — Gaucher Takes priority" (CML, Myelofibrosis, Kala-azar, Malaria, Gaucher, Thalassaemia).
Hypersplenism — Definition and Mechanism
Hypersplenism is defined by four criteria (all four must be present):
1. Splenomegaly (of any cause)
2. Cytopenias — one or more cell lines reduced (anaemia, leucopenia, thrombocytopenia, or pancytopenia)
3. Hypercellular bone marrow — compensatory expansion (marrow is doing its job; the problem is peripheral destruction)
4. Correction by splenectomy
Mechanism: enlarged spleen traps and destroys blood cells at a rate exceeding marrow compensation. The specific cell line most affected depends on the underlying cause.
Distinguish from myelosuppression: in hypersplenism the marrow is hyperplastic (reactive); in myelosuppression (aplastic anaemia, chemotherapy) the marrow is hypocellular.
Common causes of hypersplenism: portal hypertension (cirrhosis, NCPF), kala-azar, Gaucher, myelofibrosis.
SELF-CHECK
Which one of the following is NOT a criterion for diagnosing hypersplenism?
A. Hypocellular bone marrow
B. Splenomegaly
C. Pancytopenia
D. Correction of cytopenias by splenectomy
Reveal Answer
Answer: A. Hypocellular bone marrow
Hypersplenism requires a HYPERCELLULAR marrow — the marrow is working harder to compensate for peripheral destruction. A hypocellular marrow points to aplastic anaemia or marrow infiltration, not hypersplenism. The other three (splenomegaly, cytopenias, correction by splenectomy) are all included in the classic four-criterion definition.