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PA19.4 | Splenomegaly — Causes & Differentiation — Part 4

Clinical Approach to Differentiating the Cause

When you face splenomegaly, three axes guide differentiation:

1. Degree of enlargement (see block 5 table): massive splenomegaly narrows the list dramatically to the six diseases above.

2. Associated features:
• Jaundice + ascites + spider naevi → portal hypertension/cirrhosis (congestive)
• Fever + geography (Bihar) → kala-azar; fever + travel to malaria-endemic area → malaria
• Lymphadenopathy + B symptoms → lymphoma/leukaemia
• Leukocytosis + basophilia → CML; leukoerythroblastic film → myelofibrosis
• Joint disease + neutropenia → Felty syndrome
• Childhood onset + thalassaemic facies → thalassaemia major
• Bone pain + neuropathy → Gaucher/Niemann-Pick

3. Key investigations:

Test	Diagnostic value
FBC + film	Malaria parasites, spherocytes, target cells, basophilia, blast cells, leukoerythroblastic picture
LFTs + coagulation	Cirrhosis/portal hypertension
BCR-ABL (FISH/PCR)	CML
Bone marrow biopsy	Infiltration, storage disorder, fibrosis, hypercellularity in hypersplenism
Splenic aspirate / rK39 antigen test	Kala-azar
Glucocerebrosidase assay	Gaucher disease
Ultrasound abdomen + Doppler	Portal hypertension, vein thrombosis, texture

Effects of Splenectomy

Splenectomy removes filtration, immune, and reservoir functions. The haematological consequences appear on the blood film within days:

On blood film post-splenectomy:
• Howell-Jolly bodies (nuclear remnants in RBCs — normally pitted out) — pathognomonic of hyposplenic state.
• Target cells (codocytes) — excess cell membrane relative to volume after loss of pitting.
• Thrombocytosis — transient, peaks at 1–2 weeks; platelet count may reach 1,000 × 10⁹/L (thrombosis risk in reactive thrombocytosis).
• Acanthocytes (spur cells) — membrane lipid abnormality.
• Pappenheimer bodies (siderocytic granules).

Three-panel diagram showing post-splenectomy blood smear findings compared to normal blood, with associated infection risks and prevention strategies. — **Panel A:** Post-splenectomy blood smear showing Howell-Jolly bodies (nuclear remnants), target cells (bull's-eye RBCs), and thrombocytosis with annotated arrows. **Panel B:** Normal peripheral blood smear for comparison showing regular RBCs without inclusions and normal platelet count. **Panel C:** OPSI pathogens (S. pneumoniae, H. influenzae, N. meningitidis) and prevention strategies (vaccination, prophylactic antibiotics, patient education).

Infection risk — OPSI (Overwhelming Post-Splenectomy Infection):
The spleen produces IgM and opsonises encapsulated bacteria for Fc/complement-mediated phagocytosis. Loss exposes patients to:
• Streptococcus pneumoniae (commonest, most feared)
• Haemophilus influenzae type b
• Neisseria meningitidis

OPSI is a fulminant, often fatal septicaemia — mortality 50–70% once established. Prevention:
1. Vaccines: pneumococcal (PCV13/PPSV23), HiB, meningococcal — ideally 2 weeks before elective splenectomy.
2. Lifelong prophylactic phenoxymethylpenicillin (penicillin V) — especially in first 2 years and in children.
3. Patient education: fever → seek immediate medical attention.

SELF-CHECK

A 22-year-old with hereditary spherocytosis undergoes splenectomy. One week post-operatively, the blood film is reviewed. Which finding is MOST specific for the post-splenectomy state (as opposed to being present pre-operatively due to the haemolytic anaemia)?

A. Spherocytes

B. Polychromasia

C. Howell-Jolly bodies

D. Reticulocytosis

Reveal Answer

Answer: C. Howell-Jolly bodies

Howell-Jolly bodies (nuclear remnants in RBCs) are normally pitted out by the spleen. Their appearance on the film is pathognomonic of functional or anatomical asplenia — they are absent in HS before splenectomy. Spherocytes, polychromasia, and reticulocytosis are all pre-existing findings of haemolytic anaemia.