Hypersplenism

Hypersplenism is excessive sequestration and destruction of circulating blood cells by an enlarged or hyperfunctioning spleen.

The characteristic clinical pattern is:

• Splenomegaly
• One or more peripheral cytopenias
• Preserved or compensatory bone marrow production

Cytopenia can involve:

• Platelets
• Red cells
• White cells

or all three cell lines.

Thrombocytopenia is often the most prominent abnormality because a normal spleen already sequesters a substantial fraction of circulating platelets.

Hypersplenism is a syndrome caused by another disorder, not a final diagnosis.

Important causes include:

Portal and congestive

• Cirrhosis
• Portal hypertension
• Portal or splenic vein thrombosis

Haematological

• Myelofibrosis
• Lymphoma
• Leukaemia
• Haemolytic anaemia
• Thalassaemia

Infectious

• Malaria
• Visceral leishmaniasis
• Chronic systemic infection

Inflammatory

• Felty syndrome

Storage disease

• Gaucher disease

The spleen can become markedly enlarged and hyperfunctional in many of these conditions.

Patients can present with consequences of the enlarged spleen:

• Left upper quadrant discomfort
• Early satiety
• Abdominal fullness
• Mechanical pressure symptoms

or consequences of cytopenia:

Thrombocytopenia

• Easy bruising
• Mucosal bleeding
• Prolonged bleeding

Anaemia

• Fatigue
• Dyspnoea
• Tachycardia

Leukopenia or neutropenia

• Recurrent bacterial infection

A patient can have substantial hypersplenism without spontaneous bleeding because platelet function and hepatic coagulation status also influence bleeding risk.

Initial evaluation should establish both the presence of cytopenia and the underlying disease.

Obtain:

• Full blood count with differential
• Peripheral blood film
• Reticulocyte count
• Liver function
• Coagulation profile
• Renal function
• Haemolysis profile where relevant
• Disease specific investigations according to clinical context

Ultrasound or CT defines splenic size and evaluates:

• Portal vein
• Splenic vein
• Liver morphology
• Lymphadenopathy
• Focal splenic lesion

Bone marrow

Bone marrow examination is not required simply to prove hypersplenism.

It is appropriate when:

• Haematological malignancy is possible
• Pancytopenia remains unexplained
• Marrow failure must be distinguished from peripheral sequestration
• Myelofibrosis is suspected

A hypocellular failing marrow argues against uncomplicated hypersplenism as the sole explanation for cytopenia.

Treat the underlying cause

This is the first priority.

Examples include:

• Portal hypertension treatment
• Antimalarial treatment when infection is confirmed
• Disease directed therapy for lymphoma or leukaemia
• Myelofibrosis directed systemic therapy
• Treatment of autoimmune disease

Do not perform splenectomy merely to normalise an abnormal full blood count when the underlying disease can be treated directly.

Blood product support

Transfuse according to clinical need, not simply to normalise laboratory values.

Platelet transfusion in severe hypersplenism can produce only transient increases because platelets are rapidly sequestered.

Reserve transfusion for:

• Clinically significant bleeding
• Major invasive procedure
• Critical thrombocytopenia with a high bleeding risk

Indications for splenectomy

Consider splenectomy when hypersplenism produces clinically important morbidity despite appropriate treatment of the underlying disorder, such as:

• Recurrent clinically significant bleeding from severe thrombocytopenia
• Severe symptomatic anaemia or transfusion dependence caused predominantly by splenic sequestration or destruction
• Recurrent infection from severe neutropenia
• Painful or mechanically disabling splenomegaly
• Recurrent splenic infarction
• Rupture risk or previous rupture

The expected haematological benefit must be weighed against lifelong:

• Infection risk
• Thrombosis risk
• Operative morbidity

Partial splenic embolisation

Partial splenic artery embolisation can reduce functional splenic mass without complete removal.

It is useful in selected patients who:

• Have major portal hypertension
• Are poor operative candidates
• Need improvement in cytopenia

Complications include:

• Severe post embolisation pain
• Fever
• Splenic infarction
• Abscess
• Portal vein thrombosis

Excessive embolisation increases major complication risk.

Portal hypertension

Splenectomy may improve hypersplenic thrombocytopenia but does not correct the underlying portal hypertensive physiology.

Patients with cirrhosis and very large spleens have an important postoperative risk of portal and splenic venous thrombosis, so surgery should not be undertaken solely for a mildly low platelet count.