Haematology & Oncology

Hyposplenism and asplenia

Hyposplenism is reduced splenic function and asplenia is absent splenic function; both impair clearance of blood-borne organisms and make rapidly progressive infection, particularly with encapsulated bacteria, a lifelong emergency risk.

In a nutshell

Hyposplenism or asplenia increases the risk of rapidly progressive infection, especially invasive pneumococcal and meningococcal disease. Prevent it with the current UK vaccine schedule, a risk-reviewed antibiotic plan, rescue antibiotics, an alert record and travel or bite advice; any fever or systemic illness needs urgent assessment and parenteral antibiotics.

Classic presentation

A patient after splenectomy or with sickle-cell disease or coeliac disease has Howell–Jolly bodies on the blood film, or presents with fever and rapidly progressive sepsis despite initially minor symptoms.

Key points

Treat patients with absent or dysfunctional splenic function as vulnerable to overwhelming infection for life.
The major preventable threats are invasive pneumococcal and meningococcal disease; ensure current MenACWY, MenB, pneumococcal and annual influenza protection.
Extra Hib vaccination is not generally required for older hyposplenic patients, but routine childhood Hib protection should be complete.
Carry an alert card and rescue antibiotics, but never use rescue antibiotics as a reason to delay urgent medical assessment.
Fever or systemic illness is an emergency: cultures should not delay parenteral antibiotics and hospital assessment.
Use current UKHSA vaccine-product and schedule guidance because pneumococcal recommendations are transitioning to PCV20.
Animal bites, malaria exposure and babesiosis are important non-routine infection risks.

First-line investigation

Review splenectomy and underlying-disease history, examine the blood film for Howell–Jolly bodies, and arrange specialist splenic-function and cause-directed tests when functional hyposplenism is uncertain.

Management

Treat fever or systemic illness as an emergency

Arrange immediate clinical assessment, sepsis evaluation and prompt parenteral antibiotics for suspected infection; take cultures only when this will not delay treatment and admit urgently when invasive infection is possible.^1,6,3

Confirm risk and identify the cause

Review the splenic history, medications, vaccination and antibiotic records; request a blood film and investigate coeliac disease, sickle-cell disease or another associated disorder when functional hyposplenism is suspected.¹
If the diagnosis remains uncertain, discuss specialist testing such as pitted erythrocyte assessment or validated imaging rather than relying on a negative film alone.¹

Build the prevention bundle

Offer current pneumococcal, MenACWY, MenB and annual influenza protection, complete routine immunisation and use the live UKHSA schedule because pneumococcal products and intervals are changing.^1,2,4
Provide an individually reviewed antibiotic-prophylaxis plan, an emergency rescue supply, a no-functioning-spleen alert record and clear written fever advice.^1,3,7,8

Manage special exposure and post-splenectomy risk

Treat animal bites urgently, obtain travel-health advice and prescribe malaria prevention when indicated; consider tick-borne babesiosis after relevant exposure and fever or haemolysis.^1,3,5
After splenectomy or a change in immunosuppression, recheck vaccine timing, prophylaxis, rescue supply and alert documentation, and coordinate thrombosis or other non-infective complications through the relevant specialist pathway.^1,2

Review protection over the patient's lifetime

Review adherence, vaccine records, antibiotic risk–benefit, rescue-antibiotic expiry and patient understanding at routine follow-up and after any invasive infection, treatment change or new travel plan.^1,3

Exam traps

Howell–Jolly bodies are a clue to impaired splenic filtration, but their absence does not prove normal splenic immune function.
Do not teach additional Hib vaccination for older patients as a routine current UK recommendation; routine childhood Hib vaccination still applies.
Do not copy an old PPV23 schedule without checking the current UKHSA pneumococcal programme and Green Book chapter 25.
Antibiotic prophylaxis is risk- and age-dependent in current guidance; it is not accurate to say every adult must automatically take lifelong penicillin.
Rescue oral antibiotics are an emergency bridge and do not replace hospital assessment or parenteral treatment for suspected invasive infection.
A dog bite in an asplenic patient needs urgent treatment because of Capnocytophaga risk; routine penicillin prophylaxis is not sufficient cover for every bite.

Illustrations

Howell–Jolly bodies on the blood filmA blood film showing red cells containing Howell–Jolly bodies, small nuclear remnants normally removed by a functioning spleen, alongside possible target cells.Paulo Henrique Orlandi Mourao, Wikimedia Commons · CC-BY-SA-3.0

Key sources

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.