⚠️ The spleen plays a key role in filtering abnormal red cells and clearing encapsulated bacteria. Loss of splenic function (asplenia or hyposplenism) → increased risk of life-threatening infection. By far the most important pathogen is Streptococcus pneumoniae. 👉 Lifelong penicillin prophylaxis is usually recommended.

🔪 Indications for Splenectomy

Trauma (most common cause in UK)
Hereditary spherocytosis
Idiopathic thrombocytopenic purpura (ITP)
Myelofibrosis with massive splenomegaly
Occasionally for staging/treatment of haematological malignancy

🧬 Medical Causes of Hyposplenism

Sickle cell disease (auto-infarction of spleen)
Coeliac disease (functional hyposplenism in 30–50%)
Inflammatory bowel disease (less common)
Blood film may mimic post-splenectomy findings

🦠 Infection Risk Post-Splenectomy

Patients are at risk of severe infection with encapsulated organisms:

Streptococcus pneumoniae (most common;>80%)
Haemophilus influenzae type B
Neisseria meningitidis
Escherichia coli
Pseudomonas aeruginosa (in some cases)
Other unusual organisms: Capnocytophaga canimorsus (dog bites), malaria, babesiosis

🩻 Blood Film Findings (Post-Splenectomy / Hyposplenism)

Howell–Jolly bodies (nuclear DNA remnants)
Pappenheimer bodies (iron granules)
Target cells 🎯 (bullseye appearance)
Acanthocytes (spiky RBCs)
Thrombocytosis (reactive, due to splenic sequestration loss)

⚠️ Risks of Hyposplenism

Overwhelming Post-Splenectomy Infection (OPSI): fulminant sepsis, most often pneumococcal.
50% mortality despite treatment.
Increased susceptibility to malaria, babesiosis (protozoa).
↑ Risk of vascular disease, thrombosis, and autoimmune disorders.

🛡 Prevention of Infection

Pneumococcal vaccine: Conjugate vaccine (PCV-13) preferred → induces T-cell dependent response. Booster with PPSV-23 at 5 years.
Meningococcal vaccines: ACWY conjugate series + MenB vaccine.
Hib vaccine: If not previously given.
Antibiotic prophylaxis: Life-long penicillin V 250 mg BD (especially children, immunocompromised, first 2 years post-splenectomy).
Education: Patients should carry “splenectomy card” or alert bracelet. Prompt antibiotics for fever.
Travel advice: Malaria prophylaxis essential for endemic areas; avoid dog bites (risk of Capnocytophaga).

📚 Organisms to Know in Hyposplenic Patients

Streptococcus pneumoniae (major pathogen)
Haemophilus influenzae type B
Neisseria meningitidis
Escherichia coli, Pseudomonas
Malaria (mosquito vector)
Babesiosis (tick-borne)
Capnocytophaga canimorsus (dog bites) 🐶

🎯 Exam Pearls

OPSI = medical emergency: treat any fever in asplenic patient with urgent IV antibiotics.
Blood film: Howell–Jolly bodies = classic clue.
Vaccination + lifelong antibiotics = cornerstones of prevention.
Hyposplenism (e.g. coeliac, sickle cell) carries same infection risk as surgical splenectomy.

🧾 Clinical Case Examples – Splenectomy & Hyposplenism

Case 1 – Fever after Splenectomy (OPSI) 🚨 A 42-year-old man had a splenectomy 3 years ago after trauma. He presents with 2 hours of rigors, 39.5 °C fever, and malaise; HR 120, BP 92/58. 👉 Concern: Overwhelming post-splenectomy infection (OPSI), classically due to encapsulated organisms (Strep. pneumoniae, Neisseria, H. influenzae). 👉 Action (don’t delay): Sepsis six. Take cultures then give immediate broad-spectrum IV antibiotics (e.g., ceftriaxone ± vancomycin per local policy) and admit. Review long-term measures: lifelong (or ≥2 yrs) phenoxymethylpenicillin prophylaxis, standby rescue antibiotics at home, and ensure vaccines are up-to-date (PCV → PPV23, MenACWY, MenB, Hib/MenC, annual flu, COVID).

Case 2 – Functional Hyposplenism in Sickle Cell 🧬 A 15-year-old with HbSS has recurrent “colds,” one pneumonia last winter, and blood film shows Howell–Jolly bodies. Family plans travel to Ghana. 👉 Issue: Functional asplenia → increased risk of severe sepsis from encapsulated bacteria and severe malaria. 👉 Action: Optimise prophylaxis (daily penicillin V; macrolide if allergic), check/boost vaccines (PCV/PPV23, MenACWY, MenB, Hib/MenC, influenza). For travel: malaria chemoprophylaxis, mosquito avoidance, prompt medical review for fever; provide an emergency antibiotic pack with clear start-rules.

Case 3 – Post-Splenectomy Thrombocytosis & Thrombosis ⚠️ A 56-year-old woman had elective splenectomy for refractory ITP. Two weeks later platelets are 900×10⁹/L and she has new left calf pain. 👉 Concern: Reactive thrombocytosis post-splenectomy with risk of venous/portal thrombosis. 👉 Action: Urgent Doppler/CT venography as indicated; start/optimise VTE prophylaxis or anticoagulation if confirmed. Consider short-term low-dose aspirin if no contraindication (local policy). Continue infection prevention bundle: prophylactic antibiotics, education to seek urgent care with any fever, dental/animal-bite advice (asplenia → prompt co-amoxiclav for bites).

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Splenectomy and Hyposplenism