Reasoning GP · Algorithm · 1-page summary
Splenomegaly in adults
For: adults with a palpable or imaging-reported enlarged spleen, in hours or OOH. Not for: children — unexplained hepatosplenomegaly needs immediate specialist assessment (block 2); known cancers stay specialist-led.
Core rule: an enlarged spleen is a sign, not a diagnosis. Confirm it, send FBC + differential + blood film, and explain it; if unexplained in an adult, consider a suspected cancer pathway referral (NG12). Advise against contact sports while it is enlarged.
0Stop — call 999 now — before any history
- Sudden severe left upper quadrant or left shoulder-tip pain with known or suspected splenomegaly, EBV or recent trauma — especially syncope, tachycardia, hypotension or peritonism (rupture or infarction) → 999
- Haematemesis or melaena with portal hypertension (variceal bleed) → 999
- Asplenic patient with fever plus collapse, confusion, severe breathlessness, meningism, rapid deterioration or haemodynamic instability → 999
- While waiting: keep supine and warm, nil by mouth; IV access only if trained and equipped. Do not delay transfer for investigations or fluids.
1Triage — by the clinical picture
| Picture | Action |
|---|---|
| Fever after travel | Malaria film or RDT + infectious diseases / tropical advice → Urgent |
| B symptoms, nodes | Cytopenias, abnormal film, marked or rapidly enlarging spleen → Urgent haematology |
| Liver disease | Ascites, varices, jaundice, cytopenias (hypersplenism) → Urgent hepatology |
| Unexplained, well | FBC + film; consider suspected cancer pathway (block 2) |
2Screen — one row is enough
- Film suggests acute leukaemia (blasts) → Same-day haematology
- HLH: prolonged fever + splenomegaly + falling counts + very high ferritin → Same-day haematology
- Asplenic with fever, rigors or systemic illness → Same-day assessment + standby antibiotic per written plan.
- Lymphoma (NG12): unexplained adult splenomegaly → consider suspected cancer pathway (NHL), weighing fever, night sweats, breathlessness, pruritus, weight loss. Hepatosplenomegaly or leukaemia features → consider a very urgent FBC (≤48 h).
- CML: persistent leukocytosis, left shift, basophilia, thrombocytosis → Urgent haematology + BCR::ABL1
- Child or young person, unexplained: hepatosplenomegaly → Immediate specialist; splenomegaly → consider very urgent NHL referral (≤48 h).
3Assess — once blocks 0–2 are answered
☐ Gentle palpation from the right iliac fossa on inspiration; percuss Traube's space ☐ Nodes, liver, ascites, joints ☐ FBC + differential + film, U&E, LFTs + albumin, calcium, LDH ☐ Targeted: haemolysis screen, ferritin/B12/folate, CRP, EBV/CMV/HIV, pregnancy test ☐ USS abdomen to confirm if not already imaged
Avoid: routine first-line CT, vigorous palpation in EBV, delaying referral for imaging.
4Classify — only if the screen is negative
- EBV — young adult, sore throat, cervical nodes, atypical lymphocytes → supportive; still enlarged after recovery → urgent specialist.
- Portal hypertension — cirrhosis, ascites, varices, pancytopenia → hepatology; OGD surveillance.
- Haematological — CML (massive), CLL (lymphocytosis), myelofibrosis (teardrop cells), PV (raised Hb), haemolysis (spherocytes) → haematology.
- Travel infection — malaria, visceral leishmaniasis, schistosomiasis → infectious diseases.
- Other — Felty (RA + neutropenia), SLE, sarcoid → rheumatology; Gaucher (massive, pancytopenia, bone pain) → Gaucher service.
- Uncertain — persistent unexplained splenomegaly → urgent haematology (local pathway); name who reviews and when.
5Treat today — only these
- EBV: paracetamol or ibuprofen; no antibiotics; steroids not routine.
- Any enlarged spleen: no contact or collision sport, strenuous exertion, heavy lifting or abdominal-trauma risk while enlarged; after EBV at least 4 weeks (NICE CKS), no routine USS clearance. Give it in writing.
- Splenectomy or hyposplenism: PCV20 (every 5 years), MenACWY, MenB, annual flu, ≥2 weeks before elective surgery; risk-based daily phenoxymethylpenicillin (macrolide if allergic), standby course, emergency card — doses: NICE/SPC, BNF, local formulary.
- Specialist drugs (TKIs, JAK inhibitors, variceal beta-blockers): specialist-led; shared care only under a written protocol.
6Refer routinely
- Stable known cause (cirrhosis, hereditary spherocytosis) → GP watchful waiting; cirrhosis stays under hepatology. Alcohol → community alcohol service.
- Asplenic and travelling → pre-travel consultation well in advance; malaria chemoprophylaxis per TravelHealthPro.
7Never reassure by
- A normal or mildly abnormal WBC — it does not exclude lymphoma, CLL or myelofibrosis.
- A non-palpable spleen — it does not exclude significant enlargement.
- Spleen size or WBC — neither is a NICE referral threshold.
- A negative monospot in the first 7 days or in older adults.
- "Just glandular fever" — still give sports and rupture advice.
- A standby antibiotic — it never replaces same-day assessment in asplenia.
8Safety-net — say it, write it, document it
999 “Sudden severe pain high on the left of your tummy or in the tip of your left shoulder, feeling faint, or vomiting blood or black stools — call 999. Don't drive yourself.”
Asplenic: “Any fever, shivers or feeling unwell — take your standby antibiotic as your plan says and be seen the same day; 999 if confused, collapsing, very breathless or a stiff neck.” EBV: spleen or symptoms still present after recovery → review.
✓Safe to leave primary care only if — all five, documented
No block 0–2 row applies
Spleen confirmed; FBC + film sent
Cause named, or NG12 referral considered; owner and date set
Sport and trauma advice given in writing
Safety-net given; asplenia plan checked
Summary of the full Reasoning GP splenomegaly algorithm, which holds the detail, examination, causes and evidence. Sources: NICE NG12 (updated April 2026), NG52, NG50, PH43; BSH 2024 hyposplenism; UKHSA Green Book chapters 7 and 25. Clinical reference — follow local haematology, hepatology and immunisation pathways and check doses: NICE/SPC, BNF.