About This Page
This is a clinician-written, evidence-based guide aligned to the MCC Examination Objectives. It is structured by clinical presentation — the way the MCCQE tests and the way patients actually present. Management reflects current Canadian guidelines (CMA, CFPC, CPS). Always cross-reference with institutional protocols and clinical judgment.
The Bottom Line
- An enlarged spleen is a sign, not a diagnosis — confirm true enlargement, assess rupture risk, then search for infection, portal hypertension, haemolysis, haematologic malignancy, infiltrative disease or autoimmune disease.
- Start with acuity and stability before narrowing the differential.
- Use CBC with differential, smear, coagulation studies and targeted tests according to the presentation pattern.
- Escalate urgently for abnormal smear, systemic red flags, major bleeding, sepsis, thrombosis, neurologic symptoms or suspected malignancy.
- Management is cause-directed and should follow Canadian transfusion, thrombosis and cancer diagnostic pathway principles.
Approach to the Presentation
Splenomegaly is approached as a clinical presentation rather than as a single diagnosis. Begin by assessing stability, bleeding or thrombosis risk, infection/sepsis features, medication exposures, pregnancy status where relevant, and systemic red flags. Then use the pattern of the abnormality — CBC lineage, smear morphology, coagulation pathway, node distribution, spleen size, or VTE pre-test probability — to select focused investigations. For MCCQE1, the safest answer is usually the one that identifies must-not-miss disease while avoiding reflex treatment of an isolated laboratory value.
Differential Diagnosis
| diagnosis | likelihood | key features | distinguishing test |
|---|---|---|---|
| Splenic rupture or infarction | must-not-miss | Acute LUQ pain, left shoulder-tip pain, hypotension, trauma, EBV, sickle cell disease, embolic disease. | Urgent CT abdomen with contrast if stable; FAST/trauma pathway if unstable. |
| Haematologic malignancy | must-not-miss | B symptoms, lymphadenopathy, abnormal CBC, blasts or marked leukocytosis/lymphocytosis, early satiety, massive spleen. | CBC/smear, LDH, flow cytometry, BCR-ABL if CML suspected, bone marrow/lymph node biopsy. |
| Myelofibrosis / myeloproliferative neoplasm | must-not-miss | Massive splenomegaly, constitutional symptoms, anaemia, teardrop cells, leukoerythroblastosis. | CBC/smear, JAK2/CALR/MPL testing, bone marrow biopsy. |
| Portal hypertension / cirrhosis | must-not-miss | Splenomegaly with thrombocytopenia, ascites, jaundice, spider naevi, alcohol use, viral hepatitis. | Liver tests, INR/albumin, hepatitis serology, abdominal ultrasound with portal assessment. |
| Infectious mononucleosis | common | Fever, pharyngitis, posterior cervical lymphadenopathy, fatigue, splenomegaly; adolescents/young adults. | Heterophile antibody or EBV serology; atypical lymphocytes. |
| Haemolytic anaemia | common | Jaundice, dark urine, anaemia, reticulocytosis, gallstones; hereditary spherocytosis or autoimmune haemolysis. | Haemolysis labs, DAT, smear, family history. |
| HIV or chronic viral infection | less common | Generalized lymphadenopathy, fever, rash, weight loss, risk exposure, opportunistic infection symptoms. | HIV Ag/Ab testing, viral load if acute infection suspected. |
| Malaria or travel-related infection | less common | Fever, rigors, travel to endemic region, anaemia, thrombocytopenia, splenomegaly. | Thick and thin blood films or rapid malaria antigen testing. |
| Autoimmune disease | less common | Arthritis, rash, cytopenias; rheumatoid arthritis with neutropenia and splenomegaly in Felty syndrome. | ANA/ENA, rheumatoid markers, CBC pattern and clinical criteria. |
| Storage/infiltrative disease | rare | Very large spleen, hepatomegaly, cytopenias, bone pain, family history. | Specialist enzyme/genetic testing after common causes excluded. |
Red Flags & Key History
Symptoms
Sudden LUQ pain, shoulder-tip pain, syncope, hypotension or trauma — rupture/infarct concern
Drenching night sweats, weight loss, fever, pruritus or early satiety — lymphoma/MPN concern
Bleeding, bruising, recurrent infections or fatigue with cytopenias
Melena, hematemesis, ascites, jaundice, alcohol or hepatitis risk — portal hypertension
Travel fever, rigors, malaria exposure, TB exposure or HIV risk
Sore throat and profound fatigue in young adult — EBV pattern
Signs
Peritonism, hypotension or falling hemoglobin
Massive splenomegaly extending toward pelvis or across midline
Generalized lymphadenopathy or hepatomegaly
Stigmata of chronic liver disease and ascites
Pharyngitis and posterior cervical nodes
Approach to Investigation
First-line
CBC with differential and peripheral smearCytopenias, leukocytosis, lymphocytosis, blasts, teardrops, schistocytes, spherocytes, atypical lymphocytes.
Liver tests, bilirubin, INR, albuminEvaluate cirrhosis, portal hypertension, hepatitis, cholestasis and synthetic dysfunction.
LDH, haptoglobin, reticulocytesScreen for haemolysis and high-cell-turnover malignancy.
Abdominal ultrasoundConfirms spleen size and assesses liver, portal vein, ascites and focal splenic lesions.
Second-line
EBV/CMV/HIV/hepatitis testingBased on age, symptoms, exposures and liver/CBC pattern.
Malaria testingUrgent thick/thin films or rapid test for fever after endemic travel.
CT abdomen/pelvisIf malignancy suspected, massive spleen, focal lesion, trauma, infarct or unclear ultrasound.
Specialist
Flow cytometry, molecular tests, bone marrow biopsyFor suspected CLL/CML/acute leukemia/MPN/myelofibrosis or unexplained cytopenias.
Hepatology or haematology referralPortal hypertension, unexplained massive spleen, cytopenias, suspected malignancy or haemolysis.
Management Principles
MCC lymphadenopathy/haematologic objectives + Canadian cancer diagnostic pathway principles1
Safety and rupture prevention
- Urgent ED/trauma assessment for sudden LUQ pain, hypotension, trauma or suspected rupture.
- Avoid contact sports and high-impact activity in acute EBV splenomegaly until resolved according to local advice.
- Warn patients to seek urgent care for sudden LUQ pain, shoulder-tip pain, dizziness or collapse.
2
Treat the underlying cause
- EBV/CMV: supportive care; avoid unnecessary antibiotics and amoxicillin in suspected EBV.
- Portal hypertension: manage cirrhosis, screen/treat varices and address alcohol/hepatitis/metabolic liver disease.
- Suspected malignancy/MPN: urgent haematology referral for definitive diagnosis and treatment.
3
Hypersplenism and splenectomy considerations
- Manage cytopenias by treating underlying disease where possible.
- Splenectomy is specialist-directed and requires vaccination planning against encapsulated organisms.
Complications & Pitfalls
- Do not ignore rupture risk: EBV splenomegaly and trauma can cause life-threatening haemorrhage.
- Massive spleen narrows the differential: think CML, myelofibrosis, lymphoma, hairy cell leukemia and travel infections.
- Thrombocytopenia may be sequestration: not all low platelets are ITP.
- Splenomegaly plus abnormal smear is a haematology problem.
MCCQE1 Exam Tips
- 1Splenomegaly is a clue, not the final diagnosis.
- 2EBV pattern: fever, pharyngitis, posterior cervical nodes, atypical lymphocytes and splenomegaly.
- 3Massive splenomegaly plus very high WBC with left shift = CML pattern.
- 4Teardrop cells and leukoerythroblastosis = myelofibrosis or marrow infiltration pattern.
- 5Cirrhosis/portal hypertension often gives thrombocytopenia before other cytopenias.
- 6Sudden LUQ pain in mono = splenic rupture until proven otherwise.
practicetest your knowledge on splenomegalyApply what you've learnt with MCCQE1-style questions from the iatroX Q-Bank — haematologic & oncologic and beyond.
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