🩸 Haematological emergencies can deteriorate rapidly through bleeding, thrombosis, sepsis, haemolysis, marrow failure, hyperviscosity, tumour lysis or organ ischaemia. The safest first step is ABCDE assessment, early senior/haematology advice, blood tests including FBC/film/coagulation, group and save/crossmatch where needed, and rapid treatment of reversible causes. Do not delay escalation in suspected neutropenic sepsis, TTP, DIC, acute leukaemia, sickle acute chest syndrome, severe transfusion reaction or HIT with thrombosis.

🚩 Haematology Red Flags

🔥 Fever or sepsis in a patient receiving chemotherapy or with known neutropenia.
🩸 Active major bleeding, severe bruising, mucosal bleeding or intracranial bleeding symptoms.
🟣 Non-blanching purpura, skin necrosis or gangrene.
🧠 Confusion, seizures, stroke-like symptoms or severe headache with thrombocytopenia/haemolysis.
😮‍💨 Chest pain, hypoxia or respiratory symptoms in sickle cell disease.
🧪 Blasts on blood film, very high WCC or suspected acute leukaemia.
🫘 Acute kidney injury with haemolysis, tumour lysis or myeloma.
🧊 Hyperkalaemia, hypocalcaemia, hyperphosphataemia or raised urate after chemotherapy or in high-grade malignancy.
💉 Collapse, fever, flank pain or haemoglobinuria during transfusion.
🧬 New thrombosis with platelet fall after heparin exposure.

🚑 Immediate Generic Approach

🔄 Use an ABCDE approach and call senior help early.
💉 Insert IV access; take bloods before treatment if this does not delay urgent therapy.
🧪 Initial bloods: FBC, blood film, reticulocytes, U&E, LFT, CRP, LDH, bilirubin, haptoglobin, clotting, fibrinogen, D-dimer, group and save/crossmatch where appropriate.
🦠 If sepsis suspected: cultures, lactate and prompt IV antibiotics according to local sepsis/neutropenic sepsis policy.
🩸 If bleeding: activate major haemorrhage protocol if unstable; involve haematology/transfusion lab early.
📞 Seek urgent haematology advice for TTP, DIC, HIT, acute leukaemia, severe thrombocytopenia, haemolysis, hyperviscosity or sickle complications.

📊 Haematological Emergencies

Emergency	Clinical Presentation	Investigations	Immediate Management
🩸 Disseminated Intravascular Coagulation	Bleeding from venepuncture sites, gums, GI tract or wounds. Petechiae, ecchymoses, purpura or skin necrosis. Microvascular thrombosis causing renal, respiratory or neurological dysfunction. Usually secondary to sepsis, trauma, malignancy, obstetric catastrophe or major haemorrhage.	FBC: thrombocytopenia. Prolonged PT and APTT. Raised D-dimer. Low fibrinogen, especially in severe/obstetric DIC. Blood film may show schistocytes. Check lactate, renal function and underlying cause.	Treat underlying cause urgently. Sepsis pathway and IV antibiotics if infection suspected. Blood products guided by bleeding and labs: platelets, FFP, cryoprecipitate/fibrinogen concentrate. Haematology and ICU input if severe bleeding, shock or organ failure. Heparin only in selected predominantly thrombotic DIC under specialist advice.
🧠 Thrombotic Thrombocytopenic Purpura	Thrombocytopenia plus microangiopathic haemolytic anaemia. Neurological symptoms: confusion, headache, seizures, stroke-like episodes. Fever, renal impairment, abdominal pain or cardiac involvement may occur. The classic pentad is uncommon - do not wait for all five features.	FBC: severe thrombocytopenia. Blood film: schistocytes. LDH and bilirubin raised; haptoglobin low. Coagulation usually normal or near-normal, unlike DIC. ADAMTS13 activity and inhibitor testing, but do not delay treatment. Use PLASMIC score if locally used.	Urgent haematology emergency. Plasma exchange urgently. High-dose corticosteroids. Caplacizumab and rituximab may be used under specialist guidance. Avoid platelet transfusion unless life-threatening bleeding or essential procedure. Transfer to specialist TTP centre if needed.
💉 Heparin-Induced Thrombocytopenia	Platelet fall usually 5–10 days after heparin exposure. Platelet count falls by >50% from baseline, even if still “normal”. Venous or arterial thrombosis: DVT, PE, limb ischaemia, stroke, MI. Skin necrosis or acute systemic reaction after heparin bolus may occur.	Calculate 4Ts score to estimate probability. FBC trend and blood film to exclude pseudothrombocytopenia. HIT immunoassay and functional assay according to local lab pathway. Imaging for thrombosis if symptoms/signs.	Stop all heparin immediately, including flushes and heparin-coated lines. Start non-heparin anticoagulation if intermediate/high probability and bleeding risk acceptable. Options include argatroban, fondaparinux or DOAC depending on clinical setting/local policy. Avoid platelet transfusion unless serious bleeding. Avoid starting warfarin until platelets recover and specialist plan in place.
🧪 Acute Haemolytic Transfusion Reaction	Fever, chills, rigors during or soon after transfusion. Flank/back pain, chest pain, dyspnoea, hypotension. Haemoglobinuria, dark urine or renal failure. DIC, shock and death can occur.	Stop transfusion and check patient/sample identity. Send blood bag and giving set to transfusion lab. Repeat FBC, U&E, clotting, LDH, bilirubin, haptoglobin. Direct antiglobulin test. Blood cultures if bacterial contamination possible. Urine for haemoglobin.	Stop transfusion immediately. Maintain IV access with sodium chloride 0.9% using a new giving set. Call senior clinician and transfusion lab. ABCDE, fluids, treat shock, monitor urine output. Manage DIC/AKI with haematology, renal and ICU support. Do not restart the unit.
🧬 Acute Leukaemia with Tumour Lysis Syndrome	Fatigue, pallor, fever, bruising, bleeding or infections. Bone pain, lymphadenopathy, hepatosplenomegaly. TLS: nausea, weakness, arrhythmia, seizures, AKI. Electrolyte pattern: hyperkalaemia, hyperphosphataemia, hypocalcaemia, hyperuricaemia.	FBC and blood film: blasts, anaemia, thrombocytopenia or high WCC. U&E, calcium, phosphate, urate, LDH, creatinine. Clotting/fibrinogen, especially if acute promyelocytic leukaemia suspected. ECG if hyperkalaemia/hypocalcaemia. Bone marrow and flow cytometry under haematology.	Urgent haematology referral. IV hydration and close fluid balance. Rasburicase or allopurinol according to TLS risk/local policy. Correct life-threatening electrolytes immediately. Avoid potassium/phosphate-containing fluids. Renal/ICU support if severe TLS or AKI.
🧫 Neutropenic Sepsis	Fever, rigors or sepsis in a patient receiving chemotherapy or with neutropenia. May be afebrile or subtly unwell, especially older or immunosuppressed patients. Symptoms may be minimal despite severe infection. Common sources: line infection, chest, urinary, skin, gut translocation.	FBC: neutrophils often <0.5 × 10⁹/L, or expected to fall. Blood cultures including central line cultures if present. U&E, LFT, CRP, lactate, glucose. Urine, sputum, CXR or other tests guided by symptoms. Do not delay antibiotics for investigations.	Medical emergency: give IV antibiotics urgently according to local neutropenic sepsis policy. Use sepsis pathway and assess NEWS2. IV fluids and oxygen if needed. Early haematology/oncology and microbiology advice. Consider ICU if shock, hypoxia or organ dysfunction.
🧯 Severe Thrombocytopenia / Major Bleeding	Petechiae, bruising, epistaxis, gum bleeding, menorrhagia or GI bleeding. Severe headache, neurology or trauma raises concern for intracranial bleeding. Causes include ITP, marrow failure, sepsis, DIC, drugs, TTP, leukaemia.	Repeat FBC and blood film to exclude platelet clumping. Coagulation, fibrinogen, D-dimer if DIC possible. Haemolysis screen if TTP suspected. Medication review. Bone marrow tests if marrow failure/malignancy suspected.	Assess bleeding site and severity. Platelet transfusion for major/life-threatening bleeding or procedures, guided by haematology. In ITP, use steroids/IVIG for significant bleeding under specialist advice. Avoid platelet transfusion in suspected TTP unless life-threatening bleeding. Stop antiplatelets/anticoagulants if safe and clinically appropriate.
🫁 Massive PE with Haemodynamic Instability	Sudden breathlessness, pleuritic chest pain, syncope or collapse. Hypotension, shock, hypoxia and tachycardia. Signs of right heart strain: raised JVP, loud P2, RV dysfunction. May complicate malignancy, thrombophilia, surgery or immobility.	CTPA if stable enough. Bedside echo may show RV strain in unstable patient. ECG: sinus tachycardia, RBBB or right heart strain; S1Q3T3 is uncommon. Troponin/BNP may support risk stratification.	ABCDE, oxygen, IV access and senior/ICU input. Anticoagulation if no contraindication. Systemic thrombolysis for high-risk PE with shock, unless contraindicated. Consider catheter-directed therapy or surgical embolectomy if thrombolysis contraindicated/fails.
🧬 Sickle Cell Acute Painful Episode	Severe bone, chest, abdominal or limb pain. May have fever, dehydration or anaemia. Triggers: infection, cold, dehydration, hypoxia, stress. Always look for complications, not just pain.	Pain score and observations including oxygen saturations on air. FBC, reticulocytes, U&E, LFT, CRP if clinically indicated. Group and save if severe anaemia/possible transfusion. CXR if chest symptoms, hypoxia or fever.	Offer analgesia within 30 minutes of presentation. Use patient’s individual care plan if available. Oxygen if hypoxic. Hydration: avoid both dehydration and fluid overload. Antibiotics if infection suspected. Haematology advice for severe pain, anaemia, pregnancy or complications.
🫁 Sickle Acute Chest Syndrome	Chest pain, cough, fever, wheeze or breathlessness. Hypoxia or falling oxygen saturations. New pulmonary infiltrate on CXR. Can progress rapidly to respiratory failure.	CXR. Oxygen saturations and ABG/VBG if severe. FBC, reticulocytes, U&E, LFT, CRP, blood cultures if febrile. Group and save/crossmatch.	Admit and involve haematology early. Oxygen, analgesia and careful fluids. Broad-spectrum antibiotics according to local policy. Incentive spirometry if able. Simple or exchange transfusion if severe, worsening hypoxia or specialist indication. ICU if respiratory failure or rapid deterioration.
🌊 Hyperviscosity Syndrome	Headache, dizziness, confusion or visual disturbance. Mucosal bleeding, retinal haemorrhages or papilloedema. Dyspnoea, heart failure or neurological deficits. Associated with Waldenström macroglobulinaemia, myeloma, very high WCC or polycythaemia.	FBC, blood film and plasma viscosity/serum viscosity if available. U&E, calcium, immunoglobulins, serum protein electrophoresis/free light chains. Fundoscopy for retinal changes. Assess for end-organ compromise.	Urgent haematology referral. Plasma exchange for paraprotein-related hyperviscosity. Leukapheresis may be considered in selected leukostasis cases. Hydration and treat underlying disorder. Avoid red cell transfusion before viscosity addressed unless life-threatening anaemia and specialist advice.
⚪ Hyperleucocytosis / Leukostasis	Very high WCC, usually acute leukaemia. Respiratory symptoms: dyspnoea, hypoxia, pulmonary infiltrates. Neurological symptoms: headache, confusion, visual changes, stroke-like features. May coexist with DIC or tumour lysis.	FBC and urgent blood film. U&E, calcium, phosphate, urate, LDH. Clotting/fibrinogen. CXR/CT if respiratory symptoms. Flow cytometry/bone marrow under haematology.	Urgent haematology emergency. IV hydration and TLS prophylaxis/treatment. Cytoreduction with hydroxycarbamide or urgent chemotherapy under specialist direction. Leukapheresis may be considered in selected cases. Avoid unnecessary red cell transfusion until specialist advice because it can worsen viscosity.

📊 Quick Pattern Recognition

Presentation	Think Of	Immediate Action
Thrombocytopenia + schistocytes + neuro symptoms	TTP	Urgent haematology, plasma exchange, avoid platelets unless life-threatening bleeding.
Fever after chemotherapy	Neutropenic sepsis	Immediate IV antibiotics and sepsis pathway.
Platelets fall >50% 5–10 days after heparin + thrombosis	HIT	Stop all heparin, start non-heparin anticoagulant.
Bleeding + prolonged PT/APTT + low fibrinogen	DIC	Treat cause, replace blood components if bleeding.
Chest pain/hypoxia in sickle cell disease	Acute chest syndrome	CXR, oxygen, antibiotics, haematology, consider transfusion.
Acute leukaemia + hyperkalaemia/phosphate/urate	Tumour lysis syndrome	Fluids, rasburicase/allopurinol, correct electrolytes, haematology/renal.
Headache, visual symptoms, mucosal bleeding + paraprotein	Hyperviscosity	Urgent plasma exchange.

🚫 Common Pitfalls

❌ Waiting for ADAMTS13 before treating suspected TTP.
❌ Giving platelets in TTP without life-threatening bleeding.
❌ Forgetting heparin flushes in suspected HIT.
❌ Delaying antibiotics in neutropenic sepsis while waiting for neutrophil count confirmation.
❌ Missing acute chest syndrome in sickle cell disease because pain is the dominant symptom.
❌ Transfusing red cells in hyperviscosity before discussing with haematology.
❌ Treating DIC without searching for the driver: sepsis, trauma, malignancy or obstetric cause.
❌ Restarting a transfusion after a suspected serious transfusion reaction.

📝 Exam Pearls

🧠 TTP: thrombocytopenia + MAHA + neuro signs; coagulation usually normal.
🩸 DIC: bleeding/thrombosis with prolonged PT/APTT, low fibrinogen and raised D-dimer.
💉 HIT: platelet fall is often relative, not necessarily below the normal range.
🧫 Neutropenic sepsis: antibiotics are time-critical.
🧬 TLS: hyperkalaemia, hyperphosphataemia, hypocalcaemia, hyperuricaemia.
🫁 Sickle acute chest: chest symptoms + new infiltrate = emergency.
🌊 Hyperviscosity: visual disturbance + headache + mucosal bleeding.

🧠 Teaching Note

Haematological emergencies often present through a small number of mechanisms: too few cells, too many cells, abnormal clotting, abnormal haemolysis, or infection during marrow suppression. TTP and DIC both cause thrombocytopenia and schistocytes, but DIC consumes clotting factors so PT/APTT are usually abnormal, whereas TTP is primarily platelet-rich microthrombi with relatively normal coagulation tests. In sickle cell disease, pain is important, but hypoxia, fever or chest symptoms should immediately trigger concern for acute chest syndrome. The safest habit is to look at the FBC, film, coagulation screen and clinical stability together rather than treating one number in isolation.

📚 References & UK Resources

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Haematology Emergencies: Revision ✅