Free UKMLA haematology questions with explanations

A. Tumour lysis syndrome

Tumour lysis syndrome (TLS) is the correct answer: rapid lysis of highly proliferative Burkitt cells releases intracellular potassium, phosphate and nucleic acids (metabolised to urate), with hypocalcaemia from calcium phosphate precipitation, causing AKI. The biochemical pattern (hyperkalaemia, hyperphosphataemia, hyperuricaemia, hypocalcaemia) appearing here 12 hours after chemotherapy fulfils the Cairo-Bishop laboratory criteria, which run from 3 days before to 7 days after treatment.

B. Treat the pneumonia with antibiotics and supportive care

The coagulopathy of DIC is driven by the underlying condition, and the treatment that reverses it is treating that cause: here, effective antibiotics and organ support for the pneumonia. In a patient who is not bleeding and needs no procedure, abnormal numbers on their own are not an indication for blood products; transfusing plasma or platelets to normalise results adds volume, exposure and cost without evidence of benefit, and is reserved for patients who are bleeding or facing surgery. Tranexamic acid is generally avoided in DIC because fibrinolysis is protective in a microthrombotic process and inhibiting it can worsen organ ischaemia. Vitamin K does not address consumption. Non-bleeding critically ill patients still need standard thromboprophylaxis unless contraindicated.

C. Hydroxycarbamide

Older age or a previous thrombosis each defines high-risk polycythaemia vera, and this man has both. Venesection controls the haematocrit but not the thrombotic contribution of raised white cells and platelets, so cytoreduction is added. Hydroxycarbamide is the first-line agent: an oral ribonucleotide reductase inhibitor that lowers all three cell lines, is well tolerated and reduces thrombotic events. Interferon alfa is the alternative preferred in younger patients and in pregnancy. Ruxolitinib, a JAK inhibitor, is kept for disease that is resistant to or intolerant of hydroxycarbamide.

E. Ectopic erythropoietin secretion by the tumour

Renal cell carcinoma arises from proximal tubular cells and can secrete erythropoietin autonomously, so a minority of patients present with a true secondary polycythaemia, which resolves after nephrectomy. This is one of a family of paraneoplastic effects of renal cancer that also includes hypercalcaemia from parathyroid hormone-related peptide, hypertension from renin and non-metastatic hepatic dysfunction (Stauffer syndrome). The nearest alternative is polycythaemia vera driven by a JAK2 mutation, but that is a primary marrow disorder with a suppressed erythropoietin level and often a raised platelet and white cell count, whereas the tumour-driven form has a raised erythropoietin and a normal marrow. Measuring erythropoietin separates the two.

C. Extranodal marginal zone lymphoma

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (gastric MALT lymphoma) arises from chronic antigenic stimulation, most classically by H. pylori, and is recognised histologically by a small B-cell infiltrate forming characteristic lymphoepithelial lesions, with clonality confirming the diagnosis. Immunophenotype is typically CD20+, CD5-, CD10-, cyclin D1- (distinguishing it from mantle cell, follicular and CLL). H. pylori eradication is recommended as first-line therapy for localised disease, which induces remission in most cases.

B. Lymphoma

Lung cancer accounts for most cases of superior vena cava obstruction overall, but in a young never-smoker with B symptoms and an anterior mediastinal mass the most likely cause is lymphoma, particularly Hodgkin lymphoma or primary mediastinal B cell lymphoma. This distinction matters for management: lymphoma is highly chemosensitive, so tissue diagnosis before steroids or radiotherapy is the priority rather than urgent stenting. Small cell lung cancer is the tumour most likely to cause it per case, although non-small cell lung cancer accounts for more cases overall, and both occur in older heavy smokers.

D. Splenectomy

Hereditary spherocytosis results from red cell membrane protein defects (commonly ankyrin or spectrin) producing rigid spherocytes that are preferentially sequestered and destroyed in the splenic cords. Splenectomy removes the principal site of haemolysis and substantially reduces red cell destruction, transfusion need, and symptomatic anaemia, though it is typically deferred until after age 5 to 6 to mitigate post-splenectomy sepsis risk, with pre-operative pneumococcal and meningococcal (ACWY and B) vaccination per UK guidance.

D. Subcutaneous low-molecular-weight heparin at treatment dose

Treatment-dose low-molecular-weight heparin (e.g. enoxaparin 1 mg/kg twice daily or dalteparin weight-adjusted) is first-line for acute VTE in pregnancy because LMWH does not cross the placenta, has predictable pharmacokinetics, and a lower risk of heparin-induced thrombocytopenia and osteoporosis than unfractionated heparin. It should be continued throughout pregnancy and for at least 6 weeks postpartum, with a minimum total duration of 3 months.

D. International normalised ratio

Vitamin K antagonists such as warfarin inhibit hepatic synthesis of factors II, VII, IX and X, prolonging the extrinsic pathway; this is measured by the prothrombin time and standardised as the INR to allow comparability between laboratories. The INR target is 2.0–3.0 for atrial fibrillation and venous thromboembolism, and 3.0 to 3.5 for mechanical mitral valves depending on prosthesis thrombogenicity (BSH caps the target at 3.5).

D. Protamine sulfate

Protamine sulfate is a positively charged protein that binds and neutralises the negatively charged heparin molecule, rapidly reversing unfractionated heparin (and partially reversing low-molecular-weight heparin). It is given by slow intravenous injection, dosed against the amount of heparin given. The short half-life and reversibility of unfractionated heparin make it the preferred parenteral anticoagulant when rapid on-off control is needed.