Out of the aforementioned markers, low corrected calcium is the only biochemistry result consistent with the diagnosis. All of the other markers are elevated in TLS.

TLS is a potentially fatal condition occurring as a complication during the treatment of high-grade lymphomas and leukaemias. It occurs from the simultaneous breakdown (lysis) of the tumour cells and subsequent release of chemicals into the bloodstream. This leads to hyperkalaemia and hyperphosphatemia in the presence of hyponatraemia. As phosphate precipitates calcium, the serum concentration of calcium becomes low. TLS can occur in the absence of chemotherapy, but it is usually triggered by the introduction of combination chemotherapy. Awareness of the condition is critical for its prophylactic management.

Patients at high risk of TLS should be given IV rasburicase or IV allopurinol immediately prior to and during the first few days of chemotherapy. Rasburicase is a recombinant version of urate oxidase which is an enzyme that metabolizes uric acid to allantoin. Allantoin is much more water soluble than uric acid and is therefore more easily excreted by the kidneys. Patients in lower-risk groups
should be given oral allopurinol during cycles of chemotherapy in an attempt to avoid the condition.

TLS is graded according to the Cairo-Bishop scoring system as:
1. Laboratory tumour lysis syndrome
2. Clinical tumour lysis syndrome

Bombesin is a tumour marker elevated in small cell lung carcinomas, as well as in gastric carcinomas and retinoblastomas.

Tumour markers can be divided into:
1. Monoclonal antibodies
CA 125: Ovarian cancer, primary peritoneal cancer
CA 19-9: Pancreatic cancer
CA 15-3: Breast cancer

2. Tumour specific antigens
Prostate specific antigen (PSA): Prostatic carcinoma
Alpha-feto protein (AFP): Hepatocellular carcinoma, teratoma
Carcinoembryonic antigen (CEA): Colorectal cancer
S-100: Melanoma, schwannomas
Bombesin: Small cell lung carcinoma, gastric cancer

3. Enzymes
Alkaline phosphatase (ALP)
Neuron specific enolase (NSE)

4. Hormones
Calcitonin
Antidiuretic hormone (ADH)
Human chorionic gonadotropin (hCG)

Monoclonal gammopathy of undetermined significance (MGUS)—also known as benign paraproteinemia and monoclonal gammopathy—is a pre-malignant condition not necessarily leading to its malignant form—multiple myeloma. MGUS causes increase of a serum monoclonal protein (M protein). It is not associated with ostealgia or increased risk of infections. It is often mistaken for multiple myeloma, differing from the latter in, no immunosuppression, anaemia, hypercalcaemia, lytic bone lesions, or renal failure; normal levels of beta-2 microglobulin; and stable lower levels of paraproteinemia.

Sickle cell anaemia is characterised by periods of good health with intervening crises. One of the main types is aplastic crisis characterised by a sudden fall in haemoglobin without marked reticulocytosis (3%—in this case—is just above the normal range). It usually occurs secondary to parvovirus infection.

The other main types of sickle cell crises are thrombotic crisis (painful or vaso-occlusive crisis), sequestration crisis, and haemolytic crisis. Thrombotic crisis is precipitated by infection, dehydration, alcohol, change in temperature, and deoxygenation. Sequestration crisis is characterised by acute chest syndrome (i.e. fever, dyspnoea, chest/rib pain, low pO2, and pulmonary infiltrates). In haemolytic crisis, fall in haemoglobin occurs secondary to haemolysis. It is a rare type of sickle cell crises.

Polycythaemia vera (PV) is associated with a low ESR.

PV, also known as polycythaemia rubra vera, is a myeloproliferative disorder caused by clonal proliferation of marrow stem cells leading to an increase in red cell volume, often accompanied by overproduction of neutrophils and platelets. It has peak incidence in the sixth decade of life, with typical features including hyperviscosity, pruritus, splenomegaly, haemorrhage (secondary to abnormal platelet function), and plethoric appearance. PV is associated with a low ESR.

Some management options of PV include lose-dose aspirin, venesection (first-line treatment), hydroxyurea (slightly increased risk of secondary leukaemia), and radioactive phosphorus (P-32) therapy.

In PV, thrombotic events are a significant cause of morbidity and mortality. 5–15% of the cases progress to myelofibrosis or acute myeloid leukaemia (AML). The risk of having AML is increased with chemotherapy treatment.

The patient is on stage IV according to the Ann Arbor staging system for Hodgkin lymphoma (HL). The disease has spread beyond the lymph nodes into the liver (involvement of extra lymphatic organ).

HL is a malignant proliferation of lymphocytes characterised by the presence of distinctive giant cells known as Reed-Sternberg cells. It has a bimodal age distribution being most common in the third and seventh decades of life.

Staging of HL is done according to the Ann Arbor staging system:
Stage
I: Single lymph node region (I) or one extra lymphatic site (IE)

II: Two or more lymph node regions on same side of the diaphragm (II) or local extra lymphatic extension plus one or more lymph node regions on same side of the diaphragm (IIE)

III: Lymph node regions on both sides of the diaphragm (III) which may be accompanied by local extra lymphatic extension (IIIE)

IV: Diffuse involvement of one or more extra lymphatic organs or sites

Suffix
A: No B symptoms

B: Presence of at least one of the following: unexplained weight loss >10% baseline during 6 months before staging; recurrent unexplained fever >38°C; recurrent night sweats

Lead poisoning is characterised by abdominal pain, fatigue, constipation, peripheral neuropathy (mainly motor), and blue lines on gum margin in 20% of the adult patients (very rare in children).

For diagnosis, the level of lead in blood is usually considered with levels greater than 10 mcg/dL being significant. Furthermore, the blood film shows microcytic anaemia and basophilic stippling of red blood cells. Urinary coproporphyrin is increased (urinary porphobilinogen and uroporphyrin levels are normal to slightly increased). Raised serum and urine levels of delta-aminolaevulinic acid may also be seen, making it sometimes difficult to differentiate from acute intermittent porphyria.

Monoclonal gammopathy of undetermined significance (MGUS, also known as benign paraproteinemia and monoclonal gammopathy) is a pre-malignant condition not necessarily leading to its malignant form—multiple myeloma. Around 10% of patients eventually develop myeloma over 10 years, with 50% at 15 years. MGUS causes paraproteinemia and is usually asymptomatic. It is not associated with ostealgia or increased risk of infections. It is often mistaken for multiple myeloma, differing from the latter in, no immunosuppression, normal levels of beta-2 microglobulin, and stable lower levels of paraproteinemia.

Cyclophosphamide is a cytotoxic alkylating agent that acts by causing cross-linking of DNA strands. Its major adverse effects include haemorrhagic cystitis, myelosuppression, and transitional cell carcinoma.

Cardiomyopathy is caused by doxorubicin and ototoxicity is caused by cisplatin. Alopecia and weight gain are associated with a variety of chemotherapeutic agents especially those that treat breast cancers (e.g. paclitaxel).

The cytotoxic drug bleomycin can cause bleomycin-induced pneumonitis (BIP). It usually occurs during chemotherapy but can also occur up to six months post-therapy.

Cisplatin is a cytotoxic agent that acts by causing cross-linking in DNA. Its adverse effects include ototoxicity, peripheral neuropathy, hypomagnesaemia, etc.

The causative cytotoxic agents acting through the other aforementioned MOAs are as follows:

1. Doxorubicin: Stabilizes DNA topoisomerase II complex and inhibits DNA and RNA synthesis.

2. Hydroxyurea (hydroxycarbamide): Inhibits ribonucleotide reductase, decreasing DNA synthesis.

3. Mercaptopurine (6-MP): Purine analogue that is activated by HGPRTase, decreasing purine synthesis.

4. Vincristine, vinblastine: Inhibits formation of microtubules.

Philadelphia translocation, t(9;22), is a marker of poor prognosis in acute lymphoblastic leukaemia (ALL).

ALL is the malignancy of lymphoid progenitor cells affecting B or T cell lineage. This results in the arrest of lymphoid cell maturation and proliferation of immature blast cells (lymphoblasts), leading to bone marrow and tissue infiltration.

ALL is the most common type of childhood cancers. Its peak incidence is between two to three years of age.

Acute B lymphoblastic leukaemia (B-ALL) is the most common type of ALL, involving overproduction of B-cell lymphoblasts. It is manifested by low initial WCC and is associated with a good prognosis.

Poor prognostic factors for ALL include:
1. Pre-B cell or T-cell ALL (T-ALL)
2. Philadelphia translocation, t(9;22)
3. Age <2 years or >10 years
4. Male sex
5. CNS involvement
6. High initial WBC (e.g. >100 x 10^9/L)
7. non-Caucasian

All of the aforementioned listed tumours, except brain tumours, can metastasise to lungs and produce the typical CXR picture consisting of hilar lymphadenopathy with either diffuse multinodular shadows resembling miliary disease or multiple large well-defined masses (canon balls). Occasionally, cavitation or calcification may also be seen.

Most brain tumours, however, do not metastasise. Some, derived form neural elements, do so but in these cases, intraparenchymal metastases generally precede distant haematogenous spread.

Exposure to aniline dyes is a risk factor for transitional cell carcinoma. Aniline dyes are used in dyestuffs and pigment manufacturing.

The other aforementioned options are ruled out because:
1. Feed production may expose to aflatoxin (hepatocellular carcinoma).

2. Being a military personnel may expose to mustard gas (lung cancer).

3. Rubber industry may expose to nitrosamines (oesophageal and gastric cancer).

4. Refrigerant production before 1974 may expose to vinyl chloride (hepatic angiosarcoma).

Carcinoembryonic antigen (CEA) is a known tumour marker for colorectal cancer. It is not used diagnostically, but in patients with a known diagnosis of colorectal cancer associated with raised CEA levels, it can be used to monitor disease activity and help with the early identification of disease recurrence.

Tumour markers can be divided into:
1. Monoclonal antibodies
CA 125: Ovarian cancer, primary peritoneal cancer
CA 19-9: Pancreatic cancer
CA 15-3: Breast cancer

2. Tumour specific antigens
Prostate specific antigen (PSA): Prostatic carcinoma
Alpha-feto protein (AFP): Hepatocellular carcinoma, teratoma
Carcinoembryonic antigen (CEA): Colorectal cancer
S-100: Melanoma, schwannomas
Bombesin: Small cell lung carcinoma, gastric cancer

3. Enzymes
Alkaline phosphatase (ALP)
Neuron specific enolase (NSE)

4. Hormones
Calcitonin
Antidiuretic hormone (ADH)
Human chorionic gonadotropin (hCG)

This is a picture of bone marrow failure secondary to acute myeloid leukaemia (AML). AML is the acute expansion of the myeloid stem line, which may occur as a primary disease or follow the secondary transformation of a myeloproliferative disorder. It is more common over the age of 45 and is characterized by signs and symptoms largely related to bone marrow failure such as anaemia (pallor, lethargy), frequent infections due to neutropenia (although the total leucocyte count may be very high), thrombocytopaenia (bleeding), ostealgia, and splenomegaly.

The disease has poor prognosis if:
1. Age of the patient >60 years
2. >20% blasts seen after the first course of chemotherapy
3. Chromosomal aberration with deletion of part of chromosome 5 or 7.

Acute promyelocytic leukaemia (APL) is an aggressive form of AML.

Other listed options are ruled out because:
1. Von Willebrand disease: may present with epistaxis and bleeding gums in severe cases but rarely with abnormalities on blood results.

2. Acute lymphoblastic leukaemia: mostly seen in children.

3. Lymphoma: usually presents with rubbery enlargement of lymph nodes.

4. Warfarin overdose: no bilobed large mononuclear cells seen on blood film.

The patient is asymptomatic but matches the diagnostic criteria for multiple myeloma (MM). Therefore, the underlying diagnosis of this condition is smouldering multiple myeloma (SMM). SMM is an early precursor to MM. Its treatment is typically to watch and wait.

MM is a neoplasm of the bone marrow plasma cells. Peak incidence is in patients aged 60–70 years.

Clinical features of MM include:
1. Ostealgia, osteoporosis, pathological fractures (typically vertebral), and osteolytic lesions
2. Lethargy
3. Infections
4. Hypercalcaemia
5. Renal failure
6. Other features: amyloidosis e.g. macroglossia, carpal tunnel syndrome; neuropathy; hyperviscosity

Diagnosis of MM is based on the confirmation of (a) one major criterion and one minor criterion or (b) three minor criteria in an individual who has signs or symptoms of multiple myeloma.

Major criteria:
1. >30% plasma cells on bone marrow biopsy
2. Monoclonal band of paraprotein on electrophoresis: >35g/L for IgG, 20g/L for IgA, or >1g of light chains excreted in the urine per day

Minor criteria:
1. 10–30% plasma cells on bone marrow biopsy
2. Abnormal monoclonal band but levels less than listed above
3. Lytic bone lesions observed radiographically
4. Immunosuppression

St John’s wort interferes with warfarin by increasing its breakdown and decreasing its effectiveness. This leads to the need for adjustment in the dose of warfarin and careful attention to monitoring if the patient decides to continue with the drug. Ideally, an alternative antidepressant should also be considered.

The risk factors for bladder cancer are:

1. Smoking
2. Exposure to aniline dyes in the printing and textile industry
3. Exposure to rubber manufacturing
4. Cyclophosphamides
5. Schistosomiasis.

The major delayed problem with radiotherapy is the development of secondary cancers. This risk begins to appear ten years after therapy.

Gram-staining of the blood cultures of this patient will show gram-positive cocci. Gram-negative bacilli used to be the most common pathogen isolated in neutropenic sepsis, but currently, the most common pathogens are gram-positive organisms. Staphylococcus epidermidis is the most frequent causative agent, and following this are other staphylococci and streptococci species.

Neutropenic sepsis is a relatively common complication of cancer therapy—usually chemotherapy. It most commonly occurs 7-14 days after the treatment and is usually defined as a neutrophil count of <0.5 x 10^9/L in a patient undergoing anticancer treatment and who has either a temperature higher than 38°C or has other features consistent with clinically significant sepsis. Management approach includes starting empirical antibiotic therapy (piperacillin with tazobactam—Tazocin) immediately. Following this initial treatment, the patient is usually assessed by a specialist and risk-stratified to see if outpatient treatment may be possible. However, if the patient remains febrile and unwell after 48 hours, an alternative antibiotic such as meropenem is often prescribed with or without vancomycin. If patient is still not responding after 4-6 days, then an antifungal, such as amphotericin B, is started after carrying out investigations (e.g. HRCT and Aspergillus PCR) to determine the likelihood of systemic fungal infection.

The patient has paroxysmal nocturnal haemoglobinuria (PNH) complicated by acute hepatic vein thrombosis (Budd–Chiari syndrome).

PNH is an acquired clonal disorder of haematopoietic stem cells, characterised by variable combination of intravascular haemolysis, thrombosis, and bone marrow failure. Diagnosis is made by flow cytometric evaluation of blood, which confirms the CD55 and CD59 deficiencies and deficiency of expression of other GPI-linked proteins. This test is replacing older complement-based assays such as the Ham test and sucrose lysis test.

Burkitt lymphoma is associated with the c-myc gene translocation, usually t(8;14).

Burkitt lymphoma is a rare high-grade non-Hodgkin lymphoma endemic to west Africa and the mosquito belt. It has a close association with the contraction of Epstein-Barr virus (EBV). Burkitt lymphoma often presents with symmetrical painless lymphadenopathy, systemic B symptoms (fever, sweats, and weight loss), central nervous system involvement, and bone marrow infiltration. Classically in the textbooks, the patient also develops a large jaw tumour.

Other aforementioned options are ruled out because:
1. t(9;22)—Chronic myeloid leukaemia
2. t(15;17)—Acute promyelocytic leukaemia
3. t(14;18)—Follicular Lymphoma
4. t(11;14)—Mantle Cell Lymphoma

The direct Coombs test will specifically confirm immune-mediated haemolysis occurring post-transfusion in the aforementioned case.

There are two types of Coombs test used in immunohematology and immunology:

1. Direct Coombs test—It confirms autoimmune haemolytic anaemia by detecting antibodies or complement proteins attached to the surface of red blood cells.

2. Indirect Coombs test—It is used in prenatal testing of pregnant women and in testing prior to a blood transfusion. It detects antibodies floating freely in the blood, against foreign red blood cells.

The patient has paroxysmal nocturnal haemoglobinuria (PNH). The classic sign of the disease is red discolouration of the urine due to the presence of haemoglobin and hemosiderin from the breakdown of red blood cells. As the urine is more concentrated in the morning, this is when the colour is most pronounced.

PNH is an acquired clonal disorder of haematopoietic stem cells, characterised by variable combinations of intravascular haemolysis, thrombosis, and bone marrow failure. Diagnosis is made by flow cytometric evaluation of blood, which confirms the CD55 and CD59 deficiencies and deficiency of expression of other GPI-linked proteins. This test is replacing older complement-based assays such as the Ham test and sucrose lysis test.

Diagnosis of multiple myeloma (MM) is based on the confirmation of (a) one major criterion and one minor criterion or (b) three minor criteria in an individual who has signs or symptoms of multiple myeloma.

Major criteria:
1. >30% plasma cells on bone marrow biopsy
2. Monoclonal band of paraprotein on electrophoresis: >35g/L for IgG, 20g/L for IgA, or >1g of light chains excreted in the urine per day

Minor criteria:
1. 10–30% plasma cells on bone marrow biopsy
2. Abnormal monoclonal band but levels less than listed above
3. Lytic bone lesions observed radiographically
4. Immunosuppression

The most common type of Hodgkin’s lymphoma (HL) is nodular sclerosing.

HL is a malignant proliferation of lymphocytes characterised by the presence of distinctive giant cells known as Reed-Sternberg cells. It has a bimodal age distribution being most common in the third and seventh decades of life.

According to the histological classification, there are four types of HL:

1. Nodular sclerosing: most common (around 70%), more common in women, associated with lacunar cells, good prognosis

2. Mixed cellularity: Around 20%, associated with a large number of Reed-Sternberg cells, good prognosis

3. Lymphocyte-predominant: Around 5%, Reed-Sternberg cells with nuclei surrounded by a clear space found, best prognosis

4. Lymphocyte-depleted: rare, worst prognosis

Mycoplasma infection causes cold autoimmune haemolytic anaemia (AIHA). The rest of the aforementioned options cause warm AIHA.

AIHA may be divided into ‘warm’ and ‘cold’ types, according to the temperature at which the antibodies best cause haemolysis. It is most commonly idiopathic but may be secondary to a lymphoproliferative disorder, infection, or drugs.

1. Warm AIHA:
In warm AIHA, the antibody (usually IgG) causes haemolysis best at body temperature and tends to occur in extravascular sites, for example, spleen. Management options include steroids, immunosuppression, and splenectomy. It is caused by autoimmune diseases such as SLE (rarely causes mixed-type AIHA), cancers such as lymphomas and CLL, and drugs such as methyldopa.

2. Cold AIHA:
The antibody in cold AIHA is usually IgM and causes haemolysis best at 4°C and occurs more commonly intravascularly. Features may include symptoms of Raynaud’s disease and acrocyanosis. Patients do not respond well to steroids. Cold AIHA is caused by cancers such as lymphomas, and infections such as mycoplasma and EBV.

Prostate cancer is the most common primary tumour that metastasises to the bone.

Most common tumours causing bone metastasis (in descending order):
1. Prostate (32%)
2. Breast (22%)
3. Kidneys (16%)
4. Lungs
5. Thyroid

Most common sites of bone metastasis (in descending order):
1. Spine
2. Pelvis
3. Ribs
4. Skull
5. Long bones

The principal mechanism of action of taxanes (e.g. docetaxel) is the prevention of microtubule disassembly.

Other aforementioned options are ruled out because:

1. Doxorubicin: stabilizes DNA topoisomerase II complex and inhibits DNA and RNA synthesis.

2. Vincristine, vinblastine: inhibits formation of microtubules.

3. Cisplatin: causes cross-linking in DNA.