Haematological Emergencies Flashcards
What is the SBAR tool?
o Situation – state the problem or question
o Background – provide key information
o Assessment – what action have you taken
o Recommendation – what action needs to be taken next
What is thrombotic thrombocytopenic purpura (TTP)?
Pathogenesis?
Type of microangiopathic haemolytic anaemia (MAHA)
o Severely reduced activity of ADAMTS13 enzyme
o Leads to accumulation of ultra-large von Willebrand factor molecules resulting in intravascular thrombosis and shearing of red cells
What is a microangiopathic haemolytic anaemia (MAHA)?
Anaemia that results from physical damage to red cells (RBC fragmentation) following the occlusion of arterioles and capillaries (small vessels) as a result of fibrin deposition or platelet aggregation
Cause of TTP?
o Usually acquired due to autoantibody to ADAMTS13
o In rare cases inherited
Symptoms of TTP?
o Confusion, seizures, strokes
o Fever
o Renal failure
o Organ ischaemia due to thrombosis in small blood vessels
o Purplish bruising (purpura) on skin or mucous membranes
Clinical findings of TTP?
- Low platelets
- Low RBCs
- Damaged RBCs
Blood film results in TTP?
Polychromasia and fragmented red cells
What is polychromasia?
A disorder where there is an abnormally high number of immature red blood cells found in the bloodstream as a result of being prematurely released from the bone marrow during blood formation.
Investigatinons for TTP?
o Blood film
o Haemolysis screen
o ADAMTS13 levels
o Troponin (to tell you level of cardiac damage)
o Hep B/C and HIV serology
o Pregnancy test in women of childbearing potential
Risk factors for TTP?
- Pregnancy
- Cancer
- HIV
- lupus
- infections
- Some medical procedures, such as surgery and blood and marrow stem cell
Why should platelets NOT be transfused in TTP?
feeds thrombosis and can worsen condition
What immediately should be done in the treatment of TTP?
Urgent plasma exchange –> Remove antibody & replace ADAMTS13
3 steps of treatment of TTP?
- Urgent plasma exchange
- Suppress antibody production
- Prevent thrombosis
How can antibody production be suppressed in TTP?
- Steroids
2. Rituximab
What is Rituximab?
a monoclonal antibody that targets CD20 protein on surface of B cells
Why does Rituximab not reduce plasma levels?
Rituximab does not reduce plasma cells, which secrete antibodies, because they do not express CD20
How and when should thrombosis be prevented in TTP?
Aspirin and LMWH when platelets >50
A new drug used to treat TTP is Caplacizumab. Mechanism?
monoclonal antibody that binds to vWf and inhibits platelet adhesion
What are the 2 main types of acute leukaemia?
- Myeloid
2. Lymphoid
How can acute leukaemia diagnosis be confirmed?
Bone marrow biopsy
Symptoms of acute leukaemia?
pale skin.
feeling tired and breathless.
repeated infections over a short time.
unusual and frequent bleeding, such as bleeding gums or nosebleeds.
high temperature.
night sweats.
bone and joint pain.
easily bruised skin.
What should patients with severe neutropenia be monitored for?
Sepsis - give broad-spectrum antibiotics if any small sign of infection
What is multiple myeloma?
A haematopoietic disorder which is characterised by accumulation of monoclonal plasma cells, the most common localisation being the spine
What spinal problem can result from multiple myeloma?
Spinal cord compression (SCC)
What are the 2 key tests that make up a myeloma screen?
- serum protein electrophoresis
2. serum free light chains
What test should be done if SCC suspected?
MRI
Symptoms/signs of SCC?
Pain, motor defects, sensory deficits; and bowel and bladder dysfunction
High calcium levels
Treatment of SCC?
o Steroids to reduce tumour size e.g. Dexamethasone
o Radiotherapy if largely soft tissue compressing the spine
o Occasionally surgery needed
What can cause a superior vena cava obstruction (SVCO)?
Many possible causes both malignant (e.g. lymphoma) and non-malignant (e.g. thrombosis)
Symptoms of SVCO?
Pressure from mass obstructs the superior vena cava causing: o Face and upper limb swelling o Breathlessness and sweating o Headaches o Distended chest wall veins • Plethora
What should be given to a patient with SVCO while the cause is investigated?
Steroids to reduce swelling
What is tumour lysis syndrome?
Rapid breakdown of tumour cells, releasing their contents into the bloodstream
Levels of;
a) potassium
b) phosphate
c) uric acid
in tumour lysis syndrome?
Effects of this?
a) high blood levels
b) high blood levels
(as release of intracellular potassium and phosphate into circulation –> this is TOXIC)
c) elevated –> uric acid is insoluble and can form urate crystals particularly in kidneys
How and why can tumour lysis syndrome affect;
a) kidneys
b) heart
c) neurological
d) calcium levels
a) Renal failure due to:
- Urate crystals
- Deposition of calcium phosphate crystals in the kidney parenchyma
b) Cardiac arrhythmia due to hyperkalaemia
c) Confusion and seizures (often require ICU)
d) Hypocalcaemia
Why can tumour lysis syndrome lead to hypocalcaemia?
Because of the hyperphosphatemia, calcium precipitates with excess phosphate to form calcium phosphate, leading to hypocalcemia.
Effects of calcium precipitating with excess phosphate to form calcium phosphate in tumour lysis syndrome?
Deposition of calcium phosphate crystals in the kidney parenchyma –> renal failure
Treatment of tumour lysis syndrome?
o IV fluids (hydration)
o Dialysis if needed (due to renal impairment)
o Rasburicase is an enzyme which converts uric acid to more soluble form
o Medical treatment for high potassium
Mechanism of Rasburicase?
an enzyme which converts uric acid to more soluble form
What is neutropenic sepsis?
Neutropenic sepsis is a potentially life-threatening complication of neutropenia. It is defined as a temperature of greater than 38°C or any symptoms and/or signs of sepsis, in a person with an absolute neutrophil count of 0.5 x 109/L or lower.
Why can the source of infection not always be obvious in neutropenic sepsis?
- Without neutrophils you cannot easily make pus
- Without pus you cannot see many changes that you would normally associate with infection e.g. consolidation on a chest x-ray
In neutropenic sepsis, why should you NOT perform rectal or vaginal examinations?
can encourage bacteria to pass from the GI/GU tract to circulation
In neutropenic sepsis, why should you NOT perform catheter insertion or ABG?
as platelet count is also normally low so this can trigger bleeding
In neutropenic sepsis, can you take a venous blood gas?
Yes
Investigations in neutropenic sepsis?
Look for source of infection:
o Blood cultures (peripheral +/- line) and urine cultures
o Routine bloods including FBC, renal and liver function and CRP
o Chest X-ray
o VBG to check lactate levels and look for any acidosis
o COVID swabs
o Consider respiratory viral swabs, stool samples, swabs of skin lesions, atypical pneumonia screening, sputum cultures
Immediate treatment of neutropenic sepsis?
Antibiotics
What is CAR-T therapy?
o Genetically modifying patient’s own T cells
o Activates T cells and redirects them towards cancer cells
What is CAR-T therapy used to treat?
- Currently used to treat certain types of lymphoma and leukaemia
- Being explored in many different types of cancer and in autoimmune diseases
2 major possible side effects of CAR-T therapy?
o Cytokine release syndrome
o Immune cell related neurological toxicity
What is cytokine release syndrome?
Exaggerated physiological response to immune therapies resulting in release of inflammatory cytokines, producing a sepsis like presentation
What is cytokine release syndrome particularly seen following?
o CAR-T therapy (genetically modified T cells)
o Some types of antibody therapy e.g. Blinatumumab
o Some types of stem cell transplant (Haploidentical)
Symptoms of cytokine release syndrome?
fever, nausea, chills, hypotension, hypoxia, tachycardia, asthenia, headache, rash, scratchy throat, and dyspnea
CRS score based on these features
Treatment of cytokine release syndrome?
o Broad-spectrum antibiotics – at risk of neutropenic sepsis
o IV fluid and oxygen
o May require ITU support
o Tocilizumab – blocks IL6 to reduce inflammatory response
What is Tocilizumab? Mechanism?
Blocks IL6 to reduce inflammatory response.
Used in:
- Rheumatoid arthritis
- Cytokine release syndrome
- COVID (new)
What is immune cell related neurological toxicity?
- Often occurs at the same time as or just after cytokine release syndrome
- Wide range of neurological symptoms including confusion, seizure and coma
Treatment of immune cell related neurological toxicity?
May require treatment with steroids to suppress the immune cells
Neurological assessment in immune cell related neurological toxicity?
using the ICE and ICANS scores
Questions to ask yourself in unexplained anaemia?
- How symptomatic is the patient?
- Are they bleeding?
- Are they jaundiced?; May suggest they have developed haemolysis. As RBCs break down in circulation, bilirubin levels rise
- Is the rest of the full blood count normal?
- Do they have a known condition that causes anaemia?
Questions to ask yourself in bleeding?
- How unwell is the patient?; blood pressure, heart rate, conscious level
- Do I need to activate the major haemorrhage protocol?
- Do they have any risk factors for bleeding?
- Are they on any anti-coagulants that need reversing?
Questions to ask yourself in patient with thrombosis?
- Are they haemodynamically stable?
- Do they have risk factors for thrombosis? E.g. cancer, pregnancy, bed-bound
- Are there any risks to giving anti-coagulation? E.g. severe bleeding tendency (haemophilia), large GI bleed, major trauma
Questions to ask yourself in patient with low platelets?
- Are they bleeding?
- Is the rest of the full blood count normal?
- Is the clotting screen normal?
- Are they unwell for another reason? E.g. serious infection, post-operation, long course of antibiotics
- Are they on any drugs which could be responsible? E.g. IV antibiotics
