Oncological Emergencies Flashcards
What is neutropenic sepsis?
A life threatening side effect of chemotherapy when the neutrophil count is dangerously low and infection has developed. This is due to marrow suppression that occurs with these cytotoxic drugs.
What neutrophil count diagnosis neutropenic sepsis?
Less than 0.5 x 10^9/ L
Because they have a suppressed immune system they may not mount a normal immune response
What factors diagnosed neutropenic sepsis?
Neutrophil count less than 0.5 x 10^9/L
Temperature greater than 38 degrees
What is thought to be the most common site of organisms causing neutropenic sepsis?
GI organisms
But a source is only found in around 20-30%
What tests should you do to investigate for the cause of neutropenic sepsis?
Blood culture
Urine dip and culture
CXR
Examine the skin for any signs- e.g. Cellulitis
Check venous catheters for potential signs of infection- PIC or Hickman lines
Why should you have a low threshold for suspecting neutropenic sepsis?
They are immunosuppressed and so are unlikely to mount a standard immune response
What is the definition of neutropenic sepsis?
Neutrophil count less than 0.5
And either
- Temp greater than 38
- Any signs of symptoms of sepsis
What is the management of neutropenic sepsis?
It’s a medical emergency as mortality rates are high. Give ABx even without results if fever in chemotherapy patients. Delays in antibiotics result in worse outcomes.
Buzz-word- Say start a neutropenic regime.
Barrier nursing, ideally isolate in side room
Take blood cultures,
Bloods- check FBC, U&E, ESR, CRP, INR, LFTs, Lactate
CXR is indicated and urine culture
Broad spectrum IV ABx e.g Piperacillin and Tazobactam. Follow trust guidelines.
Check vital signs often e.g. every 2-4 hours
If fever persists after ABX think of virus (CMV) or fungal causes (PJP)
What should you say you will start if neutropenic sepsis is suspected?
Start a neutropenic regimen
What antibiotics should be given if neutropenic sepsis is suspected?
Piperacillin and Tazobactam IV recommended by NICE
But follow trust guidelines
What should you consider if there is failure to respond to ABx therapy?
Viral cause- CMV
Fungal cause- PJP
What is tumour lysis syndrome?
Oncological emergency that occurs due to the breakdown of lots of cells causing release of intracellular contents
When does tumour lysis often occur?
After chemotherapy but can happen spontaneously
What important factors are raised in tumour lysis syndrome?
Uric acid
Phosphate
Potassium
Why is uric acid/urate raised in tumour lysis syndrome?
Due to release of cell DNA which is broken down. DNA is broken down to purines and pyrimidines which are broken down into xanthines, xanthine oxidase converts xanthines into uric acid.
Why does a raised uric acid cause an AKI?
Uric acid precipitates to form crystals in the distal tubules and collecting system, obstruction the flow of filtrate in the nephron. Leads to AKI.
What are two important consequences of tumour lysis syndrome?
Raised urate can cause an AKI, can cause death
Raised potassium can cause arrhythmias, can cause death
What is consequence of raised phosphate due to tumour lysis?
It can precipitate with calcium to form calcium phosphate. This can also cause an AKI or deposit in the heart to cause arrhythmias.
Also, by binding with calcium it reduces circulating calcium causing hypocalcemia. This prolongs the QT interval and can cause seizures.
What are some risk factors for tumour lysis syndrome?
High tumour proliferation rate High sensitivity to chemotherapy or radiotherapy Haematological cancers Bulky disease Targeted therapies
What pre-existing patient factors may increase the risk factors for poor outcomes from tumour lysis syndrome?
Pre-existing raised urate
Background CKD
Dehydration (increased precipitation of calcium phosphate, uric acid crystals in the tubules)
What is the risk of raised potassium in tumour lysis syndrome?
Cardiac arrhythmia
What ECG features are seen with hyperkalemia?
Tall tented T waves
QT prolongation
PR prolongation
How can tumour lysis syndrome be prevented?
IV fluid hydration (decrease precipitation in kidneys)
Allopurinol- blocks xanthine oxidase to reduce uric acid
Rasburicase- enzyme that breaks uric acid to allantoin. Only for high risk cases if pre-existing raised urate.
How should hyperkalemia be treated?
Calcium gluconate 10% in 10ml
Insulin with glucose- Actrapid 10 units plus 50ml Glucose 50%
Salbutamol- 10 mg Neb
Ion exchange resins- Calcium resonium
Monitor closely with VGB for rapid results.
What is the treatment for for severe tumour lysis syndrome?
Manage hyperkalemia accordingly
If severe AKI- dialysis may be needed
What is the normal serum corrected calcium range?
2.2 to 2.7 mmol/L
How can you identify hypercalcaemia due to metastatic disease rather than parathyroid overactivity?
PTH should not be raised for hypercalcaemia due to malignancy but it will be raised for other causes but could be due to PTH secreting tumour (squamous cell carcinoma of the lung)
What causes hypercalcaemia in malignancy?
Bone metastases
PTH related protein production by tumour- e.g. with squamous cell carcinoma of the lung
What are some of the signs/symptoms of hypercalcaemia with malignancy?
Abdominal pain Dehydration Weakness Confusion Seizure Coma Nausea Polydipsia Polyuria- high calcium levels reduces re-absorption of water.
Stones, thrones, groans, bones, psychiatric overtones (confusion, coma) and cardiac (bradycardia, arrhythmias, AV block)
What is the management for hypercalcaemia?
IV Fluids- as can become dehydrated due to polyuria
IV Bisphosphonates- Zoledronic Acid IV. Bisphosphonates inhibit osteoclasts.
Calcitonin lowers calcium in the short term
Long term control malignancy
Dialysis if kidney injury and failure to manage with medical measures.
How do bisphosphonates work?
They inhibit osteoclast activity and so prevent bone breakdown.
What are some causes of hypercalcaemia?
Hyperparathyroidism
Malignancy
Excess vitamin D
Drugs- e.g. Thiazide diuretics
What is the cause of metastatic spinal cord compression?
Cancer metastases to the spinal column that compress on the spinal cord. It an emergency and an urgency spinal MRI should be requested
Which cancers are associated with bone metastases?
Lung Breast Prostate Myeloma Melanoma
What tends to cause spinal cord compression?
Collapse or compression of a vertebral body due to metastases or rarely direct compression of the spinal cord by the tumour
What are some signs/symptoms of metastatic spinal cord compression?
Back pain- thoracic back pain is normally a red flag Deep bone pain Paresthesia Weakness Loss of bladder/bowel function Difficulty walking Pain disturbs sleep
Note- signs depend upon the location
What should be done if metastatic spinal cord compression is suspected?
Urgent spinal MRI
How are spinal metastases treated?
Lie flat, neutral spine alignment
Manage pain with analgesia according to WHO pain ladder.
High dose dexamethasone 16mg OD PO - reduces swelling around the tumours
Radiotherapy- shrinks the tumour bulk
Decompressive surgery may be considered
Treatment is palliative as it is an indicator of advanced severe metastatic disease.
Note- beyond steroids the management will be discussed at cancer MDT and will consider the patients prognosis and impact on QoL
What kind of pattern is seen in cauda equina syndrome?
Lower motor neuron signs
Hyporeflexia
Hypotonia
Weakness
PAresthesia/reduced sensation
What is superior vena cava syndrome?
This occurs when the SVC becomes obstructed- most commonly due to external compression but can be due to internal invasion by the tumour. This reduces venous drainage of the head and neck, causing congestion and oedema
What tumours commonly cause SVC obstruction?
Lung cancers
Lymphomas
Other causes include clots, aortic aneurysm,
Why is SVC obstruction an emergency?
Venous congestion leads to oedema. Oedema of the airway can cause loss of a patent airway and so can cause death. SVC obstruction therefore requires urgent treatment
Cerebral oedema can also cause rises in ICP which can lead to ischaemia. This cause headache, confusion, dilated pupils…
What are the features of SVC obstruction?
Facial redness Facial swelling Breathless (reduced return to RH) Distended veins in neck and check with use of collateral vessels. Stridor if upper airway obstruction Cough (airway oedema)
What is the treatment for SVC obstruction?
ABC- Airway adjuncts if needed
Sit upright
Give oxygen if hypoxic and airway compromise
Dexamethasone 16 mg PO/24 hour to reduce swelling around tumour
SVC stenting
Treat underlying cancer
