Common neutropenic sepsis exam questions for medical finals, OSCEs and MRCP PACES

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What is the definition of neutropenic sepsis (neutropenic fever)?

Neutrophils < 1 x10⁹ / L is the most widely used criterion (thought some guidelines recommend <0.5×10⁹/L)
AND any of
Temperature > 38°C OR
Signs or symptoms indicating infection OR
Raised C-reactive protein (>80mg/L)

What can be done to prevent neutropenic sepsis (neutropenic fever)?

Improve counts
- G-CSF can be used following chemotherapy regimens with a high risk of prolonged neutropenia
Prophylaxis against infection
- Antibiotic prophylaxis with a fluoroquinolone reduces febrile episodes and mortality
- Antifungal prophylaxis with fluconazole 50mg PO once daily
- Antiviral prophylaxis with aciclovir 200mg PO three times daily

What are the causes of neutropenia?

Congenital
- Benign ethnic neutropenia; cyclical neutropenia; Chediak-Higashi
Failure of production leading to pancytopenia
- Myelosuppressive chemotherapy or irradiation is overwhelmingly the most common.
- Others include infiltration of bone marrow by cancer; vitamin B12 or folate deficiency; myelodysplastic syndrome; aplastic anaemia
Increased consumption
- Post-infectious
- Idiosyncratic drug reactions (e.g. carbimazole; clozapine; co-trimoxazole; penicillin)
- Autoimmune disease e.g. SLE; autoimmune neutropenia (antibody-mediated neutrophil destruction)
- Paroxysmal noctural haemoglobinuria
- Haemophagocytic syndrome

How do you investigate neutropenic sepsis (neutropenic fever)?

Cultures
- Blood cultures (peripheral and line), urine culture, stool if diarrhoea
- Other fluids (pus, sputum, pleural fluid, ascites, CSF, synovial fluid) as relevant for microbiology
- Relevant viral serology if clinical suspicion
Bloods
- FBC, U+E, LFT, C-reactive protein or ESR, coagulation, calcium, lactate, glucose
- Blood film
- Group and screen
- ABG/VBG
ECG
Imaging
- CXR if indicated
- Further imaging as dictated by history and examination to identify a source

When should lines be removed in neutropenic sepsis (neutropenic fever)?

Central venous lines should not be routinely removed.
They should be removed in cases of bacteraemia due to aureus, P. aeruginosa or fungal infection.

What is the myeloid reconstitution syndrome?

As the neutrophil count recovers, some patients develop worsening symptoms and signs of focal infection

What is typhilits?

Typhilis (also known as necrotising enterocolitis) is inflammation of the bowel in the context of neutropenia that is not due to a particular pathogen.
It should be managed as neutropenic sepsis initially, though if perforation occurs surgery is required. Other causes of colitis should be ruled out (norovirus, C. difficile, cytomegalovirus, ischaemia)