Drug induced neutropenia

Question 1

A 41 year old woman presents with fever and painful gums and on examination, marked gingivitis. Two weeks previously she was prescribed clotrimoxazole for a UTI. Full blood count reveals a total WBC of 1.1 and a total neutrophil count of 0.8. How would you manage here

Answer 1

Impression
Given recent administration of Cotrimoxazole and concomitant neutropenia, am provisionally concerned about a drug induced neutropenia which is a known adverse reaction for cotrimoxazole. Most concerned about complication of febrile neutropenia and sepsis.

DDx

• Infective: CMV, EBV, HIV, other bacterial
• Autoimmune
• Haematological malignancy (AML)
• Nutritional deficiencies: B12/Folate

Goals

• Initial assessment to ensure Hd stable and no systemic infection
• thorough Hx/Ex/Ix to determine likely aetiology of neutropenia
• manage underlying cause appropriately, documentation of ADR?

Question 2

Drug induced neutropenia - History

Answer 2

History
- sx: pain history, other associated sx with gingivitis (bleeding when brushing teeth, halitosis), other infective sx (fevers, chills, urine/chest)
Differentials
- Malignany: fevers, weight loss, night sweats, bone pain, lymphadenopathy
- infective: sick contacts, travel history
- nutritional Hx
- SNAP

Question 3

Drug induced neutropenia - Examination

Answer 3

Examination

• General appearance + vitals
• Signs of infection; inspect gingiva for severity
• Haematological examiantion: bruising, petechiae, hepatosplenomegaly, lymphadenopathy
• systems review: for other infective features

Question 4

Drug induced neutropenia - Investigations

Answer 4

Investigations

• bedside: UA (infection)
• Bloods: FBC + peripheral blood smear, ESR/CRP, UEC, LFT

Septic screen if febrile or indicated.
Consider
- nutritional panel, bone marrow biopsy, autoimmune serology, viral serology

Question 5

Drug induced neutropenia - Management

Answer 5

Management
- seek haematology advice early for management input

Definitive

• cease cotrimoxazole (if not already ceased): should see normalisation of neutrophil levels in 2-3 weeks
• consider administration of G-CSF which has been shown to reduce recovery and hospitalisation time (consult Haem)
• ?further bone-marrow investigations

Gingivitis

• good oral hygiene
• dentist referral
• chlorhexidine mouth wash BD for 5 days

If febrile neutropenia;
- gram positives are most common source
- commence broad spectrum IV ABx after cultures are taken;
o IV tazocin or cephalosporin
o IV Gent + Vanc if Septic shock or ICU