Infection in the immunocompramised

Question 1

Which immune cells do you need?

Answer 1

○ Neutrophils – bacterial & fungal infection​
○ Monocytes – fungal infection​
○ Eosinophils – parasitic infections​
○ T lymphocytes – fungal & viral infection, PJP​
○ B lymphocytes – bacterial infection​

Question 2

What are the supportive measures aimed at redusing risk of sepsis in haematological malignancy?

Answer 2

○ Prophylaxis​
- Antibiotics (ciprofloxacin)​
- Anti-fungal (fluconazole or itraconazole)​
- Anti-viral (acyclovir)​
- PJP (co-trimoxazole)​
○ Growth factors e.g. G-CSF​
○ Stem cell rescue/transplant​
○ Protective environment e.g. laminar flow rooms​
○ Intravenous immunoglobulin replacement​
○ Vaccination (never use live vaccines)​

Question 3

What is the cause of neutropenia?

Answer 3

marrow failure higher risk than immune destruction​

Question 4

What are the measurements for different degrees of neutropenia?

Answer 4

• < 0.5 x 10^9/l - significant risk​

- < 0.2 x 10^9/l - high risk​

Question 5

How long does neutropenia last in a high risk patient?

Answer 5

> 7 days

(AML therapy & stem cell transplantation produces profound neutropenia ~ 14-21 days)​

Question 6

What are the risk factors (other than neutropenia) in immunocompramised patients that increase the risk of infection?

Answer 6

○ Disrupted skin/ mucosal surfaces​
- Hickman line, venflons​
- Mucositis affecting GI tract​
- GVHD​ (graft versus host disease)
○ Altered flora/ antibiotic resistance​
- Prophylactic antibiotics​
○ Lymphopenia​
- Disease process e.g. Lymphoma​
- Treatment e.g. Fludarabine, ATG​
- Stem cell transplantation, GVHD​
○ Monocytopenia​
- Hairy cell leukaemia​
- Chemotherapy​

Question 7

What are the possible sites of infection?

Answer 7

○ Respiratory tract​
○ Gastrointestinal (Typhlitis)​
○ Dental sepsis ​
○ Mouth ulcers ​
○ Skin sores ​
○ Exit site of central venous catheters  ​
○ Perianal (avoid PRs!)​

Question 8

What contributes to the risk of fungal infections?

Answer 8

Monocytopenia and monocyte dysfunction

Question 9

True or false: immunocompramised pateints can get over fungal infections easily?

Answer 9

False: they are a life threatening, deep seated infection​

Question 10

Give an example of a fungal infection you might find in an immunocompramised patient

Answer 10

○ e.g. Candida species (thrush) ​

- Aspergillus​

Question 11

Where might an immunocompramised patient develop fungal infections?

Answer 11

Lung, liver, sinuses, brain

Question 12

What are the clinical features of neutropenic sepsis?

Answer 12

• Fever with no localising signs​
• Single reading of >38.5°C or 38°C on two readings one hour apart​
• Rigors​
• Chest infection/ pneumonia​
• Skin sepsis: cellulitis​
• Urinary tract infection​
• Septic shock​

Question 13

How is neutropenic sepsis managed?

Answer 13

• Resuscitation: ABC​
• Broad spectrum I.V. antibiotics​
  □ Tazocin and Gentamicin​
• If a gram positive organism is identified add vancomycin or teicoplanin​
• If no response at 72 hours add I.V. antifungal treatment e.g. Caspofungin: empiric therapy​
• CT chest/abdo/pelvis to look for source​
• Modify treatment based on culture results

Question 14

How is severe sepsis/ septic shock identified?

Answer 14

Signs of systemic inflammation (SIRS) + presumed infection and organ disfunction

Question 15

What are the sepsis 6?

Answer 15

• Administer high flow oxygen​
• Take blood cultures, other cultures, consider source control​
• Give appropriate IV antibiotics within ONE hour​
• Measure serum lactate concentration​
• Start IV fluid resuscitation ​
• Assess/measure urine output​

Question 16

How should neutropenic fever be investigated?

Answer 16

○ History and examination​
○ Blood cultures -Hickman line & peripheral​
○ CXR​
○ Throat swab & other clinical sites of infection​
○ Sputum if productive​
○ FBC, renal and liver function, coagulation screen​

Question 17

What type of patients are severly lymphopenic?

Answer 17

○ Stem cell transplant recipients, especially allogeneic​
○ Recipients of Total Body Irradiation (TBI)​
○ Graft vs Host Disease​
○ Nucleoside analogues (fludarabine) or ATG​
○ Lymphoid malignancy e.g. Lymphoma, CLL, ALL​