Sepsis

Question 0

What is the difference between bacteraemia and septicaemia?

Answer 0

BACTERAEMIA = presence of bacteria in the blood

SEPTICAEMIA = generalised sepsis

Question 1

Define systemic inflammatory response syndrome (SIRS).

Answer 1

Response to a non-specific insult e.g. ischaemia, trauma, infection

Characterised by two or more of:

• temperature 38 degrees +
• heart rate >90/min
• respiratory rate >20/min (or PACO2 < 4.3kPa)
• WBC < 4 x 10^9/l or >12 x 10^9/l

Question 2

What is the difference between sepsis, severe sepsis, and septic shock?

Answer 2

SEPSIS = systemic response to infection = SIRS + documented/presumed infection

SEVERE SEPSIS = SIRS + organ dysfunction/hypoperfusion (hypotension, reduced urine output)

SEPTIC SHOCK = severe sepsis + persistently low blood pressure despite administration of intravenous fluids

Question 3

Outline the inflammatory cascade which causes septic shock due to infection.

Answer 3

LOCAL
Endotoxin binds to macrophages -> Cytokines (TNF-alpha & IL-1) —–
SYSTEMIC SIRS
–> Cytokines released into circulation –> Homeostasis not restored –
–> Microvascular thrombosis —-> Organ ischaemia —-> organ failure

Cytokines initiate thrombin production & inhibit fibrinolysis (coagulation cascade)

Question 4

What should septic patients be given urgently (within 1hr)?

Answer 4

• High flow O2
• Take blood cultures (+other cultures +consider source control - drainage/surgery if needed)
• Administer empirical (best guess) IV antibiotics
• Measure serum lactate
• Start IV fluid resuscitation
• Commence accurate urine output measurement

Question 5

What are the causative organisms which cause meningitis?

Answer 5

NEWBORNS: group B streptococcus, E.coli, Listeria monocytogenes

CHILDREN: Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae (B)

ADULTS: N. meningitidis, S. pneumoniae

ELDERLY: N. meningitidis, S. pneumoniae, L. monocytogenes

Question 6

Outline the signs & symptoms of meningococcal meningitis. How is it treated?

Answer 6

S&S: purpuric/petaechial rash (negative glass test), fever, vomiting, photophobia, malaise, headache, rigid neck, pale & cool extremities

Complications: irreversible hypotension, respiratory failure, renal failure, increased intracranial pressure, ischaemic necrosis of peripheries

Treatment/prophylaxis: antibiotics that penetrate CSF, meningococcal C vaccine, AXWY vaccine for immunocompromised/travel

Question 7

What are the contraindications for lumbar puncture?

Answer 7

Increased intracranial pressure in CSF -> rapid decompression of brain