Infection and Immunity Flashcards
Name the most common cause of fever in children
Self-limiting viral infection
What is the definition of fever?
Temperature >37.5C
What should be done in a child <3mths if there is no clear cause for fever?
Urgent septic screen
Broad spectrum IV antibiotics
List the risk factors for infection
- Sick contacts
- Lack of immunisations
- Recent travel
- Contact with animals
- Immune deficiency
List the red flag features when presenting with fever
- Fever >38C (if <3mths) or >39C (if 3-6mths)
- Pale, mottled or cyanosed (COLOUR)
- Decreased level of consciousness
- Neck stiffness
- Bulging fontanelles
- Status epilepticus
- Focal neurological signs
- Seizures
- Significant RDS
- Bile stained vomit
- Severe dehydration or shock
How can we manage fever?
- Not seriously ill - manage at home; give parents instructions about signs to look out for
- Significantly unwell - admit; investigate and observe; SEPTIC SCREEN
List the important features present in the history of a child with sepsis
- Fever
- Poor feeding
- Miserable, irritable, lethargy
- History of focal infection
- Predisposing conditions
List the important signs present on examination of a child with sepsis
- Fever
- Tachycardia, tachypnoea, low BP
- Purpuric rash (meningococcal septicaemia)
- Shock
- Multi-organ failure
How do we manage sepsis?
- ANTIBIOTICS - start without delay; broad spectrum
- FLUIDS
- CIRCULATORY SUPPORT - may require inotropic support
- RESPIRATORY SUPPORT - give oxygen
- DIC - if bleeding occurs correct clotting derangement with FFP, cryoprecipitate and platelet transfusions
List the causes of meningitis
- Viral (most common)
- Bacterial (SEVERE)
- Fungal
- Parasitic
- Malignancy
- Autoimmune
What are the likely organisms to cause bacterial meningitis in the neonate - 3mths age group?
Group B Strep
E. Coli
Listeria monocytogenes
What are the likely organisms to cause bacterial meningitis in the 1mth - 6mth age group?
Neisseria meningitidis
Haemophilus influenza
Streptococcus pneumoniae
How can meningitis present?
- Non-specific signs (early)
- Photophobia
- Hypotonia
- Drowsiness
- Loss of consciousness
- Seizures
- Purpuric rash
- Neck stiffness
- Bulging fontanelle (infant)
- Opisthotonus (arching of back)
What investigations should be performed if meningitis is suspected?
- Lumbar puncture
- Septic screen
- Cultures - blood, throat, urine, stool
- Rapid antigen test for meningitis organisms
List the contraindications to lumbar puncture
- Cardiorespiratory instability
- Focal neurological signs
- Signs of raised ICP
- Coagulopathy
- Thrombocytopenia
- Local infection at site
- Causes undue delay in starting antibiotics
How is bacterial meningitis managed?
- IMMEDIATE ANTIBIOTICS - Ceftriaxone +/- Vancomycin
- Supportive therapy
- Rifampicin prophylaxis to close contacts (meningococcal or Hib meningitis)
List the possible complications of meningitis
- Hearing impairment
- Cranial nerve palsies and other focal neurological lesions
- Seizures
- Subdural effusion
- Hydrocephalus
- Cerebral abscess
List the common causes of viral meningitis
- Enteroviruses
- EBV
- Adenoviruses
- Mumps
What is the CSF composition in viral meningitis?
Clear
Increased lymphocytes
Normal/increased protein
Normal/decreased glucose
What is the CSF composition in bacterial meningitis?
Turbid
Very increased polymorphs
Very increased protein
Very decreased glucose
Define encephalitis
Inflammation of brain parenchyma
List the causes of encephalitis
- Direct invasion of brain by neurotoxic virus
- Post-infectious
- Slow virus infection
What are the clinical features of encephalitis?
Similar to meningitis
Most common - fever, altered consciousness, seizures
What organisms can cause encephalitis?
- Enteroviruses
- Influenza viruses
- Herpes viruses
- Mycoplasma
- B. burgdorferi
- Bartonella henselae
- Rickettsial infections
- Arboviruses
What are the clinical indicators for HSV encephalitis?
- EEG +/- CT/MRI = focal changes
2. HSV antibody production in CSF
How do we treat HSV encephalitis?
IV acyclovir for 3wks
What organisms cause toxic shock syndrome?
- Toxin producing Staphylococcus aureus
2. Group A Streptococcus
List the clinical features of toxic shock syndrome?
- Fever >39C
- Hypotension
- Diffuse, erythematous macular rash
- Mucositis
- GI dysfunction
- Renal impairment
- Liver impairment
- Clotting abnormalities and thrombocytopaenia
- CNS signs
- Desquamation of palms, soles, fingers and toes 1-2wks after onset
How can toxic shock syndrome be managed?
- ICU support required
- Areas of infection surgically debrided
- ANTIBIOTICS - 3rd generation cephalosporin + clindamycin
- IV immunoglobulins
