Bacterial, fungal + protozoal infection in childhood

Question 1

What are the most common infection-related deaths in childhood?

Answer 1

Pneumonia

Diarrhoea

Question 2

What are exotoxins? Give 2 common examples.

Answer 2

Bacterial toxins secreted by the pathogen

Examples: cholera toxin A and diphtheria toxin A

Question 3

What effects does diphtheria toxin A have on the body?

Answer 3

It inhibits protein synthesis
Acts on:
1. heart - can cause myocarditis + heart block
2. nerves - cause difficulty swallowing, paralysis + diplopia

Question 4

What are endotoxins?

Answer 4

forms part of the outer membrane of gram negative bacteria
they are released during lysis of organisms
leads to macrophage activation

Question 5

What is the endotoxin in meningococcal disease (Neisseria meningitidis)? How is it related to septic shock?

Answer 5

Endotoxin = Lipopolysaccharide (LPS)

The body will have an inflammatory reaction to LPS which will cause most of the symptoms of septic shock

Question 6

What are the results of the activation of the inflammatory cascade via LPS?

Answer 6

Cause:
myocardial depression
endothelial dysfunction = capillary leak + shock
coagulopathy

Question 7

What temperature is considered to be a fever? How does this vary depending on method of measurement?

Answer 7

> 37.8 degrees celsius = fever

• 0.5 degrees lower in mouth vs rectum
• 1 degree lower in arm vs rectum

Question 8

Which bacterial infections are common and which are severe?

Answer 8

Severe:

• septicaemia
• meningitis
• pneumonia
• epiglottitis
• septic arthritis
• osteomyelitis
• tuberculosis
• tetanus

Common:

• tonsilitis
• otitis media
• UTI
• gastroenteritis
• Impetigo

Question 9

Which encapsulated organisms cause septicaemia + meningitis?

Answer 9

Streptococcus pneumoniae
Neisseria meningitidis (Group B, C, W)
Haemophilus influenza B (HiB)

Question 10

What are the clinical symptoms of septicaemia?

Answer 10

tachycardia 
tachypnoea 
prolonged capillary refill 
low BP = late sign
rash

Question 11

What are the clinical symptoms of meningitis in a child?

Answer 11

high temperature 
headaches 
vomiting 
photophobia 
drowsiness
stiff neck

Question 12

At what age would a lumbar puncture be performed on a child?

Answer 12

> 3 months

Question 13

What type of bacteria is tetanus? Which organism is it caused by?

Answer 13

Gram positive bacillus

Clostridium tetani

Question 14

How would you treat young infants and older children infected by Strep B, E. Coli or Listeria?

Answer 14

Infants: combination fo cefotaxime/ceftriaxone and amoxicillin
Older children: Ceftriaxone

Question 15

When does neonatal sepsis occur? When is early onset and late onset?

Answer 15

First 28 days of life
Early onset = within 48 hours
Late onset = within 3 days (settles in meninges + brain)

Question 16

Name common gram positive organisms (cocci + bacilli).

Answer 16

Cocci:

• Staphylococcus
• Streptococcus
• Enterococcus

Bacilli:

• Corynebacterium
• Listeria
• Bacillus - cereus, anthracis
• Clostridium - tetani, botulinium, difficile

Question 17

What immune defects will predispose someone to pneumococcal infection?

Answer 17

1. Absent/non functional spleen
   - vulnerable to encapsulated bacteria
   - congenital asplenia
   - traumatic removal
   - hyposplenism
2. Hypogammaglobulinaemia
3. HIV infection

Question 18

What are the non-invasive and invasive clinical features of pneumococcus?

Answer 18

Non-invasive:

• acute otitis media
• sinusitis
• conjunctivitis
• pneumonia

Invasive: (enters blood)

• septicaemia
• meningitis
• peritonitis
• arthritis
• osteomyelitis

Question 19

What two vaccines are there for pneumococcal infections?

Answer 19

Pneumococcal polysaccharide vaccine (PPV)
Pneumococcal conjugate vaccine (PCV)
- protein allows the engagement of helper t cells
- protein is internalised + present as a little fragment for recognition

Question 20

What are common examples of superficial mycosis (fungal infection)?

Answer 20

Candidiasis (nappy rash) and tinea corporis (ring worm)

- occurs in normal hosts

Question 21

What are common examples of invasive mycosis (fungal infection)?

Answer 21

Rare: candidaemia (affects kidney + brain) and pulmonary aspergillosis (in children with chronic granulomatous disease)
- is an opportunistic infection - common in immunocompromised hosts

Question 22

How are protozoa classified?

Answer 22

1. Sporozoa
   - plasmodium species (malaria)
   - toxoplasma gondii (toxoplasmosis)
   - cryptosporidium (diarrhoea)
2. Amoebae
   - entamoeba histolytica
3. Flagellates
   - giardia (diarrhoea, malabsorption)
   - trypansoma (sleeping sickness, Chagas)
   - Leishmania

Question 23

What are the four main species of malaria?

Answer 23

P:

• falciparum
• vivax
• ovale
• malariae

Question 24

What signs/symptoms indicate meningitis in an infant?

Answer 24

Tense/bulging soft spot
fever
very sleepy
tachypnea/dyspnea
extreme shivering
pin prick rash/marks 
sometimes diarrhoea 
cold hands + feet
stiff body 
blotchy skin 
irritable 
vomiting/refusing to feed

Question 25

How do you manage empyema?

Answer 25

Chest drain +/- urokinase

Video assisted thoracoscopic surgery

Question 26

What are the S+S of tetanus infection in an infant?

Answer 26

Weak 
Lethargic 
Poor suck 
Spasms 
Fits

Question 27

What are the S+S of malaria infection in children?

Answer 27

Non-specific:
fever 
lethargy 
vomiting 
diarrhoea 

Severe:
Anaemia 
Resp distress
Cerebral malaria 
Hypoglycaemia