Bacteria, Fungal and Protozoal Infections Flashcards
What are the most common types of death in childhood
- pneumonia and diarrhoea
what is an example of a bacterial infection that progress rapidly in children
meningococcal septicaemia
what are prokaryotes
bacteria
what are two types of eukaryotes
- fungi
- protozoa
describe prokaryotes
= 0.2-2um in diameter
- single, circular chromosome
- no nucleus
- no organelles
- divide by binary fission
describe eukaryotes
- 10-100um in diameter
- multiple, linear chromosomes
- membrane bound nucleus
- membrane bound organelles such as golgi, ER, mitochondria
- divide by mitosis
what are the two toxins that are secreted by the host
- exotoxins
- endotoxins
What are exotoxins
bacterial toxins secreted by the host
what are endotoxins
forms part of the outer membrane of Gram – bacteria
give two examples of exotoxins
- Cholera
- diphtheria
describe what does cholera causes to happen
opening of CL- channels that lead to water into gut which leads to secretory diahorrea
what does diphtheria cause to happen
Diphtheria: sore throat with pseudo membrane
• Diphtheria Toxin A inhibits protein synthesis.
What does diphtheria act on
Acts on:
o Heart: myocarditis and heart block.
o Nerves further difficulty swallowing, paralysis, diplopia.
what does the endotoxin do
Released during lysis of the organisms.
Leads to macrophage activation
what is the immunopathology of the host
septic shock
describe the pathogenesis of meningococcal disease
- Activation of inflammatory cascade via LPS
- Causes release of pro-inflammatory cytokines such as. IL-6 and TNF- alpha
- This causes myocardial depression
- Endothelial dysfunction which causes capillary leakage and shock
- Causes a coagulopathy – takes a long time for the blood to clot as the whole coagulation cascade is abnormal
= therefore this inflammatory reaction to LPS causes most the symptoms of septic shock
inflammation reaction to LPS causes most of the …
symptoms of septic shock
What are the immunological differences in children in comparison to adults
Immunological
• Immaturity
• Lack of memory (cells).
Anatomical
• Thinner skin - premature babies have thinner skin therefore have a lack of barrier response
• Shorter airways
• Anatomy of Eustachian tube
o More straight = otitis media. - this makes it more likely for an illness to invade and progress
Exposure
• Hygiene, nursery/day-care.
infections often present in ….
fever
What is the dentition of the a fever
- Temperature above 37.8 degrees
describe the differences in measurement of temperature
0.5 lower in mouth vs. rectal
1 lower in armpit vs rectal.
what temperature is similar to rectal core temperature
= ear temperature
Name some severe bacterial infection
– Septicaemia – Meningitis – Pneumonia – Epiglottitis – Septic arthritis – Osteomyelitis – Tuberculosis – Tetanus
Name some slow bacterial infection
– Tonsillitis – Otitis media – Urinary tract infection – Gastroenteritis – Impetigo
What the three common causing meningitis and septicaemia
- streptococcus pneumonia
- neisseria meningitides
- haemophilus influenza B
describe the different groups of neisseria meningitides
o Group B and C
o Increase in Group W since 2009.
What is the definition of septicaemia
sepsis with shock
What are the clinical symptoms of septicaemia
- Tachycardia.
- Tachypnoea.
- Prolonged capillary refill- blood being sent to organs
- Low BP (late sign) - common to drop blood pressure due to shock whereas in children this is a pericardia a rest and late sign that they are going to decompensate
- Rash - doesn’t disappear usually, but you can have septicaemia without any rash
What are the clinical symptoms of meningitis
- High temperature
- Headaches
- Vomiting
- Not able to tolerate bright lights = photophobia
- Drowsiness
- Stiff Neck.
What are the causes meningitis
- accumulation of cell between Pia and arachnoid matter
- has inflammatory purulent exudate
What is the diagnosis of meningitis
- Lumbar puncture test
- CSF
What are the changes in the CSF in bacteria meningitis
- Appearance
- cells
- protein
- glucose
- Appearance = cloudy
- cells = increase in neutrophils
- protein = increase
- glucose = less than 60% of blood glucose
What are the changes in viral meningitis in the CSF
- Appearance = clear
- cells = lymphocytes increase
- protein = remain the same
- glucose= normal
What are the changes in TB meningitis in the CSF
- Appearance = opalescent
- cells = lymphocyte increase
- protein = double increase
- glucose = decrease in 60% of blood glucose
the younger the child the more …
non-specific the symptoms are for meningitis
describe how you would diagnose meningitis in a young child
- the younger the child the more non specific the symptoms are for meningitis therefore you have to have a high index of suspicion in an unwell baby
- for any child that is greater than 3 months old you can do an lumbar puncture
What are the symptoms of meningitis in infants
- Tense or bulging soft
- High temperature
- Breathing fast and difficulty breathing
- Extreme shivering
- Cold hands and feet
- Vomiting and refusing to feed
- Blotchy skin getting paler or turning blue
what vaccinations take place at
- 8 weeks old
- 12 weeks old
- 16 weeks old
- one year
8 weeks old
- Diphtheria, tetanus, peruses, polio, Hib, HepB,
- pneumoccoal (13 serotypes)
- Meningococcal group B
- rotavirus, gastroenteritis
12 weeks old
- Diphtheria, tetanus, peruses, polio, Hib, HepB,
- rotavirus
16 weeks old
- Diphtheria, tetanus, peruses, polio, Hib, HepB,
- pneumoccoal (13 serotypes)
- Meningococcal group B
one year
- Men B
- Hib and MenC
- pneumococcal
- MMR
How many serotypes does the pneumoccoal vaccination have
13 serotypes
What are the top 3 organisms that can cause problems in young infants before vaccination
- Group B streptococcus
- E.coli
- Listeria
what antibiotics can you give for GBS, E.coli and listeria
- for older children
- and young infants les than 3 months old
• Older children – Ceftriaxone – covers all 3 • Young infants (<3 months old) – Cefotaxime or ceftriaxone – Amoxicillin (penicillin derivate) also needed for Listeria cover
What is the neonatal period
Birth to the 28th day (first 28 days of life)
What can cause neonatal sepsis transmission from the mother to the baby
- maternal colonisation of the pathogens in colon and vaginal canal (mainly for GBS)
- this passes vertically onto the baby
what is the difference between early and late onset sepsis
Early onset in neonatal sepsis is the first 7 days after Birth
late onset in neonatal sepsis is 8-90 days after birth
where does late onset sepsis tend to go
tends to settle in;
- bones and joins
- meningitis
what are two types of gram positive bacteria
cocci
bacilli
name some examples of cocci and bacilli (gram positive bacteria)
Cocci
- Staphylococcus
- Streptococcus
- Enterococcus – coloniser of the gut
Bacilli
- corynebacterium
- listeria
- bacillus - such as ceros and anthracis
- Clostridum = such as tetani, botulinum, difficile
what is cerus the cause of
cause of vomiting if you reheat fried rice
What is anthracis the sue of
cause of anthrax
what does petani cause
causes tetnus
what bacteria is neither gram positive nor gram negative
mycoplasma
describe streptococcus pneumonia
- Pneumococcus
- Normal flora in 5-70% of people
- Diploccoci
- Gram positive
what does diplococci mean
a bacterium that occurs as pairs of cocci, e.g. pneumococcus
what are the vulnerable groups of people that are predisposes to developing pneumococcal infection
• Absent / non-functional spleen
– Congenital asplenia – born without a spleen
– Traumatic removal
– Hyposplenism (eg sickle cell) – spleen gets ruined as well
- Hypogammaglobulinaemia
- HIV infection
name three reasons why you might not have a spleen
– Congenital asplenia – born without a spleen
– Traumatic removal
– Hyposplenism (eg sickle cell) – spleen gets ruined as well
what bacteria does not having a spleen leave you vulnerable to and how do you treat it
• Vulnerable to encapsulated bacteria – Pneumococcus – HiB – Meningococcus • Vaccination • Lifelong penicillin daily
what are the invasive and non invasive features of pneumoccoal
Non invasive • Acute otitis media • Sinusitis • Conjunctivitis • Pneumonia
Invasive • Septicaemia • Meningitis • Peritonitis • Arthritis • Osteomyelitis
describe an example of how pneumoccoal presents as a non invasive disease
- for example the normally pneumococcus sits in the nasopharynx but in children the otitis mediais more straight therefore th eubacteria can travel to the ear through the Eustachian tube
- this causes a midd ear infection behind the ear drum
- an immune response is started
- pus builds up so that the middle ear becomes like a boil
- this can cause the eardrum to burst and pus can come out the ear
describe how pneumococcal can become an invasive disease
- the pneumococcal in the nasopharynx, this can go into the epithelium and then enter the blood
- leads to meningitis and sepsis
- causes osteomyelitis, septic arthritis and peritonitis
How do you treat empyema caused by pneumoccoal
- use a chest drain and urokinase
- use video assistant thoracoscopic surgery (VATS)
Describe how you diagnose osteomyelitis caused by pneumoccoal
- can take 10 days to show up on the X ray
- on the X ray it looks more Lucent
- can do an MRI which will show this up early
How do you treat osteomyelitis caused by pneumoccoal
- treatment is antibiotics for 7 weeks in order to make sure that the infection is cleared from the bone
How do you treat septic arthritis caused by pneumoccoal
- may need surgery to wash out the infected joint
- then goes on antibiotics
What are the two vaccinations used for pneumococcal
- Pneumococcal Polysaccharide Vaccine (PPV)
* Pneumococcal Conjugate Vaccine (PCV).
what vaccination in pneumoccoal is used for adults versus what one is used for children
- Pneumococcal Polysaccharide Vaccine (PPV) = adults
* Pneumococcal Conjugate Vaccine (PCV). = children
why is the Pneumococcal Conjugate Vaccine (PCV) given to children and not the PPV
- Children cannot have the PPV vaccination as it just contains polysaccharide and they cannot mount an immune response to that
- the PPV allows a conjugate piece of protein to be bound to the polysaccharide
Explain how the pnuemoccoal conjugate vaccine works
- the B cell binds to the bacteria polysaccharide epitope linked to the protein
- antigen is internalised and processed
- peptides from the portion component are presented to the T cell
- activated B cells then produce antibodies against the polysaccharide antigen on the surface of the bacterium
what is the main organisms that causes tuberculosis
Myobacterium tuberculosis
what are the two different types of pathways that can happen when exposed to mycobacterium tuberculosis
- Childhood exposure
- primary pulmonary infection
- successful immune response
- well adult
- then loose immunity later in life
- therefore you can have late reactivation of the pulmonary disease
- this forms a cavity
or
- Childhood exposure
- primary pulmonary infection
- Inadeqaute immune response
- progressive pulmonary disease leading to death
- or Hillary extra pulmonary disease leading to death
what causes tetanus
- Clostridium tetani, gram-positive bacillus
where are the spores for tetanus found
spores are found in the soil
what can lead you to having tetanus
- lack of maternal vaccination in pregnancy
- use of unclean blade to cut cord
- application of mud or dung to cord
What are the symptoms of neonatal tetanus
- Weak
- Lethargic
- Poor suck
- Spams
- Fits
what are the two types of fungi and give examples
Yeasts
- such as candida
Moulds
- such as aspergillum
what type of fungi is candida
yeast
What type of fungi is aspergillus
mould
describe yeasts
- unicellular
- oval or round
- asexual budding
describe moulds
- filamentous fungi
- branching filaments (Hypae)
what are common suerpiical mycosis
• Common o Candidiasis: nappy rash. o Tinea Corporis: ring worm. Treat both with topical antifungal (nystatin). • Occurs in Normal Hosts
How do you treat candida and ring worm
Treat both with topical antifungal (nystatin).
What is another word for ring work
tine corporis
what are invasive mycosis
o Candidaemia: extremely preterm infant, effects kidneys and brain.
o Pulmonary Aspergillosis: child with chronic granulomatous disease.
Impaired neutrophil function.
• Opportunistic infections in immunocompromised hosts.
how do you treat candidaemia
- IV anti fungal treatment
what problems can you have with neutrophils
- Low neutrophil count (neutropenia)
- Impaired neutrophil function (e.g. chronic granulomatous disease)
what problems can you have with T cells
Congential e.g. SCID
Acquired e.g HIV
name 3 types of protozoa
Sporozoa
amebae
flagellates
Give examples of the three types of protozoa
• SPOROZOA
– Plasmodium species (malaria)
– Toxoplasma gondii (toxoplasmosis)
– Cryptosporidium (diarrhoea)
• AMOEBAE
– Entamoeba histolytica (amoebic dysentery)
• FLAGELLATES
– Giardia (diarrhoea, malabsorption)
– Trypanasoma (sleeping sickness, Chagas)
– Leishmania (leishmaniasis)
What are the 5 main species of malaria
– P.falciparum – most severe, cerebral malaria – most important one to worry about
– P. vivax – dormant stage in the liver and they can reactivate
– P. ovale – dormant stage in the liver and they can reactivate
– P. malariae
– P, Knowlesi - emerging cause, predominantly a primate malaria, jumped from priamtes to humans,
Describe the lifecycle of malaria
- Comes from mosquitos
- Is a sportazie in the mosquito
- Female injects sportaite into the human
- Goes into the liver stage
- Comes a schizont
- Shizont ruptures
- Go into the blood cells
- Becomes a schizont into the red blood cell
- Eventually ruptures the red blood cells
what are the symptoms of malaria
• Can be non-specific
– Fever, lethargy, vomiting, diarrhoea
• Severe disease – Anaemia – Respiratory distress – Cerebral malaria (coma, seizures) – Hypoglycaemia
what are the treatments of malaria
- Artemisinin
- Combination treatment (eg Coartem: artemether-lumefantrine)
- More rapid reduction in parasitaemia
what can cause toxoplasmosis
- Oocysts excreted by cats.
- Pregnant women infected.
- Multiply in macrophages.
What is the presentation of toxoplasmosis in the neonate
- Hepatosplenomaegaly
- Funducosopy – nasty retinitis
- Ultrasound scan of the brain – ventricular dilation that can cause hydrocephalus
