Common Childhood Infectiojs Flashcards
Why do bacteria cause morbidity and mortality
Toxins
Host Immunopathology
Bacterial Exotoxin
Proteins secreted by pathogen
How does cholera cause diarrhoea
Toxin increases cAMP causing Cl- to enter gut lumen from cells via CFTR, water follow Cl-
How do cholera and diphtheria cause disease
Exotoxins
How does diphtheria toxin cause disease
Inhibits protein synthesis in heart and nerves
Bacterial Endotoxin
Lipopolysaccharides in outer membrane of gram negative bacteria released during lysis
How do endotoxins cause harm
Cause macrophage activation
Biggest cause of sepsis
Meningitis
Shock
Inadequate perfusion of internal organs
Why does shock cause tachycardia and Tachypnoea
Trying to perfuse internal organs
How do endotoxins cause meningococcal disease
Activate inflammatory cascade causing myocardial depression, endothelial dysfunction, and coagulopathy
What temperature is a fever
> 38*c
Types of temperature measurement and how they differ from rectal core temp
Rectal
Ear - similar
Mouth - 0.5 lower
Axillary - 1 lower
Why are children effected by infections differently to adults
Immunological immaturity
Lack of memory cells
Thinner skin
Shorter airways
Flatter shorter Eustachian tube
Increased exposure at nursery, etc
Decreased hygiene
Not fully vaccinated
Why are serious infections sometimes missed in babies
Non specific presentations
Organisms that cause septicaemia and meningitis
Streptococcus pneumoniae
Neisseria meningtidis B and C
Haemophilus influenzae B
Important gram positive organisms - 3 cocci, 4 bacilli
Staphylococcus
Streptococcus
Enterococcus
Corynebacterium
Bacillus
Listeria
Clostridium
BLESSCC
SSE cocci
CCLB bacilli
Types of clostridium
Tetani
Botulinum
Difficile
Types of bacillus
Cereus
Anthracis
Streptococcus pneumoniae arrangement
Diplococci
Immune defects increasing pneumococcal infection
Absent/non functional spleen
Hypogammaglobulinaemia
HIV
Are acute otitis media, sinusitis, conjunctivitis, and pneumonia invasive or non invasive
Non invasive
Are septicaemia, meningitis, peritonitis, arthritis, and osteomyelitis invasive or non invasive
Invasive
How does pneumococcus cause otitis media
Travels from back of throat to ear along Eustachian tube -> middle ear infection -> pus buildup behind ear drum -> eardrum bursts and pus comes out of ear
What can cause ear discharge in otitis media
Pus buildup behind tympanic membrane until tympanic membrane bursts
Invasive disease
Breaks mucosa
What organism causes empyema
Pneumococcus
Empyema management
Chest drain
Urokinase
Video assisted thoracoscopic surgery
Septic arthritis management
Surgically open joint and wash out with saline
Antibiotics
Does the pneumococcal polysaccharide vaccine or pneumococcal conjugate vaccine get a better response in young children
Pneumococcal conjugate vaccine
What is the effect of serotypre replacement from vaccination
Rates of disease serotypes not vaccinated against increase
2 types of fungi pathogens
Yeasts
Moulds
What types of fungal disease are opportunistic
Invasive mycoses
3 classes of Protozoa
Sporozoa
Amoebae
Flagellates
5 main malaria species
p. Falciparum
P. Vivax
P. Ovale
P. Malarias
P. Knowlesi
What stage of the malaria lifecycle causes malaria symptoms
Schizont rupture
Severe malaria disease
Anaemia
Respiratory distress
Cerebral malaria
Hypoglycaemia
Malaria treatment
Artemisin derivatives
Advantages and disadvantages of artemisin derivatives in malaria treatment
+ more effective than quinine, more rapid parasitaemia decr
- emerging resistance
Is viral DNA and RNA single or double stranded
Double DNA - except parvovirus
Single RNA - except retroviruses
Difference between positive and negative polarity RNA
Positive can be translated into protein immediately by cells
Negative must be converted to positive by RNA polymerase before translation
How are most viruses diagnosed now
PCR
Why are viruses Obligate intracellular parasites
Totally dependent on cells they infect for energy, metabolic intermediates, and most enzymes
Steps in viral life cycle
Attachment
Entry
Uncoating
Synthesis of viral components
Assembly and release
What type of viruses are measles, mumps, rubella, RSV, influenza, parainfluenza, Covid, hep C, and HIV
Enveloped RNA
What type of viruses Are papillomavirus, adenovirus, and parvovirus
Non enveloped DNA - PAP
What type of viruses are herpes, hep B, and poxviruses
Enveloped DNA
What types of virus are rotavirus, enterociruses, and Hep A
Non enveloped RNA
Herpes viruses
Herpes simplex
Varicella zoster
CMV
Epstein Barr
HHV 6/7/8
Signs of Herpes simplex in adults
Cold sore
Hepatic whitlow
2 main presentations of Herpes simplex in neonates
Disseminated HSV - sepsis-like, hepatitis, coagulopathy
HSV encephalitis - fever, seizures, Haemorrhagic infarction of white matter and cortex
How is viral infection different in early life to adult
More severe disease
More likely to become chronic
Prolonged shedding
CMV in adults
Self limiting, sub clinical or mononucleosis like illness only severe in immunocompromised
Commonest congenital infection in developed countries
CMV
Congenital CMV symptoms
Blueberry muffin rash
Sensorineural hearing loss
Congenital CMV treatment
6 month IV gangciclovir /oral valganciclovir
valganciclovir mechanism
Inhibits DNA synthesis
Most common varicella zoster complication
Secondary bacterial infection - can cause necrotising faschiatis (usually strep A)
What disease are caused by varicella zoster virus
Chicken pox
Shingles
Why is shingles more severe than chicken po
More robust immune response - immunopathology
What pathogen causes glandular fever
Epstein Barr virus
Glandular fever symptoms
Fever
Lymphadenopathy
Post viral fatigue
Burkitts lymphoma - Africa
Causes of Burkitts lymphoma
EBV Infection at early age
Chronic immunosuppression - malaria, HIV
What effects whether hep B becomes chronic
Age at infection
Younger age = more likely
Chronic hep b consequences
Cirrhosis
Hepatocellular carcinoma
Other cancers
Which Herpes viruses become latent
All
Which virus in more severe in adults than children
Varicella zoster
Which viruses can cause cancer
Epstein Barr
Hep b
Are there more treatment options for bacteria or viruses
Bacteria
