Investigating genetic disorders of childhood Flashcards
What are the most common types of death in childhood?
Pneumonia and diarrhoea
How do infections cause death of a host?
- toxins of organism
- immunopathology of the host
What are the 2 toxins of an organism
Exotoxins - bacterial toxins secreted by the host
Endotoxins - forms part of outer membrane of gram negative bacteria
What do cholera exotoxins do?
- open Cl- channels that lead to water into gut
What do diphtheria exotoxins do?
- sore throat with pseudo membrane
- inhibits protein synthesis by acting on heart (myocarditis and heart block) and nerves (swallowing/paralysis/diplopia difficulties)
What do endotoxins do?
- released during organism lysis
- leads to macrophage activation
What are the immunological differences in children compared to adults?
- immaturity (newborn babies not set to deal with viral infections - immune skewing)
- lack of memory cells
What are the anatomical immunological differences in children vs adults?
- thinner skin
- shorter airways
- anatomy of eustachian tube (more straight in otitis media)
What is the exposure immunological differences in children vs adults?
- hygiene, nursey/day care
What is fever?
- present with large range of infections
- temp > 38,2 (depending on method of measurement)
- 0.5 lower in mouth vs rectal
- 1 lower in armpit vs rectal
Which infections are severe?
Septicaemia Meningitis Pneumonia Epiglottitis Septic arthritis Osteomyelitis TB Tetanus
Which infections are more common?
- tonsillitis
- Otis media
- UTI
- gastroenteritis
- impetigo
What is septicaemia and meningitis caused by? (older children)
- strep pneumoniae
- Neisseria meningitides
- haemophilus influenza B
What are the clinical symptoms of septicaemia?
- tachycardia
- tachypnoea
- prolonged capillary refill
- low BP
- rash
(non specific presentation with shock)
What are the clinical symptoms of meningitis?
- high temp
- headaches
- vomiting
- not able to tolerate bright lights
- drowsiness
- stiff neck
How is meningitis diagnosed?
- younger child = more non-specific
- high suspicion
- > 3 months do lumbar puncture
What does the appearance of CSF change in meningitis?
- bacterial : cloudy
- viral: clear/normal
- TB: opalescent
How do the cells in CSF change in meningitis?
- bacterial: neutrophils
- viral: lymphocytes
- TB: lymphocytes
How does the blood protein and glucose in CSF change in meningitis?
- bacterial: high glucose, high protein
- viral: normal protein and glucose
- TB: very high glucose, very high protein
What causes tetanus?
- gram positive bacillus
- spores found in soil
- exotoxin interacts with NMJ
- lack of maternal vaccination in pregnancy
- use of unclean blade to cut cord
What are the common organisms found in young infants before vaccination?
- Group B strep
- E coli
- listeria
What do young infants need for protection?
cefotaxime and amoxiciliin
- older children just need ceftriaxone as don’t need amoxicillin for listeria cover as should be vaccinated
What is neonatal sepsis?
- neonatal period is 28 days
- ## maternal colonisation of pathogens in colon and vaginal canal
What is the difference between early onset and late onset sepsis?
- early onset: 48 hours
- late onset: within 3 days (settles in meninges of bones and joints)
What is streptococcus penumoniae?
- normal flora in 5-70%
- gram positive
What immune defects predispose to pneumococcal infection?
- absent/non functional spleen (vulnerable to pneumococcus, need vaccination and lifelong penicillin)
- hypogammaglobulinaemia
- HIV infection
What splenic malfunctions may predispose pneumococcal infection?
- congenital asplenia
- traumatic removal
- hyposplenism
What are the non-invasive clinical features of pneumococcal infection?
- acute otitis media
- sinusitis
- conjunctivitis
- penumonia
What is otitis media?
- pneumococcus sits in nasopharynx
- children tube more straight/horizontal so secretions don’t drain away vertically
- body amounts immune response
- pus builds up = pain
- perforation of ear drum eventually
What are the invasive clinical features of pneumococcal infection?
- pneumonia
- septicaemia
- meningitis
- peritonitis
- septic arthritis
- osteomyelitis
(gets into the blood stream -> can get sepsis, most of time have bug already but when from colonising to being invasive organism)
What is pneumococcal pneumonia?
- lobar and empyema
How is empyema treated?
- chest drain and urokinae
- VATS
(pus gotten into space around the lung, compressing lung, consequence of pneumonia, BUT can be pus in any hollow space)
What are the 2 types of pneumococcal vaccines?
- pneumococcal polysaccharide vaccine (pneuvax to older people)
- pneumococcal conjugate vaccine (proteins attached to polysaccharide, allows engagement of T helper cell, protein gets internalised and conguated protein presented as fragment for recognition as MHC, helper T cell produces signalling to produce antibody against polysaccharide)
What are the main fungi?
2 types - yeasts (oval/round) and moulds (branching filaments)
Mycoses
What are common presentations of superficial mycosis?
- candidiasis (nappy rash)
- tinea corporis (ring worm)
(treat with topical antifungal - nystatin)
What are rare presentations of invasive mycosis?
- candidemia (extremely preterm infant, effecting kidneys and brain)
- pulmonary aspergillosis (chronic granulomatous disease, impaired neutrophil function)
What is the difference between superficial and invasive mycosis?
Superficial - common and occurs in normal hosts
Invasive - rare and opportunistic infections in immunocompromised hosts
What are the classifications of protozoa?
- sporozoa
- amoebae
- flagellates
What are examples of sporozoa?
- plasmodium species (malaria)
- toxoplasma gondii
- cryptosporidium (diarrhoea)
What are the 4 main species of malaria?
Plasmodium falciparum/viva/ovale/malariae
What is an example of an amoebae?
- entamoeba histolytica (amoebic dysentery)
What are some examples of flagellates?
- giardia (diarrhoea, malabsorption)
- trypanosoma (sleeping sickness, Chagas)
- leishmania
Which infections are often present with fever?
- bacterial infections
- viral infections
- parasitic infections
- fungal infections
Which are the cocci gram positive organisms?
- staphylococcus
- streptococcus
- enterococcus
Which are the bacilli gram positive organiss?
- Corynebacterium
- listeria
- bacillus (cereus or anthracis(
- clostridium (tetani, botulinum, difficile)
