Infectious Disease Flashcards
What is an inactivated vaccine ?
Involves giving a killed version of the pathogen. They cannot cause an infection and are safe for immunocompromised patients although they may not have an adequate response.
Examples - polio, flu vaccine, hepatitis A and rabies
What is a subunit and conjugate vaccine ?
Only contains parts of the organism used to stimulate an immune response. They also cannot cause infection and are safe for immunocompromised patients. For example : pneumococcus, meningococcus, hepatitis B, pertussis, Haemophilus influenza type b, HPV and shingles
What is a live attenuated vaccines ?
A weakened version of the pathogen. They are still capable of causing infection particularly in immunocompromised patients. For example :
Measles, mumps and rubella
BCG
Chicken pox
Nasal influenza
Rotavirus
What is a toxin vaccine ?
A toxin that is normally produced by a pathogen. They cause immunity to the toxin and not the pathogen itself. For example :
Diphtheria
Tetanus
What vaccines are given at the 8 week mark ?
6 in 1 vaccine - diphtheria, tetanus, pertussis, polio, haemophilus, type B (hiB) and hepatitis B
Meningococcal type B
Rotavirus
What is vaccine are given at the 16 week mark ?
6 in 1 vaccine
Meningococcal
What vaccines is given at the 12 week mark ?
6 in 1
Pneumococcal
Rotavirus
What vaccines are included in the 6 in 1 ?
Diphtheria
Tetanus
Pertussis
Polio
Haemophilus influenza
Type B (HiB)
Hepatitis B
What vaccines are given at the 1 year mark ?
2 in 1 - Haemophilus type B and meningococcal type c
Pneumococcal
MMR
Meningococcal type b
At what age is the influenza vaccine given ( nasal vaccine ) ?
2 - 8 years old
At what age is the HPV vaccine given ?
12-13 years old
What strains of HPV cause genital warts ?
6 and 11
What strains of HPV cause cervical cancer ?
16 and 18
How does inflammation throughout the body occur in sepsis ?
The causative pathogens are recognised by macrophages, lymphocytes and mast cells. These cells release vast amounts of cytokines such as interleukins and tumour necrosis factor to alert the immune system. This immune activation leads to further release of chemicals such as nitrous oxide that causes vasodilation. This causes inflammation.
How does sepsis cause oedema ?
Many of these cytokines cause the endothelial lining of blood vessels to become more permeable. This causes fluid to leak out of the blood into the extracellular space, leading to oedema and a reduction in intravascular space.
How does sepsis cause DIC ?
Activation of the coagulation system leads to deposition of fibrin throughout the circulation further compromising organ and tissue perfusion.
It also leads to consumption of platelets and clotting factors. This leads to thrombocytopenia, haemorrhages and an inability to form clots and stop bleeding. This is called disseminated intravascular coagulopathy.
Why is the lactate levels high in sepsis ?
Blood lactate rises as a result of anaerobic respiration in the hypo-perfused tissues with an inadequate oxygen. A waste product of anaerobic respiration is lactate.
What is septic shock ?
It is diagnosed when sepsis has lead to cardiovascular dysfunction. The arterial blood pressure falls, resulting in organ hypo-perfusion. Anaerobic respiration starts.
What is the management of septic shock ?
Treated aggressively with IV fluids to improve the blood pressure and tissue perfusion.
If this fails then a child should be escalated to high dependency or intensive care where inotropes can be given ( noradrenalin ).
What are the signs of sepsis in children ?
Deranged physical observations
Prolonged CRT
Fever or hypothermia
Deranged behaviour
Poor feeding
High pitched crying
Reduced consciousness
Reduced body tone
Skin colour changes
Shock - circulatory collapse
What is the immediate management of sepsis ?
Give oxygen if evidence of shock or oxygen sats below 94%
Obtain IV access
Blood tests - FBC, U&E’s, CRP, clotting screen, blood gas
Blood cultures
Urine dipstick
Antibiotics within an hour of presentation
IV fluids
What are some additional investigations to be performed depending on suspected infection for sepsis ?
CXR
Abdominal and pelvic USS
Lumbar puncture
Meningococcal PCR
Serum cortisol if adrenal crisis
What is meningitis ?
Defined as inflammation of the meninges.
Usually due to a bacterial or viral infection
How does neisseria meningitidis present on a gram stain ?
Gram negative diplococcus
What does a rash in meningitis suggest ?
It causes the non-blanching rash.
Caused by the infection causing DIC and subcutaneous haemorrhages.
What is bacterial meningitis ?
Inflammation of the meninges caused by a bacterial infection.
Most common cause - neisseria meningitidis and streptococcus pneumoniae.
What is the most common cause of bacterial meningitis in neonates ?
Group B strep ( GBS )
How does meningitis present ?
Fever
Neck stiffness
Vomiting
Headache
Photophobia
Altered consciousness
Non-blanching rash
Seizures
How do neonates present with sepsis ?
Hypotonia
Poor feeding
Lethargy
Hypothermia
Bulging fontanelle
What are 2 special tests you can perform to look for meningeal irritation ?
Kernig’s test
Brudzinski’s test
How do you perform Kernig’s test ?
Involves lying the patient on their back, flexing one hip and knee to 90 degrees and then slowly straightening the knee whilst keeping the hip flexed at 90 degrees.
This creates a slight stretch in the meninges.
In meningitis - Spinal pain or resistance to movement
What is Brudzinski’s test ?
Involves lying the patient flat on their back and gently using your hands to lift their head and neck off the bed and flex their chin to their chest.
In a Positive test the patient involuntarily flexes their hips and knees.
How should meningitis presenting in the GP be managed ?
Urgent stat injection ( IM or IV ) of benzylpenicillin prior to transfer to hospital.
Giving antibiotics should not delay transfer to the hospital.
How should meningitis be diagnosed ?
Lumbar puncture
Meningococcal PCR - quicker than a blood culture
How is meningitis treated ?
Under 3 months - cefotaxime plus amoxicillin
Above 3 months - cetriaxone
Dexamethasone also is used in bacterial meningitis
What is the usual choice of antibiotics in post exposure prophylaxis of meningitis ?
Single dose of ciprofloxacin
What are the most common causes of viral meningitis ?
Herpes simplex virus
Enterovirus
Varicella zoster virus
How is viral meningitis diagnosed ?
A sample of CSF from the lumbar puncture should be sent for viral PCR testing.