Infectious disease Flashcards
What are examples of inactivated vaccines?
Polio
Flu vaccine
Hep A
Rabies
What are some examples of conjugate/ subunit vaccines?
Pneumococcus Meningococcus Hep B Pertussis HPV Shingles
What are inactivated vaccines?
Patient given killed version of pathogen
What are subunit and conjugate vaccines?
Patient given part of an organism in order to stimulate an immune response
What are live attenuated vaccines?
Contain a weakened version of the pathogen
Who should not be given live attenuated vaccines?
Immunocompromised patients as they can still cause infection
Give examples of live atenuated vaccines:
MMR BCG Chickenpox Nasal influenza Rotavirus
What are toxin vaccines?
Contain a toxin that is normally produced by a pathogen, and cause immunity to the toxin not that pathogen
What are some examples of toxin vaccines?
Diptheria
Tetanus
At what stages in development are vaccines given?
8 weeks 12 weeks 16 weeks 1 year 3 12-13 14
What vaccines are given at 8 weeks?
6-in-1
Meningococcal B
Rotavirus
What is included in the 6-in-1 vaccine?
Diptheria Tetanus Pertussis Polio Hib Hep B
What is included in the 12 week vaccine?
6-in-1
Pneumococcal
Rotavirus
What is given at the 16 week vaccines?
6-in-1
Meningococcal B
What vaccines are given at 1 year?
2 in 1
Pneumococcal
MMR
Meningococcal B
What is in the 2 in 1 vaccine?
HiB
Mening C
What vaccines are given at 3 years 4 motntsh?
4 in 1
MMR
What vaccines are in the 4 in 1 vaccine?
Diptheria
Tetanus
Pertussis
Polio
What vaccine is given at 12-13 years?
HPV
How many doses of the HPV vaccine are given?
2: 6-24 months apart
What vaccines are given at 14?
3 in 1
Meningococcal A, C, W & Y
What is included in the 3 in 1 vaccine?
Tetanus
Diptheria
Polio
Why is the HPV vaccine given at 12-13?
Hopefully before they become sexually active
What is the BCG vaccine and who gets it?
Offered from birth for babies who are at higher risk of tuberculosis
What white blood cells pay a key part in sepsis?
Macrophages
Lymphocytes
Mast cells
What do the WBC’s release in response to the causative pathogen?
Cytokines (Interleukins, TNF)
What is the action of the cytokines?
Activate other parts of the immune system, leading to further release of chemicals
What is the action of nitrous oxide?
Released in an immune response to cause vasodilation
What do cytokines do to blood vessels?
Cause the endothelial lining to become more permeable
Why do you get oedema in sepsis?
The blood vessels become more permeable, causing fluid to leak out into the extracellular space
What is the effect of the oedema in sepsis?
It creates space between the blood and tissues, reducing the amount of oxygen that reaches the tissues
What system is also activated in sepsis?
The coagulation system
What does the activation of the coagulation system lead to in sepsis?
Deposition of fibrin throughout the circulation, compromising organ/ tissue perfusion
Thrombocytopenia
Haemorrhages
DIC
What is disseminated intravascular coagulopathy?
Small blood clots develop throughout bloodstream and block small blood vessels
Why does blood lactate rise in sepsis?
It is a waste product which forms as a result of anaerobic respiration in hypo-perfused tissues
Why are tissues hypo-perfused in sepsis?
Chemicals cause vasodilation
Oedema reduces amount of oxygen reaching tissues
Fibrin depositions compromise perfusion
Inflammation
When does sepsis become septic shock?
When sepsis has lead to cardiovascular dysfuntion
How should septic shock be treated?
IV fluid resuscitation
Inotropes
What signs should you look out for that indicate sepsis?
Deranged obs Prolonged CRT Fever/ hypothermia Deranged behaviour Poor feeding Incosolable Reduced consciousness Floppy Skin colour changes
How are children assessed for sepsis?
Traffic light system:
Green= low risk
Amber= medium risk
Red= high risk
What features are children assessed on when looking for sepsis?
Colour Activity Respiration Circulation Other (fever, rash, seizures)
When would a child be treated immediately for sepsis?
All under 3 months with a temperature of >38
What is the immediate management of sepsis?
3 In: - IV fluids - Abx - Oxygen 3 Out: - Blood cultures -Urine ouput/ dipstick - Blood tests
What blood tests should be done when investigating sepsis?
FBC U&E CRP INR Blood gas: Lactate and acidosis
What additional investigations may be performed when diagnosing sepsis?
CXR Abdo/ pelvic USS LP Meningococcal PCR Serum cortisol
How long should antibiotics be continues if bacterial infection is the suspected cause of sepsis?
5-7 days
When would you consider stopping antibiotics in a suspected sepsis case?
When there is low suspicion of bacterial infection
Patient is well
Blood cultures and two CRP results are negative at 48 hours
What is the most common cause of fever in infants <3 months?
Bacterial
Why is it unlikely for an infant <3 months to have a viral infection?
Due to passive immunity from mother
What is meningitis?
Inflammation of the meninges
What are the meninges?
Lining of the brain and spinal cord
What meningococcal septicaemia?
Meningococcus bacterial infection in the bloodstream
What is meningococcus full name?
Niesseria meningitidis
What kind of bacteria is meningococcus?
Gram-negative diplococcus
What causes the classic ‘non-blanching’ rash in meningitis?
Meningococcal septicaemia causing DIC and subcutaneous haemorrhages
What is meningococcal meningitis?
When meningococcus infects the meninges and CSF
What are the most common causative organisms of meningitis?
Niesseria meningitidis (meningococus) Strep pneumoniae (pneumococcus)
What is the most common cause of bacterial meningitis in neonates?
Group B strep (found in the mothers vagina)
What are the typical symptoms of meningitis?
Fever Neck stiffness Vomiting Headache Photophobia Altered consciousness Seizures
What is the characteristic symptoms of meningococcal septicaemia?
Non-blanching rash
How do neonates and babies present with meningitis?
Non-specific: hypotonia Poor feeding Lethargy Hypothermia Bulging fontanelle
When is a lumbar puncture indicated in meningitis investigations?
< 1 months presenting with fever
1-3 months with fever and unwell
<1 year with unexplained fever and serious illness
What are the two special tests that can be performed to look for meningeal irritation?
Kernig’s test
Brudzinski’s test
What is Kernig’s test?
Lying the patient on their back, flexing one hip and knee to 90 degrees and then slowly straightening the knee to stretch the meninges
What is Brudzinski’s test?
Lying patient flat on back and gently lifting head and neck off bed. Positive test is if patient involuntarily flexes hips and knees
How is bacterial meningitis managed in the community?
Stat Benzylpenicillin injection prior to transfer to hospital
What should be sent off prior to starting antibiotics in an ideal worlsd?
Blood culture and CSF
Meningococcal PCR
How is bacterial meningitis treated in hospital?
Follow local guideline antibiotics
What are the typical antibiotics given to an infant <3 months to treat meningitis?
Cefotaxime + amoxicillin
What antibiotic is given to children >3months for meningitis?
Ceftriaxone
What should be added to antibiotic treatment if there is a risk of penicillin resistant pneumococcal infection?
Vancomycin
What is given to children with meningitis in addition to antibiotics and why?
Dexamethasone to reduce the frequency and severity of hearing loss and neurological damage
What must be done in all cases of bacterial meningitis and meningococcal infection?
Inform public health as they are notifiable diseases
What is given to people who have had significant exposure to a patient with meningococcal infection?
Post exposure prophylaxis: single dose of ciprofloxacin
What counts as significant exposure?
Prolonged contact with a patient with meningococcal infection within 7 days prior to onset of infection
What are the most common causes of viral meningitis?
HSV
Enterovirus
VZV
What must be done to differentiate between bacterial and viral meningitis?
LP for CSF
How is viral meningitis treated?
Tends to be milder so usually supportive
Van use aciclovir
Where is the needle inserted in a lumbar puncture and why?
L3-L4, as the spinal cord ends at L1-L2
What are CSF samples tested for after an LP?
Bacterial culture Viral PCR Cell count Protein Glucose
What should be taken at the same time as an LP and why?
Blood glucose sample to compare to CSF glucose content
What are the characteristic features of CSF sample infected with bacteria?
Cloudy High protein content Low glucose content High neutrophil count Bacterial culture positive
What are the characteristic features of a viral CSF sample?
Clear appearance
Normal (or raised) protein
Normal glucose
High lymphocyte count
Why does the CSF contain high protein and low glucose with bacterial infection?
Bacteria release proteins and use up glucose
What are the key complications of meningitis?
Hearing loss Seizures Cognitive impairment Learning disability Memory loss Cerebral palsy
What is encephalitis?
Inflammation of the brain
What are the non-infective causes of encephalitis?
Autoimmune
What is the most common cause of encephalitis?
Viral infection
What is the most common viral cause of encephalitis?
Herpes simplex virus (HSV)
Wha is the most common viral cause of encephalitis in children?
HSV-1 from cold sores
What is the most common viral cause of encephalitis in neonates?
HSV-2 from genital herpes contracted during birth
What are other viral causes of encephalitis?
VZV Cytomegalovirus EBV Enterovirus Adenovirus Influenza
How does encephalitis present?
Altered consciousness Altered cognition Unusual behaviour Acute onset of focal neurological symptoms and seizures Fever
What key investigations are done into encephalitis?
LP MRI EEG Swabs to find causative organism HIV testing
When would an LP be contraindicated and what investigation should be done instead?
GCS < 9
Haemodynamically unstable
Active seizures or post-ictal
Do CT scan instead
How is suspected encephalitis managed?
IV antivirals
What antiviral is used to treat HSV or VZV?
Aciclovir
What antiviral is used to treat CMV?
Ganciclovir
What are the complications of encephalitis?
Lasting fatigue Change in personality/ mood/ memory/ cognition Learning disability Headaches Chronic pain Movement disorders Sensory disturbance Seizures Hormonal imbalance
What causes infectious mononucleosis?
Epstein Barr Virus (EBV)
What is infectious mononucleosis also known as?
Mono
Kissing disease
Glandular fever
How is EBV spread?
Saliva of infected individuals: kissing, sharing cups, toothbrushes act
When are most people infected with EBV?
As children when it causes few symptoms
When does EBV infection tend to cause more severe symptoms?
In teenagers or young adults
What is symptomatic infection with EBV called?
Infectious mononucleosis
What are the symptoms fo IM?
Fever Sore throat Fatigue Lymphadenopathy Enlarged tonsils Splenomegaly
Why should cefalosporins and amoxicillin be avoided in glandular fever?
Cause itchy maculopapular rash
How is EBV diagnosed?
Antibody tests
What are heterophile antibodies?
Antibodies that are produces in infectious mononucleosis (and other things)
Up to how long does it take heterophile antibodies to be produced in IM?
Up to 6 weeks
How are heterophile antibodies tested for?
Monospot test
Paul-Bunnel test
What is a monospot test?
Introduces patients blood to RBC’s from horses. Antibodies will react to give a positive result
What antibodies is it possible to test for in EBV infection?
IgM
IgG
How is IM managed?
Supportive
Avoid alcohol and contact sports
What are the complications of IM?
Splenic rupture Glomerulonephritis Haemolytic anaemia Thrombocytopenia Chronic fatigue
What kind of infection is mumps?
Viral infection
How is mumps spread?
Respiratory droplets
What is the incubation period for mumps?
15-25 days
How long does mumps usually last?
1 week
How is mumps managed?
Supportively
What level of protection does the MMR vaccine offer against mumps?
80%
What is the symptoms course of mumps?
Prodrome (flu-like symptoms) followed by parotid swelling a few days later
Symptoms of complications (abdo pain, testicular pain, meningitis)
What is the characteristic feature of mumps?
Parotid gland swelling with associated pain
What are the complications of mumps?
Pancreatitis
Orchitis
Meningitis
Sensironeural hearing loss
How is mumps diagnosis confirmed?
PCR testing of saliva swab
What must be done in all mumps cases?
Notify public health
How can HIV be transmitted to children?
During pregnancy
During birth
Breastfeeding
Blood or bodily fluid exposure
How can you prevent transmission of HIV during birth?
Alter mode of delivery
Prophylactic treatment
When can normal vaginal delivery be performed when the mother has HIV?
If she has a viral load <50
When should C-section be considered in a HIV +ve mother?
Should be considered >50
Definitely performed if viral load >400
When should IV Zidovudine be given during C-section?
If the viral load is unknown or there are >10000 copies/ ml
What prophylactic treatment should low risk babies be give?
Zidovudine for 4 weeks
What prophylactic should high risk babies be given?
Zidovudine, lamivudine and nevirapine for 4 weeks
What makes a baby high risk in terms of prophylaxis treatment offered?
Mums viral load is >50 copies/ ml
Can HIV mothers breast feed?
Not recommended no matter how low the viral loaf
Why might a child under 18 months test positive for HIV despite not having the virus?
Due to maternal antibodies
When should you test children for HIV?
Babies to HIV positive parents
If immunodeficiency is suspected
Young people who are sexually active or there are other risk factors
What are the two options for HIV testing?
HIV antibody screen
HIV viral load
How and when are babies to HIV positive parents tested?
HIV viral load test at 3 months
HIV antibody test at 24 months
What are the key principles in managing HIV?
Antiretroviral therapy
Normal childhood vaccines
Prophylactic Septrin with low C4 counts
Treatment of opportunistic infections
What kind of infection is hepatitis B?
DNA virus
How is Hep B transmitted?
Direct contact with blood or bodily fluids
Vertical transmission
How quickly do most children recover from Hep B infection?
Within 2 months
What happens to a small proportion of people with Hep B infection?
Become chronic hep B carriers0 Virus DNA integrates into their own DNA
What is the risk of developing chronic hepatitis B after exposure in a neonate?
90%
What is the risk of developing chronic hepatitis B after exposure in a child <5?
30%
What is the risk of developing chronic hepatitis B after exposure in an adolescent?
<10%
Are chronic hep B carriers symptomatic?
No have normal growth and development and liver function tests
What happens to <5% of chronic hep B carriers?
Develop liver cirrhosis
What are the different antigens and antibodies you can look for in Hep B infection?
HBsAg HBeAg HBcAb HBsAb HBV DNA
What is HBsAg and what does it signify?
Surface antigen
Indicates active Hep B infection
What is HBeAg and what does it signify?
E antigen
Marker of viral replication and implies high infectivity
What is HBcAb and what does it indiate?
Core antibodies
Implies past or current infection
What is HBsAb and what does it indicate?
Surface antibody
Implies vaccination or past/ current infection
What is HBV DNA and what does it indicate?
Direct count of viral load
When screening for hep B, what is initially looked for?
HBcAb and HBsAg for previous and active infection
If HBcAb and HBsAg are positive, what is then looked for?
HBeAg and HBV DNA (Viral load)
What can HBcAb help distinguish between?
Acute, chronic and past infection
What does the level of HBeAg correlate with?
The infectivity
Which children should be tested for hep B?
Those with hep B positive mums
Migrants from endemic areas
Close contacts of patients with hep B
What should neonates with hep B positive mothers be given within 24 hours of birth?
Hep B vaccine
Hep B immunoglobulin infusion
What additional measures to babies born to hep B positive mothers recieve?
Hep B vaccine and Ig infusion at birth
Addition vaccine at 1 and 12 months
Test for HBsAg at 1
Is it safe for a hep B positive mother to breastfeed?
Yes if baby has been properly vaccinated
What does the hep B vaccine involve?
Injecting hep B surface antigen
3 doses at different intervals
How is Hep B managed?
Supportive
Regular follow up with chronic cases
What kind of virus is Hep C?
RNA virus
How is hep C spread?
By blood and bodily fluids
Is there a vaccine for hep C?
No
What is the disease course of Hep C in adults?
1 in 4 make full recovery
3 in 4 develop chronic hep C
What are the complications of hep C?
Liver cirrhosis
Hepatocellular carcinoma
What percentage of babies the Hep C infected mothers develop the virus?
5-15%
Do babies and children get affected by hep C?
No symptoms or pathology associated
How is Hep C tested for?
Hep C antibody
Hep C RNA testing
How is Hep C managed in adults?
Curable using direct acting antivirals
How is Hep C managed in children?
Test babies at 18 months with positive mothers
Often clear is spontaneously
Treatment typically delayed until adulthood
