Infections and Immunity Flashcards

1
Q

What immunisations are given <1yr? (8)

A

8 weeks (2 months):

1) 6-in-1 vaccine
2) Pneumococcal (PCV) vaccine
3) Rotavirus vaccine
4) MenB

12 weeks (3 months):

5) 6-in-1 vaccine - 2nd dose
6) Rotavirus vaccine - 2nd dose

16 weeks (4 months):

7) 6-in-1 vaccine - 3rd dose
8) PCV - 2nd dose
9) MenB - 2nd dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What immunisations are given aged 1-15yr? (10)

A

1 year:

1) Hib/MenC - 1st dose
2) MMR - 1st dose
3) PCV - 3rd dose
4) MenB - 3rd dose

2-10yrs:
5) Flu vaccine - every year

3yrs and 4 months:

6) MMR - 2nd dose
7) 4-in-1 pre-school booster

12-13yr:
8) HPV vaccine

14yr:

9) 3-in-1 teenage booster
10) MenACWY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What immunisations are given to adults? (3)

A

65yr:

1) Pneumococcal (PPV) vaccine
2) Flu vaccine (and every year after)

70yr:
3) Shingles vaccine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What immunisations are offered to pregnant women? (2)

A
Flu vaccine - during flu season
Whooping cough (pertussis) vaccine - from 16 wks
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is in the 6-in-1 vaccine?

A

DHHPTW

1) Diptheria
2) Hep B
3) Hib - Haemophilus influenza type b
4) Polio
5) Tetanus
6) Whooping cough - pertussis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is in the 4-in-1 pre-school booster?

A

DTPP

1) Diphtheria
2) Tetanus
3) Whooping cough - pertussis
4) Polio

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is in the 3-in-1 teenage booster?

A

DTP

1) Diphtheria
2) Tetanus
3) Polio

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which vaccines are live? (3)

A

1) Influenza
2) MMR
3) Rotavirus (oral)

+ BCG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When does meningitis mostly occur in children?

A

Mostly in first 5 years of life

75% of cases are <15yrs

Younger children are at greater risk of brain damage and are more difficult to diagnose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does bacterial infection of the meninges occur, and why is this more likely to occur in children?

A

Colonisation of nasopharyngeal epithelium

Invasion of blood then meninges - BBB is less developed in children so these bugs are more likely to reach the meninges and cause infection

Cerebral oedema caused by inflammation + leaky vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the pathophysiology of viral meningitis?

A

Infection of a mucus membrane followed by lymph node involvement

Primary viraemia = causes viral illness

Secondary viraemia = involved organs such as liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are some risk factors for neonatal meningitis? (6)

A

1) Low birth weight (<2500g)
2) Prematurity
3) Premature rupture of membranes
4) Traumatic delivery
5) Fetal hypoxia
6) Maternal peripartum infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the most common bacterial causative organisms of meningitis in neonates? (3)

A

1) Group B strep
2) E coli
3) Listeria monocytogenes

+ other coliforms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the most common bacterial causative organisms of meningitis in infants (1 month to 2 years) (4)

A

Streptococcus pneumoniae
Neisseria meningitides
Haemophilus Influenza B
Meningococcus C

**The last 2 are both now vaccinated against and so their incidence has dropped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the most common causative organisms of meningitis in adolescents / adults? (3)

A

1) Neisseria meningitidis
2) Streptococcus pneumoniae
3) Listeria monocytogenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What symptoms may meningitis present with? (13)

A

Photophobia, neck stiffness and headache are the classical distinguishing symptoms but the young child (infant) might not have these making diagnosis more difficult

Infants may have non-specific signs of infection

  • High-pitched cry
  • Bulging fontanelle
  • Poor feeding
  • Respiratory distress

Other meningitic signs

  • Irritable
  • Vomitting
  • Drowsiness
  • Seizures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are some signs of raised ICP? (6)

A

1) Papilloedema
2) Altered / LOC
3) Bulging fontanelle in neonates
4) Increased BP
5) Decreased HR
6) Irregular respirations
7) Focal neurological signs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is meningitis vs meningococcal septicaemia?

A

Meningitis = inflammation of the leptomeninges that surround the brain and spinal cord

  • Various causative organisms
  • May have neck stiffness / photophobia
  • Unlikely to have a rash

Meningococcal septicaemia = systemic infection

  • CAUSED BY NEISSERIA MENINGITIDIS
  • Rapidly spreading purpuric rash
  • May or may not also have meningitis
  • Often fatal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What signs of meningism can be found on examination

A

1) Kernig’s sign - unable to extend knee when thigh flexed to 90 degrees
2) Brudunski’s sign - involuntary lifting of leg when lying supine and head is raised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What investigations are done in meningitis? (6)

A

Do not delay abx by more than 30 mins

1) Bloods - FBC, U&Es, CRP, glucose, blood cultures, gases
2) CT head
3) LP unless contraindicated
4) Urine for MC+S
5) Nasal / throat swabs
6) CXR - lung abscess

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What would the LP results be in bacterial vs viral meningitis?

A

Viral:

  • Clear / hazy appearance
  • Lymphocytes +
  • Protein +
  • Glucose = Normal

Bacterial:

  • Cloudy / purprulent
  • Neutrophils ++
  • Protein ++
  • Glucose = Low
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

List some contraindications to LP (7)

A

1) Raised ICP = stabilise first
2) Shock = stabilise first
3) After convulsions = stabilise first
4) Respiratory insufficiency = stabilise frist

5) Abnormal clotting
6) Infection at LP site
7) Extensive purpura

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is a pyrexia?

What is a red flag?

What is an amber flag?

A

Temp of 38 degrees celsius or more

Infants <3 months, fever of more than 38 = red flag

Infants 3-6 months, fever of over 39 = amber flag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the treatment of suspected meningococcal meningitis in the community?

A

If in doubt - treat as bacterial

IM benzylpenicillin single dose

<10yr = 1g
1-9yr = 600mg
<1yr = 300mg
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the treatment of suspected bacterial meningitis in hospital?

A

<3 months = IV cefotaxime + amoxicillin/ampicillin to cover listeria

> 3 months = IV ceftriaxone
+ dexamethasone to reduce neurological sequelae

Symptomatic treatment - antipyretics, analgesics, IV fluids

Inform PHE - they offer ciprofloxacin to all close contacts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Which bacterium and which virus cause the highest morbidity/mortality in meningitis?

A

Streptococcus pneumoniae

HSV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are some complications of meningitis?

A

Immediate:

  • Septic shock
  • Seizures
  • DIC
  • Cerebral oedema
  • Hydrocephalus (blockage of ventricular outlet)

Delayed:

  • Hearing loss (follow up includes hearing test)
  • Epilepsy
  • Cerebral palsy (if <2yr)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What vaccinations are given as prevention for meningitis and when are they given?

A

Men B vaccine is given at 2, 4 and 12-13 months

Meningitis ACWY given at 13-18 years old

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What type of bacteria is Neisseria meningitides?

A

Gram -ve diplococci

30
Q

What groups are there of Neisseria meningitides?

A

A, B, C, W, Y

31
Q

What are the early signs of meningococcal septicaemia? (6)

A

1) Fever
2) Mottling
3) Leg pain
4) Cold peripheries
5) Breathing difficulties
6) Non-blanching rash >12hrs

32
Q

What are some early complications of meningococcal septicaemia? (4)

A

1) DIC
2) AKI
3) Adrenal haemorrhage
4) Circulatory collapse

33
Q

How should non-blanching rash lesions be referred to depending on their size?

A
<3mm = petechial
3-10mm = purpura
>10mm = ecchymosis
34
Q

What is the classic surgical sieve pneumonic

A

VITAMIN CDE

Vascular
Infective / Inflammatory
Trauma
Autoimmune
Metabolic
Iatrogenic
Neoplastic
Congenital / Coagulopathy 
Developmental / Digestive
Endocrine / Environment
35
Q

What is a vascular condition causing purpura?

A

Henoch-Schonlein purpura

36
Q

What is the distribution of purpura in Henoch-Schonlein purpura?

What is the platelet count?

A

Pupura distributed across extensor surfaces, buttocks and ankles

Normal platelet count

37
Q

What is an infective / inflammatory cause of purpura?

A

Meningococcal disease

38
Q

What is the distribution of purpura in meningococcal disease?

A

Diffuse macular rash - appear before your eyes

Give immediate IM Benzylpenicillin !!!!

39
Q

What coagulopathies can cause purpura?

A

Thrombocytopenia

DIC

Scurvy (vit C deficiency causes weak capillary walls)

40
Q

What is the course of purpura in thrombocytopenia?

A

Petechial rash followed by a purpuric rash

Usually acute onset in the weeks following a URTI

41
Q

What is Henoch-Schonlein purpura? What are it’s main features?

A

IgA-mediated, autoimmune hypersensitivity vasculitis of childhood

Main features:

  • Purpura
  • Arthritis
  • Abdominal pain
  • GI bleeding
  • Glomerulonephritis
42
Q

Define:

1) Sepsis
2) Septicaemia
3) Septic shock

A

Sepsis = systemic inflammatory response + source of infection

Septicaemia = blood borne infection which causes sepsis

Septic shock = severe sepsis causing hypotension and compromised tissue perfusion

43
Q

Describe the process of septic shock

A

Bacterial toxins cause systemic inflammatory response:

1) Vasodilation
2) Increased microvascular permeability
3) Tissue hypoxia
4) Myocardial depression
5) DIC

44
Q

How may early signs of compensated shock present?

A
Tachycardia
Cool peripheries
Tachypnoea
Decreased urine output 
Inc cap refill time
O2 sats <95%
Confusion / LOC
Hypotension (later)

NB high fever can also cause tachycardia and peripheral vasoconstriction which may present similarly to early compensated shock

If septicaemia is meningococcal = look for signs of meningitis and non-blanching petechial/purpuric rash as an early sign (not always present) - in 30% rash is blanching and maculopapular

45
Q

What is involved in a septic screen in children?

A

Septic screen = CRAP blood

Cultures - blood, urine, stool, CSF (if no raised ICP), indwelling catheters
Radiography - CXR, AXR
ABG - metabolic acidosis
Pee (urinalysis)
Bloods - FCB (raised WCC), U&Es, LFTs, CRP, ESR, glucose, calcium, phosphate, clotting

46
Q

Which vaccine commonly gives a fever in the days following its administration?

A

MMR

Parents often bring children to A&E but advise them this is a self-limiting reaction

47
Q

List some ddx for a child presenting with a fever and a rash (7)

A

1) Measles
2) Rubella
3) Roseola
4) Scarlett fever
5) Fifth disease
6) Hand food and mouth disease
7) Chicken pox
8) Meningococcaemia

48
Q

List some ddx for a febrile child with a swelling in the neck (5)

A

1) Cervical adenitis
2) Infectious mononucleosis (EBV)
3) Mumps
4) Thyroiditis (often no fever)
5) Mastoiditis

49
Q

List some ddx of a child with pyrexia of unknown origin (6)

A

1) Infective endocarditis
2) Osteomyelitis
3) Collagen vascular disease
4) IBD
5) Neoplastic disease
6) Factitious fever

50
Q

List some ddx of a febrile child with recurrent infections (2)

A

1) HIV / AIDS

2) Hyposplenism / splenectomy

51
Q

What virus causes chickenpox?

A

Varicella-Zoster virus (HHV-3)

52
Q

What does reactivation of VZV lead to?

A

Shingles

53
Q

What is the incubation period of chicken pox?

A

10-21 days

54
Q

What is the usual duration of the rash in chickenpox?

A

6-10 days

55
Q

What is the recommended isolation period for chicken pox?

A

Until all the lesions are crusted over (usually 5-6 days)

56
Q

Describe the type of rash and distribution in chickenpox

A

Vesicular rash

Occurs in crops starting on trunk and spreading to face and extremities

Erythematous macules -> papules -> vesicles filled with clear fluid on erythematous base -> eruption of vesicles -> crusted papules -> hypopigmentation of healed lesions

Can have multiple stages on body at once

57
Q

What is the first feature of chickenpox? How long does this last?

A

Pyrexia and malaise for 1-2 days prior to onset of lesions

58
Q

How else does chickenpox present?

A
Headache
Malaise
Abdo Pain
Itchy rash
Shallow ulcers of the mucous membranes
Coryzal
59
Q

What may occur when immunocompromised get chickenpox?

A

Pneumonia
Large and bleeding vesicles
DIC

60
Q

What investigations are done for chickenpox?

A

Diagnosis clinical

PCR of vesicle fluid - confirms diagnosis

61
Q

What is the management of chickenpox in an otherwise healthy individual?

A
  • Advise re fluid intake, avoid scratching and keep nails short, avoid contact with pregnant women/neonates/immunocompromised
  • Use paracetamol for analgesia and pyrexia
  • Antihistamines and emollients for pruritis
62
Q

Why are NSAIDs not advised for chickenpox?

A

Possible association with necrotising soft tissue infections

63
Q

What populations require antiviral treatment for chickenpox?

A

IV aciclovir:

  • Immunocompromised
  • Systemic disease
  • Pt on high dose steroids
  • New lesions appearing after 8 days

PO aciclovir:
- >12yr

64
Q

What are some complications of chickenpox?

A

1) Secondary infection of skin lesions (e.g. Group A strep (step pyogenes) can produce necrotising fasciitis and toxic shock syndrome)
2) Viral pneumonia
3) Encephalitis
4) CNS complications e.g. benign cerebellar ataxia

65
Q

Why is chickenpox late in pregnancy concerning?

A

It can cause premature delivery

If rash appears within a week of delivery or 2 days after, there is a risk of neonatal chickenpox

66
Q

Why is neonatal chickenpox concerning?

A

There is transplacental transmission of virus but not antibody, and there is no time for IgG to develop and the baby is at 30% risk of death from severe pneumonia or fulminant hepatitis

NB IgG can cross the placenta (initial IgM cannot) - so if at least a week passes between rash and delivery is fine as IgG will have developed

67
Q

Why is chickenpox within first 2 weeks of pregnancy concerning?

A

Risk of congenital varicella syndrome

  • IUGR
  • Microcephaly
  • Cortical atrophy
  • Limb hypoplasia
68
Q

What is the treatment of neonatal chickenpox?

A

Immunoglobulin and aciclovir

69
Q

How is chickenpox transmitted?

A

Respiratory droplets or direct contact with vesicular fluid

70
Q

When should parents be advised they can reenter their children to school with chickenpox?

A

6 days after the last spots appear

71
Q

Why is ceftriaxone contraindicated in babies < 3 months?

A

It displaces bilirubin from albumin binding sites, resulting in higher levels of bilirubin that accumulate in the tissues