Infections

Question 1

The 2007 NICE Feverish illness in children guidelines introduced a ‘traffic light’ system for risk stratification of children under the age of 5 years presenting with a fever.

What is the traffic light system?

Answer 1

Question 2

What is the management for the traffic light system, depending on the colour?

Answer 2

• Green → child managed at home w/ appt care advice, incl when to seek further help
• Amber → provide parents w/ safety net or refer to paed specialist for further assessment; a safety net includes verbal/written info on warning symptoms + how further healthcare can be accessed, a follow-up appt, liaison w/ other HCPs eg. out-of-hours providers, for further follow up
• Red → refer child urgently to paed specialist

Oral Abx should not be prescribed to children w/ fever without apparent source. If a pneumonia is suspected but child is not going to be referred to hospital then a CXR does not need to be routinely performed.

Question 3

Gastroenteritis is inflammation of the GI tract secondary to infection.

What are the causes?

Answer 3

• Viral → Rotavirus (most common particularly in children under 5), adenovirus, enterovirus, norovirus
• Bacterial → Campylobacter Jejuni (most common), E. Coli, salmonella, shigella

Toxins from bacteria can also cause gastroenteritis such as staph aureus, bacillus cereus + clostridium perfringens. Responsible pathogen damages villi leading to malabsorption of intestinal contents and osmotic diarrhoea. Toxins bind to receptors in the intestine leading to release of chloride ions and causing secretory diarrhoea.

Question 4

What are clinical features of gastroenteritis?

Answer 4

• Acute onset of diarrhoea + vomiting
• Disease severity depends on degree of dehydration
• Other symptoms: fever, headache, lethargy, abdo pain, poor feeding, dysuria, weight loss

Dehydration more likely in those: under age of 1, low birth weight, stopped breastfeeding, 5+ episodes diarrhoea or 2 episodes vomiting in 24hrs and those who have signs of malnutrition.

Question 5

What are the investigations for gastroenteritis?

Answer 5

• Ask about dietary intake (seafood, unwashed veg, uncooked meat, takeaways), recent travel + exposure to other individuals unwell
• Most cases are mild, w/ clear history so no investigations needed
• Stool examination is primary test, stool to be sent if:
  
  • there is diagnostic doubt
  • patient septic
  • blood or mucus in stool
  • child immunocompromised
  • diarrhoea >2wks

Question 6

How do you assess for dehydration?

Answer 6

Question 7

What is the management of gastroenteritis?

Answer 7

• Use NG route to give fluids if child is not shocked + not vomiting
• If giving IV fluids use isotonic crystalloid such as 0.9% saline
• Amount of fluid to give is calculated by adding maintenance + the estimated deficit (and sometimes ongoing losses)
• Always discuss route, volume and rates of rehydration with a senior
• Isolate children with diarrhoea and vomiting
• Antibiotics not regularly prescribed as most cases viral

Question 8

What are common viral causes of meningitis infection?

Answer 8

• Accounts for 2/3rds of all cases
• Enteroviruses most common, self-limiting
• Other causes: EBV, adenovirus, VZV, CMV
• Herpes simplex rare but devestating cause of meningoencephalitis, usually acquired from mother in neonates during delivery

Question 9

What are bacterial causes of meningitis in children?

Answer 9

• Children under 3 months of age:
  
  • Group B strep
  • E. Coli
  • Listeria
• 3 months to 16 years:
  
  • Strep pneumoniae
  • Neisseria meningitides
  • Haemophilus influenzae type B

Fungal causes are rare but more common in immunocompromised (most common is cryptococcus)

Question 10

What are clinical features of meningitis in children?

Answer 10

Question 11

What investigations are done for suspected meningitis?

Answer 11

• FBC, U+Es, LFTs
• CRP, blood culture, viral PCR, meningococcal PCR
• Lactate, Glucose, Blood gas
• CT scan if any neurological signs/raised ICP
• Lumbar puncture

Question 12

For meningitis, lumbar puncture is used to confirm diagnosis, determine the antibiotic sensitivities to any bacteria found and to determine the length of treatment according to the organism. CSF samples can also be sent for meningococcal and viral PCR on top of bacterial culture.

What is the difference in LP samples between bacterial, viral and tuberculosis?

Answer 12

Absolute contraindications to LP:

• Signs of raised ICP (relative HTN, bradycardia, focal neuro signs, papilloedema, doll’s eyes, fluctuating level of consciousness)
• Cardiopulmonary compromise
• Infection of overlying skin
• Coagulopathy of thrombocytopenia

Question 13

What is the management of meningitis?

Answer 13

• ABCDE in child w/ signs of shock, seizures or raised ICP
• Abx → ceftriaxone IV 4g OD
• Aciclovir IV 10mg/kg 8hrly if viral encephalitis suspected
• Amoxicillin IV if immunocompromised or >55yrs to cover for listeria
• If in GP setting → IM benzylpenicillin
• Report to public health authorities

Question 14

What are the signs of shock in a child?

Answer 14

• Increased resp rate
• Sinus tachycardia
• Hypotension
• Oliguria
• Cold
• Klammy
• Slow cap refill

Question 15

What is the ABCDE approach for emergencies in children?

Answer 15

Question 16

Staph aureus is the main staph species responsible for causing disease.

What skin infections can it cause?

Answer 16

• Cellulitis
• Orbital cellulitis
• Abscesses
• Impetigo

Question 17

What invasive infections/diseases can staph aureus?

Answer 17

• Osteomyelitis
• Septic arthritis
• Pneumonia
• Septicaemia
• Endocarditis

Question 18

Staph Aureus organism can cause diesease directly but is also capable of produycing toxins which then act as super antigens. These cause a massive T-cell activation and cytokine release, which can cause toxic shock syndrome.

What is the treatment for Staph Aureus infection?

Answer 18

• Depends on site + severity
• Beta-lactam Abx → FLUCLOXACILLIN
• Penicillin allergic? → erythromycin (macrolide)
• MRSA? → vancomycin (glycopeptide)

Question 19

What are streptococcal infections?

Answer 19

• Cause wide range of infections
• Like staph, they can cause skin + soft tissue infections
• Can cause serious invasive disease - meningitis, toxic shock syndrome, septicaemia

Treatment depends on disease but will often be penicillin

Question 20

What can streptococcus pneumoniae cause?

Answer 20

• Mild infections → otitis media, pharyngitis, conjunctivitis, sinusitis
• Serious invasive infections → pneumonia, meningitis, sepsis

Commonly carries as a commensal organism in the nasopharynx of healthy children, it can be spread to those at risk by respiratory droplets

Question 21

What does Group A beta-haemolytic streptococcus cause?

Answer 21

• AKA strep pyogenes
• Commonly causes pharyngitis (diagnosed w/ throat swab)
• Can also cause necrotising fasciitis, toxic shock syndrome + bacteraemia
• Also causes puerperal sepsis, scarlet fever + longer term effects post-infection eg. rheumatic fever, post-streptococcal glomerulonephritis + paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS)

Question 22

What can group B streptococcus cause?

Answer 22

• Common commensal in genital tract of women
• Can result in neonatal sepsis
• Women who are known to be GBS positive should receive intrapartum ABx to reduce risk of neonatal GBS disease

Question 23

What are features of chicken pox?

Answer 23

• Varicella zoster virus
• Spread through contact with infected individuals
• Incubation period = 10-21 days
• Prodromal features (1-2 days b4 rash): malaise, headache, abdo pain
• Itchy rash: macules → papules → vesicles which crust over
• Rash starts on head/trunk before spreading
• Child will be infectious from 48hrs before the onset of rash until all lesions have crusted over (5 days after)
• Diagnosis commonly clinical, although swabs taken + PCR performed if required

Question 24

Treatment for chicken pox is indicated in asymptomatic neonates (if mother acquires chickenpox within 7 days prior to delivery, or up to 4 days after), adolescent children and immunocompromised children.

What is the treatment for chicken pox?

Answer 24

• Keep cool, trim nails
• Calamine lotion
• School exclusion (infectious period, 1-2 days before + 5 days after rash)
• Immunocomproised pts + newborns with peripartum exposure → varicella zoster immunoglobulin (VZIG), if chickenpox develops then IV aciclovir should be considered

Question 25

What are **key** **features** of the pertussis infection?

Answer 25

* Incubation period 10-14 days * Caused by *Bordetella Pertussis* * Children infectious for roughly **3 weeks after onset** of classical symptoms * Successful **vaccination** against it

Question 26

What are the **clinical features** of pertussis?

Answer 26

* Illness has **catarrhal phase** (due to build up of mucus) w/ **fever** that is followed by **paroxysmal cough**, hence name of "100 day cough" * Child coughing in a persistent series, one after the other until they have run out of air and then taking a large inhalation against an inflammed upper airway * resulting sound described as a "whoop" * this phase can be very prolonged + result in **vomiting** and **apnoea** in infants

Question 27

What **investigations** can be done for pertussis?

Answer 27

* **Postnasal swabs** → can be used to culture the bacteria or for direct immunofluorescence testing but are only useful in the first few weeks of the illness. After this period, serology for antibodies against pertussis may be utilised * **FBC** → demonstrated elevated WCC

Question 28

What is the **management** of pertussis?

Answer 28

* Most cases can be treated at home with good **education** + **reassurance** * _Low_ threshold for admitting children **under 6 months** * Abx with **erythromycin** can be used to reduce the infectiveness of illness but unlikely to alter clinical course * Recommended in cases that present within 21 days of onset of symptoms

Question 29

What do the following terms mean/refer to? * **Primary TB** * **Secondary TB** * **Miliary TB** * **Active TB** * **Latent TB**

Answer 29

* **Primary TB** → when TB infection first occurs * **Secondary TB** → reactivation of latent TB; may be precipitated by impaired immunity * **Miliary TB** → occurs when primary infection is not adequately contained + there is severe disease from haematogenous spread * **Active TB** → TB causing symptoms + contagious disease * **Latent TB** → occur when TB is present in the body but is inactive

Question 30

Children with **pneumonia**, **pleural effusion** or a **cavitating mass** not responding to antibiotics should be considered for TB. What are **clinical features** of TB?

Answer 30

* **Fever** of unknown origin * Faltered **growth** * Bloody **cough** * **Night sweats** * **Weight loss** * **Lethargy** * Unexplained **lymphadenopathy**

Question 31

Both **latent** and **active** TB should be treated. The ultimate goal of treatment is to achieve **sterilisation** of the TB lesion in the shortest time possible. Duration of treatment for active TB is usually at least **6 months**. What are the **drugs** for **management** of TB?

Answer 31

* **Rifampacin** → works by inhibiting RNA polymerase in bacteria, thus stopping RNA synthesis, SE: hepatitis * **Isoniazid** → works by inhibiting growth of bacterial cell wall, SE: hepatitis, pancytopenia, peripheral neuropathy * **Pyrazinamide** → inhibits bacterial growth, SE: joint pain, hepatitis * **Ethambutol** → works by inhibting growth of bacterial cell wall, SE: optic neuritis, hepatitis

Question 32

What are **features** of **HIV**?

Answer 32

* HIV is an **RNA virus** of the *Retroviridae* family * HIV infects lymphocytes, macrophages, monocytes and dendritic cells * Incubation period is **2-4 weeks**, though it can be longer * Most children acquire HIV through **vertical transmission**, which may occur antenatally, perinatally or postnatally (via breast milk)

Question 33

How might HIV **present** in a **newborn**, occuring in the first few months of life?

Answer 33

* Pneumocytis jirovecii pneumonia * Lymphadenopathy * Hepatosplenomegaly * Encephalopathy * Faltering growth * Chronic diarrhoea * Oral thrush * Disseminated TB infection

Question 34

What is **Roseola infantum**?

Answer 34

* AKA sixth disease * 3-5 days of **high fever** that rapidly disappears and then a **rash** will appear * Rash → **macular/maculopapular** lasts hours-2days in a well child * Nearly always less than 2 years of age

Question 35

What are **clinical features** of **rubella**?

Answer 35

* No prodrome except in adolescents/adults → headache, fever, anorexia - all precedes rash by 1-5 days * **Erythematous** (pink), **macules**, starts face/centrally and spreads to trunk/extremeties - lasts 3-5 days * mild/no fever * **suboccipital and postauricular lymphadenopathy**

Question 36

What are the clinical features of **measles**?

Answer 36

* **Koplik spots** start in prodrome + continue for several days after rash starts * Bluish/grey/white spots on red base - buccal mucosa * **Brick red rash**, maculopapular - behind ears, face → trunk/extremities, lasts 3-5days * Irritable, fever esp 1^st 1-2 days

Question 37

What are features of **erythema infectiosum**?

Answer 37

* = **fifth disease** = slapped-cheek syndrome * winter/spring, school-age children * rash → **fiery red on cheeks** (slapped-cheeks) + **circumoral pallor** → **erythematous maculopapular rash on trunk and limbs** * rash may come/go over 1-3 weeks * caused by parvovirus