Specific bacterial infections

Question 1

What do you do if a child presents with a fever and purpuric rash?

Answer 1

IM Benzylpenicillin ASAP and hospital admission

Sign of meningococcal septicaemia (rash starts anywhere and spreads) - lesions are not blanching on palpation, irregular in size and have a necrotic centre.

Question 2

Where is Strep pneumoniae carried?

Answer 2

1) In the nasopharynx of everyone, causes minor infection such as otitis media and more invasive infections.
2) More common in young infants as their immune system is not as strong.
3) (Included in the vaccination programme)

Question 3

Which children are at increased risk from pneumococcal infections? What do they require?

Answer 3

1) Hyposplenism (sickle cell disease and nephrotic syndrome)

2) They need daily prophylactic penicillin to cover strains not covered by vaccine

Question 4

How does Impetigo (staph/strep infection) present?

Answer 4

1) Localised, highly contagious (unlike others) - skin infection in infants and young kids.
2) MORE COMMON where an existing skin condition is present (atopic eczema)
3) Affects face, neck and hands
4) Begin as erythematous macule, become vesicular pustular, then rupture - resulting in characteristic HONEY COLOURED CRUSTED LESIONS.

Question 5

How is Impetigo treated?

Answer 5

Mild - Mupirocin (cream/ointment)
Severe - Flucloxacillin
SHOULD NOT GO TO SCHOOL - until lesions dry
Nasal cream containing mucopirocin OR chlorhexidine and neomycin.

Question 6

Scalded skin syndrome presentation?

Answer 6

1) Separation of epidermal skin through gradual cell layers
Infants and kids with:
- fever
- purulent crusting 
- infection around eyes and mouth
- erythema
- tenderness of skin

O/E - Nikolsky sign (epidermis separates on gentle pressure)

Question 7

How is scalded skin syndrome treated?

Answer 7

1) IV Flucloxacillin
2) monitor fluids
3) Analgesia

Question 8

How is tuberculosis transmitted?

Answer 8

• Respiratory route (close proximity, infectious load, underlying immunodeficiency - increased risk of transmission)
• Children not usually infectious (but can acquire from an infected household member)
• TB infection and TB disease are different. TB infection (latent TB) more likely to progress to disease in kids

Question 9

What is Primary TB?

Answer 9

• Describes first infection with Mycobacterium tuberculosis. - A non-immune host is exposed to the bacteria and may develop primary infection of the lungs.
• Small granulomatous lesions called a Ghon focus (seen on upper lobe of lung on CXR develops), combined with hilar lymph nodes - Ghon complex.
• Initial lesion usually heals and calcifies, some bacteria remain inside - capable of lying dormant for many years.
• Immunocompromised patients can develop disseminated disease - biliary TB (spreads to other organs).

Question 10

Reactivation TB:

Answer 10

• Majority of cases are due to reactivation of latent infection (POST PRIMARY TB) - due to depression of host immune system.
• In HIV patients - newly acquired TB is common.
• Can be local or disseminated (see extra-pulmonary symptoms).

Question 11

Clinical presentation of TB (systemic and pulmonary):

Answer 11

• Extra-pulmonary involvement far less common in primary disease.
• Systemic features: weight loss, anorexia, low grade fever, night sweats.
• Pulmonary features: Could be asymptomatic
  1) Productive cough (occasional haemoptysis), cough for more than 3 weeks.
  2) Chest pain
  3) Breathlessness
  4) Pleuritic pain (if involved)
  5) Hoarse voice (if laryngeal involvement)
  6) Associated with: Consolidation, pulmonary collapse (caused by compression of a lobar bronchus by enlarged nodes)

Question 12

Extrapulmonary TB symptoms?

Answer 12

1) Lymph node TB - swelling and discharge
2) Bones
3) Abdominal TB - ascites, ileal malabsorption
4) Genitourinary TB - epididimytis, frequency, dysuria, haematuria
5) CNS TB - bacilli in CSF and on meninges, thick exudate produced due to meningeal inflammation/low-grade meningitis (random CNS palsies and raised ICP symptoms)

Question 13

How is TB diagnosed?

Answer 13

1) CXR - patchy/nodular shadows in the upper zones with loss of volume, fibrosis.
2) Sputum - Ziehl-Neelson stain for acid/alcohol-fast bacilli, (gastric washings <8yrs on 3 consecutive mornings to obtain acid fast bacilli)
3) LP + CSF studies - all cases of miliary TB due to rate of spread to meninges.
4) Histology - caseating granulomata
5) Mantoux skin test - positive suggests immune response + contact with TB - can be false positive due to previous BCG vaccination. False negatives can occur as biliary TB/immunosuppressed won’t react. Cannot easily distinguish infection and disease.
6) Interferon Gamma Release Assays (IGRAs) - uses antigens specific to M. tuberculosis to distinguish between infection and BCG vaccine (exposure to TB not active disease detected).
7) Test for HIV - Mantoux and IGRA are UNREACTIVE in immunosuppression.
Neither Mantoux nor IGRA can reliably distinguish infection and disease (latent or active) - correlate with clinical signs and symptoms.

Question 14

How is TB managed?

Answer 14

ALL CASES OF TB MUST BE NOTIFIED TO PUBLIC HEALTH ENGLAND.

1) Patients with fully sensitive TB require 6 months of treatment (in CNS TB need 12 months): Rifampicin (6m), Isoniazid (6m + pyridoxine weekly to prevent peripheral neuropathy in children post-puberty), Pyrazinamide (2m), Ethambutol (2m) - RIPE
2) IF TB meningitis - give dexamethasone for 1 month
3) Latent TB (Asymptomatic but positive Mantoux): Rifampicin and Isoniazid - 3 months (decrease risk of reactivation in later life).

Question 15

Prevention of TB:

Answer 15

1) Neonatal BCG vaccination: no longer offered routinely - recommended in neonates from high risk groups, reduces risk of disseminated and CNS TB, DO NOT GIVE to HIV positive and immunocompromised patients (dissemination risks).
2) Active case finding, detection and Tx of TB via community nursing team using Mantoux and IGRAs.