Paeds - Resp Flashcards
Viral induced wheeze
Acute wheeze caused by viral infection
Viral induced wheeze pathophsy
Small kids have small airways. Viral infections cause some inflam and oedema + smooth muscle contraction in the airways.
Negligable in older airways but big flow reduction in small kids as dictated by Poiseuille’s Law (Flow rate proportional to radius to the power of 4) - half the diameter = flow rate decreases by 16
-> wheeze; restricted ventilation + RESP DISTRESS
Viral induced wheeze prognosis
Tends to be a FHx
Some kids are more prone to it and they tend to be at increased risk of developing ASTHMA when older
Viral Wheeze vs Asthma
Viral wheeze specifically tends to be:
- In younger kids (< 3 y/o)
- Only occurs in viral infection. Asthma is also exacerbated by factors like exercise, cold, allergies, strong emotions etc
- No atopic history
However, this is not definitive and there is a lot of overlap
Viral induced wheeze Px
Viral infection for a 1-2 days and then:
- SOB
- Signs of RESP DISTRESS
- EXPIRATORY WHEEZE throughout chest
Viral induced wheeze Mx
Same as acute asthma
- Supplementary O2
- Bronchodilators (salbutamol, ipratropium bromide, magnesium sulphate, aminophylline - step up as required)
- Steroids (prednisolone or hydrocortisone)
- Abx only if infection at least suspected
For mild can usually be managed with outpatient salbutamol
Mod - severe = step up as required:
- salbutamol (10 puffs/2hrs)
- Nebulisers
- Prednisoline
- Hydrocortisone
- IV MgSO4
- IV salbutamol
- IV aminophylline
When can kids be discharged after a mod-severe viral induced wheeze
ONce they are well on 6 puffs of salbutamol every 4 hours
- Must step down to at least this before discharge
Continue reducing at home till only taking as required
Epiglottitis aet
- HAEMOPHILUS INFLUENZAE type B (HiB) - most severe
- same pathogens that can cause pharyngitis (EBV, strep A, Mycoplasma pneumoniae, neisseria Gonorrhoea etc) - less common tho
More likely to get if immunocompromised
Epiglottitis epid
- Previously most common in children 2-4 y/o
- Now rare due to Hib vaccine
Epiglottitis Sx
- Fever + sore throat
- Dysphagia
- SOB
- STRIDOR
- Drooling
May TRIPOD in an effort to get in more air
Epiglottitis Dx
Acutely: clinical Dx
- Hx of immunocompromise/no immunisation
- LATERAL CERVICAL X-RAY -> Thumb sign (helps confirm)
- Laryngoscopy = GOLD
(avoid looking in airways as may agitate child)
Microbio:
- GRAM -VE COCCOBACILLI, usually ENCAPSULATED (HiB)
- Unencapsulated = Non-Typable Haem Influ
Epiglottitis Tx
DOXYCYCLINE or CO-AMOXICLAV (for HiB)
(HiB not susceptible to macrolides i.e. clari/erithromycin + oft resistant to amoxicillin)
Croup
Acute Laryngo-tracheobronchitis - the inflam causes partial obstruction -> Stridor + sob
Croup Epidemiology
- esp in kids 6 MONTHS to 6 YRS but particularly in <3 y/o
- More common in autumn (+ early winter)
- 1 in 6 kids affected at least once in life
Croup aet
Main cause = PARAINFLUENZA VIRUS
- Resp syncitial virus
- Flu A
- Other resp viruses: EBV, Rhino, Adeno
- Measles (RNA paramyovirus)
Can uncommonly get bacterial croup - more severe
Croup Sx
- Fever, Hoarse voice
- BARKING COUGH
- STRIDOR (milder than epiglottitis but in the same way worsens if distressed)
- Increased resp effort: intercostal recessions, cyanosis
- Worse at NIGHT; may improve in cooler air
Croup Tx
- Mild: Single dose of DEXAMETHASONE - improves inflam and Sx
- Severe: may need admission -> monitor, O2 supplement + NEBULISED BUDESONIDE (ics)
- If v concerned airway may close up -> NEBULISED ADRENALINE
- Keep the child calm - crying exacerbates
Croup Dx
Clinical
- Throat swabs for causative organism
- Lateral cervical X-ray in severe/atypical can show -> ‘Steeple sign’ - SUBGLOTTIC NARROWING
DDx for resp distress
- Epiglottitis
- Croup
- Foreign body aspiration
- Asthma attack
- Bacterial tracheitis (high fever + rapidly progressing resp distress)
Bronchiolitis
Widespread chest infection causing infalm + congestion of bronchioles
Bronchiolitis epid
- Typically in kids 1-12 months - rare kids older than that
- Mainly in winter
Bronchiolitis main causative organism
Resp Syncitial Virus
Bronchiolitis Sx
- Cough
- Wheeze
- Increased breathing effort
- Intercostal recession
- Grunting
- Nasal flaring
- Tachypnoea
Bronchiolitis Dx
Mainly clinical
CXR id severe / worried about complications
Bronchiolitis Mx
Prophylaxis: Give PALIVIZUMAB if high risk
- Supportive: Hydration; Nutrition; Fever management
- O2 Therapy -> may need to escalate to ventilation if severe
- Antiviral: RIbavirin if v severe
Bronchiolitis complication
BRONCHIOLITIS OBLITERANS (aka popcorn lung) - rare chronic complication
Caused by overactive cellular repair and build-up of scar tissue following inflam (could be from inhaling harmful substance, not just infection).
Scarring -> narrowing + reduced O2 absorption
Can be progressive -> resp failure
Oft a complication seen in lung transplant patients due to organ rejection
Asthma
Heterogenous inflam disease of airways -> chronic inflammation -> bronchospasm -> narrowing -> airflow obs
- Typically episodic
Characteristic factors
- Airway hyperresponsiveness
- Bronchiole inflammation
- Mucus hypersecretion
- Airway obstruction (REVERSIBLE)
What are the 2 main types of asthma
Allergic (70%) - ie Extrinsic asthma
- Linked to exposure to common allergens (pollen, dust mites, mould)
- Typically presents in childhood
- Theory:
- Genetics + hygiene hypothesis - Immune mechanism:
- IgE MEDIATED - Type 1 hypersensitivity
Non-allergic (30%) - ie Intrinsic
- Linked to other conditions like COPD
- Can be later onset
- Harder to treat
Asthma epidm
- nearly 10% of kids in UK have
- 3 deaths/day in UK (typically in younger people)
- Both over + underdiagnosed - non-specific symptoms
RFx for asthma
- FHx
- PHx of atopy
Asthma Sx
- Cough
- SOB
- Wheeze (widespread during acute episode)
- Chest tightness
- Diurnal variation
- Reversible Sx (tho can become irreversible if chronically poorly controlled -> scarring)
Triggered by allergenic factors
Asthma allergic pathway
For T2-hi asthma:
- Dendritic cells recognise + present allergen peptides to naive t cells
- Th2 pathway -> CYTOKINES (IL-4, 5 + 13)
- B cells -> IgE release -> bind to primed mast cells -> degranulation
- Airway SM contraction
Need initial sensitisation first
Asthma Neutrophilic pathway
T2-lo asthma (non-allergic):
- Epithelium produces ALARMINs
- Dendritic cell -> Naeive T helper -> Th1 + 17 -> Neurophils
- release of IFNg + TNFa
Asthma Dx
- Focussed Hx
- SERIAL PEAK FLOW
- SPIROMETRY (airflow capacity)
- If unclear FeNO testing
Trial a SABA to see if it works
Asthma Tx
- Personalised Asthma plan
- Metered dose inhaler + spacer - teach technique (+ avoid triggers)
- SABA as required + very low / low dose ICS (200 mcg/day - e.g. Clenel)
- Add LTRA (under 5s) or LABA (over 5s) if needed
- Can increase ICS to low dose (400 mcg) then medium dose (800 mcg) as required
- Can add theophylline + refer to specialist if needing high dose therapy
If refractory - daily oral steroids alongsidemedium dose ICS - try to reduce oral steroids when possible tho
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Cystic fibrosis
Progessive Autosomal Recessive condition affecting CHLORIDE CHANNELS
CF Epidem
- 1/2500 kids in UK are likely to have CF
- 1/25 carriers
- Median life expectancy = 47 yrs
CF aet
Mutations in CFTR gene on chromosome 7 - cause CHLORIDE CHANNEL defects -> thick mucus secretions.
Most common is Delta-F508 -> abnormal GLYCOSYLATION + subsequant DEGRADATION of CFTR protein before it reaches cell membrane.
Also disrupts Epithelial sodium channels as when less chloride actively transported -> increased passive REABSORPTION of sodium -> MORE CHLORIDE + LESS WATER in secretions
CF RFx
- FHx
- Caucasians
CF Px
- Neonates = delayed, viscous meconium. Possibly meconium ileus.
- Infants: salty sweat; FALTERING GROWTH, Recurrent chest infections
- Toddlers: failure to thrive, recurrent chest infections, MALABSORPTION
- Delayed puberty
- Infertility in males due to absence of vas deferens
CF Dx
- SCREENING: Neonatal blood spot test -> RAISED blood IMMUNOREACTIVE TRYPSINOGEN
- SWEAT TEST (chloride conc in sweat)
- Genetic testing
Also - FECAL ELASTASE (to confirm reduced pancreatic function - will be low)
CF Mx
- Daily CHEST PHYSIO + exercise (shift mucus)
- Prophyl Abx (for chest infections)
- MUCOLYTICS:
- Nebulised hypertonic saline
- Nebulised DNase (Dornase alfa)
- Pancreatic enzyme supplementation + fat-soluble vit supps / high calorie diet (as pancreatic secretions affected)
- Regular flu vaccine + PNEUMOCOCCAL vaccine
- Consider lung transplants if end-stage pulm disease
Also fertility treatment + genetic counselling for family
How often are pts with CF followed up + what is being checked
Typically followed-up every 6 months:
- Check sputum for colonisation e.g. from pseudomonas
- Screen for DIABETES, OSTEOPOROSIS, VIT D DEF, LIVER FAILURE
Causes of wheeze
Recurrent:
- Persistent infantile wheeze
- Viral episodic/induced wheeze (typically <6 yrs)
- Asthma (typically in kids >6 yrs)
Other:
- CF
- Chronic lung disease of newborn
- Tracheo-bronchomalacia (insp stridor due to airways occasionally collapsing in on themselves)
- Ciliary dyskinesia (wet cough; no gut problems)
- GORD
- Chronic aspiration
- Immunodef
- Persistent bacterial bronchitis
Acute asthma management
- O2 supp if needed (in life threatening esp)
- Beta agonist - Inhaled/Nebulised SALBULTAMOL (10 puffs - keep repeating with little breaks between each block until improve)
- Consider adding ipratropium bromide and then MgSO4 if not responding to SABA alone - Steroids: Prednisolone 1 mg/kg or IV hydrocrotisone (oral intake difficult)
- usually ~3 days but keep for longer if needed
May need IV SALBUTAMOL bolus if v severe
- IV MgSO4 if the kid not responding to 1st line stuff
Other: IV Aminophylline if life-threatening + not responding
Examples of ICS
- Becolmethasone
- Budesonide
- Fluticasone
Example of LABA
- Saleterol
- Formoterol
Always given in a combined inhaler with ICS to ensure taking both of them
Causes of failure to respond to asthma meds
- Adherence
- Wrong diagnosis
- Environmental factors (esp smoking)
- Choice of meds/devices
- Bad disease severity
SE of ICS
- Sore mouth/throat
- Hoarse voice
- Cough
- ORAL THRUSH
Long term:
- Temporarily impaired growth (must monitor)
- Suppresses adrenals - uncommonly people can go into adrenal crisis
(Risk of osteoporosis not greatly raised)
Minimise dose + maximise targeting
Main causative organism for LRTI/persistent wheeze in kids
Resp Syncitial Virus - 0.5-2% hospitalised
- tends to be most severe cause of viral pneumonia in kids
Pneumococcus action
Colonises the NASOPHARYNX
- Infect upper airways -> Otitis media + sinusitis
- Lower airways -> Bacterial bronchitis + Pneumonia (typically complicated e.g. with effusion)
Can caused ‘OCCULT’ SEPTICAEMIA; Pneumonia with associated septicaemia + MENINGITIS
Pneumonia Definition + stages
Inflammation of lung parenchyma (excluding bronchi); visible on XR-> Congestion
- Red hepatisation - increased infiltration of blood cells
- Grey hepatisation - immune cells start breaking down
- Resolution
Pneum Dx
Cough And/or Difficulty breathing (<14 days - i.e. its acute) AND increased resp rate
- > 2 months old - >60 breaths /min = high
- 2-11 months = >50/min
- > 11 months = > 40/min
On CXR (NOT DONE ROUTINELY):
- DENSE/fluffy OPACITY in portion/whole of LOBE or lung
- May or may not have AIR BRONCHOGRAMS
What is indicative of bacterial pneum
- FEVER > 38.5 C
- CHEST RECESSION
- RESP rate > 50/min
Up until 3 y/o
In older kids SOB/diff breathing more common
Most common bacterial causes of pneumonia
- Pneumococcus
- HiB
- S aureus
- K pneumoniae
- Mycobacterium TB
Common viral causes of pneumonia
- RSV
- Flu A + B
- Paraflu
- Adenovirus
- Human metapneumovirus
Just take a swab anyway if kids have pneum
What time of year is resp infections in kids most common
Autumne - BACK TO SCHOOL
Unusual causes of pneum
Mycoplasma pneumoniae
Chlamydia spp.
Pseudomonas spp.
Escherichia coli
Measles
Varicella
Strep A
Pertussis
Histoplasmosis and toxoplasmosis
In HIV more are possible e.g. Pneumocystis jiroveci, TB
Bacterial bronchitis vs Pneumonia
Pneum in parencyma while bronchitis is in larger airways
Bacterial bronchitis is a main cause of persistant cough (> 3wks)
- Acute presentation is pretty similar for both
Bacterial bronchitis Mx
- 6 wk Abx
- Bronchoscopy if not responding
- HiB; Morexella etc
Bronchiectasis Mx
- Prophylactic ABx
- CHest physio + exercise (to improve mucocillary clearance)
