Respiratory: pneumonia Flashcards
What is acute bronchitis?
- a lower respiratory tract infection which causes inflammation in the bronchial airways.
- a clinical diagnosis characterized by cough due to acute inflammation of the trachea and large airways but with no evidence of pneumonia.
What is pneumonia?
- an infection of the lung tissue
- the air sacs in the lungs become filled with microorganisms, fluid and inflammatory cells, affecting the function of the lungs
What usually causes acute bronchitis?
viral infection
* rhinovirus, enterovirus, influenza A&B, parainfluenza, coronavirus, RSV, adenovirus most common
* bacteria in 1-10% cases: strep pneumoniae, h.influenzae, moraxella catarrhalis.
What usually causes CAP?
- usually bacterial infection (organism usually not identified)
- Most common: strep pneumoniae,H.influenzae, staph aureus, group A strep, morazella catarrhalis.
- atypicals: mycoplasma pneumoniae, chlamydia, legionella
- viruses: influenza A&B, RSV, adenovirus, coronavirus
How should the severity of CAP be assessed?
- clinical judgement and the CRB-65 score for mortality risk
What is the CRB-65 score?
- 1 point given for each feature:
- confusion (to place,person,time, or AMT <=8)
- Raised Resp Rate >=30
- Low BP SBP <90 or DBP <=60
- Age >=65
0=low risk death
1 or 2 = intermediate risk (1-10%)
3 or 4 = high risk (>10%)
What is the management of acute bronchitis?
when are ABX indicated?
- self care: fluids, paracetamol/ibuprofen, honey, cough meds
- stop smoking
- return if not better after 3-4 weeks or feel very unwell
- ABX not needed - cough lasts 3-4 weeks
- ABX given for higher risk pts: comorbidities (CVS, renal, lung, NMD, immunosuppressed, CF) or age >65 with 2 of following, or age >80 with one of following:
- hospital admission in last yr
- DM type 1 or 2
- CHF
- oral steroids
If a CRP has been done for acute bronchitis, when should ABX be given?
CRP 20-100 - delayed ABX
CRP >100 - ABX
What is the first line ABX for acute bronchitis in adults?
- doxycycline 200mg day one, then 100mg OD for 4 days (total 5 days)
- Amoxicillin in pregnant women (500mg TDS for 5 days). Erythromycin in pregnant with penicillin allergy (250-500mg QDS 5 days)
Which ABX are indicated for acute bronchitis aged 12-17?
- amoxicillin 500mg TDS for 5 days
- Erythromycin in pregnant with penicillin allergy (250-500mg QDS 5 days)
When should someone with CAP be referred to hospital?
- sepsis/very unwell/requiring oxygen
- not improving with ABX
- Paeds - seek advice
- CRB-65 for adults:
- 3 or more - urgent admission
- 2 - consider admission
- 1- consider admission
- 0- home treatment
Which ABX are indicated for CAP CRB score 0 (low severity)?
adults
- amoxicillin 500mg TDS for 5 days (incl in pregnancy)
- pen allergy:oral doxycycline 200mg day 1, then 100mg OD for 4 days. Or oral erythromycin in pregnancy with pen all 500mg QDS for 5days.
seek advice if : not improving within 3/7, very unwell
Which ABX are indicated for CAP CRB score 1 or 2 (moderate severity)?
adults
if appropriate for home Rx:
* amoxicillin 500mg TDS 5 days AND (if atypicals suspected) clarithromycin 500mg BD for 5 days/ Use erythromycin 500mg QDS 5 days in pregnancy.
* if pen allergic - doxycycline 5 days, or clarithromycin 5 days.
Which ABX are indicated for CAP CRB score 3 or 4 (high severity)?
- co-amoxiclav 500/125 TDS or 1.2 g IV TDS for 5 days PLUS clarithromycin 500mg BD PO/IV 5 days OR erythromycin in pregnancy 500mg QDS for 5 days.
- If pen all: levofloxacin 500mg BD po/IV 5 days
What are the side effects of levofloxacin?
fluroquinolone:
* MSK - tendonitis and tendon rupture (esp if age >60 or on steroids)
* Nervous system (esp with NSAIDS)- seizures, peripheral neuropathy
* Psych - psychosis, depression, suicide
* AA, aortic dissection (esp if risk fx)
* Now only allowed to px if other ABX inappropriate.
What is the ABX treatment for non-severe CAP in children?
age <1, age 1-4, age 5-17
*Age <1: amoxicillin 125mg TDS 5/7
* Age 1-4: amoxicillin 250mg TDS 5/7
* Age 5-17: amoxicillin 500mg TDS 5/7.
* If pen all: clarithromycin age 1 month -17 years, or doxycyline if aged 12-17 years
Which ABX are indicated for severe CAP in children?
- co-amoxiclav TDS suspension or IV 5/7
- PLUS (if atypicals suspected) clarithromycin PO/IV 5 days
What advice should patients be given about the speed of improvement in CAP?
- 1 week — fever should have resolved.
- 4 weeks — chest pain and sputum production should have substantially reduced.
- 6 weeks — cough and breathlessness should have substantially reduced.
- 3 months — most symptoms should have resolved but fatigue might still be present.
- 6 months — symptoms should have fully resolved.
How should someone with CAP be followed up in primary care?
- reassess if symptoms and signs do not improve as expected, or worsen -Consider admission
- sputum sample - review abx
- CXR after 6 weeks if: symptoms persist after Rx, higher risk of underlying cancer e.g smoker or age >50.
- stop smoking
- pneumococcal and influenza imms once recovered.
What Ix should be considered for CAP in primary care?
- CRP - if LRTI diagnosed but unclear if it is pneumonia/whether ABX indicated
*CXR - if at risk of underlying lung cancer, or uncertain diagnosis (not usually needed for initial Rx of CAP in community) - sputum culture if moderate severity CAP being managed in community.
What are the contraindications to clarithromycin (macrolide)?
- taking other drugs that prolong QT
- History of QT prolongation
- Hypokalaemia (risk of QT prolongation) - do not give to patients with hypokalaemia.
- severe hepatic plus renal impairment (excreted by liver)
- caution with myaesthenia gravis
What are the important drug interactions with clarithromycin?
- CCBs - increased hypotension
- colchicine - toxicity
- CYP enzyme inducers (rifampicin, phenytoin, carbamazepine) - induce metabolism of clari - subtheraputic levels
- digoxin - increases digoxin levels
- edoxaban - increases edoxaban
- oral hypoglycaemics and insulin - significant hypos
- statins (metabolised by CYP) - increased statin plasma levels - myopathy.
- Warfarin- rise in INR
- Drugs prolonging QT interval
- Drugs causing hypokalaemia (e.g furosemide, prednisolone) - can lead to prolonged QT
What are the contraindications to doxycycline (tetracycline)?
- pregnant/breastfeeding - deposited in growing bones and teeth - discoloration and hypoplasia of teeth
- Cautions:
- hepatic impairment
- myaesthenia - increased muscle weakness
- SLE - exacerbates syx
- renal impairment
How is TB investigated?
- Mantoux test
- If mantoux positive - interferon gamma assay
- if symptomatic - sputum - Ziehl-Nielsen stain and culture.
