Respiratory Infections Flashcards
What upper respiratory tract conditions can be caused by infection?
URT = above vocal cords common cold - coryza sore throat - pharyngitis sinusitis epiglottitis
How can we get the common cold?
Cold viruses (rhinoviruses) proliferate best at about 32 degrees - in cold temperatures the air around our noses can drop to these temperatures making them suitable for rhinoviruses.
What lower respiratory tract conditions can be caused by infection?
LRT = below vocal cords acute bronchitis acute exacerbation of COPD pneumonia influenza
What does acute sinusitis involve?
Preceded by common cold
Purulent nasal discharge
can be treated with antibiotics but no evidence
What are the clinical features of an acute exacerbation of COPD?
Usually preceded by upper respiratory tract infection
Increased sputum production which is now purulent
SOB
more wheezy
on examination: coarse crackles, may be cyanosed, ankle oedema in advanced disease.
How should you manage an acute exacerbation of chronic bronchitis?
Primary care: antibiotics eg clarithromycin, amoxicillin; bronchodilators; short course of steroids in some cases
Admit to hospital if: evidence of respiratory failure, not coping at home
Management in hospital: antibiotics eg clarithromycin, amoxicillin; inhaled bronchodilatrs; short course of steroids in some cases; measure ABGs; CXR to look for underlying respiratory disease; oxygen if in respiratory failure
If you suspect a pneumonia and on CXR there is opacification which obscures the right heart border, what is the most likely diagnosis?
Right middle lobe pneumonia
What is “red hepatisation”?
Consolidation of the lung lobe(s) as a result of pnemuonia which is red and resembles liver tissue, hence the name.
What might you see on a histological slide of a lungs biopsy from a patient with pneumonia?
Infiltration of inflammatory cells filling the alveoli - not leaving much room for gas exchange.
What are the symptoms and signs of pneumonia?
Symptoms: Malaise, anorexia, sweats, fever, rigors, myalgia, arthralgia, headache, confusion, cough, pleurisy, haemoptysis, dyspnoea, preceding URT infection, abdominal pain, diarrhoea.
Signs: fever, rigors, herpes labialis, tachypnoea, crackles, rub, cyanosis, hypotension
What investigations would you do for pneumonia?
CXR, blood culture, sputum culture, serology, FBC, ABG, LFTs, Urea, CRP, bronchoscopy/bronchoalveolar lavage
How do you assess the severity of a community acquired pneumonia?
CURB65 score (only useful in community acquired, not hospital acquired) C = confusion (new) U = urea >7mmol/l R = respiratory rate >30 B = Blood pressure < 90 systolic OR <61 diastolic 65 = aged 65 or over
Each one of these scores one point
0-1: mild, can treat at home
2: moderate - requires hospital treatment
3 or more: severe pneumonia
Other than CURB65 what are some other indicators of severity of pbeumonia?
Temperature 40
Cyanosis, PO2 30
multi-lobar involvement
What is the management of community acquired pneumonia?
Antibiotics: amoxicillin and doxycycline Oxygen - aim for sats of 94-98% fluids bed rest no smoking
What are the complications of pneumonia?
Respiratory failure
Pleural effusion
Empyema
Death
What kind of antibiotic cover is required for hospital acquired pneumonia?
Gram negative
What kind of antibiotic cover is required for aspiration pneumonia?
Anaerobic
What is unusual about the clinical features of legionella pneumonia?
Chest signs may be absent
GI disturbance is common
What is the significance of sexual history in a patient presenting with a pneumonia?
Pneumonia can be a presenting feature of HIV.
When are the influenza and pneumococcal vaccines indicated?
Over 65
Chronic chest, heart, liver or renal disease
Diabetes
Immunocompromised eg splenectomy, AIDS, chemotherapy, steroids
influenza vaccine only: healthcare workers
What does acute bronchitis involve?
preceded by common cold, not life-threatening
virus/inflammatory cells go down airways into LRT
Get productive cough, fever (minority of cases), normal chest exam, normal chest xray, may have transient wheeze (common in children)
Do NOT give antibiotics (unless there is underlying chronic lung disease)
What does the common cold involve?
Acute viral infection of nasal passages, often accompanied by a sore throat and sometimes a mild fever
spreads by droplets and fomites
complications include sinusitis and acute bronchitis
What are the clinical features of influenza?
Incubation period = 1-4 days
symptoms include: fever (up to 40 degrees), chills, headache, sore throat, myalgia, malaise, anorexia, dry cough, prostration
clear nasal discharge
evidence of complications
bed bound for 3-4 days, recovery of about 5-6 days
What are complications of influenza?
death
primary viral pneumonia - cough, bloody sputum and respiratory failure within 24 hours of initial onset of fever
secondary bacterial pneumonia - new fever on day 7
myositis (skeletal or cardiac)
encephalitis
depression
Give examples of anti-viral drugs and why they are used.
Neuramidase inhibitors: -Zanamavir - inhaler -Osletamavir (tamiflu) - oral Benefits of oseltamavir: - reduce duration of symptoms by one day - reduce antibiotic use - may reduce infectivity
How can presence of influenza virus be detected?
PCR - from nasopharyngeal or throat swab
How can influenza be prevented?
Killed vaccine: contains 2 influenza A viruses and one influenza B virus; given to adults at risk of complications and healthcare workers
Live attenuated vaccine: attenuated by cold virus; contains 2 influenza A viruses and one influenza B virus; given intra-nasally to children
anti-virals can be given as prophylaxis after contact with virus but this is not done very often
How can infection with an atypical be confirmed?
Serology
