LRTI Flashcards
What are the main diagnostic techniques for LRTI’s?
Microscopy, culture of sputum and blood, antigen detection, PCR (NAAT - nucleic acid amplification test), serology (ELISA), latex agglutination etc.
Describe a bronchioalveolar lavage (BAL).
Local airway sample collected at bronchoscopy or catheter aspirate in a ventilated patient. Can quantitate culture in CFU/ml. Less liable to contamination and so more accurate diagnosis.
Name some common respiratory viruses.
IAV, IBV, PIV, adenovirus, rhinovirus, metapneumovirus, coronavirus, RSV etc.
In children: RSV, PIV3, IAV, IBV and adenovirus.
When would antibody detection be used?
When it is difficult to culture or detect an organism directly. Mostly now replaced by PCR. IgM is a marker of current infection. IgG is a marker of past infection. Rising titres now used to measure response to vaccination.
Name 3 difficult to diagnose bacterial infections.
Legionella pneumophila, Chlamydia psittaci, Chlamydia pneumoniae and Coxiella burnetti (Q fever).
Which stain must be used when culturing Mycoplasma?
ZN stain.
Name common bacterial causes of LRTI’s.
Strep pneumoniae, HiB, Moraxella catarrhalis, Mycoplasma pneumoniae and Chlamydia pneumoniae.
What are the 5 main illnesses caused by LRTI’s in children?
Pneumonia (will have very > temp), bronchitis, bronchiolitis, empyema and tracheitis.
Describe tracheitis.
Prolonged croup with fever and biphasic stridor. It is between croup and epiglottitis. Can be caused by Staph, Strep or augmentin use.
Describe bronchitis.
Very common. Endobronchial infection that causes a loose rattly cough and vomiting. Caused by Haemophilus or Pneumococcus. Self-limiting. Caused by bacterial disturbance of mucociliary clearance. First winter bad, second better, third fine.
What are the criteria for persistent bacteria bronchitis?
Wet cough, over 1 month and goes with antibiotics.
Describe bronchiolotis.
Affects 30-40% of infants and is usually caused by RSV. Nasal stuffiness, poor feeding, tachypnea, crackles etc. Not recurrent and only occurs
What is recommended for management of LRTI’s?
Nothing if symptoms are mild. Oral amoxicillin first line and oral macrolide second choice. Only given IV if child is vomiting.
Can pertussis still infect those who are vaccinated?
Yes, just means they cannot pass it on.
What is an empyema?
A complication of pneumonia in which the infection extends into the pleural space. Causes chest pain and patient will be very unwell. Use antibiotics and drain. Better prognosis in children than in adults.
What are the symptoms of pneumonia?
Malaise, fever, pleuritic chest pain (inspiration), cough, purulent sputum and SOB.
What are the clinical signs of pneumonia?
Pyrexia, tachypnea, central cyanosis, dullness on percussion of affected lobes, bronchial breath sounds, inspiratory crepitations and increased vocal resonance.
Which organisms most commonly cause pneumonia?
Strep pneumoniae, Haemophilus influenzae or viruses.
How is the severity of pneumonia scored?
CURB 65. Confusion, Blood urea over 7, RR over 30, Diastolic BP under 60 and > age 65.
0: low risk, treated at home with amoxicillin/clarithromycin/doxycycline. 1-2: hospital, amoxicillin/clarithromycin/levofloxacin. 3-5: > risk death and need for ITU, co-amoxiclav and clarithromycin/levofloxacin.
What additional treatment can be given to penumonia patients?
O2, IV fluids, CPAP, intubation and ventilation.
What are the complications of pneumonia?
Septicaemia, acute kidney injury, empyema, lung abscess, haemopytic anaemia and ARDS.
What are the differential diagnoses for pneumonia?
LC, PE, cardiac failure and pulmonary vasculitis (Wegners granulomatosis).
Define bronchiectasis.
Abnormal widening of the bronchi or their branches which causes a risk of infection.
What are the causes of bronchiectasis?
Idiopathic, CF, childhood infections such as measles, immotile cilia syndrome, hypogammaglobulinaemia and allergic bronchopulmonary aspergillosis (ABPA)
What are the symptoms and signs of bronchiectasis?
SYMPTOMS: chronic cough, daily copious sputum production. SIGNS: finger clubbing, coarse inspiratory crepitations on auscultation.
Which organisms commonly cause bronchiectasis?
Haemophilus influenzae, S.aureus and Pseudomonas aeuriginosa.
What are the investigations for bronchiectasis:
HRCT thorax, sputum culture, serum immunoglobulins, total IgE and aspergillus precipitins and CF genotyping.
What are the treatment options available for bronchiectasis?
Chest physio, treatment of infections with antibiotics and may require inhaled therapy (ICS/B2 agonists).
