Resp: Whooping Cough, Pneumonia, TB Flashcards
What is whooping cough caused by
Bordatella pertussis
Appearance of bordatella pertussis
GRAM-NEGATIVE, ENCAPSULATED COCCOBACILLUS
Name three species that cause whooping cough
- Bordatella pertussis
- Bordatella parapertussis
- Bordatella Bronchiseptica
How does whooping cough spread
Droplet infection
What virulence factors aid infection by bordatella pertussis
- Filamentous ham agglutinin and fimbriae aid adherence
- Adenylate cyclase toxins inhibit phagocytic chemotaxis and T cell activation
- Pertussis toxin is an A/B toxin
- Tracheal cytotoxin and dermonecrotic toxin
Role of pertussis toxin
Inhibits alveolar macrophage host defence (ADP ribosylates G proteins)
Role of tracheal cytotoxins
Epithelial necrosis
What causes chronic inflammation in whooping cough
- Lymphoid hyperplasia
2. Th17 skewing of mine response
Clinical presentation of whooping cough
- UNDER 5 with chronic cough
- Vomit follows cough
- Fever or weight loss
- Febrile but vital signs stable
- Sub-conjunctival haemorrhage
- Lungs clear when auscultation
How long is the incubation period of whooping cough
7-10 days
What is the catarrhal phase of whooping cough
- Patient highly infectious
- Cultures from respiratory cultures ar positive
- Malaise
- Anorexia
- Rhinorhoea
- Conjunctivitis
What is the paroxysmal phase of whooping cough
- Begins a week after catarrhal phase
- Coughing spasms
- Classic inspiratory whoop in younger individuals
- Coughing spasms that end in vomiting
- Cough for 14 days
What is the paroxysmal phase of whooping cough associated with
- Pneumonia
- Encephalopathy
- Sub-conjunctival haemorrhage
What causes the inspiratory whoop
- Resp tract is compromised by mucus secretion and oedema
How is whooping cough diagnosed
- Chronic cough + history of contact
- PCR tests
- Culture of nasopharyngeal swab!!
How is whooping cough treated
- Antimicrobials (Clarithromycin)
- Antibiotics can’t be used in paroxysmal stage
- Vaccination (dTap vaccine) at 2,3,4 months and 3-4 years
What is the dTap vaccine
- Diphtheria
- Tetanus
- Acellular pertussis
What causes acute laryngotracheobronchitis
- Parainfluenza virus
What age is affected by acute laryngotracheobronchitis
Children under the age of 3
Pathophysiology of acute laryngotracheobronchitis
- Inflammatory oedema extend sto vocal cords and epiglottis causing narrowing of the airway
- Progressive airway obstruction occurs with recession of soft tissue in neck and abdo during inspiration
- CYANOSIS
Clinical presentation of acute laryngotracheobronchitis
- 3 year old
- Barking cough
- Febrile
- Rep rate of 40
- Cyanosis
- Intercostal recession
- Inspiratory stridor
Diagnosis of acute laryngotracheobronchitis
- Voice is horse with barking cough
2. Audible stridor
How is acute laryngotracheobronchitis treated
- Nebulised adrenaline
2. Dexamethasone (IM or oral)
Define pneumonia
- Inflammation of lung substances
What part of the lungs are effected
Dial airways and alveoli
What is community acquired pneumonia
- No underlying immunosuppression or malignancy
What causes community acquired pneumonia
- Strep pneumoniae
- Haemophilus pneumonia
- Mycoplasma pneumoniae
- Staphylococcu aureus
- E.coli
- Klebsiella pneumoniae
What is lobar pneumonia
When the infection is localised to one whole lobe
What is diffuse pneumonia
Multiple lobules and respirartoy bronchioles are affected (bronchopneumonia)
Define hospital-acquired pneumonia
- New onset of cough with prurulent sputum
- X-ray showing consolidation
- Patinets staying in beyond 48 hours after admission
- Patients in healthcare setting for more than 3 months
What people are effected by hospital-acquired pneumonia
- Elderly
- Ventilator-associated
- Post operative
What causative organisms are in HAP
1. AEROBIC GRAM-NEGATIVE bacilli: Pseudomonas aerguinosa E.coli Klebsiella Pneumoniae Staph Aureus sue to MRSA
What patients are susceptible to S.aureus infections in hospital (pneumonia)
- Diabetes Mellitus
2. Head trauma
What is the most common organism causing pneumonia in immunocompromised patients
Pneumocystis jiroveci
What is aspiration pneumonia
- Acute aspiration of gastric contents into the lung which cause intense destruction
Where is aspiration pneumoniae seen
- Stroke
- MG
- Bulbar palsies
- Lack of consciousness
What is Mendelson syndrome
Pneumonia caused by aspiration of anaesthesia
Risk factors of pneumonia
- Under 16
- Over 65
- Co-morbidities (HIV, diabetes, CF, COPD)
- Smoking
- Excess alcohol
- IV drug use
- Prolonged corticosteroids
How is pneumonia spread
- Respiratory droplets
Why does pneumococcal pneumonia not respond to penicillin
Lack a cell wall
Pathophysiology of pneumonia
- Bacteria translocate to normally sterile distal airway
- Host defence overwhelmed, alveolar macrophages instruct th17 cells to stimulate neutrophilsto secrete pus (inflammatory exudates) into alveolar space
- Inflammatory cells are apoptosed (when disease resolves)
What causes pneumonia to become severe
- Excessive inflammation
- Lung injury
- Failure to resolve without lung damage
Clinical presentation of pneumonia
- Fever
- Night sweats
- Raised resp rate
- Productive cough
- Absence of upper resp tract symptoms
- RIgors
- Low BP
- Malaise
- Anorexia
- Dyspnoea
- Breathlessness
- Coarse crackles on auscultation (consolidation of lung parenchyma)
- Dull to percussion
- Decreased air entry
- Bronchial breath sounds
- Dry or productive cough
- Prurient sputum (rusty suptum CHARACTERISTIC of strep pneumonia)
- Pleuritic chest pain
- Cyanosis
- Confusion
Differential diagnosis of pneumonia
- TB or lung cancer
Diagnostic of pneumonia
- CXR
- FBC
- U+ E, LFTs
- Pulse oximetry / ABG
- HIV test
- Sputum culture and antibiotic sensitivities with gram stain
- Blood culture
- Serology
- CURB-65 test to assess severity of CAP
Role of FBC in pneumonia
- Elevated in strep pneumoniae (WCC)
2. ESR and CRP
What is CURB-65
- Confusion
- Urea (greater than 7 mol/L)
- Respiratory rate (greater than 30)
- BP less than 90 mmHg or 60mmHg diastolic
- Age greater than 65
What is a CURB score of 0-1
Mild
CURB score of 2
Moderate, admit to hospital
CURB score of 3-5
Admite, severe and monitor closely