wheezy cough and breathlessness Flashcards
what is bronchiectasis?
- Abnormal and permanently dilated airways
- Bronchial walls become inflamed, thickened and irreversibly damaged
- Mucociliary transport mechanism is impaired and frequent bacterial infections occur
how is bronchiectasis characterised clinically?
productive cough with large amounts of discoloured sputum and dilated, thickened bronchi, detected on CT
what is the aetiology of bronchiectasis?
-Cystic fibrosis is the most common cause in developed countries. -Others: post infectious, immunodeficiency, genetic, aspiration or inhalation injury, connective tissue disorders, IBD, focal bronchial obstruction
what causes the dilation and thickening of the bronchi seen in bronchiectasis?
due to chronic inflammation elicited by the host response to micro-organisms colonising the airways
what is the result of the chronic inflammation seen in bronchiectasis?
- bronchial wall oedema and increased mucus production
- neutrophils, T cells, immune effector cells recruited and release cytokines, proteases, reactive oxygen mediators implicated in progressive destruction of airways
describe the viscous cycle seen in bronchiectasis?
initial insult to airways by primary infection leads to increased inflammation, causing bronchial damage, serves as nidus for subsequent colonisation. airways are predisposed to subsequent inflammatory reactions and progressive airway damage and recurrent infections
what are the clinical features of mild bronchiectasis?
only produce yellow or green sputum after an infection. Localised areas of the lung may be affected, depending on position sputum production with position
what are the clinical features of bronchiectasis as the condition worsens?
patients suffer persistent halitosis, recurrent febrile episodes with malaise and episodes of pneumonia. Clubbing occurs and course crackles heard over infected areas (lung bases).
what are the clinical features of severe bronchiectasis?
continuous production of foul smelling, thick, khaki coloured sputum. Haemoptysis can occur as blood strained sputum or as massive haemorrhage. Breathlessness due to airflow limitation
what investigations would be carried out for a patient with suspected bronchiectasis?
- chest X-ray
- CT
- sputum
- sinus X-rays
- serum immunoglobulins
- sweat electrolytes (suspect CF)
- mucociliary clearance
what would be shown on CXR in a patient with bronchiectasis?
dilated bronchi with thickened bronchial walls and multiple cysts containing fluid, but can be normal
what would CT show in a patient with bronchiectasis?
scanning-reveals thickened, dilated bronchi and cysts at the end of the bronchioles. Characteristically the airways are larger than their associated blood vessels
what would a sputum test show for a patient with bronchiectasis?
examination and culture. Main pathogens are staph. Aureus, pseudomonas aeruginosa, H.influenzae and anaerobes
why would you do a sinus X-ray for a patient with bronchiectasis?
30% also have rhinosinusitis
what would serum immunoglobulins show in a patient with bronchiectasis?
upto 10% of adults with bronchiectasis have antibody class or subclass deficiency (IgA). Some have normal antibody class levels but fail to respond to respiratory pathogens. Response to pneumococcal and Hib vaccines may be impaired
how is mucociliary clearance measured?
nasal clearance of saccharin. Time to taste of a 1mm cube of saccharin measured (normally <30 minutes)
what are the treatment options for bronchiectasis?
postural drainage
antibiotics (ifCF)
bronchodilators (useful in patients with demonstratable airflow limitation)
anti-inflammatory agents (inhaled or oral steroids can decrease rate of progression)
surgery (rare for condition to be localised enough for resection to be practical)
what is postural drainage?
patients are trained by physiotherapists to tip themselves so that the affected lobes are uppermost at least 3 times a day for 10-20 minutes
What is type 1 respiratory failure?
a low level of oxygen in the blood (hypoxemia) with either a normal (normocapnia) or low (hypocapnia) level of carbon dioxide (PaCO2) but not an increased level (hypercapnia).
what is acute type 2 respiratory failure?
In a person withtype 2 acute respiratory failure, the lungs are not removing enough carbon dioxide. Thistypeofrespiratory failurecauses carbon dioxide levels to be high
what is acute on chronic type 2 respiratory failure?
Type 2(hypercapnic)respiratory failure: in which PaCO2 > 50 mmHg. Hypoxemia is common and it is due torespiratorypumpfailure. Alsorespiratory failureis classified according to its onset, course and duration intoacute,chronicandacuteon top ofchronic respiratory failure
in type 1 respiratory failure, what is…
- pH
- PaO2
- PaCO2
- Bicarbonate
- normal/high
- low
- normal/low
- normal
in acute type 2 respiratory failure, what is…
- pH
- PaO2
- PaCO2
- Bicarbonate
- normal/low
- low
- high
- normal/rising
in acute on chronic type 2 respiratory failure, what is…
- pH
- PaO2
- PaCO2
- Bicarbonate
- normal
- low
- high
- raised
what is the most common type of respiratory failure?
type 1
what is the usual underlying mechanism for type 1 respiratory failure?
ventilation perfusion mismatch
what are the common causes of type 1 respiratory failure?
severe acute asthma
pneumonia
pulmonary embolism
pulmonary oedema
what is the usual underlying mechanism of type 2 respiratory failure?
ventilatory failure
rise in PaCO2 not matched by increase in alveolar ventilation because of
-insufficient ventilatory drive
-excessive breathing
-inability of lungs to pump air in and out
what are the common causes of type 2 respiratory failure?
neuromuscular disorders
CNS depression
tension pneumothorax
commonest-acute COPD exacerbation
what is the management of type 2 respiratory failure?
-treat cause eg antibiotics for COPD exacerbation
-supportive care
-chemical or mechanical ventilation
-do not give high flow oxygen
check ABG after 20 mins
what is the initial management of type 1 respiratory failure?
give oxygen by facemask
assisted ventilation is PO2 <8kpa even with 0% O2
what is tidal volume?
amount of air inhaled during a normal breath
what is expiratory reserve volume?
amount of air that can be exhaled after a normal exhalation
what is inspiratory reserve volume?
amount of air that can be further inhaled after a normal inhalation
what is residual volume?
air left in the lungs after a forced exhalation
what is vital capacity?
maximum amount of air that can be moved in or out of the lungs in a single respiratory cycle
what is inspiratory capacity?
volume of air that can be inhaled in addition to a normal exhalation
what is functional residual capacity?
volume of air remaining after a normal exhlation
what is total lung capacity?
total volume of air in the lungs after maximal inspiration
what is forced respiratory volume (FEV1)?
how much air can be forced out of the lungs over a specific time period (1 second)
what is the 5 step approach to arterial blood gas interpretation?
- how is the patient
- is the patient hypoxaemic
- is the patient acidaemic or alkalaemic
- respiratory component (PaCO2)
- metabolic component (bicarbonate/base excess)
when interpretting the respiratory component what does a PaCO2>6kPa suggest?
respiratory acidosis
or respiratory compensation for metabolic acidosis
when interpretting the respiratory component what does a PaCO2<4.7kPa suggest?
respiratory alkalosis or respiratory compensation for metabolic acidosis
when interpretting the metabolic component what does bicarbonate <22mmol/l (or base excess
metabolic acidosis or renal compensation for respiratory alkalosis
when interpretting the metabolic component what does bicarbonate >26mmol/l (or base excess >+2mmol/l) suggest?
metabolic alkalosis or renal compensation for respiratory acidosis
what does the acronym ROME stand for (with regards to arterial blood gas interpretation)?
Respiratory=Opposite -low pH + high PaCO2 (acidosis) -high pH +low PaCO2 (alkalosis) Metabolic=Equal -low pH +low bicarb (acidosis) -high pH+high bicarb (alkalosis)
when acid base homeostasis is disturbed and blood pH declines how is homeostasis restored?
Acidosis
- brain and arterial receptors stimulated
- increase resp rate
- decrease blood CO2
- decrease blood bicarb
- increase pH
when acid base homeostasis is disturbed and blood pH increases how is homeostasis restored?
alkalosis
- brain and arterial receptors stimulated
- decrease resp rate
- increase blood CO2
- increase bicarb
- decrease pH