Academic Week 2 Flashcards
What is the definition of Asthma?
Asthma is the presence of symptoms (1+ of wheeze, breathlessness, chest tightness or cough) and of variable airflow obstruction. They may also have airway hyperresponsiveness or airway inflammation as part of the disease.
Alternatively, Asthma is a heterogenous disease characterised by chronic airway inflammation. There will be a history of symptoms such as wheeze, SOB, chest tightness and cough which may vary over time and in intensity. There will be variable expiratory airflow limitation.
What is an endotype?
This is the biological process which drives the phenotype
How is asthma diagnosed?
History of characteristic symptoms and evidence of variable airflow limitation. This is tested with bronchodilator reversibility testing and a 12% improvement in spirometry confirms asthma. Spirometry is the GOLD standard test.
Define an asthma exacerbation
An acute or sub-acute worsening of symptoms and lung function compared with normal status
How should an asthma exacerbation be treated?
ABCDE approach. A severe attack will have the patient sitting hunched over, tachypnoeic, tachycardic, SATs lower than 90, using words not sentences and accessory muscles in use. Peak flow less than 50% predicted.
They need short acting beta agonists (salbutamol and ipratropium bromide), oxygen, oral steroids and IV steroids. Consider IV magnesium as a bronchodilator or high dose inhaled corticosteroids.
All patients who have had an exacerbation are at increased risk of having another one as chronic asthma care may not be good enough.
When is an asthma exacerbation life threatening?
PEF > 33%, silent chest, cyanosis, poor respiratory effort, arrhythmias, hypotension, exhaustion and altered consciousness.
What is the most common new presentation of HIV?
Pneumonia with pneumocystitis jirovecii the causative organism. This has a classic Bat wing presentation on X-ray.
What are the risk factors for pneumonia?
People who regularly take inhaled corticosteroids, those who smoke, aged over 65 and travel history.
How can pneumonias be differentiated on X-ray?
Bacterial pneumonia has a lobar consolidation in a focal area whereas viral pneumonia has a ground glass presentation.
What is the most common cause of pneumonia?
Streptococcus Pneumonia
What is the CURB65 score?
This is used to assess management of pneumonia. Greater than 3 means there is significant risk of death within the next 30 days.
C = Confused on admission?
U = Blood Urea Level - greater than 7 is concerning
R = Respiratory rate greater than 30
B = Blood pressure below 90/60
65 = Aged over 65?
How does the CURB65 score relate to treatment?
CURB65: 0-1 = Amoxicillin
CURB65: 2 = Amoxicillin and erythromycin
CURB65: 3+ = Co-amoxiclav and clarithromycin
HAPs and VAPs will need broader cover because there is an increased risk of anaerobe infection.
How is pulmonary TB treated?
This can either be treated with rifampicin and Isoniazid for 4 months or rifampicin, Isoniazid, pyrazinamide and ethambutanol for 2 months.
How is TB tested for?
The Montu test is a skin test where TB proteins are inserted under the skin. If the area of induration becomes very large then it is likely the person has TB.
TB contact tracing can also be done through IGRA blood tests where T cell are exposed TB antigens to see if they react.
How should flu be treated in people at high risk?
A PCR test can be done to confirm the diagnosis. Treatment is with supportive care and Oseltamivir if it has been caught early enough.
What are the causes of lung cancer?
Smoking (daily but no threshold), passive smoke (1.3x risk), asbestos exposure, radioactive emissions, volatile hydrocarbons, diesel fuel and pulmonary fibrosis.
What are the symptoms of lung cancer?
Haemoptysis, cough, wheeze, chest pain and breathlessness. These are non-specific and often presents late. Many cases are found on imaging for other reasons.
Lung cancer should always be confirmed on CT.
Describe metastatic manifestations of lung cancer?
Intrathoracic manifestations include Horner’s syndrome, left recurrent laryngeal nerve palsy, SVC obstruction, phrenic nerve palsy, pericardial effusion, pleural effusion and dysphagia.
Extrathoracic metastases include brain, liver, bone and adrenal metastases.
Lung cancer also also present with finger clubbing, Cushing’s syndrome and gynaecomastia.
What cancers metastasise to the lungs?
Breast, GI and sarcomas.
How should lung cancer be managed?
The first step is to measure lung function with spirometry.
Performance should then be assessed and scored: 0 - Able to carry out normal activities 1 - Able to carry out light work 2 - Unable to carry out light work 3 - Limited self care 4 - Completely disabled
CT biopsies or flexible bronchoscopy biopsies are used to stage the tumour. A PET scan uses a radioisotope to stage the tumour. Lymph nodes are needed to determine if surgery is viable.
EBUS is a bronchoscope with a USS to check lymph nodes and avoid surgery if possible. Pleural effusions which are found will need draining.
What are small cell lung tumours?
These are extremely aggressive tumours which have a very poor prognosis.
What types of lung cancers are treatable?
Squamous, adenocarcinomas and non-small cell tumours of unknown morphology.
What types of lung cancers can be targeted with tyrosine kinase inhibitors?
These target single genomic drivers such as EGFR, ALK, ROS1, BRAF, NTRK, MET, RET and HER2.
These are almost always adenocarcinomas. The FISH test is used to check for ALK mutations.
What types of lung cancers can be treated with immune modulators?
These work by attacking PD-L1 and tumour mutational burden (TMB)
What is the definition of general anaesthetic?
This is the absence of sensation associated with a reversible loss of consciousness. These drugs work via the CNS.
Generally how do anaesthetic drugs work?
- Inhibition of the excitatory pathways and neurotransmitters in the CNS, this reduces neural transmission and leads to reduced consciousness (Glutamate is targeted by ketamine via the NMDA receptor)
- Potentiation of the inhibitory pathways and neurotransmitters in the CNS, this reduces neuronal transmission leading to unconsciousness. (Glycine and GABA)
Describe how the GABAa receptor works
The GABAa receptor is a pentameric (5 sub units) chloride channel. The chloride ions are negatively charged to make the membrane potential more negative and prevent action potential being proposed at the threshold potential is harder to reach with an excitatory impulse.
many anaesthetics cause an increase in GABAa movement making the neurone more negatively charged. This causes unconsciousness.
What is the binding site of most general anaesthetics?
The beta subunit of the GABAa receptor.
What is an induction agent and give some examples?
This is a drug which is used to get a patient to sleep. IV agents will achieve this within a minute but other options are available.
The two most common IV drugs used are propofol and thiopentone.
What does thiopentone do?
Reduces airway reflexes, causes respiratory depression, reduces cardiac output, causes tachycardia and vasodilation and will cause unconsciousness. There is a risk of severe anaphylaxis and reduced renal output.
What does propofol do?
This causes reduced airway reflexes, vasodilation, hypotension, unconsciousness, antiemetic, hyperlipidaemia and can turn urine green.
What are inhalation anaesthetics and what are they used for?
Once induction has been achieved, anaesthesia is maintained with inhalation anaesthetics. These include isoflurane, desflurane and sevoflurane. These are often administered with oxygen and nitrous oxide.
Sevoflurane can also be used as an induction agent.
What is the significance of nitrous oxide in anaesthetics?
Nitrous oxide is not a very potent anaesthetic but is a strong analgesic. Entonox is when nitrous oxide is mixed with oxygen.
When should nitrous oxide not be given?
Pneumothorax or severe emphysema, air embolus, skull fractures and intestinal obstruction.
