Respiratory (Pleural diseases and lung cancer) Flashcards
pneumothorax
collection of air in the pelural space
can be primary or secondary
Primary spontaneous pneumothorax
These occur in people without lung disease, however, there are risk factors:
- Smoking
- Male sex
- Family history
- Tall and slender build, especially people with Marfan’s syndrome
*
Secondary spontaneous pneumothorax
These occur in people who have lung disease. Risk factors are:
- Asthma
- COPD
- Idiopathic pulmonary fibrosis
- Connective tissue diseases such as rheumatoid arthritis
- Tuberculosis
- Pneumocystis jirovecii pneumonia in people who have HIV
other causes of pneumothorax
Traumatic pneumothorax:
- Often following penetrating chest trauma (e.g. stabbing, gunshots, fractured ribs)
Iatrogenic pneumothorax:
- Common causes are mechanical ventilation, central line placement, and lung biopsy
Catamenial pneumothorax – pneumothorax at the time of menstruation
- Due to thoracic endometriosis
presentation of pneumothorax
- Dyspnoea
- Pleuritic chest pain: This is chest pain that is worse when breathing in
- Tachypnoea
Examination may show:
* Ipsilateral reduced breath sounds
* Ipsilateral hyper-resonance on percussion
pneumothorax: severe signs of respiratory distress and haemodynamic instability may suggest
presence of tension pnuemothorax
pathophysiology of tension pneumothorax
In a tension pneumothorax, injured pleural tissue leads to the formation of a one-way valve. This allows air to enter the pleural space during inspiration, but it cannot escape during expiration, leading to an increase in intrathoracic pressure.
** Obstructive circulatory** shock follows, where the heart, lungs, and major blood vessels are compressed, leading to haemodynamic compromise.
Risk factors are similar to that of a pneumothorax, along with blunt or penetrating chest trauma (such as knife stabbings).
presentation of tension pneumothorax
haemodynamic instability should
- Tracheal deviation away from the affected side – due to increasing intrathoracic pressure as more air enters
- Signs of respiratory distress:
- Hypotension – due to cardiac outflow obstruction
- Tachycardia – due to the heart trying to compensate for outflow obstruction
- Altered levels of consciousness
- Sweating
investigations for normal pneumothorax
Chest x-ray(posteroanterior):
* Done initially and shows a visible rim between the lung margin and chest wall and absent lung markings between the lung margin and chest wall
Chest CT:
* Considered if the diagnosis is uncertain or there is a complex case
Arterial blood gases:
* Should only be done if oxygen saturations are <92%
* Usually shows hypoxia depending on the severity
investigation for tension pneumothorax
nil- straight to needle decompression
classification of size of pneumothorax
The size of the pneumothorax affects the rate of resolution and is used to guide whether management is carried out. The distance between the pleural surface and the lung edge is measured at the level of the hilum:
If ≤2cm – small pneumothorax
If >2cm – large pneumothorax
Management: Primary pneumothorax
Always remember to rule out a tension pneumothorax.
- If <2cm and patient is not short of breath: discharge and review as an outpatient
- If >2cm and/or patient is short of breath: Attempt aspiration. If aspiration fails, insert a chest drain
-> 2nd intercostal muscle or triangle of safety
Management: Secondary pneumothorax
- If >50 years old + >2cm and/or patient is short of breath: insert a chest drain
- If 1-2cm: attempt aspiration
- If aspiration fails, insert a chest drain
- If <1cm: give oxygen and admit for 24 hours and review
management of recurrent pneumothorax
pleurectomy, pleural abrasion and pleurodesis
management of tension pneumothorax
- Immediate decompression + high flow oxygen– insert a large-bore cannula through the second intercostal space in the mid-clavicular line:
* A ‘hiss’ of air arising can confirm the diagnosis - Insert chest drain immediately after decompression and admit to hospital: This is inserted into the ‘triangle of safety’ – mid-axillary line of the 5th intercostal space
Pleural effusion
When excessive fluid accumulates in the pleural space, this is known as a pleural effusion.
causes of pleural effusion can be split into
Transudate and Exudate
The causes of pleural effusion can be transudates or exudates depending on their protein
transudate
protein <30g/L
occurs due to increased hydrostatic pressure
- congestive heart failure
- cirrhosis
- nephrotic syndrome
- PE
- hypoalbuminemia
- Hypothyroidisms
- Meigs syndrome
exudate
protein >30g/l
occurs due to inflammation and increased capillary permeability
- pneumonia
- cancer
- TB
- PE
- autoimmune
- pancreatitis
presentation of pleural effusion
- Dyspnoea:
- Dullness to percussion on examination:
- Reduced breath sounds over the area of effusion
- Pleuritic chest pain
- Cough
- Features of associated conditions such as heart failure
pleural effusion investigations
Chest x-ray:
- Shows blunting or blurring of the costophrenic angles
- Shows a clear fluid level
- The trachea deviates away from the opacification
Thoracic ultrasound:
- Useful for guiding thoracentesis and more specific than X-rays for detecting pleural effusions
CT with contrast:
- To investigate underlying cause
Pleural aspiration + microscopy, culture, sensitivities, cytology, and biochemistry:
Done with ultrasound guidance
- Exudates:
Protein level >30 g/L - Transudates:
Protein level <30 g/L
If the protein level is borderline (between 25-35 g/L), use Light’s criteria (see below)
Pleural Fluid Interpretation
Blood
- Malignancy
- Pulmonary embolism
- Trauma
Pleural pH
Reduced pleural pH (<7.20) can be caused by:
- Infection
- Empyema
- Malignancy
- Connective tissue diseases – rheumatoid arthritis and systemic lupus erythematosus
- Tuberculosis
- Oesophageal rupture
Pleural glucose
Reduced pleural glucose (<3.3 mmol/L) can be caused by:
- Empyema
- Malignancy
- Connective tissue diseases – rheumatoid arthritis and systemic lupus erythematosus
- Tuberculosis
- Oesophageal rupture
Other measures
- White cell count and differential: Elevated counts suggest malignancy or tuberculosis
- Lactate dehydrogenase (LDH): Used in Light’s criteria (see below)
- Pleural fluid amylase: Elevated counts suggest pancreatitis or oesophageal rupture
Light’s criteria for pleural effusion
Light’s criteria should be used if the pleural fluid protein level is between 25-35 g/L. An exudate is likely if any one of the following applies:
- Pleural fluid divided by serum protein is >0.5
- Pleural fluid LDH divided by serum LDH >0.6
- Pleural fluid LDH more than 2/3s of the upper limit of normal serum LDH
management of pleural effusion
-
1st-line: pleural aspiration:
This is involved in diagnosing and identifying the underlying cause of the effusion and may provide therapeutic relief, however, the effusion can often recur - Chest drains may be inserted which are then removed once the underlying cause has been treated
- Other options include surgical shunts, indwelling drainage catheters, or pleurodesis (adhesion of the visceral and parietal pleura)
lung cancers are usually
bronchial carcinomas
* Non-small cell lung cancers (NSCLCs) – around 85% of cases
* Small cell lung cancers (SCLCs) – around 15% of cases
Lung cancer metastases are common and typical sites are
the bone, kidney, breast, prostate, GI tract, ovaries, and cervix.
Non-small cell lung cancers (NSCLCs)
They can be further divided into:
1) Adenocarcinoma
2)
* Most common type
* Often seen in non-smokers
* Lung periphery
2) Squamous carcinoma (smoking key risk factor)
3)
* Often presents as an obstruction of the bronchus leading to infection
3) Large cell carcinoma
4) Carcinoid tumours - flushing, diarrhoea
Small cell lung cancers (SCLCs)
Small cell lung cancers (SCLCs) arise from Kulchitsky cells which are part of the amine precursor uptake and decarboxylation (APUD) system. APUD cells make polypeptides and amines that act as hormones or neurotransmitters. SCLCs often have paraneoplastic features (see below) as a result of this.
Smoking key RF
SCLCs carry a poor prognosis as they are aggressive and rapidly growing. They often spread early and are nearly always inoperable at presentation.
Risk Factors of lung cancers
- Active or passive smoking
- Chronic obstructive pulmonary disease (COPD)
- Increased age
- Family history
- Asbestos exposure
presentation of lung cancer
- Dyspnoea
- Cough
- Haemoptysis- red flag
- Unexplained weight loss- red-flag
- Chest pain or discomfort
- Hoarseness: some tumours, particularly Pancoast tumours (tumours of the apex of the lung) can press on the recurrent laryngeal nerve, leading to hoarseness
- Horner’s syndrome
- Features of paraneoplastic syndromes – see below
Paraneoplastic syndromes of lung cancer
is a set of signs and symptoms emerging as a consequence of a tumour in the body, typically due to the production of molecules (such as hormones) by tumour cells, or the immune response against the tumour itself. Paraneoplastic syndromes vary depending on the type of lung cancer present.
paraneoplastic syndrome: adenocarcinoma
Gynaecomastia due to ectopic hCG secretion:
The hCG acts as LH and stimulates the production of more oestrogen
paraneoplastic syndrome: small cell arcinoma
- Ectopic anti-diuretic hormone (ADH) secretion leading to a syndrome of inappropriate ADH secretion (SIADH) resulting in hyponatraemia
- Ectopic adrenocorticotropic hormone (ACTH)secretion leading to features of Cushing’s syndrome
- Lambert-Eaton myasthenic syndrome (LEMS) due to the formation of antibodies against voltage-gated calcium ion channels:
- These are antibodies that are made against the tumour cell that happen to also act against voltage-gated calcium ion channels
paraneoplastic syndrome: squamous cell carcioma
- Parathyroid hormone-related protein (PTH-rp) secretion leading to hypercalcaemia
- Ectopic thyroid-stimulating hormone secretion (TSH) leading to thyrotoxicosis
Refer using a suspected cancer (2-week wait) pathway for lung cancer if:
- There are chest x-ray features that suggest lung cancer
- ≥40 years with unexplained haemoptysis
when to offer x-ray
Offer an urgent chest x-ray within 2 weeks if patients have 2 or more of the following, or if they have ever smoked and have one of the following:
- Cough
- Fatigue
- Shortness of breath
- Chest pain
- Weight loss
- Appetite loss
Consider an urgent chest x-ray within 2 weeks if patients are ≥40 with any of the following:
- Persistent or recurrent chest infections
- Finger clubbing
- Supraclavicular or persistent cervical lymphadenopathy
- Chest signs suggestive of cancer
- Thrombocytosis – this can be a marker for potential cancers
investigations for lung cancer
Chest x-rays:
* The first investigation performed on all patients with suspected lung cancer
CT chest with contrast:
* The investigation of choice for lung cancer
* The contrast helps differentiate lymph nodes from blood vessels
Bronchoscopy:
* To allow a biopsy to be taken for histological diagnosis
* Positron emission tomography (PET)-
CT scan:
* Done in potentially curable patients to localise pathology
Bloods
- FBC- thrombocytosis
- LFT- mets
- UEs- hyponatraemia due to SIADH
Bone scan
- mets
CT or MRI or brain
- brain metastasis
management of lung cancer
Management options are put in place using a multidisciplinary approach. In NSCLC, surgery may be an option, along with radiotherapy and chemotherapy. Many patients with SCLC, however, have metastases at the time of presentation, and are less suitable for surgery, leaving chemotherapy and radiotherapy as treatment options.
Treatments such as endobronchial stenting and debulking can be used in palliative care to relieve bronchial obstruction.
Mesothelioma
- Mesothelioma is a cancer that develops from the mesothelial lining of the lungs and is strongly associated with asbestos exposure.
- Other less common sites that can be affected are the lining of the abdomen, the pericardium, or the tunica vaginalis surrounding the testes.
Asbestos-Related Lung Diseases
Asbestos is a fibre-like material that was once used in insulating buildings. Its use has been fully banned since 1999. People exposed to asbestos often develop lung disease, and the risk of developing asbestos-related diseases increases with the duration and degree of exposure.
Asbestos exposure can lead to the development of:
Benign diseases:
* Pleural plaques – most common
* Pleural thickening
Interstitial lung disease:
* Asbestosis – usually causes lower lobe fibrosis
Malignant disease:
* Mesothelioma
* Lung cancer
RF mesothelioma
- Asbestos exposure
- Age >75 years – this is because the latency period between asbestos exposure and the development of mesothelioma is around 20-40 years, so most patients are older adults
presentation of mesothelioma
Mesothelioma should be suspected in a patient with new painless pleural effusions, especially if they have chest pain or a history of asbestos exposure. Patients may have:
- Progressively worsening shortness of breath
- Chest pain:
- Cough: usually dry
- Constitutional symptoms: These are fevers, night sweats, weight loss, and fatigue
- Reduced breath sounds on examination:
- Usually due to pleural effusions or obstruction
- Dullness to percussion on examination:
- Usually due to pleural effusions
Investigations for mesothelioma
Chest x-ray:
* May show pleural effusions or pleural thickening
* There may also be signs of asbestos exposure e.g. lower zone lung fibrosis
CT chest with contrast:
* More sensitive for identifying mesothelioma
Pleural fluid analysis:
* If a pleural effusion is present, the fluid should be sent for microscopy, culture and sensitivities, biochemistry, and cytology
Pleural biopsy via thoracoscopy
- Allows for histological diagnosis
