Pulmonary alveolar proteinosis (PAP) is a lung condition that is caused by a build-up of proteins and other substances in the alveoli. The alveoli are the part of the lungs that contain air. PAP has the following symptoms:
Shortness of breath, also called dyspnoea
Chest pain or tightness
Fever
Weight loss
Cough (sometimes, but not always)
Low levels of oxygen in the blood
Nail clubbing (abnormal growth of toenails or fingernails)

Serologic studies are generally not useful for PAP. Flexible bronchoscopy with bronchoalveolar lavage (BAL) remains the criterion standard. Elevated levels of the proteins SP-A and SP-D in serum and BAL fluid may be useful. Elevated titer of neutralizing autoantibody against GM-CSF (immunoglobulin G [IgG] isotype) in serum and BAL fluid may be useful. Recent studies have proposed that deficiency of GM-CSF causes pulmonary alveolar proteinosis (PAP); all patients studied had the antibody to GM-CSF. Serum lactate dehydrogenase (LDH) level is usually elevated, but this finding is nonspecific.

High-resolution computed tomography (HRCT) scan of the chest demonstrates areas of patchy ground-glass opacification with smooth interlobular septal thickening and intralobular interstitial thickening, which produces a polygonal pattern referred to as crazy paving.

Light microscopy of the lung parenchymal tissue shows alveoli filled with a granular PAS base-reactive and diastase-resistant eosinophilic material.

The tumour has only invaded the visceral pleura and measures 3cm in the greatest dimension. Hence it is designated at T2. Ipsilateral peribronchial and/or hilar lymph node involvement would make it N1. There is no distal metastasis so M would be 0.

Alpha-1-antitrypsin (AAT) is a member of the serine proteinase inhibitor (serpin) family of proteins with a broad spectrum of biological functions including inhibition of proteases, immune modulatory functions, and the transport of hormones.

A single dose of intravenous magnesium sulphate is safe and may improve lung function and reduce intubation rates in patients with acute severe asthma. Intravenous magnesium sulphate may also reduce hospital admissions in adults with acute asthma who have had little or no response to standard treatment.

Consider giving a single dose of intravenous magnesium sulphate to patients with acute severe asthma (PEF <50% best or predicted) who have not had a good initial response to inhaled bronchodilator therapy. Magnesium sulphate (1.2–2 g IV infusion over 20 minutes) should only be used following consultation with senior medical staff.

Primary spontaneous pneumothorax is an abnormal accumulation of air in the space between the lungs and the chest cavity (called the pleural space) that can result in the partial or complete collapse of a lung. This type of pneumothorax is described as primary because it occurs in the absence of lung disease such as emphysema. Spontaneous means the pneumothorax was not caused by an injury such as a rib fracture. Primary spontaneous pneumothorax is likely due to the formation of small sacs of air (blebs) in lung tissue that rupture, causing air to leak into the pleural space. Air in the pleural space creates pressure on the lung and can lead to its collapse. A person with this condition may feel chest pain on the side of the collapsed lung and shortness of breath. Patients are typically aged 18-40 years, tall, thin, and, often, are smokers.

In small pneumothoraxes with minimal symptoms, no active treatment is required. These patients can be safely discharged with early outpatient review and should be given written advice to return if breathlessness worsens. Patients who have been discharged without intervention should be advised that air travel should be avoided until a radiograph has confirmed resolution of the pneumothorax.

Salbutamol stimulates beta-2 adrenergic receptors, which are the predominant receptors in bronchial smooth muscle (beta-2 receptors are also present in the heart in a concentration between 10% and 50%).

Stimulation of beta-2 receptors leads to the activation of enzyme adenyl cyclase that forms cyclic AMP (adenosine-mono-phosphate) from ATP (adenosine-tri-phosphate). This increase of cyclic AMP relaxes bronchial smooth muscle and decrease airway resistance by lowering intracellular ionic calcium concentrations. Salbutamol relaxes the smooth muscles of airways, from trachea to terminal bronchioles.

Increased cyclic AMP concentrations also inhibits the release of bronchoconstrictor mediators such as histamine and leukotriene from the mast cells in the airway.

If a pleural effusion is present, a diagnostic thoracentesis may be performed and analysed for pH, lactate dehydrogenase, glucose levels, specific gravity, and cell count with differential. Pleural fluid may also be sent for Gram stain, culture, and sensitivity. Acid-fast bacillus testing may also be considered and the fluid may be sent for cytology if cancer is suspected.

The following findings are suggestive of an empyema or parapneumonic effusion that will likely need a chest tube or pigtail catheter for complete resolution:
-Grossly purulent pleural fluid
-pH level less than 7.2
-WBC count greater than 50,000 cells/µL (or polymorphonuclear leukocyte count of 1,000 IU/dL)
-Glucose level less than 60 mg/dL
-Lactate dehydrogenase level greater than 1,000 IU/mL
-Positive pleural fluid culture

The most often used golden criteria for empyema are pleural effusion with macroscopic presence of pus, a positive Gram stain or culture of pleural fluid, or a pleural fluid pH under 7.2 with normal peripheral blood ph.

Historically, high rates of maternal and fetal death have been reported for pregnant women with pulmonary hypertension (30–56% and 11–28%, respectively). The causes of poor maternal outcomes are varied and include risk of death from right heart failure and stroke from intracardiac shunting. Furthermore, there is a high peri-/post-partum risk due to haemodynamic stress, bleeding complications and the use of general anaesthesia, which can all lead to right heart failure.
The most common risk to the foetus is death, with premature birth and growth retardation being reported in successfully delivered children.
CXR is not contraindicated in pregnancy. D-dimers are not used as a diagnostic aid as they are almost always elevated in pregnancy. Nifedipine, although contraindicated in pregnant women may be used judiciously if the need arises.

The Stages of COPD:
Mild COPD or Stage 1—Mild COPD with a FEV1 about 80 percent or more of normal.
Moderate COPD or Stage 2—Moderate COPD with a FEV1 between 50 and 80 percent of normal.
Severe COPD or Stage 3—Severe emphysema with a FEV1 between 30 and 50 percent of normal.
Very Severe COPD or Stage 4—Very severe or End-Stage COPD with a lower FEV1 than Stage 3, or people with low blood oxygen levels and a Stage 3 FEV1.

This patient has a FEV1 percent of 37 which falls within the stage 3 or severe COPD.
During stage 3 COPD, you will likely experience significant lung function impairment. Many patients will experience an increase in COPD flare-ups or exacerbations. For some people, the increase in flare-ups means they could need to be hospitalized at times as well.

Inhaled corticosteroid (ICS) use in combination with long-acting β2-agonists (LABAs) was shown to provide improved reductions in exacerbations, lung function, and health status. ICS-LABA combination therapy is currently recommended for patients with a history of exacerbations despite treatment with long-acting bronchodilators alone. The presence of eosinophilic bronchial inflammation, detected by high blood eosinophil levels or a history of asthma or asthma–COPD overlap, may define a population of patients in whom ICSs may be of particular benefit.

The Towards a Revolution in COPD Health (TORCH) trial was a pivotal, double-blind, placebo-controlled, randomized study comparing salmeterol plus fluticasone propionate (50 and 500 µg, respectively, taken twice daily) with each component alone and placebo over 3 years.26 Patients with COPD were enrolled if they had at least a 10-pack-year smoking history, FEV1 <60% predicted, and an FEV1:FVC ratio ≤0.70.26 Among 6,184 randomized patients, the risk of death was reduced by 17.5% with the ICS-LABA combination vs placebo (P=0.052). ICS-LABA significantly reduced the rate of exacerbations by 25% compared with placebo (P<0.001) and improved health status and FEV1 compared with either component alone or placebo.

Bronchiectasis is a long-term condition where the airways of the lungs become abnormally widened, leading to a build-up of excess mucus that can make the lungs more vulnerable to infection. The most common symptoms of bronchiectasis include:
– a persistent productive cough
– breathlessness.

The 3 most common causes in the UK are:
– a lung infection in the past, such as pneumonia or whooping cough, that damages the bronchi
– underlying problems with the immune system (the body’s defence against infection) that make the bronchi more vulnerable to damage from an infection
– allergic bronchopulmonary aspergillosis (ABPA) – an allergy to a certain type of fungi that can cause the bronchi to become inflamed if spores from the fungi are inhaled

The carotid body consists of chemosensitive cells at the bifurcation of the common carotid artery that respond to changes in oxygen tension and, to a lesser extent, pH. In contrast to central chemoreceptors (which primarily respond to PaCO2) and the aortic bodies (which primarily have circulatory effects: bradycardia, hypertension, adrenal stimulation, and also bronchoconstriction), carotid bodies are most sensitive to PaO2. At a PaO2 of approximately 55-60 mmHg, they send their impulses via CN IX to the medulla, increasing ventilatory drive (increased respiratory rate, tidal volume, and minute ventilation). Thus, patients who rely on hypoxic respiratory drive will typically have a resting PaO2 around 60 mm Hg.

Squamous-cell carcinoma is the most common histological type of lung cancer to cavitate (82% of cavitary primary lung cancer), followed by adenocarcinoma and large cell carcinoma. Multiple cavitary lesions in primary lung cancer are rare, however, multifocal bronchoalveolar cell carcinoma can occasionally have multiple cavitary lesions. Small cell carcinoma is not known to cavitate.

Lofgren’s syndrome is an acute form of sarcoidosis characterized by erythema nodosum, bilateral hilar lymphadenopathy (BHL), and polyarthralgia or polyarthritis. Other symptoms include anterior uveitis, fever, ankle periarthritis, and pulmonary involvement.

Löfgren syndrome is usually an acute disease with an excellent prognosis, typically resolving spontaneously from 6-8 weeks to up to 2 years after onset. Pulmonologists, ophthalmologists, and rheumatologists often define this syndrome differently, describing varying combinations of arthritis, arthralgia, uveitis, erythema nodosum, hilar adenopathy, and/or other clinical findings.

High Altitude Cerebral Oedema (HACE) is a severe and potentially fatal manifestation of high altitude illness and is often characterized by ataxia, fatigue, and altered mental status. HACE is often thought of as an extreme form/end-stage of Acute Mountain Sickness (AMS). Although HACE represents the least common form of altitude illness, it may progress rapidly to coma and death as a result of brain herniation within 24 hours, if not promptly diagnosed and treated.

HACE generally occurs after 2 days above 4000m but can occur at lower elevations (2500m) and with faster onset. Some, but not all, individuals will suffer from symptoms of AMS such as headache, insomnia, anorexia, nausea prior to transitioning to HACE. Some may also have concomitant High Altitude Pulmonary Oedema (HAPE). HACE in isolation is rare, but the absence of concomitant HAPE or symptoms of AMS prior to deterioration does not rule-out the presence of HACE.

Most cases develop as a progression of AMS and will include a history of recent ascent to altitude and prior complaints/findings of AMS including a headache, fatigue, nausea, insomnia, and/or light-headedness. Some may also have signs/symptoms of HAPE. Transition to HACE is heralded by signs of encephalopathy including ataxia (usually the earliest clinical finding) and altered mentation which may range from mild to severe. Other symptoms may include a more severe headache, difficulty speaking, lassitude, a decline in the level of consciousness, and/or focal neurological deficits or seizures.

The mainstay of treatment is the immediate descent of at least 1000m or until symptoms improve. If descent is not an option, one may use a portable hyperbaric chamber and/or supplemental oxygen to temporize illness, but this should never replace or delay evaluation/descent when possible. If available, dexamethasone 8mg for one dose, followed by 4mg every 6 hours should be given to adults via PO, IM, or IV routes.
Acetazolamide has proven to be beneficial in only a single clinical study. The suggested dosing regimen for Acetazolamide is 250 mg PO, given twice daily. Though effective in alleviating or temporizing symptoms, none of the adjunct treatment modalities are definitive or a replacement for an immediate descent.

Type I pneumocyte: The cell responsible for the gas (oxygen and carbon dioxide) exchange that takes place in the alveoli. It is a very thin cell stretched over a very large area. This type of cell is susceptible to a large number of toxic insults and cannot replicate itself.
Type II pneumocyte: The cell responsible for the production and secretion of surfactant (the molecule that reduces the surface tension of pulmonary fluids and contributes to the elastic properties of the lungs). The type 2 pneumocyte is a smaller cell that can replicate in the alveoli and will replicate to replace damaged type 1 pneumocytes. Alveolar macrophages are the primary phagocytes of the innate immune system, clearing the air spaces of infectious, toxic, or allergic particles that have evaded the mechanical defences of the respiratory tract, such as the nasal passages, the glottis, and the mucociliary transport system. The main role of goblet cells is to secrete mucus in order to protect the mucous membranes where they are found. Goblet cells accomplish this by secreting mucins, large glycoproteins formed mostly by carbohydrates.

Flow-volume loop is an easy, non-invasive diagnostic tool that can be used even in severely-ill patients. It can provide information about the location of the obstruction and can differentiate between obstructive pulmonary disease and upper-airway obstruction. Therefore, it is recommended to obtain a flow-volume loop during the assessment of patients with upper airway obstruction.

The normal partial pressure reference values are:
– PaO2 more than 80 mmHg (11 kPa)
– PaCO2 less than 45 mmHg (6.0 kPa).
This patient has an elevated PaCO2 (7.4kPa)
Hypoxemia (PaO2 <8kPa) with hypercapnia (PaCO2 >6.0kPa).
The pH is also lower than 7.35 at 7.3

Type 2 respiratory failure is caused by inadequate alveolar ventilation; both oxygen and carbon dioxide are affected. Defined as the build-up of carbon dioxide levels (PaCO2) that has been generated by the body but cannot be eliminated. The underlying causes include:
– Increased airways resistance (chronic obstructive pulmonary disease, asthma, suffocation)
– Reduced breathing effort (drug effects, brain stem lesion, extreme obesity)
– A decrease in the area of the lung available for gas exchange (such as in chronic bronchitis)
– Neuromuscular problems (Guillain–Barré syndrome, motor neuron disease)
– Deformed (kyphoscoliosis), rigid (ankylosing spondylitis), or flail chest.

Caplan’s syndrome is defined as the association between silicosis and rheumatoid arthritis (RA). It is rare and usually diagnosed in an advanced stage of RA. It generally affects patients with a prolonged exposure to silica.

Caplan’s syndrome presents with rheumatoid lung nodules and pneumoconiosis. Originally described in coal miners with progressive massive fibrosis, it may also occur in asbestosis, silicosis and other pneumoconiosis. Chest radiology shows multiple, round, well defined nodules, usually 0.5 – 2.0 cm in diameter, which may cavitate and resemble tuberculosis.

The following drugs should be used as normal during pregnancy:
short acting β2 -agonists
long acting β2- agonists
inhaled corticosteroids
oral and intravenous theophyllines

Use steroid tablets as normal when indicated during pregnancy for severe asthma. Steroid tablets should never be withheld because of pregnancy.
If leukotriene receptor antagonists are required to achieve adequate control of asthma then they should not be withheld during pregnancy.

Churg-Strauss disease (CSD) is one of three important fibrinoid, necrotizing, inflammatory leukocytoclastic systemic small-vessel vasculitides that are associated with antineutrophil cytoplasm antibodies (ANCAs).
The first (prodromal) phase of Churg-Strauss disease (CSD) consists of asthma usually in association with other typical allergic features, which may include eosinophilia. During the second phase, the eosinophilia is characteristic (see below) and ANCAs with perinuclear staining pattern (pANCAs) are detected. The treatment would therefore be different from asthma. For most patients, especially those patients with evidence of active vasculitis, treatment with corticosteroids and immunosuppressive agents (cyclophosphamide) is considered first-line therapy