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.

Meconium ileus equivalent (MIE) can be defined as a clinical manifestation in cystic fibrosis (CF) patients caused by acute intestinal obstruction by putty-like faecal material in the cecum or terminal ileum. A broader definition includes a more chronic condition in CF patients with abdominal pain and a coecal mass which may eventually pass spontaneously. The condition occurs only in CF patients with exocrine pancreatic insufficiency (EPI). It has not been seen in other CF patients nor in non-CF patients with EPI. The frequency of these symptoms has been reported as 2.4%-25%.

The treatment should primarily be non-operative. Specific treatment with N-acetylcysteine, administrated orally and/or as an enema is recommended. Enemas with the water soluble contrast medium, meglucamine diatrizoate (Gastrografin), provide an alternative form for treatment and can also serve diagnostic purposes. It is important that the physician is familiar with this disease entity and the appropriate treatment with the above mentioned drugs. Non-operative treatment is often effective, and dangerous complications following surgery can thus be avoided.

Alveolar haemorrhage (AH) is a rare, but serious manifestation of SLE. It may occur early or late in disease evolution. Extrapulmonary disease may be minimal and may be masked in patients who are already receiving immunosuppressants for other symptoms of SLE.

DLCO or TLCO (diffusing capacity or transfer factor of the lung for carbon monoxide (CO)) is the extent to which oxygen passes from the air sacs of the lungs into the blood.
Factors that can increase the DLCO include polycythaemia, asthma (can also have normal DLCO) and increased pulmonary blood volume as occurs in exercise. Other factors are left to right intracardiac shunting, mild left heart failure (increased blood volume) and alveolar haemorrhage (increased blood available for which CO does not have to cross a barrier to enter).

A study conducted showed that the average post smoking cessation weight gain was about 2 kg.
Withdrawal symptoms usually peak after 1–3 days and then decrease over a period of 3–4 weeks. After this time, the body has expelled most of the nicotine, and the withdrawal effects are mainly psychological.

Though a common community pathogen, Staphylococcus Aureas is found twice as frequently in pneumonias in hospitalized patients. It often attacks the elderly and patients with CF and arises as a co-infection with influenza viral pneumonia. The clinical course is characterized by high fevers, chills, a cough with purulent bloody sputum, and rapidly progressing dyspnoea. The gross pathology commonly reveals an acute bronchopneumonia pattern that may evolve into a necrotizing cavity with congested lungs and airways that contain a bloody fluid and thick mucoid secretions.

Infection with Klebsiella organisms occurs in the lungs, where they cause destructive changes. Necrosis, inflammation, and haemorrhage occur within lung tissue, sometimes producing a thick, bloody, mucoid sputum described as currant jelly sputum.
The illness typically affects middle-aged and older men with debilitating diseases such as alcoholism, diabetes, or chronic bronchopulmonary disease. An increased tendency exists toward abscess formation, cavitation, empyema, and pleural adhesions.

In mild-to-moderate heroin overdoses, arterial blood gas (ABG) analysis reveals respiratory acidosis. In more severe overdoses, tissue hypoxia is common, leading to mixed respiratory and metabolic acidosis.

The normal range for PaCO2 is 35-45 mmHg (4.67 to 5.99 kPa). Respiratory acidosis can be acute or chronic. In acute respiratory acidosis, the PaCO2 is elevated above the upper limit of the reference range (i.e., >45 mm Hg) with an accompanying academia (i.e., pH < 7.35). In chronic respiratory acidosis, the PaCO2 is elevated above the upper limit of the reference range, with a normal or near-normal pH secondary to renal compensation and an elevated serum bicarbonate levels (i.e., >30 mEq/L).

Arterial blood gases with pH = 7.31; pCO2 = 7.4 kPa; pO2 = 8.1 kPa would indicate respiratory acidosis.

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.

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.

Extrinsic allergic alveolitis (EAA) refers to a group of lung diseases that can develop after exposure to certain substances. The name describes the origin and the nature of these diseases:

‘extrinsic’ – caused by something originating outside the body
‘allergic’ – an abnormally increased (hypersensitive) body reaction to a common substance
‘alveolitis’ – inflammation in the small air sacs of the lungs (alveoli)

Symptoms can include: fever, cough, worsening breathlessness and weight loss. The diagnosis of the disease is based on a history of symptoms after exposure to the allergen and a range of clinical tests which usually includes: X-rays or CT scans, lung function and blood tests.

EAA is not a ‘new’ occupational respiratory disease and occupational causes include bacteria, fungi, animal proteins, plants and chemicals.

Examples of EAA include:

Bird fancier’s lung (BFL) is a type of hypersensitivity pneumonitis (HP). It is triggered by exposure to avian proteins present in the dry dust of the droppings and sometimes in the feathers of a variety of birds. The lungs become inflamed, with granuloma formation. Birds such as pigeons, parakeets, cockatiels, shell parakeets (budgerigars), parrots, turtle doves, turkeys and chickens have been implicated.

People who work with birds or own many birds are at risk. Bird hobbyists and pet store workers may also be at risk. This disease is an inflammation of the alveoli in the lungs caused by an immune response to inhaled allergens from birds. Initial symptoms include shortness of breath (dyspnoea), especially after sudden exertion or when exposed to temperature change, which can resemble asthma, hyperventilation syndrome or pulmonary embolism. Chills, fever, non-productive cough and chest discomfort may also occur.

A definitive diagnosis can be difficult without invasive testing, but extensive exposure to birds combined with reduced diffusing capacity are strongly suggestive of this disease. X-ray or CT scans will show physical changes to the lung structure (a ground glass appearance) as the disease progresses. Precise distribution and types of tissue damage differ among similar diseases, as does response to treatment with Prednisone.

Studies have shown that benefits of Long-tern oxygen therapy (LTOT) include improved exercise tolerance, with improved walking distance, and ability to perform daily activities, reduction of secondary polycythaemia, improved sleep quality and reduced sympathetic outflow, with increased sodium and water excretion, leading to improvement in renal function.

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.

Carbon monoxide (CO) is a colourless, odourless gas produced by incomplete combustion of carbonaceous material. Clinical presentation in patients with CO poisoning ranges from headache and dizziness to coma and death. Hyperbaric oxygen therapy can significantly reduce the morbidity of CO poisoning, but a portion of survivors still suffer significant long-term neurologic and affective sequelae.

Complaints:
Malaise, flulike symptoms, fatigue
Dyspnoea on exertion
Chest pain, palpitations
Lethargy
Confusion
Depression
Impulsiveness
Distractibility
Hallucination, confabulation
Agitation
Nausea, vomiting, diarrhoea
Abdominal pain
Headache, drowsiness
Dizziness, weakness, confusion
Visual disturbance, syncope, seizure
Faecal and urinary incontinence
Memory and gait disturbances
Bizarre neurologic symptoms, coma

Vital signs may include the following:
Tachycardia
Hypertension or hypotension
Hyperthermia
Marked tachypnoea (rare; severe intoxication often associated with mild or no tachypnoea)
Although so-called cherry-red skin has traditionally been considered a sign of CO poisoning, it is in fact rare.

The clinical diagnosis of acute carbon monoxide (CO) poisoning should be confirmed by demonstrating an elevated level of carboxyhaemoglobin (HbCO). Either arterial or venous blood can be used for testing. Analysis of HbCO requires direct spectrophotometric measurement in specific blood gas analysers. Elevated CO levels of at least 3–4% in non-smokers and at least 10% in smokers are significant.

Extrinsic allergic alveolitis (EAA) refers to a group of lung diseases that can develop after exposure to certain substances. The name describes the origin and the nature of these diseases:

‘extrinsic’ – caused by something originating outside the body
‘allergic’ – an abnormally increased (hypersensitive) body reaction to a common substance
‘alveolitis’ – inflammation in the small air sacs of the lungs (alveoli)

Symptoms can include: fever, cough, worsening breathlessness and weight loss. The diagnosis of the disease is based on a history of symptoms after exposure to the allergen and a range of clinical tests which usually includes: X-rays or CT scans, lung function and blood tests.

EAA is not a ‘new’ occupational respiratory disease and occupational causes include bacteria, fungi, animal proteins, plants and chemicals.

Examples of EAA include:

Farmer’s lung
This is probably the most common occupational form of EAA and is the outcome of an allergic response to a group of microbes, which form mould on vegetable matter in storage. During the handling of mouldy straw, hay or grain, particularly in a confined space such as a poorly ventilated building, inhalation of spores and other antigenic material is very likely.

There also appears to be a clear relationship between water content of crops, heating (through mould production) and microbial growth, and this would apply to various crops and vegetable matter, with the spores produced likely to cause EAA.

Farmer’s lung can be prevented by drying crops adequately before storage and by ensuring good ventilation during storage. Respiratory protection should also be worn by farm workers when handling stored crops, particularly if they have been stored damp or are likely to be mouldy.

Acute epiglottitis is a life-threatening disorder with serious implications to the anaesthesiologist because of the potential for laryngospasm and irrevocable loss of the airway. There is inflammatory oedema of the arytenoids, aryepiglottic folds and the epiglottis; therefore, supraglottitis may be used instead or preferred to the term acute epiglottitis.

Acute epiglottitis can occur at any age. The responsible organism used to be Hemophilus influenzae type B (Hib), but infection with group A b-haemolytic Streptococci has become more frequent after the widespread use of Hemophilus influenzae vaccination.

The typical presentation in epiglottitis includes acute occurrence of high fever, severe sore throat and difficulty in swallowing with the sitting up and leaning forward position in order to enhance airflow. There is usually drooling because of difficulty and pain on swallowing. Acute epiglottitis usually leads to generalized toxaemia. The most common differential diagnosis is croup and a foreign body in the airway. A late referral to an acute care setting with its serious consequences may result from difficulty in differentiation between acute epiglottitis and less urgent causes of a sore throat, shortness of breath and dysphagia.

Subcutaneous low molecular weight heparin (LMWH) is the preferred treatment for most patients with acute DVT, including in pregnancy. A large meta-analyses comparing LMWH to unfractionated heparin (UFH) showed that LMWH decreased the risk of mortality, recurrent veno-thrombo embolism (VTE), and haemorrhage compared with heparin. Other advantages of LMWH may include more predictable therapeutic response, ease of administration and monitoring, and less heparin-induced thrombocytopenia. Disadvantages of LMWH include cost and longer half-life compared with heparin.

Warfarin, which is administered orally, is used if long-term anticoagulation is needed. The international normalized ratio (INR) is followed, with a target range of 2-3. Warfarin crosses the placenta and is teratogenic, causing a constellation of anomalies known as warfarin embryopathy, with greatest risk between the sixth and twelfth week of gestation.
Other options are not indicated for use.

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

Nice guidelines for lung reduction surgery:

FEV1 > 20% predicted
PaCO2 < 7.3 kPa
TLco > 20% predicted
Upper lobe predominant emphysema

This patient has pCO2 of 7.4 so she is unsuitable for referral for lung reduction surgery.

Classic clinical features associated with active pulmonary TB are as follows (elderly individuals with TB may not display typical signs and symptoms):
– Cough
– Weight loss/anorexia
– Fever
– Night sweats
– Haemoptysis
– Chest pain (can also result from tuberculous acute pericarditis)
– Fatigue

Test:
Acid-fast bacilli (AFB) smear and culture – Using sputum obtained from the patient.
AFB stain is quick but requires a very high organism load for positivity, as well as the expertise to read the stained sample. This test is more useful in patients with pulmonary disease.
Obtain a chest radiograph to evaluate for possible associated pulmonary findings. If chest radiography findings suggest TB and a sputum smear is positive for AFB, initiate treatment for TB.

Alpha1-antitrypsin (AAT) deficiency, first described in 1963, is one of the most common inherited disorders amongst white Caucasians. Its primary manifestation is early-onset of pan acinar emphysema. In adults, alpha1-antitrypsin deficiency leads to chronic liver disease in the fifth decade. As a cause of emphysema, it is seen in non-smokers in the fifth decade of life and during the fourth decade of life in smokers.

Symptoms of alpha1-antitrypsin (AAT) deficiency emphysema are limited to the respiratory system. Dyspnoea is the symptom that eventually dominates alpha1-antitrypsin deficiency. Similar to other forms of emphysema, the dyspnoea of alpha1-antitrypsin deficiency is initially evident only with strenuous exertion. Over several years, it eventually limits even mild activities.
The serum levels of some of the common genotypes are:
•PiMM: 100% (normal)
•PiMS: 80% of normal serum level of A1AT
•PiSS: 60% of normal serum level of A1AT
•PiMZ: 60% of normal serum level of A1AT, mild deficiency
•PiSZ: 40% of normal serum level of A1AT, moderate deficiency
•PiZZ: 10–15% (severe alpha 1-antitrypsin deficiency)

In asthma, a reversible increase in residual volume (RV), functional residual capacity (FRC), and total lung capacity (TLC) may occur. There is a fall in FEV1, FVC and gas transfer.

β-blockers are the class of drug most often chosen to treat glaucoma, although other medical therapies are available. Systemic absorption of timolol eye drops can cause unsuspected respiratory impairment and exacerbation of asthma. Physicians should be alert to the possibility of respiratory side-effects of topical therapy with β-blockers. Leukotriene antagonists and salbutamol are used in asthma treatment. HRT and ferrous sulphate do not lead to the exacerbation of asthma.

The NICE 2019 guidelines states that in patients who are uncontrolled with a SABA (Salbutamol) and ICS (Beclomethasone), LTRA should be added.
If asthma is uncontrolled in adults (aged 17 and over) on a low dose of ICS as maintenance therapy, offer a leukotriene receptor antagonist (LTRA) in addition to the ICS and review the response to treatment in 4 to 8 weeks.

V/Q scanning carries a slightly increased risk of childhood cancer compared with CTPA – 1/280,000 versus less than 1/1,000,000 – but carries a lower risk of maternal breast cancer. The rest of the options are true.

Asthma is a condition characterized by airway hyperresponsiveness, which results in reversible increases in bronchial smooth muscle tone, and variable amounts of inflammation of the bronchial mucosa.
During an acute asthma attack, the already inflamed airways narrow further due to bronchospasm, which leads to increased airway resistance. Because of the increased smooth muscle tone during an asthma attack, the airways also tend to close at abnormally high lung volumes, trapping air behind occluded or narrowed small airways. Thus the acute asthmatic will breathe at high lung volumes, his functional residual capacity will be elevated, and he will inspire close to total lung capacity. The accessory muscles of respiration are often used to maintain the lungs in a hyperinflated state.

During episodes of acute asthma, pulmonary function tests reveal an obstructive pattern. This includes a decrease in the rate of maximal expiratory air flow (a decrease in FEV1 and the FEV1/FVC ratio) due to the increased resistance, and a reduction in forced vital capacity (FVC) correlating with the level of hyperinflation of the lungs. Because these patients breathe at such high lung volumes (near the top of the pressure-volume curve, where lung compliance greatly decreases), they must exert significant effort to create an extremely negative pleural pressure, and consequently fatigue easily. Overinflation also reduces the curvature of the diaphragm, making it less efficient in generating further negative pleural pressure.

Idiopathic pulmonary fibrosis (IPF) is a condition in which the lungs become scarred and breathing becomes increasingly difficult.
The most common signs and symptoms of idiopathic pulmonary fibrosis are shortness of breath and a persistent dry, hacking cough. Many affected individuals also experience a loss of appetite and gradual weight loss.

The clinical findings of IPF are bibasilar reticular abnormalities, ground glass opacities, or diffuse nodular lesions on high-resolution computed tomography and abnormal pulmonary function studies that include evidence of restriction (reduced VC with an increase in FEV1/FVC ratio) and/or impaired gas exchange (increased P(A-a)O2 with rest or exercise or decreased diffusion capacity of the lung for carbon monoxide [DLCO]).

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.

In any patient with asthma, a decreasing PaO2 and an increasing PaCO2, even into the normal range, indicates severe airway obstruction that is leading to respiratory muscle fatigue and patient exhaustion.

Chest tightness and cough, which are the most common symptoms of asthma, are probably the result of inflammation, mucus plugs, oedema, or smooth muscle constriction in the small peripheral airways. Because major obstruction of the peripheral airways can occur without recognizable increases of airway resistance or FEV1, the physiologic alterations in acute exacerbations are generally subtle in the early stages. Poorly ventilated alveoli subtending obstructed bronchioles continue to be perfused, and as a consequence, the P(A-a)O2 increases and the PaO2 decreases. At this stage, ventilation is generally increased, with excessive elimination of carbon dioxide and respiratory alkalemia.

CURB Pneumonia Severity Score:
– Confusion (abbreviated Mental Test Score <=8) (1 point)
– Urea (BUN > 19 mg/dL or 7 mmol/L) (1 point)
– Respiratory Rate > 30 per minute (1 point)
– Blood Pressure: diastolic < 60 or systolic < 90 mmHg (1 point) Based on the CURB Pneumonia Severity Score, the patient has severe pneumonia. According to the 2009 Centres for Medicare and Medicaid Services (CMS) and Joint Commission consensus guidelines, inpatient treatment of pneumonia should be given within four hours of hospital admission (or in the emergency department if this is where the patient initially presented) and should consist of the following antibiotic regimens, which are also in accordance with IDSA/ATS guidelines. For non-intensive care unit (ICU) patients:
Beta-lactam (intravenous [IV] or intramuscular [IM] administration) plus macrolide (IV or oral [PO])
Beta-lactam (IV or IM) plus doxycycline (IV or PO)
Antipneumococcal quinolone monotherapy (IV or IM)

If the patient is younger than 65 years with no risk factors for drug-resistant organisms, administer macrolide monotherapy (IV or PO)

For ICU patients:
IV beta-lactam plus IV macrolide
IV beta-lactam plus IV antipneumococcal quinolone

If the patient has a documented beta-lactam allergy, administer IV antipneumococcal quinolone plus IV aztreonam.

The most suitable antibiotic therapy for this patient is therefore Intravenous co-amoxiclav + clarithromycin.