What spirometry result is expected in alpha-1 antitrypsin deficiency?

Alpha-1 antitrypsin deficiency will result in an obstructive pattern on spirometry, similar to chronic obstructive pulmonary disease (COPD). The two important factors to consider in spirometry are the FEV1 and the FEV1/FVC ratio. In obstructive disease, the FEV1 is reduced due to narrowed airways, while the FVC remains normal. This results in a reduced FEV1/FVC ratio. Therefore, in alpha-1 antitrypsin deficiency, we would expect to see a reduced FEV1 and FEV1/FVC ratio on spirometry.

Understanding Alpha-1 Antitrypsin Deficiency

Alpha-1 antitrypsin deficiency is a genetic condition that occurs when the liver fails to produce enough of a protein called alpha-1 antitrypsin (A1AT). A1AT is responsible for protecting cells from enzymes that can cause damage, such as neutrophil elastase. This deficiency is inherited in an autosomal recessive or co-dominant fashion, with alleles classified by their electrophoretic mobility as M for normal, S for slow, and Z for very slow. The normal genotype is PiMM, while heterozygous individuals have PiMZ. Homozygous PiSS individuals have 50% normal A1AT levels, while homozygous PiZZ individuals have only 10% normal A1AT levels.

The classic manifestation of A1AT deficiency is emphysema, which is a type of chronic obstructive pulmonary disease. This condition is most commonly seen in young, non-smoking patients. However, the evidence base is conflicting regarding the risk of emphysema. Non-smokers with A1AT deficiency are at a lower risk of developing emphysema, but they may pass on the A1AT gene to their children. Patients with A1AT deficiency who manifest disease usually have the PiZZ genotype.

In addition to emphysema, A1AT deficiency can also cause liver problems such as cirrhosis and hepatocellular carcinoma in adults, and cholestasis in children. Diagnosis is made by measuring A1AT concentrations and performing spirometry, which typically shows an obstructive pattern. Management includes avoiding smoking, supportive measures such as bronchodilators and physiotherapy, and intravenous A1AT protein concentrates. In severe cases, lung volume reduction surgery or lung transplantation may be necessary.

Psittacosis is a disease caused by the bacterium Chlamydia psittaci, which is typically transmitted to humans through exposure to infected birds. Symptoms include fever, cough, headache, and sore throat, as well as a characteristic facial rash. Diagnosis is confirmed through serology tests, and treatment involves the use of tetracyclines or macrolides. Mycoplasma pneumoniae is another bacterium that can cause atypical pneumonia, with symptoms including fever, malaise, myalgia, headache, and a rash. Streptococcus pneumoniae is the most common cause of community-acquired pneumonia, while Legionella pneumophila can cause Legionnaires’ disease, which presents with fever, cough, dyspnea, and systemic symptoms. Coxiella burnetii is the bacterium responsible for Q fever, which can be transmitted by animals and arthropods and presents with non-specific symptoms. In the scenario presented, the patient’s history of exposure to infected birds and the presence of a rash suggest a diagnosis of psittacosis.

Different Types of Lung Diseases and their Spirometry Patterns

Scoliosis and Lung Function
Severe scoliosis can affect the respiratory muscles and the natural movements of the thoracic cage, leading to a restrictive pattern in pulmonary function tests. This can prevent the lungs from expanding correctly, compromising their function.

Cystic Fibrosis and Lung Function
In early stage cystic fibrosis, the presence of inflammation and thick secretions in the airways can cause an obstructive pattern in spirometry tests. As damage to the lung tissue occurs, a restrictive component can also develop, resulting in a combined obstructive and restrictive pattern.

Emphysema and Lung Function
Emphysema is a type of obstructive lung disease characterized by abnormal and irreversible enlargement of air spaces and alveolar wall destruction. This leads to airflow limitation and a spirometry pattern typical of obstructive lung disease.

Asthma and Lung Function
Asthma is an inflammatory disorder of the airways that causes hyperresponsiveness and constriction of the airways in response to various stimuli. This leads to airflow limitation and a spirometry pattern typical of obstructive lung disease.

Bronchiectasis and Lung Function
Bronchiectasis is characterized by abnormal and irreversible dilatation of the bronchial walls, leading to accumulation of secretions and recurrent inflammation of the airways. This produces an obstructive pattern in pulmonary function tests.

In summary, different types of lung diseases can affect lung function in various ways, leading to different spirometry patterns. Understanding these patterns can help in the diagnosis and management of these conditions.

The Significance of Finger Clubbing in Respiratory and Non-Respiratory Diseases

Finger clubbing, the loss of the natural angle between the nail and the nailbed, is a significant clinical sign that can indicate underlying respiratory and non-respiratory diseases. Suppurative lung diseases such as long-standing bronchiectasis, acute lung abscesses, and empyema are commonly associated with finger clubbing. However, uncomplicated bronchitis and chronic obstructive pulmonary disease (COPD) do not typically cause clubbing, and patients with COPD who develop clubbing should be promptly investigated for other causes, particularly lung cancer.

Finger clubbing is also commonly found in fibrosing alveolitis (idiopathic pulmonary fibrosis), asbestosis, and malignant diseases such as bronchial carcinoma and mesothelioma. In cases where finger clubbing is associated with hypertrophic pulmonary osteoarthropathy, a painful osteitis of the distal ends of the long bones of the lower arms and legs, it is designated grade IV.

Overall, finger clubbing is an important clinical sign that should prompt further investigation to identify underlying respiratory and non-respiratory diseases.

Management of Acute Asthma

Acute asthma is classified by the British Thoracic Society (BTS) into three categories: moderate, severe, and life-threatening. Patients with any of the life-threatening features should be treated as having a life-threatening attack. A fourth category, Near-fatal asthma, is also recognized. Further assessment may include arterial blood gases for patients with oxygen saturation levels below 92%. A chest x-ray is not routinely recommended unless the patient has life-threatening asthma, suspected pneumothorax, or failure to respond to treatment.

Admission criteria include a previous near-fatal asthma attack, pregnancy, an attack occurring despite already using oral corticosteroid, and presentation at night. All patients with life-threatening asthma should be admitted to the hospital, and patients with features of severe acute asthma should also be admitted if they fail to respond to initial treatment. Oxygen therapy should be started for hypoxaemic patients. Bronchodilation with short-acting beta₂-agonists (SABA) is recommended, and all patients should be given 40-50mg of prednisolone orally daily. Ipratropium bromide and IV magnesium sulphate may also be considered for severe or life-threatening asthma. Patients who fail to respond require senior critical care support and should be treated in an appropriate ITU/HDU setting. Criteria for discharge include stability on discharge medication, checked and recorded inhaler technique, and PEF levels above 75% of best or predicted.

Symptoms and Signs of Pulmonary Embolism

Pulmonary embolism (PE) is a serious condition that can be life-threatening. It is important to recognize the symptoms and signs of PE to ensure prompt diagnosis and treatment. Here are some of the common symptoms and signs of PE:

Dyspnoea: This is the most common symptom of PE, present in about 75% of patients. Dyspnoea can occur at rest or on exertion.

Tachypnoea: This is defined as a respiratory rate of more than 20 breaths per minute and is present in about 55% of patients with PE.

Tachycardia: This is present in about 25% of cases of PE. It is important to note that a transition from tachycardia to bradycardia may suggest the development of right ventricular strain and potentially cardiogenic shock.

New-onset atrial fibrillation: This is a less common feature of PE, occurring in less than 10% of cases. Atrial flutter, atrial fibrillation, and premature beats should alert the doctor to possible right-heart strain.

Bradycardia: This is not a classic feature of PE. However, if a patient with PE transitions from tachycardia to bradycardia, it may suggest the development of right ventricular strain and potentially cardiogenic shock.

In summary, dyspnoea, tachypnoea, tachycardia, and new-onset atrial fibrillation are some of the common symptoms and signs of PE. It is important to have a high level of suspicion for PE, especially in high-risk patients, to ensure prompt diagnosis and treatment.

Understanding Metabolic Acidosis and Anion Gap

Metabolic acidosis is a condition that occurs when the body produces too much acid or when the kidneys are not able to remove enough acid from the body. It is commonly classified according to the anion gap, which can be calculated by subtracting the sum of chloride and bicarbonate levels from the sum of sodium and potassium levels. The normal range for anion gap is 10-18 mmol/L. If a question supplies the chloride level, it may be a clue that the anion gap should be calculated.

There are two types of metabolic acidosis based on anion gap levels. Normal anion gap or hyperchloraemic metabolic acidosis is caused by gastrointestinal bicarbonate loss, prolonged diarrhea, ureterosigmoidostomy, fistula, renal tubular acidosis, drugs, ammonium chloride injection, and Addison’s disease. On the other hand, raised anion gap is caused by lactate, ketones, urate, acid poisoning, and other factors.

Metabolic acidosis secondary to high lactate levels may be subdivided into two types: lactic acidosis type A and lactic acidosis type B. Lactic acidosis type A is caused by sepsis, shock, hypoxia, and burns, while lactic acidosis type B is caused by metformin. Understanding the different types of metabolic acidosis and anion gap levels can help in diagnosing and treating the condition.

Identifying the Probable Cause of Pulmonary Fibrosis

Methotrexate is the correct answer as it is a well-known drug-related cause of pulmonary fibrosis, which is the probable cause of the patient’s symptoms. Hydroxychloroquine, azathioprine, ciclosporin, and penicillamine are not known to cause pulmonary fibrosis, although some of them have the potential to cause pneumonitis. Ciclosporin has been studied as a treatment for the disease, but it is not recommended by NICE. Therefore, it is important to identify the probable cause of pulmonary fibrosis to provide appropriate treatment and prevent further complications.

The recommended initial investigation for suspected occupational asthma is serial peak expiratory flow rates at home and at work, according to SIGN (Scottish Intercollegiate Guidelines Network) referenced by NICE. CT of the thorax is inappropriate due to high radiation doses and chest radiograph is not part of the initial work-up for occupational asthma as it is unlikely to show specific evidence. Skin-prick testing is only recommended for high-molecular-weight agents and spirometry is not recommended as an initial investigation for occupational asthma, but may be appropriate for surveillance in industries with risk of the condition.

According to NICE 2017 guidelines, if a patient with asthma is not effectively managed with a SABA + ICS, the first step should be to add a LTRA rather than a LABA.

The management of asthma in adults has been updated by NICE in 2017, following the 2016 BTS guidelines. One of the significant changes is in ‘step 3’, where patients on a SABA + ICS whose asthma is not well controlled should be offered a leukotriene receptor antagonist instead of a LABA. NICE does not follow the stepwise approach of the previous BTS guidelines, but to make the guidelines easier to follow, we have added our own steps. The steps range from newly-diagnosed asthma to SABA +/- LTRA + one of the following options, including increasing ICS to high-dose, a trial of an additional drug, or seeking advice from a healthcare professional with expertise in asthma. Maintenance and reliever therapy (MART) is a form of combined ICS and LABA treatment that is only available for ICS and LABA combinations in which the LABA has a fast-acting component. It should be noted that NICE does not recommend changing treatment in patients who have well-controlled asthma simply to adhere to the latest guidance. The definitions of what constitutes a low, moderate, or high-dose ICS have also changed, with <= 400 micrograms budesonide or equivalent being a low dose, 400 micrograms - 800 micrograms budesonide or equivalent being a moderate dose, and > 800 micrograms budesonide or equivalent being a high dose for adults.