Before performing arterial blood gas sampling, it is necessary to disinfect the skin. This is typically done using alcohol, which should be applied and given enough time to dry completely before proceeding with the skin puncture. In the UK, it is common to use solutions that combine alcohol with Chlorhexidine, such as Chloraprep® (2).

Further Reading:

Arterial blood gases (ABG) are an important diagnostic tool used to assess a patient’s acid-base status and respiratory function. When obtaining an ABG sample, it is crucial to prioritize safety measures to minimize the risk of infection and harm to the patient. This includes performing hand hygiene before and after the procedure, wearing gloves and protective equipment, disinfecting the puncture site with alcohol, using safety needles when available, and properly disposing of equipment in sharps bins and contaminated waste bins.

To reduce the risk of harm to the patient, it is important to test for collateral circulation using the modified Allen test for radial artery puncture. Additionally, it is essential to inquire about any occlusive vascular conditions or anticoagulation therapy that may affect the procedure. The puncture site should be checked for signs of infection, injury, or previous surgery. After the test, pressure should be applied to the puncture site or the patient should be advised to apply pressure for at least 5 minutes to prevent bleeding.

Interpreting ABG results requires a systematic approach. The core set of results obtained from a blood gas analyser includes the partial pressures of oxygen and carbon dioxide, pH, bicarbonate concentration, and base excess. These values are used to assess the patient’s acid-base status.

The pH value indicates whether the patient is in acidosis, alkalosis, or within the normal range. A pH less than 7.35 indicates acidosis, while a pH greater than 7.45 indicates alkalosis.

The respiratory system is assessed by looking at the partial pressure of carbon dioxide (pCO2). An elevated pCO2 contributes to acidosis, while a low pCO2 contributes to alkalosis.

The metabolic aspect is assessed by looking at the bicarbonate (HCO3-) level and the base excess. A high bicarbonate concentration and base excess indicate alkalosis, while a low bicarbonate concentration and base excess indicate acidosis.

Analyzing the pCO2 and base excess values can help determine the primary disturbance and whether compensation is occurring. For example, a respiratory acidosis (elevated pCO2) may be accompanied by metabolic alkalosis (elevated base excess) as a compensatory response.

The anion gap is another important parameter that can help determine the cause of acidosis. It is calculated by subtracting the sum of chloride and bicarbonate from the sum of sodium and potassium.

The two-level PE Wells score has been simplified to determine the likelihood of a pulmonary embolism (PE) into two outcomes: likely or unlikely. A score of over 4 indicates that a PE is likely, while a score of 4 points or less indicates that a PE is unlikely.

The allocation of points is as follows:

– Clinical symptoms and signs of deep vein thrombosis (DVT) = 3 points
– An alternative diagnosis that is less likely than a PE = 3 points
– Heart rate greater than 100 = 1.5 points
– Immobilization for more than 3 days or recent surgery within 4 weeks = 1.5 points
– Previous history of DVT or PE = 1.5 points
– Presence of haemoptysis = 1 point
– Malignancy (currently on treatment, treated in the last 6 months, or palliative care) = 1 point.

A person’s level of consciousness is determined by their alertness. In this case, the score for alertness is 0, indicating that the person is not alert. Based on the scoring system, a total score of 4 suggests a moderate case of croup. Moderate croup is typically diagnosed when the scores range from 3 to 5.

Further Reading:

Croup, also known as laryngotracheobronchitis, is a respiratory infection that primarily affects infants and toddlers. It is characterized by a barking cough and can cause stridor (a high-pitched sound during breathing) and respiratory distress due to swelling of the larynx and excessive secretions. The majority of cases are caused by parainfluenza viruses 1 and 3. Croup is most common in children between 6 months and 3 years of age and tends to occur more frequently in the autumn.

The clinical features of croup include a barking cough that is worse at night, preceded by symptoms of an upper respiratory tract infection such as cough, runny nose, and congestion. Stridor, respiratory distress, and fever may also be present. The severity of croup can be graded using the NICE system, which categorizes it as mild, moderate, severe, or impending respiratory failure based on the presence of symptoms such as cough, stridor, sternal/intercostal recession, agitation, lethargy, and decreased level of consciousness. The Westley croup score is another commonly used tool to assess the severity of croup based on the presence of stridor, retractions, air entry, oxygen saturation levels, and level of consciousness.

In cases of severe croup with significant airway obstruction and impending respiratory failure, symptoms may include a minimal barking cough, harder-to-hear stridor, chest wall recession, fatigue, pallor or cyanosis, decreased level of consciousness, and tachycardia. A respiratory rate over 70 breaths per minute is also indicative of severe respiratory distress.

Children with moderate or severe croup, as well as those with certain risk factors such as chronic lung disease, congenital heart disease, neuromuscular disorders, immunodeficiency, age under 3 months, inadequate fluid intake, concerns about care at home, or high fever or a toxic appearance, should be admitted to the hospital. The mainstay of treatment for croup is corticosteroids, which are typically given orally. If the child is too unwell to take oral medication, inhaled budesonide or intramuscular dexamethasone may be used as alternatives. Severe cases may require high-flow oxygen and nebulized adrenaline.

When considering the differential diagnosis for acute stridor and breathing difficulty, non-infective causes such as inhaled foreign bodies

Osteoporosis and fragility fractures are more likely to occur in individuals with low levels of estrogen. Menopause, which causes a decrease in estrogen, can lead to estrogen deficiency. Estrogen plays a role in preventing bone breakdown by inhibiting osteoclast activity. After menopause, there is an increase in osteoclast activity, resulting in a rapid decline in bone mineral density. Osteoporosis is also associated with the long-term use of corticosteroids.

Further Reading:

Fragility fractures are fractures that occur following a fall from standing height or less, and may be atraumatic. They often occur in the presence of osteoporosis, a disease characterized by low bone mass and structural deterioration of bone tissue. Fragility fractures commonly affect the wrist, spine, hip, and arm.

Osteoporosis is defined as a bone mineral density (BMD) of 2.5 standard deviations below the mean peak mass, as measured by dual-energy X-ray absorptiometry (DXA). Osteopenia, on the other hand, refers to low bone mass between normal bone mass and osteoporosis, with a T-score between -1 to -2.5.

The pathophysiology of osteoporosis involves increased osteoclast activity relative to bone production by osteoblasts. The prevalence of osteoporosis increases with age, from approximately 2% at 50 years to almost 50% at 80 years.

There are various risk factors for fragility fractures, including endocrine diseases, GI causes of malabsorption, chronic kidney and liver diseases, menopause, immobility, low body mass index, advancing age, oral corticosteroids, smoking, alcohol consumption, previous fragility fractures, rheumatological conditions, parental history of hip fracture, certain medications, visual impairment, neuromuscular weakness, cognitive impairment, and unsafe home environment.

Assessment of a patient with a possible fragility fracture should include evaluating the risk of further falls, the risk of osteoporosis, excluding secondary causes of osteoporosis, and ruling out non-osteoporotic causes for fragility fractures such as metastatic bone disease, multiple myeloma, osteomalacia, and Paget’s disease.

Management of fragility fractures involves initial management by the emergency clinician, while treatment of low bone density is often delegated to the medical team or general practitioner. Management considerations include determining who needs formal risk assessment, who needs a DXA scan to measure BMD, providing lifestyle advice, and deciding who requires drug treatment.

Medication for osteoporosis typically includes vitamin D, calcium, and bisphosphonates. Vitamin D and calcium supplementation should be considered based on individual needs, while bisphosphonates are advised for postmenopausal women and men over 50 years with confirmed osteoporosis or those taking high doses of oral corticosteroids.

Alteplase (rt-pA) is a recommended treatment for acute ischaemic stroke in adults if it is initiated within 4.5 hours of the onset of stroke symptoms. It is crucial to exclude intracranial haemorrhage through appropriate imaging techniques before starting the treatment. The initial dose of alteplase is 0.9 mg/kg, with a maximum of 90 mg. This dose is administered intravenously over a period of 60 minutes. The first 10% of the dose is given through intravenous injection, while the remaining amount is administered through intravenous infusion. For more information, please refer to the NICE guidelines on stroke and transient ischaemic attack in individuals aged 16 and above.

The following list provides a summary of common causes for different acid-base disorders.

Respiratory alkalosis can be caused by hyperventilation, such as during periods of anxiety. It can also be a result of conditions like pulmonary embolism, CNS disorders (such as stroke or encephalitis), altitude, pregnancy, or the early stages of aspirin overdose.

Respiratory acidosis is often associated with chronic obstructive pulmonary disease (COPD) or life-threatening asthma. It can also occur due to pulmonary edema, sedative drug overdose (such as opiates or benzodiazepines), neuromuscular disease, obesity, or other respiratory conditions.

Metabolic alkalosis can be caused by vomiting, potassium depletion (often due to diuretic usage), Cushing’s syndrome, or Conn’s syndrome.

Metabolic acidosis with a raised anion gap can occur due to lactic acidosis (such as in cases of hypoxemia, shock, sepsis, or infarction) or ketoacidosis (such as in diabetes, starvation, or alcohol excess). It can also be a result of renal failure or poisoning (such as in late stages of aspirin overdose, methanol or ethylene glycol ingestion).

Metabolic acidosis with a normal anion gap can be caused by conditions like renal tubular acidosis, diarrhea, ammonium chloride ingestion, or adrenal insufficiency.

Excessive intake of lithium is linked to the development of low anion gap acidosis. In cases of lithium overdose, a common outcome is the occurrence of low anion gap acidosis.

Further Reading:

Arterial blood gases (ABG) are an important diagnostic tool used to assess a patient’s acid-base status and respiratory function. When obtaining an ABG sample, it is crucial to prioritize safety measures to minimize the risk of infection and harm to the patient. This includes performing hand hygiene before and after the procedure, wearing gloves and protective equipment, disinfecting the puncture site with alcohol, using safety needles when available, and properly disposing of equipment in sharps bins and contaminated waste bins.

To reduce the risk of harm to the patient, it is important to test for co-lateral circulation using the modified Allen test for radial artery puncture. Additionally, it is essential to inquire about any occlusive vascular conditions or anticoagulation therapy that may affect the procedure. The puncture site should be checked for signs of infection, injury, or previous surgery. After the test, pressure should be applied to the puncture site or the patient should be advised to apply pressure for at least 5 minutes to prevent bleeding.

Interpreting ABG results requires a systematic approach. The core set of results obtained from a blood gas analyser includes the partial pressures of oxygen and carbon dioxide, pH, bicarbonate concentration, and base excess. These values are used to assess the patient’s acid-base status.

The pH value indicates whether the patient is in acidosis, alkalosis, or within the normal range. A pH less than 7.35 indicates acidosis, while a pH greater than 7.45 indicates alkalosis.

The respiratory system is assessed by looking at the partial pressure of carbon dioxide (pCO2). An elevated pCO2 contributes to acidosis, while a low pCO2 contributes to alkalosis.

The metabolic aspect is assessed by looking at the bicarbonate (HCO3-) level and the base excess. A high bicarbonate concentration and base excess indicate alkalosis, while a low bicarbonate concentration and base excess indicate acidosis.

Analyzing the pCO2 and base excess values can help determine the primary disturbance and whether compensation is occurring. For example, a respiratory acidosis (elevated pCO2) may be accompanied by metabolic alkalosis (elevated base excess) as a compensatory response.

The anion gap is another important parameter that can help determine the cause of acidosis. It is calculated by subtracting the sum of chloride and bicarbonate from the sum of sodium and potassium.

This is a complex situation that presents both ethical and medico-legal challenges. While patients have a right to confidentiality, it is important to recognize that this right is not absolute and may not apply in every circumstance. There are certain situations where it is appropriate to breach confidentiality, such as when mandated by law or when there is a threat to public health. However, it is crucial to make every effort to persuade the patient against disclosure and to inform them of your intentions.

In this particular case, the patient has disclosed to you that they have recently been diagnosed with HIV, which they believe was contracted from a sexual encounter outside of their marriage. They have explicitly stated that they do not want you to inform their wife, who is in the early stages of pregnancy. Before taking any action, it is advisable to gather all the relevant facts and confirm the patient’s HIV diagnosis through their health records, including any other blood-borne viruses.

If the facts are indeed confirmed, it is important to continue efforts to persuade the patient of the necessity for their wife to be informed. If she has been exposed, she could greatly benefit from testing and starting antiretroviral therapy. Additionally, specialized care during early pregnancy could help prevent transmission of the virus to the unborn child. However, if the patient continues to refuse disclosure, you have the right to breach confidentiality, but it is crucial to inform the patient of your intentions beforehand. Seeking support from your defense organization is also recommended in such situations.

For further information, you may refer to the GMC Guidance on Confidentiality, specifically the section on disclosing information about serious communicable diseases.

Croup is identified by a cough that sounds like a seal barking, especially worse during the night. Before the barking cough, there may be initial symptoms of a cough, runny nose, and congestion for 12 to 72 hours. Other signs of croup include a high-pitched sound when breathing (stridor), difficulty breathing (respiratory distress), and fever.

Further Reading:

Croup, also known as laryngotracheobronchitis, is a respiratory infection that primarily affects infants and toddlers. It is characterized by a barking cough and can cause stridor (a high-pitched sound during breathing) and respiratory distress due to swelling of the larynx and excessive secretions. The majority of cases are caused by parainfluenza viruses 1 and 3. Croup is most common in children between 6 months and 3 years of age and tends to occur more frequently in the autumn.

The clinical features of croup include a barking cough that is worse at night, preceded by symptoms of an upper respiratory tract infection such as cough, runny nose, and congestion. Stridor, respiratory distress, and fever may also be present. The severity of croup can be graded using the NICE system, which categorizes it as mild, moderate, severe, or impending respiratory failure based on the presence of symptoms such as cough, stridor, sternal/intercostal recession, agitation, lethargy, and decreased level of consciousness. The Westley croup score is another commonly used tool to assess the severity of croup based on the presence of stridor, retractions, air entry, oxygen saturation levels, and level of consciousness.

In cases of severe croup with significant airway obstruction and impending respiratory failure, symptoms may include a minimal barking cough, harder-to-hear stridor, chest wall recession, fatigue, pallor or cyanosis, decreased level of consciousness, and tachycardia. A respiratory rate over 70 breaths per minute is also indicative of severe respiratory distress.

Children with moderate or severe croup, as well as those with certain risk factors such as chronic lung disease, congenital heart disease, neuromuscular disorders, immunodeficiency, age under 3 months, inadequate fluid intake, concerns about care at home, or high fever or a toxic appearance, should be admitted to the hospital. The mainstay of treatment for croup is corticosteroids, which are typically given orally. If the child is too unwell to take oral medication, inhaled budesonide or intramuscular dexamethasone may be used as alternatives. Severe cases may require high-flow oxygen and nebulized adrenaline.

When considering the differential diagnosis for acute stridor and breathing difficulty, non-infective causes such as inhaled foreign bodies

Thyroid storm is a rare condition that affects only 1-2% of patients with hyperthyroidism. However, it is crucial to diagnose it promptly because it has a high mortality rate of approximately 10%. Thyroid storm is often triggered by a physiological stressor, such as stopping antithyroid therapy prematurely, recent surgery or radio-iodine treatment, infections (especially chest infections), trauma, diabetic ketoacidosis or hyperosmolar diabetic crisis, thyroid hormone overdose, pre-eclampsia. It typically occurs in patients with Graves’ disease or toxic multinodular goitre and presents with sudden and severe hyperthyroidism. Symptoms include high fever (over 41°C), dehydration, rapid heart rate (greater than 140 beats per minute) with or without irregular heart rhythms, low blood pressure, congestive heart failure, nausea, jaundice, vomiting, diarrhea, abdominal pain, confusion, agitation, delirium, psychosis, seizures, or coma.

To diagnose thyroid storm, various blood tests should be conducted, including a full blood count, urea and electrolytes, blood glucose, coagulation screen, CRP, and thyroid profile (T4/T3 and TSH). A bone profile/calcium test should also be done as 10% of patients develop hypocalcemia. Blood cultures should be taken as well. Other important investigations include a urine dipstick/MC&S, chest X-ray, and ECG.

The management of thyroid storm involves several steps. Intravenous fluids, such as 1-2 liters of 0.9% saline, should be administered. Airway support and management should be provided as necessary. A nasogastric tube should be inserted if the patient is vomiting. Urgent referral for inpatient management is essential. Paracetamol (1 g PO/IV) can be given to reduce fever. Benzodiazepines, such as diazepam (5-20 mg PO/IV), can be used for sedation. Steroids, like hydrocortisone (100 mg IV), may be necessary if there is co-existing adrenal suppression. Antibiotics should be prescribed if there is an intercurrent infection. Beta-blockers, such as propranolol (80 mg PO), can help control heart rate. High-dose carbimazole (45-60 mg/day) is recommended.