The usual approach to managing SIADH without neurological symptoms is to restrict fluid intake. In this case, the patient has SIADH, as evidenced by low serum osmolality due to low sodium levels. It is important to note that the patient’s urine osmolality is high despite the low serum osmolality.

Further Reading:

Syndrome of inappropriate antidiuretic hormone (SIADH) is a condition characterized by low sodium levels in the blood due to excessive secretion of antidiuretic hormone (ADH). ADH, also known as arginine vasopressin (AVP), is responsible for promoting water and sodium reabsorption in the body. SIADH occurs when there is impaired free water excretion, leading to euvolemic (normal fluid volume) hypotonic hyponatremia.

There are various causes of SIADH, including malignancies such as small cell lung cancer, stomach cancer, and prostate cancer, as well as neurological conditions like stroke, subarachnoid hemorrhage, and meningitis. Infections such as tuberculosis and pneumonia, as well as certain medications like thiazide diuretics and selective serotonin reuptake inhibitors (SSRIs), can also contribute to SIADH.

The diagnostic features of SIADH include low plasma osmolality, inappropriately elevated urine osmolality, urinary sodium levels above 30 mmol/L, and euvolemic. Symptoms of hyponatremia, which is a common consequence of SIADH, include nausea, vomiting, headache, confusion, lethargy, muscle weakness, seizures, and coma.

Management of SIADH involves correcting hyponatremia slowly to avoid complications such as central pontine myelinolysis. The underlying cause of SIADH should be treated if possible, such as discontinuing causative medications. Fluid restriction is typically recommended, with a daily limit of around 1000 ml for adults. In severe cases with neurological symptoms, intravenous hypertonic saline may be used. Medications like demeclocycline, which blocks ADH receptors, or ADH receptor antagonists like tolvaptan may also be considered.

It is important to monitor serum sodium levels closely during treatment, especially if using hypertonic saline, to prevent rapid correction that can lead to central pontine myelinolysis. Osmolality abnormalities can help determine the underlying cause of hyponatremia, with increased urine osmolality indicating dehydration or renal disease, and decreased urine osmolality suggesting SIADH or overhydration.

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.

This patient is currently experiencing neuropathic pain due to spinal metastases from their lung malignancy.

The first line of treatment for neuropathic pain includes options such as amitriptyline, duloxetine, gabapentin, or pregabalin. If the initial treatment is not effective or well-tolerated, one of the remaining three drugs can be considered. If the second and third drugs tried also prove to be ineffective or not well-tolerated, it may be necessary to switch to a different medication. Tramadol should only be considered as a last resort for acute rescue therapy.

For more information on the pharmacological management of neuropathic pain in adults, please refer to the NICE guidance.

Norovirus is the leading cause of gastroenteritis in adults in the UK. Viruses are responsible for the majority of cases of infectious diarrhea, with norovirus being the most common culprit in adults. Among young children, rotavirus is the primary pathogen, although its prevalence has decreased since the introduction of a rotavirus vaccine. As of 2023, rotavirus remains the most common cause of viral gastroenteritis in children.

Further Reading:

Gastroenteritis is a transient disorder characterized by the sudden onset of diarrhea, with or without vomiting. It is caused by enteric infections with viruses, bacteria, or parasites. The most common viral causes of gastroenteritis in adults include norovirus, rotavirus, and adenovirus. Bacterial pathogens such as Campylobacter jejuni and coli, Escherichia coli, Clostridium perfringens, Bacillus cereus, Staphylococcus aureus, Salmonella typhi and paratyphi, and Shigella dysenteriae, flexneri, boydii, and sonnei can also cause gastroenteritis. Parasites such as Cryptosporidium, Entamoeba histolytica, and Giardia intestinalis or Giardia lamblia can also lead to diarrhea.

Diagnosis of gastroenteritis is usually based on clinical symptoms, and investigations are not required in many cases. However, stool culture may be indicated in certain situations, such as when the patient is systemically unwell or immunocompromised, has acute painful diarrhea or blood in the stool suggesting dysentery, has recently taken antibiotics or acid-suppressing medications, or has not resolved diarrhea by day 7 or has recurrent diarrhea.

Management of gastroenteritis in adults typically involves advice on oral rehydration. Intravenous rehydration and more intensive treatment may be necessary for patients who are systemically unwell, exhibit severe dehydration, or have intractable vomiting or high-output diarrhea. Antibiotics are not routinely required unless a specific organism is identified that requires treatment. Antidiarrheal drugs, antiemetics, and probiotics are not routinely recommended.

Complications of gastroenteritis can occur, particularly in young children, the elderly, pregnant women, and immunocompromised individuals. These complications include dehydration, electrolyte disturbance, acute kidney injury, haemorrhagic colitis, haemolytic uraemic syndrome, reactive arthritis, Reiter’s syndrome, aortitis, osteomyelitis, sepsis, toxic megacolon, pancreatitis, sclerosing cholangitis, liver cirrhosis, weight loss, chronic diarrhea, irritable bowel syndrome, inflammatory bowel disease, acquired lactose intolerance, Guillain-Barré syndrome, meningitis, invasive entamoeba infection, and liver abscesses.

Based on the child’s medical history, it appears that they have multiple areas of infected eczema. In such cases, the NICE guidelines recommend starting treatment with flucloxacillin as the first-line option for bacterial infections. This is because staphylococcus and/or streptococcus bacteria are the most common causes of these infections. Swabs should only be taken if there is a likelihood of antibiotic resistance or if a different pathogen is suspected. In cases where the child is allergic to flucloxacillin, erythromycin can be used as an alternative. If the child cannot tolerate erythromycin, clarithromycin is the recommended option. For more information, you can refer to the NICE Clinical Knowledge Summary on the management of infected eczema.

Stevens-Johnson syndrome is a severe and potentially deadly form of erythema multiforme. It can be triggered by anything that causes erythema multiforme, but it is most commonly seen as a reaction to medication within 1-3 weeks of starting treatment. Initially, there may be symptoms like fever, fatigue, joint pain, and digestive issues, followed by the development of severe mucocutaneous lesions that are blistering and ulcerating.

Stevens-Johnson syndrome and toxic epidermal necrolysis are considered to be different stages of the same mucocutaneous disease, with toxic epidermal necrolysis being more severe. The extent of epidermal detachment is used to differentiate between the two. In Stevens-Johnson syndrome, less than 10% of the body surface area is affected by epidermal detachment, while in toxic epidermal necrolysis, it is greater than 30%. An overlap syndrome occurs when detachment affects between 10-30% of the body surface area.

Several drugs can potentially cause Stevens-Johnson syndrome and toxic epidermal necrolysis, including tetracyclines, penicillins, vancomycin, sulphonamides, NSAIDs, and barbiturates.

Acute kidney injury (AKI), previously known as acute renal failure, is a sudden decline in kidney function. This leads to the accumulation of urea and other waste products in the body, as well as disturbances in fluid balance and electrolyte levels. AKI can occur in individuals with previously normal kidney function or those with pre-existing kidney disease, known as acute-on-chronic kidney disease. It is a relatively common condition, with approximately 15% of adults admitted to hospitals in the UK developing AKI.

AKI is categorized into three stages based on specific criteria. In stage 1, there is a rise in creatinine levels of 26 micromol/L or more within 48 hours, or a rise of 50-99% from baseline within 7 days (1.5-1.99 times the baseline). Additionally, a urine output of less than 0.5 mL/kg/hour for more than 6 hours is indicative of stage 1 AKI.

Stage 2 AKI is characterized by a creatinine rise of 100-199% from baseline within 7 days (2.0-2.99 times the baseline), or a urine output of less than 0.5 mL/kg/hour for more than 12 hours.

In stage 3 AKI, there is a creatinine rise of 200% or more from baseline within 7 days (3.0 or more times the baseline). Alternatively, a creatinine rise to 354 micromol/L or more with an acute rise of 26 micromol/L or more within 48 hours, or a rise of 50% or more within 7 days, is indicative of stage 3 AKI. Additionally, a urine output of less than 0.3 mL/kg/hour for 24 hours or anuria (no urine output) for 12 hours also falls under stage 3 AKI.

The maximum safe dose of plain lidocaine is 3 mg per kilogram of body weight, with a maximum limit of 200 mg. However, when lidocaine is administered with adrenaline in a 1:200,000 ratio, the maximum safe dose increases to 7 mg per kilogram of body weight, with a maximum limit of 500 mg.

In this particular case, the patient weighs 60 kg, so the maximum safe dose of lidocaine hydrochloride would be 60 multiplied by 7 mg, resulting in a total of 420 mg.

For more detailed information on lidocaine hydrochloride, you can refer to the BNF section dedicated to this topic.

Haemothorax often leads to reduced or absent air entry, a dull percussion sound, and decreased fremitus on the affected side. Commonly observed symptoms in patients with haemothorax include decreased or absent air entry, a dull percussion note when the affected side is tapped, reduced fremitus on the affected side, and in cases of massive haemothorax, tracheal deviation away from the affected side. Other signs that may be present include a rapid heart rate (tachycardia), rapid breathing (tachypnoea), low blood pressure (hypotension), and signs of shock.

Further Reading:

Haemothorax is the accumulation of blood in the pleural cavity of the chest, usually resulting from chest trauma. It can be difficult to differentiate from other causes of pleural effusion on a chest X-ray. Massive haemothorax refers to a large volume of blood in the pleural space, which can impair physiological function by causing blood loss, reducing lung volume for gas exchange, and compressing thoracic structures such as the heart and IVC.

The management of haemothorax involves replacing lost blood volume and decompressing the chest. This is done through supplemental oxygen, IV access and cross-matching blood, IV fluid therapy, and the insertion of a chest tube. The chest tube is connected to an underwater seal and helps drain the fluid, pus, air, or blood from the pleural space. In cases where there is prompt drainage of a large amount of blood, ongoing significant blood loss, or the need for blood transfusion, thoracotomy and ligation of bleeding thoracic vessels may be necessary. It is important to have two IV accesses prior to inserting the chest drain to prevent a drop in blood pressure.

In summary, haemothorax is the accumulation of blood in the pleural cavity due to chest trauma. Managing haemothorax involves replacing lost blood volume and decompressing the chest through various interventions, including the insertion of a chest tube. Prompt intervention may be required in cases of significant blood loss or ongoing need for blood transfusion.

Congenital adrenal hyperplasia (CAH) is a group of inherited disorders that are caused by autosomal recessive genes. The majority of affected patients, over 90%, have a deficiency of the enzyme 21-hydroxylase. This enzyme is encoded by the 21-hydroxylase gene, which is located on chromosome 6p21 within the HLA histocompatibility complex. The second most common cause of CAH is a deficiency of the enzyme 11-beta-hydroxylase. The condition is rare, with an incidence of approximately 1 in 500 births in the UK. It is more prevalent in the offspring of consanguineous marriages.

The deficiency of 21-hydroxylase leads to a deficiency of cortisol and/or aldosterone, as well as an excess of precursor steroids. As a result, there is an increased secretion of ACTH from the anterior pituitary, leading to adrenocortical hyperplasia.

The severity of CAH varies depending on the degree of 21-hydroxylase deficiency. Female infants often exhibit ambiguous genitalia, such as clitoral hypertrophy and labial fusion. Male infants may have an enlarged scrotum and/or scrotal pigmentation. Hirsutism, or excessive hair growth, occurs in 10% of cases.

Boys with CAH often experience a salt-losing adrenal crisis at around 1-3 weeks of age. This crisis is characterized by symptoms such as vomiting, weight loss, floppiness, and circulatory collapse.

The diagnosis of CAH can be made by detecting markedly elevated levels of the metabolic precursor 17-hydroxyprogesterone. Neonatal screening is possible, primarily through the identification of persistently elevated 17-hydroxyprogesterone levels.

In infants presenting with a salt-losing crisis, the following biochemical abnormalities are observed: hyponatremia (low sodium levels), hyperkalemia (high potassium levels), metabolic acidosis, and hypoglycemia.

Boys experiencing a salt-losing crisis will require fluid resuscitation, intravenous dextrose, and intravenous hydrocortisone.

Affected females will require corrective surgery for their external genitalia. However, they have an intact uterus and ovaries and are capable of having children.

The long-term management of both sexes involves lifelong replacement of hydrocortisone (to suppress ACTH levels).

Postural tremor is frequently seen as a neurological side effect in individuals taking sodium valproate. Additionally, a resting tremor may also manifest. It has been observed that around 25% of patients who begin sodium valproate therapy develop a tremor within the first year. Other potential side effects of sodium valproate include gastric irritation, nausea and vomiting, involuntary movements, temporary hair loss, weight gain in females, and impaired liver function.

The Lake Louise score is widely accepted as the standard method for evaluating the seriousness of Acute Mountain Sickness (AMS). The scoring system, outlined below, is used to determine the severity of AMS. A score of 3 or higher is indicative of AMS.

Further Reading:

High Altitude Illnesses

Altitude & Hypoxia:
– As altitude increases, atmospheric pressure decreases and inspired oxygen pressure falls.
– Hypoxia occurs at altitude due to decreased inspired oxygen.
– At 5500m, inspired oxygen is approximately half that at sea level, and at 8900m, it is less than a third.

Acute Mountain Sickness (AMS):
– AMS is a clinical syndrome caused by hypoxia at altitude.
– Symptoms include headache, anorexia, sleep disturbance, nausea, dizziness, fatigue, malaise, and shortness of breath.
– Symptoms usually occur after 6-12 hours above 2500m.
– Risk factors for AMS include previous AMS, fast ascent, sleeping at altitude, and age <50 years old.
– The Lake Louise AMS score is used to assess the severity of AMS.
– Treatment involves stopping ascent, maintaining hydration, and using medication for symptom relief.
– Medications for moderate to severe symptoms include dexamethasone and acetazolamide.
– Gradual ascent, hydration, and avoiding alcohol can help prevent AMS.

High Altitude Pulmonary Edema (HAPE):
– HAPE is a progression of AMS but can occur without AMS symptoms.
– It is the leading cause of death related to altitude illness.
– Risk factors for HAPE include rate of ascent, intensity of exercise, absolute altitude, and individual susceptibility.
– Symptoms include dyspnea, cough, chest tightness, poor exercise tolerance, cyanosis, low oxygen saturations, tachycardia, tachypnea, crepitations, and orthopnea.
– Management involves immediate descent, supplemental oxygen, keeping warm, and medication such as nifedipine.

High Altitude Cerebral Edema (HACE):
– HACE is thought to result from vasogenic edema and increased vascular pressure.
– It occurs 2-4 days after ascent and is associated with moderate to severe AMS symptoms.
– Symptoms include headache, hallucinations, disorientation, confusion, ataxia, drowsiness, seizures, and manifestations of raised intracranial pressure.
– Immediate descent is crucial for management, and portable hyperbaric therapy may be used if descent is not possible.
– Medication for treatment includes dexamethasone and supplemental oxygen. Acetazolamide is typically used for prophylaxis.

The typical pH range for blood is 7.35-7.45. The blood gases indicate a condition called respiratory acidosis, which is partially corrected by metabolic processes. This condition may also be referred to as type 2 respiratory failure, characterized by low oxygen levels and high carbon dioxide levels in the blood.

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.

Central retinal artery occlusion (CRAO) is characterized by sudden, painless, and unilateral loss of vision. The appearance of the retina in CRAO is distinct from that of CRVO. It shows a pale retina with narrowed blood vessels. A notable feature is the presence of a ‘cherry-red spot’ at the center of the macula, which is supplied by the underlying choroid. Additionally, examination often reveals an afferent pupillary defect.

On the other hand, branch retinal artery occlusion (BRAO) typically affects only one quadrant of the retina, leading to visual field deficits in that specific area rather than complete loss of vision.

The recommended first-line antibiotics for eradicating H. pylori are amoxicillin in combination with either clarithromycin or metronidazole. According to NICE guidelines, for H. pylori-associated ulcers not caused by NSAID use, a 7-day eradication therapy is advised. This therapy consists of taking amoxicillin 1 g twice daily, along with either clarithromycin 500 mg twice daily or metronidazole 400 mg twice daily. Additionally, a proton pump inhibitor should be taken twice daily, with several options available. Please refer to the yellow box at the end of the notes for appropriate PPI choices.

Further Reading:

Peptic ulcer disease (PUD) is a condition characterized by a break in the mucosal lining of the stomach or duodenum. It is caused by an imbalance between factors that promote mucosal damage, such as gastric acid, pepsin, Helicobacter pylori infection, and NSAID drug use, and factors that maintain mucosal integrity, such as prostaglandins, mucus lining, bicarbonate, and mucosal blood flow.

The most common causes of peptic ulcers are H. pylori infection and NSAID use. Other factors that can contribute to the development of ulcers include smoking, alcohol consumption, certain medications (such as steroids), stress, autoimmune conditions, and tumors.

Diagnosis of peptic ulcers involves screening for H. pylori infection through breath or stool antigen tests, as well as upper gastrointestinal endoscopy. Complications of PUD include bleeding, perforation, and obstruction. Acute massive hemorrhage has a case fatality rate of 5-10%, while perforation can lead to peritonitis with a mortality rate of up to 20%.

The symptoms of peptic ulcers vary depending on their location. Duodenal ulcers typically cause pain that is relieved by eating, occurs 2-3 hours after eating and at night, and may be accompanied by nausea and vomiting. Gastric ulcers, on the other hand, cause pain that occurs 30 minutes after eating and may be associated with nausea and vomiting.

Management of peptic ulcers depends on the underlying cause and presentation. Patients with active gastrointestinal bleeding require risk stratification, volume resuscitation, endoscopy, and proton pump inhibitor (PPI) therapy. Those with perforated ulcers require resuscitation, antibiotic treatment, analgesia, PPI therapy, and urgent surgical review.

For stable patients with peptic ulcers, lifestyle modifications such as weight loss, avoiding trigger foods, eating smaller meals, quitting smoking, reducing alcohol consumption, and managing stress and anxiety are recommended. Medication review should be done to stop causative drugs if possible. PPI therapy, with or without H. pylori eradication therapy, is also prescribed. H. pylori testing is typically done using a carbon-13 urea breath test or stool antigen test, and eradication therapy involves a 7-day triple therapy regimen of antibiotics and PPI.

According to the brit-thoracic guidelines, if a patient with COPD continues to experience respiratory acidosis even after receiving standard medical therapy for one hour, it is recommended to consider using non-invasive ventilation (NIV). This is especially important if the patient’s hypoxia and hypercapnia are worsening despite the initial treatment.

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 zone of hyperaemia, located at the outermost part of the burn, experiences heightened tissue perfusion. Typically, this area will return to its normal tissue state.

Burn injuries can be classified based on their type (degree, partial thickness or full thickness), extent as a percentage of total body surface area (TBSA), and severity (minor, moderate, major/severe). Severe burns are defined as a >10% TBSA in a child and >15% TBSA in an adult.

When assessing a burn, it is important to consider airway injury, carbon monoxide poisoning, type of burn, extent of burn, special considerations, and fluid status. Special considerations may include head and neck burns, circumferential burns, thorax burns, electrical burns, hand burns, and burns to the genitalia.

Airway management is a priority in burn injuries. Inhalation of hot particles can cause damage to the respiratory epithelium and lead to airway compromise. Signs of inhalation injury include visible burns or erythema to the face, soot around the nostrils and mouth, burnt/singed nasal hairs, hoarse voice, wheeze or stridor, swollen tissues in the mouth or nostrils, and tachypnea and tachycardia. Supplemental oxygen should be provided, and endotracheal intubation may be necessary if there is airway obstruction or impending obstruction.

The initial management of a patient with burn injuries involves conserving body heat, covering burns with clean or sterile coverings, establishing IV access, providing pain relief, initiating fluid resuscitation, measuring urinary output with a catheter, maintaining nil by mouth status, closely monitoring vital signs and urine output, monitoring the airway, preparing for surgery if necessary, and administering medications.

Burns can be classified based on the depth of injury, ranging from simple erythema to full thickness burns that penetrate into subcutaneous tissue. The extent of a burn can be estimated using methods such as the rule of nines or the Lund and Browder chart, which takes into account age-specific body proportions.

Fluid management is crucial in burn injuries due to significant fluid losses. Evaporative fluid loss from burnt skin and increased permeability of blood vessels can lead to reduced intravascular volume and tissue perfusion. Fluid resuscitation should be aggressive in severe burns, while burns <15% in adults and <10% in children may not require immediate fluid resuscitation. The Parkland formula can be used to calculate the intravenous fluid requirements for someone with a significant burn injury.

Discitis is an infection that affects the space between the intervertebral discs in the spine. This condition can have serious consequences, including the formation of abscesses and sepsis. The most common cause of discitis is usually Staphylococcus aureus, but other organisms like Streptococcus viridans and Pseudomonas aeruginosa may be responsible in certain cases, especially in immunocompromised individuals and intravenous drug users. Gram-negative organisms like Escherichia coli and Mycobacterium tuberculosis can also cause discitis, particularly in cases of Pott’s disease.

There are several risk factors that increase the likelihood of developing discitis. These include having undergone spinal surgery (which occurs in about 1-2% of patients post-operatively), having an immunodeficiency, being an intravenous drug user, being under the age of eight, having diabetes mellitus, or having a malignancy.

The typical symptoms of discitis include back or neck pain (which occurs in over 90% of cases), pain that often wakes the patient from sleep, fever (present in 60-70% of cases), and neurological deficits (which can occur in up to 50% of cases). In children, a refusal to walk may also be a symptom.

When diagnosing discitis, magnetic resonance imaging (MRI) is the preferred imaging modality due to its high sensitivity and specificity. It is important to image the entire spine, as discitis often affects multiple levels. Plain radiographs are not very sensitive to the early changes of discitis and may appear normal for 2-4 weeks. Computed tomography (CT) scanning is also not very sensitive in detecting discitis.

Treatment for discitis involves hospital admission for intravenous antibiotics. Before starting the antibiotics, it is recommended to send three sets of blood cultures and a full set of blood tests, including a C-reactive protein (CRP) test, to the laboratory.

A typical antibiotic regimen for discitis would include intravenous flucloxacillin 2 g every 6 hours as the first-line treatment if there is no penicillin allergy. Intravenous vancomycin may be used if the infection was acquired in the hospital, if there is a high risk of methicillin-resistant Staphylococcus aureus (MRSA) infection, or if there is a documented penicillin allergy.

Chest X-rays are not typically recommended as a routine investigation for acute asthma. However, they may be necessary in specific situations. These situations include suspected pneumomediastinum or consolidation, as well as cases of life-threatening asthma. Additionally, if a patient fails to respond adequately to treatment or requires ventilation, a chest X-ray may be performed. It is important to note that these circumstances warrant the use of chest X-rays, but they are not routinely indicated for the investigation of acute asthma.

Altitude sickness is usually experienced at altitudes above 2,500 meters (8,000 ft), although some individuals may be affected at lower altitudes. It is important to note that climbers in the UK, where the highest peak is Ben Nevis at 1,345 meters, do not need to worry about altitude sickness.

Further Reading:

High Altitude Illnesses

Altitude & Hypoxia:
– As altitude increases, atmospheric pressure decreases and inspired oxygen pressure falls.
– Hypoxia occurs at altitude due to decreased inspired oxygen.
– At 5500m, inspired oxygen is approximately half that at sea level, and at 8900m, it is less than a third.

Acute Mountain Sickness (AMS):
– AMS is a clinical syndrome caused by hypoxia at altitude.
– Symptoms include headache, anorexia, sleep disturbance, nausea, dizziness, fatigue, malaise, and shortness of breath.
– Symptoms usually occur after 6-12 hours above 2500m.
– Risk factors for AMS include previous AMS, fast ascent, sleeping at altitude, and age <50 years old.
– The Lake Louise AMS score is used to assess the severity of AMS.
– Treatment involves stopping ascent, maintaining hydration, and using medication for symptom relief.
– Medications for moderate to severe symptoms include dexamethasone and acetazolamide.
– Gradual ascent, hydration, and avoiding alcohol can help prevent AMS.

High Altitude Pulmonary Edema (HAPE):
– HAPE is a progression of AMS but can occur without AMS symptoms.
– It is the leading cause of death related to altitude illness.
– Risk factors for HAPE include rate of ascent, intensity of exercise, absolute altitude, and individual susceptibility.
– Symptoms include dyspnea, cough, chest tightness, poor exercise tolerance, cyanosis, low oxygen saturations, tachycardia, tachypnea, crepitations, and orthopnea.
– Management involves immediate descent, supplemental oxygen, keeping warm, and medication such as nifedipine.

High Altitude Cerebral Edema (HACE):
– HACE is thought to result from vasogenic edema and increased vascular pressure.
– It occurs 2-4 days after ascent and is associated with moderate to severe AMS symptoms.
– Symptoms include headache, hallucinations, disorientation, confusion, ataxia, drowsiness, seizures, and manifestations of raised intracranial pressure.
– Immediate descent is crucial for management, and portable hyperbaric therapy may be used if descent is not possible.
– Medication for treatment includes dexamethasone and supplemental oxygen. Acetazolamide is typically used for prophylaxis.

A tension pneumothorax occurs when there is an air leak from the lung or chest wall that acts like a one-way valve. This causes air to build up in the pleural space without any way to escape. As a result, pressure in the pleural space increases and pushes the mediastinum into the opposite hemithorax. If left untreated, this can lead to cardiovascular instability, shock, and cardiac arrest.

The clinical features of tension pneumothorax include respiratory distress and cardiovascular instability. Tracheal deviation away from the side of the injury, unilateral absence of breath sounds on the affected side, and a hyper-resonant percussion note are also characteristic. Other signs include distended neck veins and cyanosis, which is a late sign. It’s important to note that both tension pneumothorax and massive haemothorax can cause decreased breath sounds on auscultation. However, percussion can help differentiate between the two conditions. Hyper-resonance suggests tension pneumothorax, while dullness suggests a massive haemothorax.

Tension pneumothorax is a clinical diagnosis and should not be delayed for radiological confirmation. Requesting a chest X-ray in this situation can delay treatment and put the patient at risk. Immediate decompression through needle thoracocentesis is the recommended treatment. Traditionally, a large-bore needle or cannula is inserted into the 2nd intercostal space in the midclavicular line of the affected hemithorax. However, studies on cadavers have shown better success in reaching the thoracic cavity when the 4th or 5th intercostal space in the midaxillary line is used in adult patients. ATLS now recommends this location for needle decompression in adults. The site for needle thoracocentesis in children remains the same, using the 2nd intercostal space in the midclavicular line. It’s important to remember that needle thoracocentesis is a temporary measure, and the insertion of a chest drain is the definitive treatment.

Le Fort fractures are intricate fractures of the midface, which involve the maxillary bone and the surrounding structures. These fractures can occur in a horizontal, pyramidal, or transverse direction. The distinguishing feature of Le Fort fractures is the separation of the pterygomaxillary due to trauma. They make up approximately 10% to 20% of all facial fractures and can have severe consequences, both in terms of potential life-threatening situations and disfigurement.

The causes of Le Fort fractures vary depending on the type of fracture. Common mechanisms include motor vehicle accidents, sports injuries, assaults, and falls from significant heights. Patients with Le Fort fractures often have concurrent head and cervical spine injuries. Additionally, they frequently experience other facial fractures, as well as neuromuscular injuries and dental avulsions.

The specific type of fracture sustained is determined by the direction of the force applied to the face. Le Fort type I fractures typically occur when a force is directed downward against the upper teeth. Le Fort type II fractures are usually the result of a force applied to the lower or mid maxilla. Lastly, Le Fort type III fractures are typically caused by a force applied to the nasal bridge and upper part of the maxilla.

Peptic ulcer disease is most commonly caused by NSAIDs, making them the leading drug cause. However, h.pylori infection is the primary cause of peptic ulcers, with NSAIDs being the second most common cause.

Further Reading:

Peptic ulcer disease (PUD) is a condition characterized by a break in the mucosal lining of the stomach or duodenum. It is caused by an imbalance between factors that promote mucosal damage, such as gastric acid, pepsin, Helicobacter pylori infection, and NSAID drug use, and factors that maintain mucosal integrity, such as prostaglandins, mucus lining, bicarbonate, and mucosal blood flow.

The most common causes of peptic ulcers are H. pylori infection and NSAID use. Other factors that can contribute to the development of ulcers include smoking, alcohol consumption, certain medications (such as steroids), stress, autoimmune conditions, and tumors.

Diagnosis of peptic ulcers involves screening for H. pylori infection through breath or stool antigen tests, as well as upper gastrointestinal endoscopy. Complications of PUD include bleeding, perforation, and obstruction. Acute massive hemorrhage has a case fatality rate of 5-10%, while perforation can lead to peritonitis with a mortality rate of up to 20%.

The symptoms of peptic ulcers vary depending on their location. Duodenal ulcers typically cause pain that is relieved by eating, occurs 2-3 hours after eating and at night, and may be accompanied by nausea and vomiting. Gastric ulcers, on the other hand, cause pain that occurs 30 minutes after eating and may be associated with nausea and vomiting.

Management of peptic ulcers depends on the underlying cause and presentation. Patients with active gastrointestinal bleeding require risk stratification, volume resuscitation, endoscopy, and proton pump inhibitor (PPI) therapy. Those with perforated ulcers require resuscitation, antibiotic treatment, analgesia, PPI therapy, and urgent surgical review.

For stable patients with peptic ulcers, lifestyle modifications such as weight loss, avoiding trigger foods, eating smaller meals, quitting smoking, reducing alcohol consumption, and managing stress and anxiety are recommended. Medication review should be done to stop causative drugs if possible. PPI therapy, with or without H. pylori eradication therapy, is also prescribed. H. pylori testing is typically done using a carbon-13 urea breath test or stool antigen test, and eradication therapy involves a 7-day triple therapy regimen of antibiotics and PPI.

Scleritis is a serious condition characterized by inflammation of the sclera, the white outer layer of the eye. It often affects both eyes, with bilateral involvement seen in about half of the cases. While the cause of scleritis can be unknown (idiopathic), it is associated with systemic inflammatory diseases like rheumatoid arthritis in approximately one-third of patients. In fact, scleritis can sometimes be the initial manifestation of these inflammatory conditions.

The clinical features of scleritis include moderate to severe pain, which can be felt in the brow or jaw. The pain worsens with eye movement and may disrupt sleep. The onset of symptoms is typically gradual. Other common symptoms include sensitivity to light (photophobia), excessive tearing (epiphora), and redness of both the superficial and deep episcleral vessels. The affected eye may also be tender to touch, and there may be a decrease in visual acuity. Some individuals may have a history of previous episodes of scleritis.

In summary, scleritis is a serious inflammatory disease of the sclera that can be associated with systemic inflammatory conditions. It presents with significant pain, often referred to the brow or jaw, and worsened by eye movement. Other symptoms include photophobia, excessive tearing, and redness of the episcleral vessels. It is important to recognize scleritis as it can be the first sign of underlying inflammatory diseases.

Chlamydia trachomatis is a type of Gram-negative bacteria that is responsible for causing the sexually transmitted infection known as chlamydia. This bacterium is typically either coccoid or rod-shaped in its appearance.

There are various serological variants of C. trachomatis, and each variant is associated with different patterns of disease. Specifically, types D-K of this bacterium are responsible for causing genitourinary infections.

Chlamydia is the most commonly diagnosed sexually transmitted infection in the United Kingdom and is also the leading preventable cause of infertility worldwide. Interestingly, around 50% of men infected with chlamydia do not experience any symptoms, while at least 70% of infected women remain asymptomatic. However, if left untreated, chlamydia can lead to complications such as pelvic inflammatory disease, ectopic pregnancy, and tubal infertility in women. In men, it can result in proctitis, epididymitis, and epididymo-orchitis.

Thiazide diuretics, like bendroflumethiazide and hydrochlorothiazide, have the potential to raise levels of uric acid in the blood, which can worsen gout symptoms in individuals who are susceptible to the condition.

Other medications, such as diuretics, beta-blockers, ACE inhibitors, and non-losartan ARBs, are also linked to an increased risk of gout.

On the other hand, calcium-channel blockers like amlodipine and verapamil, as well as losartan, have been found to lower uric acid levels and are associated with a reduced risk of gout.

The earliest ECG change typically observed in hyperkalemia is the presence of tall tented T-waves.

Further Reading:

Vasoactive drugs can be classified into three categories: inotropes, vasopressors, and unclassified. Inotropes are drugs that alter the force of muscular contraction, particularly in the heart. They primarily stimulate adrenergic receptors and increase myocardial contractility. Commonly used inotropes include adrenaline, dobutamine, dopamine, isoprenaline, and ephedrine.

Vasopressors, on the other hand, increase systemic vascular resistance (SVR) by stimulating alpha-1 receptors, causing vasoconstriction. This leads to an increase in blood pressure. Commonly used vasopressors include norepinephrine, metaraminol, phenylephrine, and vasopressin.

Electrolytes, such as potassium, are essential for proper bodily function. Solutions containing potassium are often given to patients to prevent or treat hypokalemia (low potassium levels). However, administering too much potassium can lead to hyperkalemia (high potassium levels), which can cause dangerous arrhythmias. It is important to monitor potassium levels and administer it at a controlled rate to avoid complications.

Hyperkalemia can be caused by various factors, including excessive potassium intake, decreased renal excretion, endocrine disorders, certain medications, metabolic acidosis, tissue destruction, and massive blood transfusion. It can present with cardiovascular, respiratory, gastrointestinal, and neuromuscular symptoms. ECG changes, such as tall tented T-waves, prolonged PR interval, flat P-waves, widened QRS complex, and sine wave, are also characteristic of hyperkalemia.

In summary, vasoactive drugs can be categorized as inotropes, vasopressors, or unclassified. Inotropes increase myocardial contractility, while vasopressors increase systemic vascular resistance. Electrolytes, particularly potassium, are important for bodily function, but administering too much can lead to hyperkalemia. Monitoring potassium levels and ECG changes is crucial in managing hyperkalemia.

Phaeochromocytoma is characterized by certain clinical features, including paroxysmal hypertension, palpitations, headache, tremor, and profuse sweating. This patient exhibits paroxysmal symptoms that align with phaeochromocytoma, such as high blood pressure (systolic readings exceeding 220 mmHg are common), headache, sweating, and feelings of anxiety and fear. It is important to note that individuals with conditions like congenital adrenal hyperplasia, diabetes insipidus, and Addisonian crisis typically experience low blood pressure.

Further Reading:

Phaeochromocytoma is a rare neuroendocrine tumor that secretes catecholamines. It typically arises from chromaffin tissue in the adrenal medulla, but can also occur in extra-adrenal chromaffin tissue. The majority of cases are spontaneous and occur in individuals aged 40-50 years. However, up to 30% of cases are hereditary and associated with genetic mutations. About 10% of phaeochromocytomas are metastatic, with extra-adrenal tumors more likely to be metastatic.

The clinical features of phaeochromocytoma are a result of excessive catecholamine production. Symptoms are typically paroxysmal and include hypertension, headaches, palpitations, sweating, anxiety, tremor, abdominal and flank pain, and nausea. Catecholamines have various metabolic effects, including glycogenolysis, mobilization of free fatty acids, increased serum lactate, increased metabolic rate, increased myocardial force and rate of contraction, and decreased systemic vascular resistance.

Diagnosis of phaeochromocytoma involves measuring plasma and urine levels of metanephrines, catecholamines, and urine vanillylmandelic acid. Imaging studies such as abdominal CT or MRI are used to determine the location of the tumor. If these fail to find the site, a scan with metaiodobenzylguanidine (MIBG) labeled with radioactive iodine is performed. The highest sensitivity and specificity for diagnosis is achieved with plasma metanephrine assay.

The definitive treatment for phaeochromocytoma is surgery. However, before surgery, the patient must be stabilized with medical management. This typically involves alpha-blockade with medications such as phenoxybenzamine or phentolamine, followed by beta-blockade with medications like propranolol. Alpha blockade is started before beta blockade to allow for expansion of blood volume and to prevent a hypertensive crisis.

Anaemia can be categorized based on the size of red blood cells. Microcytic anaemia, characterized by a mean corpuscular volume (MCV) of less than 80 fl, can be caused by various factors such as iron deficiency, thalassaemia, anaemia of chronic disease (which can also be normocytic), sideroblastic anaemia (which can also be normocytic), lead poisoning, and aluminium toxicity (although this is now rare and mainly affects haemodialysis patients).

On the other hand, normocytic anaemia, with an MCV ranging from 80 to 100 fl, can be attributed to conditions like haemolysis, acute haemorrhage, bone marrow failure, anaemia of chronic disease (which can also be microcytic), mixed iron and folate deficiency, pregnancy, chronic renal failure, and sickle-cell disease.

Lastly, macrocytic anaemia, characterized by an MCV greater than 100 fl, can be caused by factors such as B12 deficiency, folate deficiency, hypothyroidism, reticulocytosis, liver disease, alcohol abuse, myeloproliferative disease, myelodysplastic disease, and certain drugs like methotrexate, hydroxyurea, and azathioprine.

It is important to understand the different causes of anaemia based on red cell size as this knowledge can aid in the diagnosis and management of this condition.

Public Health England (PHE) has a primary goal of promptly identifying potential disease outbreaks and epidemics. While accuracy of diagnosis is important, it is not the main focus. Since 1968, clinical suspicion of a notifiable infection has been sufficient for reporting.
Registered medical practitioners (RMPs) are legally obligated to notify the designated proper officer at their local council or local health protection team (HPT) if they suspect cases of certain infectious diseases.
The Health Protection (Notification) Regulations 2010 specify the diseases that RMPs must report to the proper officers at local authorities. These diseases include acute encephalitis, acute infectious hepatitis, acute meningitis, acute poliomyelitis, anthrax, botulism, brucellosis, cholera, COVID-19, diphtheria, enteric fever (typhoid or paratyphoid fever), food poisoning, haemolytic uraemic syndrome (HUS), infectious bloody diarrhoea, invasive group A streptococcal disease, Legionnaires’ disease, leprosy, malaria, measles, meningococcal septicaemia, mumps, plague, rabies, rubella, severe acute respiratory syndrome (SARS), scarlet fever, smallpox, tetanus, tuberculosis, typhus, viral haemorrhagic fever (VHF), whooping cough, and yellow fever. However, as of April 2010, ophthalmia neonatorum is no longer considered a notifiable disease in the UK.