Atropine acts as a blocker for muscarinic acetylcholine receptors, making it an antagonist. It is commonly administered during peri-arrest bradycardia. In adults, a dose of 500 mcg is given every 3-5 minutes, with a maximum total dose of 3mg. On the other hand, the initial intravenous dose of amiodarone is 300 mg. Amiodarone works by prolonging repolarization and decreasing myocardial excitability. Additionally, lidocaine functions by blocking sodium channels.

Further Reading:

In the management of respiratory and cardiac arrest, several drugs are commonly used to help restore normal function and improve outcomes. Adrenaline is a non-selective agonist of adrenergic receptors and is administered intravenously at a dose of 1 mg every 3-5 minutes. It works by causing vasoconstriction, increasing systemic vascular resistance (SVR), and improving cardiac output by increasing the force of heart contraction. Adrenaline also has bronchodilatory effects.

Amiodarone is another drug used in cardiac arrest situations. It blocks voltage-gated potassium channels, which prolongs repolarization and reduces myocardial excitability. The initial dose of amiodarone is 300 mg intravenously after 3 shocks, followed by a dose of 150 mg after 5 shocks.

Lidocaine is an alternative to amiodarone in cardiac arrest situations. It works by blocking sodium channels and decreasing heart rate. The recommended dose is 1 mg/kg by slow intravenous injection, with a repeat half of the initial dose after 5 minutes. The maximum total dose of lidocaine is 3 mg/kg.

Magnesium sulfate is used to reverse myocardial hyperexcitability associated with hypomagnesemia. It is administered intravenously at a dose of 2 g over 10-15 minutes. An additional dose may be given if necessary, but the maximum total dose should not exceed 3 g.

Atropine is an antagonist of muscarinic acetylcholine receptors and is used to counteract the slowing of heart rate caused by the parasympathetic nervous system. It is administered intravenously at a dose of 500 mcg every 3-5 minutes, with a maximum dose of 3 mg.

Naloxone is a competitive antagonist for opioid receptors and is used in cases of respiratory arrest caused by opioid overdose. It has a short duration of action, so careful monitoring is necessary. The initial dose of naloxone is 400 micrograms, followed by 800 mcg after 1 minute. The dose can be gradually escalated up to 2 mg per dose if there is no response to the preceding dose.

It is important for healthcare professionals to have knowledge of the pharmacology and dosing schedules of these drugs in order to effectively manage respiratory and cardiac arrest situations.

Severe hypothermia is defined as having a core body temperature below 28ºC. The Royal College of Emergency Medicine (RCEM) also uses the term profound hypothermia to describe individuals with a core temperature below 20ºC.

Further Reading:

Hypothermic cardiac arrest is a rare situation that requires a tailored approach. Resuscitation is typically prolonged, but the prognosis for young, previously healthy individuals can be good. Hypothermic cardiac arrest may be associated with drowning. Hypothermia is defined as a core temperature below 35ºC and can be graded as mild, moderate, severe, or profound based on the core temperature. When the core temperature drops, basal metabolic rate falls and cell signaling between neurons decreases, leading to reduced tissue perfusion. Signs and symptoms of hypothermia progress as the core temperature drops, initially presenting as compensatory increases in heart rate and shivering, but eventually ceasing as the temperature drops into moderate hypothermia territory.

ECG changes associated with hypothermia include bradyarrhythmias, Osborn waves, prolonged PR, QRS, and QT intervals, shivering artifact, ventricular ectopics, and cardiac arrest. When managing hypothermic cardiac arrest, ALS should be initiated as per the standard ALS algorithm, but with modifications. It is important to check for signs of life, re-warm the patient, consider mechanical ventilation due to chest wall stiffness, adjust dosing or withhold drugs due to slowed drug metabolism, and correct electrolyte disturbances. The resuscitation of hypothermic patients is often prolonged and may continue for a number of hours.

Pulse checks during CPR may be difficult due to low blood pressure, and the pulse check is prolonged to 1 minute for this reason. Drug metabolism is slowed in hypothermic patients, leading to a build-up of potentially toxic plasma concentrations of administered drugs. Current guidance advises withholding drugs if the core temperature is below 30ºC and doubling the drug interval at core temperatures between 30 and 35ºC. Electrolyte disturbances are common in hypothermic patients, and it is important to interpret results keeping the setting in mind. Hypoglycemia should be treated, hypokalemia will often correct as the patient re-warms, ABG analyzers may not reflect the reality of the hypothermic patient, and severe hyperkalemia is a poor prognostic indicator.

Different warming measures can be used to increase the core body temperature, including external passive measures such as removal of wet clothes and insulation with blankets, external active measures such as forced heated air or hot-water immersion, and internal active measures such as inhalation of warm air, warmed intravenous fluids, gastric, bladder, peritoneal and/or pleural lavage and high volume renal haemofilter.

The recommended dose of etomidate for rapid sequence intubation (RSI) is typically 0.3mg per kilogram of body weight. For example, a patient weighing 70 kilograms would receive a dose of 21mg (70 x 0.3 = 21mg). This dosage falls within the accepted range of 0.15-0.3 mg/kg as suggested by the British National Formulary (BNF). Therefore, the only option within this range is the fourth option.

Further Reading:

There are four commonly used induction agents in the UK: propofol, ketamine, thiopentone, and etomidate.

Propofol is a 1% solution that produces significant venodilation and myocardial depression. It can also reduce cerebral perfusion pressure. The typical dose for propofol is 1.5-2.5 mg/kg. However, it can cause side effects such as hypotension, respiratory depression, and pain at the site of injection.

Ketamine is another induction agent that produces a dissociative state. It does not display a dose-response continuum, meaning that the effects do not necessarily increase with higher doses. Ketamine can cause bronchodilation, which is useful in patients with asthma. The initial dose for ketamine is 0.5-2 mg/kg, with a typical IV dose of 1.5 mg/kg. Side effects of ketamine include tachycardia, hypertension, laryngospasm, unpleasant hallucinations, nausea and vomiting, hypersalivation, increased intracranial and intraocular pressure, nystagmus and diplopia, abnormal movements, and skin reactions.

Thiopentone is an ultra-short acting barbiturate that acts on the GABA receptor complex. It decreases cerebral metabolic oxygen and reduces cerebral blood flow and intracranial pressure. The adult dose for thiopentone is 3-5 mg/kg, while the child dose is 5-8 mg/kg. However, these doses should be halved in patients with hypovolemia. Side effects of thiopentone include venodilation, myocardial depression, and hypotension. It is contraindicated in patients with acute porphyrias and myotonic dystrophy.

Etomidate is the most haemodynamically stable induction agent and is useful in patients with hypovolemia, anaphylaxis, and asthma. It has similar cerebral effects to thiopentone. The dose for etomidate is 0.15-0.3 mg/kg. Side effects of etomidate include injection site pain, movement disorders, adrenal insufficiency, and apnoea. It is contraindicated in patients with sepsis due to adrenal suppression.

Blood transfusion is a crucial treatment that can save lives, but it also comes with various risks and potential problems. These include immunological complications, administration errors, infections, and immune dilution. While there have been improvements in safety procedures and a reduction in transfusion use, errors and adverse reactions still occur.

Delayed haemolytic transfusion reactions (DHTRs) typically occur 4-8 days after a blood transfusion, but can sometimes manifest up to a month later. The symptoms are similar to acute haemolytic transfusion reactions but are usually less severe. Patients may experience fever, inadequate rise in haemoglobin, jaundice, reticulocytosis, positive antibody screen, and positive Direct Antiglobulin Test (Coombs test). DHTRs are more common in patients with sickle cell disease who have received frequent transfusions.

These reactions are caused by the presence of a low titre antibody that is too weak to be detected during cross-match and unable to cause lysis at the time of transfusion. The severity of DHTRs depends on the immunogenicity or dose of the antigen. Blood group antibodies associated with DHTRs include those of the Kidd, Duffy, Kell, and MNS systems. Most DHTRs have a benign course and do not require treatment. However, severe haemolysis with anaemia and renal failure can occur, so monitoring of haemoglobin levels and renal function is necessary. If an antibody is detected, antigen-negative blood can be requested for future transfusions.

Here is a summary of the main transfusion reactions and complications:

1. Febrile transfusion reaction: Presents with a 1-degree rise in temperature from baseline, along with chills and malaise. It is the most common reaction and is usually caused by cytokines from leukocytes in transfused red cell or platelet components. Supportive treatment with paracetamol is helpful.

2. Acute haemolytic reaction: Symptoms include fever, chills, pain at the transfusion site, nausea, vomiting, and dark urine. It is the most serious type of reaction and often occurs due to ABO incompatibility from administration errors. The transfusion should be stopped, and IV fluids should be administered. Diuretics may be required.

3. Delayed haemolytic reaction: This reaction typically occurs 4-8 days after a blood transfusion and presents with fever, anaemia, jaundice and haemoglobuinuria. Direct antiglobulin (Coombs) test positive. Due to low titre antibody too weak to detect in cross-match and unable to cause lysis at time of transfusion. Most delayed haemolytic reactions have a benign course and require no treatment. Monitor anaemia and renal function and treat as required.

A patient with central vertigo would typically show a normal head impulse test result, indicating a normal vestibulo-ocular reflex. However, they would likely have an abnormal alternate cover test result, with a slight vertical correction, suggesting a central lesion like a stroke. A positive Romberg’s test can identify instability related to vertigo but cannot differentiate between peripheral and central causes. On the other hand, a positive Unterberger’s test indicates labyrinth dysfunction but does not indicate a central cause.

Further Reading:

Vertigo is a symptom characterized by a false sensation of movement, such as spinning or rotation, in the absence of any actual physical movement. It is not a diagnosis itself, but rather a description of the sensation experienced by the individual. Dizziness, on the other hand, refers to a perception of disturbed or impaired spatial orientation without a false sense of motion.

Vertigo can be classified as either peripheral or central. Peripheral vertigo is more common and is caused by problems in the inner ear that affect the labyrinth or vestibular nerve. Examples of peripheral vertigo include BPPV, vestibular neuritis, labyrinthitis, and Meniere’s disease. Central vertigo, on the other hand, is caused by pathology in the brain, such as in the brainstem or cerebellum. Examples of central vertigo include migraine, TIA and stroke, cerebellar tumor, acoustic neuroma, and multiple sclerosis.

There are certain features that can help differentiate between peripheral and central vertigo. Peripheral vertigo is often associated with severe nausea and vomiting, hearing loss or tinnitus, and a positive head impulse test. Central vertigo may be characterized by prolonged and severe vertigo, new-onset headache, recent trauma, cardiovascular risk factors, inability to stand or walk with eyes open, focal neurological deficit, and a negative head impulse test.

Nystagmus, an involuntary eye movement, can also provide clues about the underlying cause of vertigo. Central causes of vertigo often have nystagmus that is direction-changing on lateral gaze, purely vertical or torsional, not suppressed by visual fixation, non-fatigable, and commonly large amplitude. Peripheral causes of vertigo often have horizontal nystagmus with a torsional component that does not change direction with gaze, disappears with fixation of the gaze, and may have large amplitude early in the course of Meniere’s disease or vestibular neuritis.

There are various causes of vertigo, including viral labyrinthitis, vestibular neuritis, benign paroxysmal positional vertigo, Meniere’s disease, vertebrobasilar ischemia, and acoustic neuroma. Each of these disorders has its own unique characteristics and may be associated with other symptoms such as hearing loss, tinnitus, or neurological deficits.

When assessing a patient with vertigo, it is important to perform a cardiovascular and neurological examination, including assessing cranial nerves, cerebellar signs, eye movements, gait, coordination, and evidence of peripheral neuropathy.

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.

NICE has emphasized that there are particular symptoms and indications that may indicate specific diseases as the underlying cause of a fever. In the case of herpes simplex encephalitis, the following symptoms and signs may suggest its presence: the presence of a focal neurological sign, focal seizures, and a decreased level of consciousness. For more information on this topic, you may refer to the NICE guidelines on the assessment and initial management of fever in children under the age of 5, as well as the NICE Clinical Knowledge Summary on the management of feverish children.

The timing of the initial rise, peak, and return to normality of various cardiac enzymes can serve as a helpful guide. Creatine kinase, the main cardiac isoenzyme, typically experiences an initial rise within 4-8 hours, reaches its peak at 18 hours, and returns to normal within 2-3 days. Myoglobin, which lacks specificity due to its association with skeletal muscle damage, shows an initial rise within 1-4 hours, peaks at 6-7 hours, and returns to normal within 24 hours. Troponin I, known for its sensitivity and specificity, exhibits an initial rise within 3-12 hours, reaches its peak at 24 hours, and returns to normal within 3-10 days. HFABP, or heart fatty acid binding protein, experiences an initial rise within 1.5 hours, peaks at 5-10 hours, and returns to normal within 24 hours. Lastly, LDH, predominantly found in cardiac muscle, shows an initial rise at 10 hours, peaks at 24-48 hours, and returns to normal within 14 days.

Gout is a form of arthritis that causes a swollen, tender, red, and hot joint. Initially, it was believed to primarily affect wealthy individuals due to dietary connections, but it is now becoming more prevalent and is estimated to impact around 1-2% of the Western population. This increase may be attributed to longer lifespans and changes in our eating habits. Additionally, there is a positive correlation between the rising rates of metabolic disease and gout.

While gout commonly affects the metatarsal-phalangeal joint of the big toe (approximately 50% of cases), it can also impact other joints such as the fingers, wrists, knees, and ankles. The pain experienced during an episode is often excruciating, and these episodes typically last about a week. Approximately half of the patients experience a recurrence within a year.

Hyperuricemia is the underlying cause of gout. Uric acid, a byproduct of purine metabolism, is typically eliminated through the kidneys. However, in about 90% of cases, hyperuricemia occurs due to the under-excretion of urate, while the remaining 10% is caused by overproduction. Elevated urate levels increase the likelihood of crystal formation. Measuring uric acid levels in the blood can be misleading, as some individuals with high levels do not develop gout, and levels can be normal during an attack. The crystallization process is complex and more likely to occur in cooler temperatures (which is why the feet are often affected, and symptoms worsen at night), during acidosis, and when there are rapid fluctuations in uric acid levels.

Diagnosing gout is primarily based on clinical evaluation. If there is a rapid onset of severe pain, swelling, and tenderness that reaches its peak within 6-12 hours, accompanied by redness, it strongly suggests crystal inflammation. The presence of monosodium urate crystals in synovial fluid or tophi confirms the diagnosis. When these crystals are examined under polarized light, they exhibit negative birefringence. Since gout symptoms can be mistaken for septic arthritis, if there is uncertainty in the diagnosis and the joint has been aspirated, it should also be sent for gram-staining.

Tophi are painless, hard lumps that develop when hyperuricemia persists for an extended period. They often appear on the elbows and ears.

Verruca acuminata, also known as Condylomata acuminata, are genital warts. These warts are typically transmitted through sexual activity and are primarily caused by different subtypes of the human papillomavirus (HPV). They usually appear in clusters, can be pedunculated, and vary in size between 1-5 mm. Immunosuppression increases the risk, and some studies suggest that 25% of affected patients will acquire a second sexually transmitted infection.

Condylomata lata, on the other hand, are warty-plaque like lesions found on the genitals and perianal area during secondary syphilis.

Verruca vulgaris, commonly known as common warts, present as raised warts with a roughened surface. They are most frequently observed on the hands.

Verruca planae, which are smooth and flattened flesh-colored warts, can occur in large numbers. They are commonly seen on the face, hands, neck, wrists, and knees.

Lastly, Verruca plantaris, also known as plantar warts or verrucas, manifest as hard and painful lumps, often with black specks in the center. These warts are typically found only on pressure points on the soles of the feet.