Benzodiazepines are medications that are utilized to address emergence phenomena, which are characterized by restlessness and distressing hallucinations experienced upon awakening from ketamine sedation or induction. These phenomena are more frequently observed in older children and adults, affecting approximately one out of every three adults. To manage emergence phenomena, benzodiazepines may be administered. It is important to note that the RCEM does not recommend preventive treatment and suggests addressing emergence phenomena as they arise.

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.

Generally speaking, if a child shows clinical signs of dehydration but does not exhibit shock, it can be assumed that they are 5% dehydrated. On the other hand, if shock is also present, it can be assumed that the child is 10% dehydrated or more. To put it in simpler terms, 5% dehydration means that the body has lost 5 grams of fluid per 100 grams of body weight, which is equivalent to 50 milliliters per kilogram of fluid. Similarly, 10% dehydration implies a loss of 100 milliliters per kilogram of fluid.

The clinical features of dehydration and shock are summarized below:

Dehydration (5%):
– The child appears unwell
– The heart rate may be normal or increased (tachycardia)
– The respiratory rate may be normal or increased (tachypnea)
– Peripheral pulses are normal
– Capillary refill time (CRT) is normal or slightly prolonged
– Blood pressure is normal
– Extremities feel warm
– Decreased urine output
– Reduced skin turgor
– Sunken eyes
– Depressed fontanelle
– Dry mucous membranes

Clinical shock (10%):
– The child appears pale, lethargic, and mottled
– Tachycardia (increased heart rate)
– Tachypnea (increased respiratory rate)
– Weak peripheral pulses
– Prolonged CRT
– Hypotension (low blood pressure)
– Extremities feel cold
– Decreased urine output
– Decreased level of consciousness

SCUBA divers face the potential danger of developing pulmonary barotrauma, which can lead to conditions like arterial gas embolism (AGE) or pneumothorax. Based on the patient’s diving history and clinical symptoms, it is highly likely that they are experiencing a left-sided pneumothorax caused by barotrauma. To confirm the presence of pneumothorax, a chest X-ray is usually performed, unless the patient shows signs of tension pneumothorax. In such cases, immediate decompression is necessary, which can be achieved by inserting a chest tube.

Further Reading:

Decompression illness (DCI) is a term that encompasses both decompression sickness (DCS) and arterial gas embolism (AGE). When diving underwater, the increasing pressure causes gases to become more soluble and reduces the size of gas bubbles. As a diver ascends, nitrogen can come out of solution and form gas bubbles, leading to decompression sickness or the bends. Boyle’s and Henry’s gas laws help explain the changes in gases during changing pressure.

Henry’s law states that the amount of gas that dissolves in a liquid is proportional to the partial pressure of the gas. Divers often use atmospheres (ATM) as a measure of pressure, with 1 ATM being the pressure at sea level. Boyle’s law states that the volume of gas is inversely proportional to the pressure. As pressure increases, volume decreases.

Decompression sickness occurs when nitrogen comes out of solution as a diver ascends. The evolved gas can physically damage tissue by stretching or tearing it as bubbles expand, or by provoking an inflammatory response. Joints and spinal nervous tissue are commonly affected. Symptoms of primary damage usually appear immediately or soon after a dive, while secondary damage may present hours or days later.

Arterial gas embolism occurs when nitrogen bubbles escape into the arterial circulation and cause distal ischemia. The consequences depend on where the embolism lodges, ranging from tissue ischemia to stroke if it lodges in the cerebral arterial circulation. Mechanisms for distal embolism include pulmonary barotrauma, right to left shunt, and pulmonary filter overload.

Clinical features of decompression illness vary, but symptoms often appear within six hours of a dive. These can include joint pain, neurological symptoms, chest pain or breathing difficulties, rash, vestibular problems, and constitutional symptoms. Factors that increase the risk of DCI include diving at greater depth, longer duration, multiple dives close together, problems with ascent, closed rebreather circuits, flying shortly after diving, exercise shortly after diving, dehydration, and alcohol use.

Diagnosis of DCI is clinical, and investigations depend on the presentation. All patients should receive high flow oxygen, and a low threshold for ordering a chest X-ray should be maintained. Hydration is important, and IV fluids may be necessary. Definitive treatment is recompression therapy in a hyperbaric oxygen chamber, which should be arranged as soon as possible. Entonox should not be given, as it will increase the pressure effect in air spaces.

Sexually transmitted eye infections can be quite severe and are often characterized by prolonged mucopurulent discharge. The two main causes of these infections are Chlamydia trachomatis and Neisseria gonorrhoea. Differentiating between the two can be done by considering certain features.

Chlamydia trachomatis infection typically presents with chronic low-grade irritation and mucous discharge that lasts for more than two weeks in sexually active individuals. Pre-auricular lymphadenopathy, or swelling of the lymph nodes in front of the ear, may also be present. Most cases of this infection are unilateral, affecting only one eye, but there is a possibility of it being bilateral, affecting both eyes.

On the other hand, Neisseria gonorrhoea infection tends to develop rapidly, usually within 12 to 24 hours. It is characterized by copious mucopurulent discharge, swelling of the eyelids, and tender preauricular lymphadenopathy. This type of infection carries a higher risk of complications, such as uveitis, severe keratitis, and corneal perforation.

Based on the patient’s symptoms, it appears that they are more consistent with a Chlamydia trachomatis infection, especially considering the slower and more gradual onset of their symptoms.

There is ongoing debate regarding the most effective antibiotic treatment for these infections. Some options include topical tetracycline ointment to be applied four times a day for six weeks, oral doxycycline to be taken twice a day for one to two weeks, oral azithromycin with a single dose of 1 gram followed by 500 mg orally for two days, or oral erythromycin to be taken four times a day for one week.

Peri-orbital cellulitis, also known as preseptal cellulitis, is an infection that affects the eyelid and the skin surrounding the eye in front of the orbital septal. On the other hand, orbital cellulitis is a medical emergency that occurs when there is an infection in the tissues of the eye located behind the orbital septum.

The most common organisms that cause these infections include Streptococcus pneumoniae, Staphylococcus aureus, Streptococcus pyogenes, and Haemophilus influenzae.

Peri-orbital cellulitis may present with various symptoms, such as swelling of the eyelid, redness around the eye, discharge, difficulty closing the eye, conjunctival injection, mild fever, teary eyes, and discomfort.

To distinguish orbital cellulitis from peri-orbital cellulitis, it is important to look out for additional symptoms, including pain when moving the eye, protrusion of the eye (proptosis), redness of the eye (red desaturation), vision loss, eye muscle paralysis (ophthalmoplegia), double vision (diplopia), and optic nerve damage (optic neuropathy). These symptoms indicate a more severe condition that requires immediate medical attention.

Plasmodium falciparum malaria is transmitted by female mosquitoes of the Anopheles genus. While it can be found worldwide, it is most prevalent in Africa. The incubation period for this type of malaria is typically between 7 to 14 days.

The parasite, known as sporozoites, invades hepatocytes (liver cells). Inside the hepatocyte, the parasite undergoes asexual reproduction, resulting in the production of merozoites. These merozoites are then released into the bloodstream and invade the red blood cells of the host.

Currently, the recommended treatment for P. falciparum malaria is artemisinin-based combination therapy (ACT). This involves combining fast-acting artemisinin-based compounds with drugs from different classes. Some of the companion drugs used in ACT include lumefantrine, mefloquine, amodiaquine, sulfadoxine/pyrimethamine, piperaquine, and chlorproguanil/dapsone. Artemisinin derivatives such as dihydroartemisinin, artesunate, and artemether are also used.

In cases where artemisinin combination therapy is not available, oral quinine or atovaquone with proguanil hydrochloride can be used as alternatives. However, quinine is not well-tolerated for prolonged treatment and should be combined with another drug, typically oral doxycycline (or clindamycin for pregnant women and young children).

For severe or complicated cases of falciparum malaria, it is recommended to manage the patient in a high dependency unit or intensive care setting. Intravenous artesunate is indicated for all patients with severe or complicated falciparum malaria, as well as those at high risk of developing severe disease (e.g., if more than 2% of red blood cells are parasitized) or if the patient is unable to take oral treatment. After a minimum of 24 hours of intravenous artesunate treatment and once the patient has shown improvement and can tolerate oral treatment, a full course of artemisinin combination therapy should be administered.

The primary treatment option for hypertensive encephalopathy, a condition characterized by sudden confusion, severe headache, and coordination problems due to significantly elevated blood pressure, is labetalol.

Further Reading:

A hypertensive emergency is characterized by a significant increase in blood pressure accompanied by acute or progressive damage to organs. While there is no specific blood pressure value that defines a hypertensive emergency, systolic blood pressure is typically above 180 mmHg and/or diastolic blood pressure is above 120 mmHg. The most common presentations of hypertensive emergencies include cerebral infarction, pulmonary edema, encephalopathy, and congestive cardiac failure. Less common presentations include intracranial hemorrhage, aortic dissection, and pre-eclampsia/eclampsia.

The signs and symptoms of hypertensive emergencies can vary widely due to the potential dysfunction of every physiological system. Some common signs and symptoms include headache, nausea and/or vomiting, chest pain, arrhythmia, proteinuria, signs of acute kidney failure, epistaxis, dyspnea, dizziness, anxiety, confusion, paraesthesia or anesthesia, and blurred vision. Clinical assessment focuses on detecting acute or progressive damage to the cardiovascular, renal, and central nervous systems.

Investigations that are essential in evaluating hypertensive emergencies include U&Es (electrolyte levels), urinalysis, ECG, and CXR. Additional investigations may be considered depending on the suspected underlying cause, such as a CT head for encephalopathy or new onset confusion, CT thorax for suspected aortic dissection, and CT abdomen for suspected phaeochromocytoma. Plasma free metanephrines, urine total catecholamines, vanillylmandelic acid (VMA), and metanephrine may be tested if phaeochromocytoma is suspected. Urine screening for cocaine and/or amphetamines may be appropriate in certain cases, as well as an endocrine screen for Cushing’s syndrome.

The management of hypertensive emergencies involves cautious reduction of blood pressure to avoid precipitating renal, cerebral, or coronary ischemia. Staged blood pressure reduction is typically the goal, with an initial reduction in mean arterial pressure (MAP) by no more than 25% in the first hour. Further gradual reduction to a systolic blood pressure of 160 mmHg and diastolic blood pressure of 100 mmHg over the next 2 to 6 hours is recommended. Initial management involves treatment with intravenous antihypertensive agents in an intensive care setting with appropriate monitoring.

The key components of first aid for snake bites in the UK involve immobilizing the patient and the affected limb, as well as administering paracetamol for pain relief. When it comes to venomous snake bites, it is important to immobilize the limb using a splint or sling, but not to use a tourniquet or pressure bandage for adder bites. In certain areas, such as NSW, Australia, where venomous snakes can cause rapidly progressing and life-threatening paralysis, pressure bandage immobilization is recommended. However, this is not the case in the UK. Anti-venom is not always necessary for adder bites, and its administration should be based on a thorough assessment of the patient’s condition and the presence of appropriate indications. Paracetamol is the preferred choice for pain relief in UK snake bites, as aspirin and ibuprofen can worsen bleeding tendencies that may result from adder bites. Similarly, heparin should be avoided for the same reason.

Further Reading:

Snake bites in the UK are primarily caused by the adder, which is the only venomous snake species native to the country. While most adder bites result in minor symptoms such as pain, swelling, and inflammation, there have been cases of life-threatening illness and fatalities. Additionally, there are instances where venomous snakes that are kept legally or illegally also cause bites in the UK.

Adder bites typically occur from early spring to late autumn, with the hand being the most common site of the bite. Symptoms can be local or systemic, with local symptoms including sharp pain, tingling or numbness, and swelling that spreads proximally. Systemic symptoms may include spreading pain, tenderness, inflammation, regional lymph node enlargement, and bruising. In severe cases, anaphylaxis can occur, leading to symptoms such as nausea, vomiting, abdominal pain, diarrhea, and shock.

It is important for clinicians to be aware of the potential complications and complications associated with adder bites. These can include acute renal failure, pulmonary and cerebral edema, acute gastric dilatation, paralytic ileus, acute pancreatitis, and coma and seizures. Anaphylaxis symptoms can appear within minutes or be delayed for hours, and hypotension is a critical sign to monitor.

Initial investigations for adder bites include blood tests, ECG, and vital sign monitoring. Further investigations such as chest X-ray may be necessary based on clinical signs. Blood tests may reveal abnormalities such as leukocytosis, raised hematocrit, anemia, thrombocytopenia, and abnormal clotting profile. ECG changes may include tachyarrhythmias, bradyarrhythmias, atrial fibrillation, and ST segment changes.

First aid measures at the scene include immobilizing the patient and the bitten limb, avoiding aspirin and ibuprofen, and cleaning the wound site in the hospital. Tetanus prophylaxis should be considered. In cases of anaphylaxis, prompt administration of IM adrenaline is necessary. In the hospital, rapid assessment and appropriate resuscitation with intravenous fluids are required.

Antivenom may be indicated in cases of hypotension, systemic envenoming, ECG abnormalities, peripheral neutrophil leucocytosis, elevated serum creatine kinase or metabolic acidosis, and extensive or rapidly spreading local swelling. Zagreb antivenom is commonly used in the UK, with an initial dose of 8 mL.

Renal colic, also known as ureteric colic, refers to a sudden and intense pain in the lower back caused by a blockage in the ureter, which is the tube that carries urine from the kidney to the bladder. This condition is commonly associated with the presence of a urinary tract stone.

The main symptoms of renal or ureteric colic include severe abdominal pain on one side, starting in the flank or loin area and radiating to the groin or testicle in men, or to the labia in women. The pain comes and goes in spasms, lasting for minutes to hours, with periods of no pain or a dull ache. Nausea, vomiting, and the presence of blood in the urine are often accompanying symptoms.

The pain experienced during renal or ureteric colic is often described as the most intense pain a person has ever felt, with many women comparing it to the pain of childbirth. Restlessness and an inability to find relief by lying still are common signs, which can help differentiate renal colic from peritonitis. Previous episodes of similar pain may also be reported by the individual. In cases where there is a concomitant urinary infection, fever and sweating may be present. Additionally, the person may complain of painful urination, frequent urination, and straining when the stone reaches the junction between the ureter and the bladder, as the stone irritates the detrusor muscle.

It is important to seek urgent medical attention if certain conditions are met. These include signs of systemic infection or sepsis, such as fever or sweating, or if the person is at a higher risk of acute kidney injury, such as having pre-existing chronic kidney disease, a solitary or transplanted kidney, or suspected bilateral obstructing stones. Hospital admission is also necessary if the person is dehydrated and unable to consume fluids orally due to nausea and/or vomiting. If there is uncertainty regarding the diagnosis, it is recommended to consult further resources, such as the NICE guidelines on the assessment and management of renal and ureteric stones.

Organophosphate poisoning is characterized by a set of symptoms known as SLUDGE (Salivation, Lacrimation, Urination, Defecation, Gastric cramps, Emesis). Additionally, individuals affected may experience pinpoint pupils, profuse sweating, tremors, and confusion. Organophosphates serve as the foundation for various weaponized nerve agents like Sarin and VX, which were infamously employed by the terrorist group Aum Shinrikyo during multiple attacks in Tokyo in the mid-1990s. While SLUDGE is a commonly used acronym to recall the clinical features, it is important to note that other symptoms such as pinpoint pupils, profuse sweating, tremors, and confusion are not included in the acronym.

Further Reading:

Chemical incidents can occur as a result of leaks, spills, explosions, fires, terrorism, or the use of chemicals during wars. Industrial sites that use chemicals are required to conduct risk assessments and have accident plans in place for such incidents. Health services are responsible for decontamination, unless mass casualties are involved, and all acute health trusts must have major incident plans in place.

When responding to a chemical incident, hospitals prioritize containment of the incident and prevention of secondary contamination, triage with basic first aid, decontamination if not done at the scene, recognition and management of toxidromes (symptoms caused by exposure to specific toxins), appropriate supportive or antidotal treatment, transfer to definitive treatment, a safe end to the hospital response, and continuation of business after the event.

To obtain advice when dealing with chemical incidents, the two main bodies are Toxbase and the National Poisons Information Service. Signage on containers carrying chemicals and material safety data sheets (MSDS) accompanying chemicals also provide information on the chemical contents and their hazards.

Contamination in chemical incidents can occur in three phases: primary contamination from the initial incident, secondary contamination spread via contaminated people leaving the initial scene, and tertiary contamination spread to the environment, including becoming airborne and waterborne. The ideal personal protective equipment (PPE) for chemical incidents is an all-in-one chemical-resistant overall with integral head/visor and hands/feet worn with a mask, gloves, and boots.

Decontamination of contaminated individuals involves the removal and disposal of contaminated clothing, followed by either dry or wet decontamination. Dry decontamination is suitable for patients contaminated with non-caustic chemicals and involves blotting and rubbing exposed skin gently with dry absorbent material. Wet decontamination is suitable for patients contaminated with caustic chemicals and involves a warm water shower while cleaning the body with simple detergent.

After decontamination, the focus shifts to assessing the extent of any possible poisoning and managing it. The patient’s history should establish the chemical the patient was exposed to, the volume and concentration of the chemical, the route of exposure, any protective measures in place, and any treatment given. Most chemical poisonings require supportive care using standard resuscitation principles, while some chemicals have specific antidotes. Identifying toxidromes can be useful in guiding treatment, and specific antidotes may be administered accordingly.