Onchocerciasis is a parasitic disease caused by the filarial nematode Onchocerca volvulus. It is transmitted through the bites of infected blackflies of Simulium species, which carry immature larval forms of the parasite from human to human.

In the human body, the larvae form nodules in the subcutaneous tissue, where they mature to adult worms. After mating, the female adult worm can release up to 1000 microfilariae a day.

Onchocerciasis is currently endemic in 30 African countries, Yemen, and a few isolated regions of South America. Approximately 37 million people worldwide are currently infected.

Symptoms start to occur around a year after the patient is infected. The earliest symptom is usually an intensely itchy rash. Various skin manifestations occur, including scattered, red, pruritic papules (acute papular onchodermatitis), larger, chronic, hyperpigmented papules (chronic papular onchodermatitis), lichenified, oedematous, hyperpigmented papules and plaques (lichenified onchodermatitis), areas of skin atrophy with loss of elasticity (‘Lizard skin’), and depigmented areas with a ‘leopard skin appearance, usually on shins.

Ocular involvement provides the common name associated with onchocerciasis, river blindness, and it can involve any part of the eye. Almost a million people worldwide have at least a partial degree of vision loss caused by onchocerciasis. Initially, there may be intense watering, foreign body sensation, and photophobia. This can progress to conjunctivitis, iridocyclitis, and chorioretinitis. Secondary glaucoma and optic atrophy may also occur.

In a number of countries, onchocerciasis has been controlled through spraying of blackfly breeding sites with insecticide. The drug ivermectin is the preferred treatment for onchocerciasis.

The Canadian C-spine assessment includes evaluating for tenderness along the midline of the spine, checking for any abnormal sensations in the limbs, and assessing the ability to rotate the neck 45 degrees to the left and right. While a significant portion of the assessment relies on gathering information from the patient’s history, there are also physical examination components involved. These include testing for tenderness along the midline of the cervical spine, asking the patient to perform neck rotations, ensuring they are comfortable in a sitting position, and assessing for any sensory deficits in the limbs. It is important to note that any reported paraesthesia in the upper or lower limbs can also be taken into consideration during the assessment.

Further Reading:

When assessing for cervical spine injury, it is recommended to use the Canadian C-spine rules. These rules help determine the risk level for a potential injury. High-risk factors include being over the age of 65, experiencing a dangerous mechanism of injury (such as a fall from a height or a high-speed motor vehicle collision), or having paraesthesia in the upper or lower limbs. Low-risk factors include being involved in a minor rear-end motor vehicle collision, being comfortable in a sitting position, being ambulatory since the injury, having no midline cervical spine tenderness, or experiencing a delayed onset of neck pain. If a person is unable to actively rotate their neck 45 degrees to the left and right, their risk level is considered low. If they have one of the low-risk factors and can actively rotate their neck, their risk level remains low.

If a high-risk factor is identified or if a low-risk factor is identified and the person is unable to actively rotate their neck, full in-line spinal immobilization should be maintained and imaging should be requested. Additionally, if a patient has risk factors for thoracic or lumbar spine injury, imaging should be requested. However, if a patient has low-risk factors for cervical spine injury, is pain-free, and can actively rotate their neck, full in-line spinal immobilization and imaging are not necessary.

NICE recommends CT as the primary imaging modality for cervical spine injury in adults aged 16 and older, while MRI is recommended as the primary imaging modality for children under 16.

Different mechanisms of spinal trauma can cause injury to the spine in predictable ways. The majority of cervical spine injuries are caused by flexion combined with rotation. Hyperflexion can result in compression of the anterior aspects of the vertebral bodies, stretching and tearing of the posterior ligament complex, chance fractures (also known as seatbelt fractures), flexion teardrop fractures, and odontoid peg fractures. Flexion and rotation can lead to disruption of the posterior ligament complex and posterior column, fractures of facet joints, lamina, transverse processes, and vertebral bodies, and avulsion of spinous processes. Hyperextension can cause injury to the anterior column, anterior fractures of the vertebral body, and potential retropulsion of bony fragments or discs into the spinal canal. Rotation can result in injury to the posterior ligament complex and facet joint dislocation.

This child is displaying a typical pattern of symptoms for type I diabetes mellitus. He has recently experienced increased urination, excessive thirst, weight loss, and fatigue. Blood tests have revealed metabolic acidosis, and the presence of ketones in his urine indicates the development of diabetic ketoacidosis.

Salicylate poisoning initially leads to respiratory alkalosis, followed by metabolic acidosis. Salicylates, like aspirin, stimulate the respiratory center in the medulla, causing hyperventilation and respiratory alkalosis. This is usually the first acid-base imbalance observed in salicylate poisoning. As aspirin is metabolized, it disrupts oxidative phosphorylation in the mitochondria, leading to an increase in lactate levels due to anaerobic metabolism. The accumulation of lactic acid and acidic metabolites then causes metabolic acidosis.

Further Reading:

Salicylate poisoning, particularly from aspirin overdose, is a common cause of poisoning in the UK. One important concept to understand is that salicylate overdose leads to a combination of respiratory alkalosis and metabolic acidosis. Initially, the overdose stimulates the respiratory center, leading to hyperventilation and respiratory alkalosis. However, as the effects of salicylate on lactic acid production, breakdown into acidic metabolites, and acute renal injury occur, it can result in high anion gap metabolic acidosis.

The clinical features of salicylate poisoning include hyperventilation, tinnitus, lethargy, sweating, pyrexia (fever), nausea/vomiting, hyperglycemia and hypoglycemia, seizures, and coma.

When investigating salicylate poisoning, it is important to measure salicylate levels in the blood. The sample should be taken at least 2 hours after ingestion for symptomatic patients or 4 hours for asymptomatic patients. The measurement should be repeated every 2-3 hours until the levels start to decrease. Other investigations include arterial blood gas analysis, electrolyte levels (U&Es), complete blood count (FBC), coagulation studies (raised INR/PTR), urinary pH, and blood glucose levels.

To manage salicylate poisoning, an ABC approach should be followed to ensure a patent airway and adequate ventilation. Activated charcoal can be administered if the patient presents within 1 hour of ingestion. Oral or intravenous fluids should be given to optimize intravascular volume. Hypokalemia and hypoglycemia should be corrected. Urinary alkalinization with intravenous sodium bicarbonate can enhance the elimination of aspirin in the urine. In severe cases, hemodialysis may be necessary.

Urinary alkalinization involves targeting a urinary pH of 7.5-8.5 and checking it hourly. It is important to monitor for hypokalemia as alkalinization can cause potassium to shift from plasma into cells. Potassium levels should be checked every 1-2 hours.

In cases where the salicylate concentration is high (above 500 mg/L in adults or 350 mg/L in children), sodium bicarbonate can be administered intravenously. Hemodialysis is the treatment of choice for severe poisoning and may be indicated in cases of high salicylate levels, resistant metabolic acidosis, acute kidney injury, pulmonary edema, seizures and coma.

To diagnose orthostatic hypotension, there needs to be a decrease in systolic blood pressure of at least 20 mmHg (or 30 mmHg for individuals with hypertension) and/or a decrease in diastolic blood pressure of at least 10 mmHg within 3 minutes of standing. This confirms the presence of orthostatic hypotension.

Further Reading:

Blackouts, also known as syncope, are defined as a spontaneous transient loss of consciousness with complete recovery. They are most commonly caused by transient inadequate cerebral blood flow, although epileptic seizures can also result in blackouts. There are several different causes of blackouts, including neurally-mediated reflex syncope (such as vasovagal syncope or fainting), orthostatic hypotension (a drop in blood pressure upon standing), cardiovascular abnormalities, and epilepsy.

When evaluating a patient with blackouts, several key investigations should be performed. These include an electrocardiogram (ECG), heart auscultation, neurological examination, vital signs assessment, lying and standing blood pressure measurements, and blood tests such as a full blood count and glucose level. Additional investigations may be necessary depending on the suspected cause, such as ultrasound or CT scans for aortic dissection or other abdominal and thoracic pathology, chest X-ray for heart failure or pneumothorax, and CT pulmonary angiography for pulmonary embolism.

During the assessment, it is important to screen for red flags and signs of any underlying serious life-threatening condition. Red flags for blackouts include ECG abnormalities, clinical signs of heart failure, a heart murmur, blackouts occurring during exertion, a family history of sudden cardiac death at a young age, an inherited cardiac condition, new or unexplained breathlessness, and blackouts in individuals over the age of 65 without a prodrome. These red flags indicate the need for urgent assessment by an appropriate specialist.

There are several serious conditions that may be suggested by certain features. For example, myocardial infarction or ischemia may be indicated by a history of coronary artery disease, preceding chest pain, and ECG signs such as ST elevation or arrhythmia. Pulmonary embolism may be suggested by dizziness, acute shortness of breath, pleuritic chest pain, and risk factors for venous thromboembolism. Aortic dissection may be indicated by chest and back pain, abnormal ECG findings, and signs of cardiac tamponade include low systolic blood pressure, elevated jugular venous pressure, and muffled heart sounds. Other conditions that may cause blackouts include severe hypoglycemia, Addisonian crisis, and electrolyte abnormalities.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting around 5% of patients over the age of 70-75 years and 10% of patients aged 80-85 years. While AF can cause palpitations and inefficient cardiac function, the most important aspect of managing patients with AF is reducing the increased risk of stroke.

AF can be classified as first detected episode, paroxysmal, persistent, or permanent. First detected episode refers to the initial occurrence of AF, regardless of symptoms or duration. Paroxysmal AF occurs when a patient has 2 or more self-terminating episodes lasting less than 7 days. Persistent AF refers to episodes lasting more than 7 days that do not self-terminate. Permanent AF is continuous atrial fibrillation that cannot be cardioverted or if attempts to do so are deemed inappropriate. The treatment goals for permanent AF are rate control and anticoagulation if appropriate.

Symptoms of AF include palpitations, dyspnea, and chest pain. The most common sign is an irregularly irregular pulse. An electrocardiogram (ECG) is essential for diagnosing AF, as other conditions can also cause an irregular pulse.

Managing patients with AF involves two key parts: rate/rhythm control and reducing stroke risk. Rate control involves slowing down the irregular pulse to avoid negative effects on cardiac function. This is typically achieved using beta-blockers or rate-limiting calcium channel blockers. If one drug is not effective, combination therapy may be used. Rhythm control aims to restore and maintain normal sinus rhythm through pharmacological or electrical cardioversion. However, the majority of patients are managed with a rate control strategy.

Reducing stroke risk in patients with AF is crucial. Risk stratifying tools, such as the CHA2DS2-VASc score, are used to determine the most appropriate anticoagulation strategy. Anticoagulation is recommended for patients with a score of 2 or more. Clinicians can choose between warfarin and novel oral anticoagulants (NOACs) for anticoagulation.

Before starting anticoagulation, the patient’s bleeding risk should be assessed using tools like the HAS-BLED score or the ORBIT tool. These tools evaluate factors such as hypertension, abnormal renal or liver function, history of bleeding, age, and use of drugs that predispose to bleeding.

A phaeochromocytoma is an uncommon functional tumor that develops from chromaffin cells in the adrenal medulla. Extra-adrenal paragangliomas, also known as extra-adrenal pheochromocytomas, are closely associated but less prevalent tumors that originate in the ganglia of the sympathetic nervous system. These tumors release catecholamines and result in a range of symptoms and indications linked to hyperactivity of the sympathetic nervous system.

Antihistamines do not help in treating the life-threatening aspects of anaphylaxis and should not be used instead of adrenaline. However, they can be used to relieve symptoms such as skin reactions and itching once the patient’s condition has stabilized. The appropriate dose of cetirizine for children between the ages of 2 and 6 is 2.5-5 mg. It is important to note that chlorpheniramine is no longer recommended. The recommended doses of oral cetirizine for different age groups are as follows: less than 2 years – 250 micrograms/kg, 2-6 years – 2.5-5 mg, 6-11 years – 5-10 mg, 12 years and older – 10-20 mg.

Further Reading:

Anaphylaxis is a severe and life-threatening allergic reaction that affects the entire body. It is characterized by a rapid onset and can lead to difficulty breathing, low blood pressure, and loss of consciousness. In paediatrics, anaphylaxis is often caused by food allergies, with nuts being the most common trigger. Other causes include drugs and insect venom, such as from a wasp sting.

When treating anaphylaxis, time is of the essence and there may not be enough time to look up medication doses. Adrenaline is the most important drug in managing anaphylaxis and should be administered as soon as possible. The recommended doses of adrenaline vary based on the age of the child. For children under 6 months, the dose is 150 micrograms, while for children between 6 months and 6 years, the dose remains the same. For children between 6 and 12 years, the dose is increased to 300 micrograms, and for adults and children over 12 years, the dose is 500 micrograms. Adrenaline can be repeated every 5 minutes if necessary.

The preferred site for administering adrenaline is the anterolateral aspect of the middle third of the thigh. This ensures quick absorption and effectiveness of the medication. It is important to follow the Resuscitation Council guidelines for anaphylaxis management, as they have recently been updated.

In some cases, it can be challenging to determine if a patient had a true episode of anaphylaxis. In such cases, serum tryptase levels may be measured, as they remain elevated for up to 12 hours following an acute episode of anaphylaxis. This can help confirm the diagnosis and guide further management.

Overall, prompt recognition and administration of adrenaline are crucial in managing anaphylaxis in paediatrics. Following the recommended doses and guidelines can help ensure the best outcomes for patients experiencing this severe allergic reaction.

This patient presents with symptoms and signs that are consistent with an atypical pneumonia, most likely caused by an infection with Mycoplasma pneumoniae. The clinical features of Mycoplasma pneumoniae infection include a flu-like illness that precedes respiratory symptoms, along with fever, myalgia, headache, diarrhea, and cough (initially dry but often becoming productive). Focal chest signs typically develop later in the course of the illness.

Mycoplasma pneumoniae infection is commonly associated with the development of erythema multiforme, a rash characterized by multiple red lesions on the limbs that evolve into target lesions a few days after the rash appears. Additionally, this infection can also cause Steven-Johnson syndrome. It is worth noting that haemolytic anaemia with cold agglutinins can complicate Mycoplasma pneumoniae infections, providing further evidence for the diagnosis.

The recommended first-line antibiotic for treating this case would be a macrolide, such as clarithromycin. Doxycycline can also be used but is generally considered a second-line option.

Women have three options when requesting emergency contraception. The first option is Levonelle 1.5 mg, which contains levonorgestrel and can be used up to 72 hours after unprotected sexual intercourse (UPSI). If vomiting occurs within 2 hours of taking the tablet, another one should be given. Levonelle mainly works by preventing ovulation.

The second option is ulipristal acetate, the newest treatment available. It can be used up to 120 hours after UPSI. If vomiting occurs within 3 hours of ingestion, another tablet should be given. Ulipristal acetate also works by inhibiting ovulation. However, it should be avoided in patients taking enzyme-inducing drugs, those with severe hepatic impairment, or those with severe asthma requiring oral steroids.

The third option is the copper IUD, which can be fitted up to 5 days after UPSI or ovulation, whichever is longer. The failure rate of the copper IUD is less than 1 in 1000, making it 10-20 times more effective than oral emergency contraceptive options. It is important to note that Levonelle and ulipristal may be less effective in women with higher BMIs.