Lidocaine is a medication that is available in a concentration of 10 mg per milliliter. The maximum recommended dose of lidocaine is 18 milliliters.

Further Reading:

Local anaesthetics, such as lidocaine, bupivacaine, and prilocaine, are commonly used in the emergency department for topical or local infiltration to establish a field block. Lidocaine is often the first choice for field block prior to central line insertion. These anaesthetics work by blocking sodium channels, preventing the propagation of action potentials.

However, local anaesthetics can enter the systemic circulation and cause toxic side effects if administered in high doses. Clinicians must be aware of the signs and symptoms of local anaesthetic systemic toxicity (LAST) and know how to respond. Early signs of LAST include numbness around the mouth or tongue, metallic taste, dizziness, visual and auditory disturbances, disorientation, and drowsiness. If not addressed, LAST can progress to more severe symptoms such as seizures, coma, respiratory depression, and cardiovascular dysfunction.

The management of LAST is largely supportive. Immediate steps include stopping the administration of local anaesthetic, calling for help, providing 100% oxygen and securing the airway, establishing IV access, and controlling seizures with benzodiazepines or other medications. Cardiovascular status should be continuously assessed, and conventional therapies may be used to treat hypotension or arrhythmias. Intravenous lipid emulsion (intralipid) may also be considered as a treatment option.

If the patient goes into cardiac arrest, CPR should be initiated following ALS arrest algorithms, but lidocaine should not be used as an anti-arrhythmic therapy. Prolonged resuscitation may be necessary, and intravenous lipid emulsion should be administered. After the acute episode, the patient should be transferred to a clinical area with appropriate equipment and staff for further monitoring and care.

It is important to report cases of local anaesthetic toxicity to the appropriate authorities, such as the National Patient Safety Agency in the UK or the Irish Medicines Board in the Republic of Ireland. Additionally, regular clinical review should be conducted to exclude pancreatitis, as intravenous lipid emulsion can interfere with amylase or lipase assays.

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 lower back or flank and radiating to the groin or genital area 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.

People experiencing renal or ureteric colic are usually restless and unable to find relief by lying still, which helps to distinguish this condition from peritonitis. They may have a history of previous episodes and may also present with fever and sweating if there is an associated urinary infection. Some individuals 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.

In terms of pain management, the first-line treatment for adults, children, and young people with suspected renal colic is a non-steroidal anti-inflammatory drug (NSAID), which can be administered through various routes. If NSAIDs are contraindicated or not providing sufficient pain relief, intravenous paracetamol can be offered as an alternative. Opioids may be considered if both NSAIDs and intravenous paracetamol are contraindicated or not effective in relieving pain. Antispasmodics should not be given to individuals with suspected renal colic.

For more detailed information, you can refer to the NICE guidelines on the assessment and management of renal and ureteric stones.

If the serum ascites albumin gradient (SAAG) is greater than 1.1 g/dL (or >11 g/L), it means that the ascites is caused by portal hypertension. On the other hand, a low gradient SAAG (< 1.1 g/dL or <11 g/L) indicates that the ascites is not associated with increased portal pressure and may be caused by conditions such as tuberculosis, pancreatitis, infections, serositis, various types of peritoneal cancers (peritoneal carcinomatosis), and pulmonary infarcts. Further Reading: Cirrhosis is a condition where the liver undergoes structural changes, resulting in dysfunction of its normal functions. It can be classified as either compensated or decompensated. Compensated cirrhosis refers to a stage where the liver can still function effectively with minimal symptoms, while decompensated cirrhosis is when the liver damage is severe and clinical complications are present. Cirrhosis develops over a period of several years due to repeated insults to the liver. Risk factors for cirrhosis include alcohol misuse, hepatitis B and C infection, obesity, type 2 diabetes, autoimmune liver disease, genetic conditions, certain medications, and other rare conditions. The prognosis of cirrhosis can be assessed using the Child-Pugh score, which predicts mortality based on parameters such as bilirubin levels, albumin levels, INR, ascites, and encephalopathy. The score ranges from A to C, with higher scores indicating a poorer prognosis. Complications of cirrhosis include portal hypertension, ascites, hepatic encephalopathy, variceal hemorrhage, increased infection risk, hepatocellular carcinoma, and cardiovascular complications. Diagnosis of cirrhosis is typically done through liver function tests, blood tests, viral hepatitis screening, and imaging techniques such as transient elastography or acoustic radiation force impulse imaging. Liver biopsy may also be performed in some cases. Management of cirrhosis involves treating the underlying cause, controlling risk factors, and monitoring for complications. Complications such as ascites, spontaneous bacterial peritonitis, oesophageal varices, and hepatic encephalopathy require specific management strategies. Overall, cirrhosis is a progressive condition that requires ongoing monitoring and management to prevent further complications and improve outcomes for patients.

The connection between latex sensitivity and food allergy is commonly known as the latex-fruit syndrome. Foods that have been found to be allergenic in relation to latex are categorized into high, moderate, or low risk groups.

High risk foods include banana, avocado, chestnut, and kiwi fruit.

Moderate risk foods include apple, carrot, celery, melon, papaya, potato, and tomato.

Citrus fruits and pears are considered to have a low risk of causing allergic reactions in individuals with latex sensitivity.

Neisseria gonorrhoeae is a type of bacteria that causes the sexually transmitted infection known as gonorrhoea. It is a Gram-negative diplococcus, meaning it appears as pairs of bacteria under a microscope. This infection is most commonly seen in individuals between the ages of 15 and 35, and it is primarily transmitted through sexual contact. One important characteristic of Neisseria gonorrhoeae is its ability to undergo antigenic variation, which means that recovering from an infection does not provide immunity and reinfection is possible.

When Neisseria gonorrhoeae infects the body, it first attaches to the genitourinary epithelium using pili, which are hair-like structures on the surface of the bacteria. It then invades the epithelial layer and triggers a local acute inflammatory response. In men, the clinical features of gonorrhoea often include urethritis (inflammation of the urethra) in about 80% of cases, dysuria (painful urination) in around 50% of cases, and mucopurulent discharge. Rectal infection may also occur, usually without symptoms, but it can cause anal discharge. Pharyngitis, or inflammation of the throat, is usually asymptomatic in men.

In women, the clinical features of gonorrhoea commonly include vaginal discharge in about 50% of cases, lower abdominal pain in around 25% of cases, dysuria in 10-15% of cases, and pelvic/lower abdominal tenderness in less than 5% of cases. Endocervical discharge and/or bleeding may also be present. Similar to men, rectal infection is usually asymptomatic but can cause anal discharge, and pharyngitis is usually asymptomatic in women as well.

Complications of Neisseria gonorrhoeae infection can be serious and include pelvic inflammatory disease (PID) in women, epididymo-orchitis or prostatitis in men, arthritis, dermatitis, pericarditis and/or myocarditis, hepatitis, and meningitis.

To diagnose gonorrhoea, samples of pus from the urethra, cervix, rectum, or throat should be collected and promptly sent to the laboratory in specialized transport medium. Traditionally, diagnosis has been made using Gram-stain and culture techniques, but newer PCR testing methods are becoming more commonly used.

If a patient with a zygoma fracture experiences visual disturbance, limited eye movements (especially upward gaze), or shows a teardrop sign on a facial X-ray, it is important to refer them urgently to ophthalmology or maxillofacial surgeons.

Further Reading:

Zygomatic injuries, also known as zygomatic complex fractures, involve fractures of the zygoma bone and often affect surrounding bones such as the maxilla and temporal bones. These fractures can be classified into four positions: the lateral and inferior orbital rim, the zygomaticomaxillary buttress, and the zygomatic arch. The full extent of these injuries may not be visible on plain X-rays and may require a CT scan for accurate diagnosis.

Zygomatic fractures can pose risks to various structures in the face. The temporalis muscle and coronoid process of the mandible may become trapped in depressed fractures of the zygomatic arch. The infraorbital nerve, which passes through the infraorbital foramen, can be injured in zygomaticomaxillary complex fractures. In orbital floor fractures, the inferior rectus muscle may herniate into the maxillary sinus.

Clinical assessment of zygomatic injuries involves observing facial asymmetry, depressed facial bones, contusion, and signs of eye injury. Visual acuity must be assessed, and any persistent bleeding from the nose or mouth should be noted. Nasal injuries, including septal hematoma, and intra-oral abnormalities should also be evaluated. Tenderness of facial bones and the temporomandibular joint should be assessed, along with any step deformities or crepitus. Eye and jaw movements must also be evaluated.

Imaging for zygomatic injuries typically includes facial X-rays, such as occipitomental views, and CT scans for a more detailed assessment. It is important to consider the possibility of intracranial hemorrhage and cervical spine injury in patients with facial fractures.

Management of most zygomatic fractures can be done on an outpatient basis with maxillofacial follow-up, assuming the patient is stable and there is no evidence of eye injury. However, orbital floor fractures should be referred immediately to ophthalmologists or maxillofacial surgeons. Zygomatic arch injuries that restrict mouth opening or closing due to entrapment of the temporalis muscle or mandibular condyle also require urgent referral. Nasal fractures, often seen in conjunction with other facial fractures, can be managed by outpatient ENT follow-up but should be referred urgently if there is uncontrolled epistaxis, CSF rhinorrhea, or septal hematoma.

Digoxin-specific antibody (DigiFab) is an antidote used to counteract digoxin overdose. It is a purified and sterile preparation of digoxin-immune ovine Fab immunoglobulin fragments. These fragments are derived from healthy sheep that have been immunized with a digoxin derivative called digoxin-dicarboxymethoxylamine (DDMA). DDMA is a digoxin analogue that contains the essential cyclopentanoperhydrophenanthrene: lactone ring moiety coupled to keyhole limpet hemocyanin (KLH).

DigiFab has a higher affinity for digoxin compared to the affinity of digoxin for its sodium pump receptor, which is believed to be the receptor responsible for its therapeutic and toxic effects. When administered to a patient who has overdosed on digoxin, DigiFab binds to digoxin molecules, reducing the levels of free digoxin in the body. This shift in equilibrium away from binding to the receptors helps to reduce the cardiotoxic effects of digoxin. The Fab-digoxin complexes are then eliminated from the body through the kidney and reticuloendothelial system.

The indications for using DigiFab in cases of acute and chronic digoxin toxicity are summarized below:

Acute digoxin toxicity:
– Cardiac arrest
– Life-threatening arrhythmia
– Potassium level >5 mmol/l
– Ingestion of >10 mg of digoxin (in adults)
– Ingestion of >4 mg of digoxin (in children)
– Digoxin level >12 ng/ml

Chronic digoxin toxicity:
– Cardiac arrest
– Life-threatening arrhythmia
– Significant gastrointestinal symptoms
– Symptoms of digoxin toxicity in the presence of renal failure

A fasting plasma glucose level of 7.0 mmol/l or higher is indicative of diabetes mellitus. However, it is important to note that hyperglycemia can also occur in individuals with acute infection, trauma, circulatory issues, or other forms of stress, and may only be temporary. Therefore, it is not recommended to diagnose diabetes based on a single test result, and the test should be repeated for confirmation.

Further Reading:

Diabetes Mellitus:
– Definition: a group of metabolic disorders characterized by persistent hyperglycemia caused by deficient insulin secretion, resistance to insulin, or both.
– Types: Type 1 diabetes (absolute insulin deficiency), Type 2 diabetes (insulin resistance and relative insulin deficiency), Gestational diabetes (develops during pregnancy), Other specific types (monogenic diabetes, diabetes secondary to pancreatic or endocrine disorders, diabetes secondary to drug treatment).
– Diagnosis: Type 1 diabetes diagnosed based on clinical grounds in adults presenting with hyperglycemia. Type 2 diabetes diagnosed in patients with persistent hyperglycemia and presence of symptoms or signs of diabetes.
– Risk factors for type 2 diabetes: obesity, inactivity, family history, ethnicity, history of gestational diabetes, certain drugs, polycystic ovary syndrome, metabolic syndrome, low birth weight.

Hypoglycemia:
– Definition: lower than normal blood glucose concentration.
– Diagnosis: defined by Whipple’s triad (signs and symptoms of low blood glucose, low blood plasma glucose concentration, relief of symptoms after correcting low blood glucose).
– Blood glucose level for hypoglycemia: NICE defines it as <3.5 mmol/L, but there is inconsistency across the literature.
– Signs and symptoms: adrenergic or autonomic symptoms (sweating, hunger, tremor), neuroglycopenic symptoms (confusion, coma, convulsions), non-specific symptoms (headache, nausea).
– Treatment options: oral carbohydrate, buccal glucose gel, glucagon, dextrose. Treatment should be followed by re-checking glucose levels.

Treatment of neonatal hypoglycemia:
– Treat with glucose IV infusion 10% given at a rate of 5 mL/kg/hour.
– Initial stat dose of 2 mL/kg over five minutes may be required for severe hypoglycemia.
– Mild asymptomatic persistent hypoglycemia may respond to a single dose of glucagon.
– If hypoglycemia is caused by an oral anti-diabetic drug, the patient should be admitted and ongoing glucose infusion or other therapies may be required.

Note: Patients who have a hypoglycemic episode with a loss of warning symptoms should not drive and should inform the DVLA.

Hepatitis B surface antigen (HBsAg) is a protein found on the surface of the hepatitis B virus. It is the first marker to appear in the blood after exposure to the virus, usually within 1 to 2 weeks. Symptoms of hepatitis B typically develop around 4 weeks after exposure. HBsAg can be detected in high levels in the blood during both acute and chronic hepatitis B infections. Its presence indicates that the person is infectious and can transmit the virus to others. The body naturally produces antibodies to HBsAg as part of the immune response to the infection. In fact, HBsAg is used to create the hepatitis B vaccine.

Hepatitis B surface antibody (anti-HBs) indicates that a person has recovered from a hepatitis B infection and is now immune to the virus. It can also develop in individuals who have been successfully vaccinated against hepatitis B.

Total hepatitis B core antibody (anti-HBc) appears at the onset of symptoms in acute hepatitis B and remains detectable for life. Its presence indicates that a person has either had a previous or ongoing infection with the hepatitis B virus, although the exact timing of the infection cannot be determined. Anti-HBc is not present in individuals who have received the hepatitis B vaccine.

IgM antibody to hepatitis B core antigen (IgM anti-HBc) indicates a recent or acute infection with the hepatitis B virus, typically within the past 6 months.

The intravascular volume of an infant is approximately 80 ml/kg, while in older children it is around 70 ml/kg. Dehydration itself does not lead to death, but shock can occur when there is a loss of 20 ml/kg from the intravascular space. Clinical dehydration becomes evident only after total losses greater than 25 ml/kg.

The table below summarizes the maintenance fluid requirements for well and normal children:

Bodyweight: First 10 kg
Daily fluid requirement: 100 ml/kg
Hourly fluid requirement: 4 ml/kg

Bodyweight: Second 10 kg
Daily fluid requirement: 50 ml/kg
Hourly fluid requirement: 2 ml/kg

Bodyweight: Subsequent kg
Daily fluid requirement: 20 ml/kg
Hourly fluid requirement: 1 ml/kg

For a well and normal child weighing less than 10 kg, the hourly maintenance fluid requirement is 4 ml/kg. Therefore, for this child, the hourly maintenance fluid requirement would be:

9 x 4 ml/hour = 36 ml/hour