Patients who have a STEMI caused by a blockage in the left circumflex artery (LCX) will usually show ST elevation in leads I and AVL. These leads correspond to the high lateral area of the heart, which is supplied by the LCX artery.

Further Reading:

Acute Coronary Syndromes (ACS) is a term used to describe a group of conditions that involve the sudden reduction or blockage of blood flow to the heart. This can lead to a heart attack or unstable angina. ACS includes ST segment elevation myocardial infarction (STEMI), non-ST segment elevation myocardial infarction (NSTEMI), and unstable angina (UA).

The development of ACS is usually seen in patients who already have underlying coronary heart disease. This disease is characterized by the buildup of fatty plaques in the walls of the coronary arteries, which can gradually narrow the arteries and reduce blood flow to the heart. This can cause chest pain, known as angina, during physical exertion. In some cases, the fatty plaques can rupture, leading to a complete blockage of the artery and a heart attack.

There are both non modifiable and modifiable risk factors for ACS. non modifiable risk factors include increasing age, male gender, and family history. Modifiable risk factors include smoking, diabetes mellitus, hypertension, hypercholesterolemia, and obesity.

The symptoms of ACS typically include chest pain, which is often described as a heavy or constricting sensation in the central or left side of the chest. The pain may also radiate to the jaw or left arm. Other symptoms can include shortness of breath, sweating, and nausea/vomiting. However, it’s important to note that some patients, especially diabetics or the elderly, may not experience chest pain.

The diagnosis of ACS is typically made based on the patient’s history, electrocardiogram (ECG), and blood tests for cardiac enzymes, specifically troponin. The ECG can show changes consistent with a heart attack, such as ST segment elevation or depression, T wave inversion, or the presence of a new left bundle branch block. Elevated troponin levels confirm the diagnosis of a heart attack.

The management of ACS depends on the specific condition and the patient’s risk factors. For STEMI, immediate coronary reperfusion therapy, either through primary percutaneous coronary intervention (PCI) or fibrinolysis, is recommended. In addition to aspirin, a second antiplatelet agent is usually given. For NSTEMI or unstable angina, the treatment approach may involve reperfusion therapy or medical management, depending on the patient’s risk of future cardiovascular events.

Theophylline is a medication used to treat severe asthma. It is a bronchodilator that comes in modified-release forms, which can maintain therapeutic levels in the blood for 12 hours. Theophylline works by inhibiting phosphodiesterase and blocking the breakdown of cyclic AMP. It also competes with adenosine on A1 and A2 receptors.

Achieving the right dose of theophylline can be challenging because there is a narrow range between therapeutic and toxic levels. The half-life of theophylline can be influenced by various factors, further complicating dosage adjustments. It is recommended to aim for serum levels of 10-20 mg/l six to eight hours after the last dose.

Unlike many other medications, the specific brand of theophylline can significantly impact its effects. Therefore, it is important to prescribe theophylline by both its brand name and generic name.

Several factors can increase the half-life of theophylline, including heart failure, cirrhosis, viral infections, and certain drugs. Conversely, smoking, heavy drinking, and certain medications can decrease the half-life of theophylline.

There are several drugs that can either increase or decrease the plasma concentration of theophylline. Calcium channel blockers, cimetidine, fluconazole, macrolides, methotrexate, and quinolones can increase the concentration. On the other hand, carbamazepine, phenobarbitol, phenytoin, rifampicin, and St. John’s wort can decrease the concentration.

The clinical symptoms of theophylline toxicity are more closely associated with acute overdose rather than chronic overexposure. Common symptoms include headache, dizziness, nausea, vomiting, abdominal pain, rapid heartbeat, dysrhythmias, seizures, mild metabolic acidosis, low potassium, low magnesium, low phosphates, abnormal calcium levels, and high blood sugar.

Seizures are more prevalent in acute overdose cases, while chronic overdose typically presents with minimal gastrointestinal symptoms. Cardiac dysrhythmias are more common in chronic overdose situations compared to acute overdose.

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.

A recognized criterion for referral to the burns unit is when a burn involves the upper limb, any burn that has not healed in 7 days, any burn with significant blistering, a burn with a pain score on presentation greater than 8 out of 10 on a visual analogue scale, or a burn that covers 3% or more of the total body surface area in an adult.

Further Reading:

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.

During the third trimester of pregnancy, the use of selective serotonin reuptake inhibitors (SSRIs) has been associated with a discontinuation syndrome and persistent pulmonary hypertension of the newborn. It is important to be aware of the adverse effects of various drugs during pregnancy. For example, ACE inhibitors like ramipril, if given in the second and third trimester, can cause hypoperfusion, renal failure, and the oligohydramnios sequence. Aminoglycosides such as gentamicin can lead to ototoxicity and deafness. High doses of aspirin can result in first-trimester abortions, delayed onset labor, premature closure of the fetal ductus arteriosus, and fetal kernicterus. However, low doses (e.g., 75 mg) do not pose significant risks. Late administration of benzodiazepines like diazepam during pregnancy can cause respiratory depression and a neonatal withdrawal syndrome. Calcium-channel blockers, if given in the first trimester, may cause phalangeal abnormalities, while their use in the second and third trimester can lead to fetal growth retardation. Carbamazepine has been associated with hemorrhagic disease of the newborn and neural tube defects. Chloramphenicol can cause grey baby syndrome. Corticosteroids, if given in the first trimester, may cause orofacial clefts. Danazol, if administered in the first trimester, can result in masculinization of the female fetuses genitals. Pregnant women should avoid handling crushed or broken tablets of finasteride as it can be absorbed through the skin and affect male sex organ development. Haloperidol, if given in the first trimester, may cause limb malformations, while its use in the third trimester increases the risk of extrapyramidal symptoms in the neonate. Heparin can lead to maternal bleeding and thrombocytopenia. Isoniazid can cause maternal liver damage and neuropathy and seizures in the neonate. Isotretinoin carries a high risk of teratogenicity, including multiple congenital malformations, spontaneous abortion, and intellectual disability. The use of lithium in the first trimester increases the risk of fetal cardiac malformations, while its use in the second and third trimesters can result in hypotonia, lethargy, feeding problems, hypothyroidism, goiter, and nephrogenic diabetes insipidus.

The Royal College of Emergency Medicine (RCEM) recommends asking four important questions to individuals showing signs and symptoms of carbon monoxide poisoning. These questions can be easily remembered using the acronym COMA. The questions are as follows:
1. Is anyone else in the house, including pets, experiencing similar symptoms?
2. Do the symptoms improve when you are outside of the house?
3. Are the boilers and cooking appliances in your house properly maintained?
4. Do you have a functioning carbon monoxide alarm?

Further Reading:

Carbon monoxide (CO) is a dangerous gas that is produced by the combustion of hydrocarbon fuels and can be found in certain chemicals. It is colorless and odorless, making it difficult to detect. In England and Wales, there are approximately 60 deaths each year due to accidental CO poisoning.

When inhaled, carbon monoxide binds to haemoglobin in the blood, forming carboxyhaemoglobin (COHb). It has a higher affinity for haemoglobin than oxygen, causing a left-shift in the oxygen dissociation curve and resulting in tissue hypoxia. This means that even though there may be a normal level of oxygen in the blood, it is less readily released to the tissues.

The clinical features of carbon monoxide toxicity can vary depending on the severity of the poisoning. Mild or chronic poisoning may present with symptoms such as headache, nausea, vomiting, vertigo, confusion, and weakness. More severe poisoning can lead to intoxication, personality changes, breathlessness, pink skin and mucosae, hyperpyrexia, arrhythmias, seizures, blurred vision or blindness, deafness, extrapyramidal features, coma, or even death.

To help diagnose domestic carbon monoxide poisoning, there are four key questions that can be asked using the COMA acronym. These questions include asking about co-habitees and co-occupants in the house, whether symptoms improve outside of the house, the maintenance of boilers and cooking appliances, and the presence of a functioning CO alarm.

Typical carboxyhaemoglobin levels can vary depending on whether the individual is a smoker or non-smoker. Non-smokers typically have levels below 3%, while smokers may have levels below 10%. Symptomatic individuals usually have levels between 10-30%, and severe toxicity is indicated by levels above 30%.

When managing carbon monoxide poisoning, the first step is to administer 100% oxygen. Hyperbaric oxygen therapy may be considered for individuals with a COHb concentration of over 20% and additional risk factors such as loss of consciousness, neurological signs, myocardial ischemia or arrhythmia, or pregnancy. Other management strategies may include fluid resuscitation, sodium bicarbonate for metabolic acidosis, and mannitol for cerebral edema.

Narrow QRS complex tachycardia is a term used to describe a fast heart rhythm with a pulse rate over 100 bpm and a QRS duration shorter than 120 ms.

Further Reading:

Supraventricular tachycardia (SVT) is a type of tachyarrhythmia that originates from the atria or above the bundle of His in the heart. It includes all atrial and junctional tachycardias, although atrial fibrillation is often considered separately. SVT typically produces a narrow QRS complex tachycardia on an electrocardiogram (ECG), unless there is an underlying conduction abnormality below the atrioventricular (AV) node. Narrow complex tachycardias are considered SVTs, while some broad complex tachycardias can also be SVTs with co-existent conduction delays.

SVT can be classified into three main subtypes based on where it arises: re-entrant accessory circuits (the most common type), atrial tachycardias, and junctional tachycardias. The most common SVTs are AVNRT (AV nodal re-entry tachycardia) and AVRT (AV re-entry tachycardia), which arise from accessory circuits within the heart. AVNRT involves an accessory circuit within the AV node itself, while AVRT involves an accessory pathway between the atria and ventricles that allows additional electrical signals to trigger the AV node.

Atrial tachycardias originate from abnormal foci within the atria, except for the SA node, AV node, or accessory pathway. Junctional tachycardias arise in the AV junction. The ECG features of SVTs vary depending on the type. Atrial tachycardias may have abnormal P wave morphology, an isoelectric baseline between P waves (in atrial flutter), and inverted P waves in certain leads. AVNRT may show pseudo R waves in V1 or pseudo S waves in certain leads, with an RP interval shorter than the PR interval. AVRT (WPW) may exhibit a delta wave on a resting ECG and retrograde P waves in the ST segment, with an RP interval shorter than the PR interval. Junctional tachycardias may have retrograde P waves before, during, or after the QRS complex, with inverted P waves in certain leads and upright P waves in others.

Treatment of SVT follows the 2021 resuscitation council algorithm for tachycardia with a pulse. The algorithm provides guidelines for managing stable patients with SVT.

In the UK, peptic ulcer disease is the leading cause of upper gastrointestinal bleeding. It surpasses all other listed causes combined in terms of prevalence.

Further Reading:

Upper gastrointestinal bleeding (UGIB) refers to the loss of blood from the gastrointestinal tract, occurring in the upper part of the digestive system. It can present as haematemesis (vomiting blood), coffee-ground emesis, bright red blood in the nasogastric tube, or melaena (black, tarry stools). UGIB can lead to significant hemodynamic compromise and is a major health burden, accounting for approximately 70,000 hospital admissions each year in the UK with a mortality rate of 10%.

The causes of UGIB vary, with peptic ulcer disease being the most common cause, followed by gastritis/erosions, esophagitis, and other less common causes such as varices, Mallory Weiss tears, and malignancy. Swift assessment, hemodynamic resuscitation, and appropriate interventions are essential for the management of UGIB.

Assessment of patients with UGIB should follow an ABCDE approach, and scoring systems such as the Glasgow-Blatchford bleeding score (GBS) and the Rockall score are recommended to risk stratify patients and determine the urgency of endoscopy. Transfusion may be necessary for patients with massive hemorrhage, and platelet transfusion, fresh frozen plasma (FFP), and prothrombin complex concentrate may be offered based on specific criteria.

Endoscopy plays a crucial role in the management of UGIB. Unstable patients with severe acute UGIB should undergo endoscopy immediately after resuscitation, while all other patients should undergo endoscopy within 24 hours of admission. Endoscopic treatment of non-variceal bleeding may involve mechanical methods of hemostasis, thermal coagulation, or the use of fibrin or thrombin with adrenaline. Proton pump inhibitors should only be used after endoscopy.

Variceal bleeding requires specific management, including the use of terlipressin and prophylactic antibiotics. Oesophageal varices can be treated with band ligation or transjugular intrahepatic portosystemic shunts (TIPS), while gastric varices may be treated with endoscopic injection of N-butyl-2-cyanoacrylate or TIPS if bleeding is not controlled.

For patients taking NSAIDs, aspirin, or clopidogrel, low-dose aspirin can be continued once hemostasis is achieved, NSAIDs should be stopped in patients presenting with UGIB.

Septic arthritis occurs when an infectious agent invades a joint, causing it to become purulent. The main symptoms of septic arthritis include pain in the affected joint, redness, warmth, and swelling of the joint, and difficulty moving the joint. Patients may also experience fever and systemic upset. The most common cause of septic arthritis is Staphylococcus aureus, but other bacteria such as Streptococcus spp., Haemophilus influenzae, Neisseria gonorrhoea, and Escherichia coli can also be responsible.

According to the current recommendations by NICE and the BNF, the initial treatment for septic arthritis is flucloxacillin. However, if a patient is allergic to penicillin, clindamycin can be used instead. If there is a suspicion of MRSA infection, vancomycin is the recommended choice. In cases where gonococcal arthritis or a Gram-negative infection is suspected, cefotaxime is the preferred treatment. The suggested duration of treatment is typically 4-6 weeks, although it may be longer if the infection is complicated.

Infantile hypertrophic pyloric stenosis is a condition characterized by the thickening and enlargement of the smooth muscle in the antrum of the stomach, leading to the narrowing of the pyloric canal. This narrowing can easily cause obstruction. It is a relatively common condition, occurring in about 1 in 500 live births, and is more frequently seen in males than females, with a ratio of 4 to 1. It is most commonly observed in first-born male children, although it can rarely occur in adults as well.

The main symptom of infantile hypertrophic pyloric stenosis is vomiting, which typically begins between 2 to 8 weeks of age. The vomit is usually non-bilious and forcefully expelled. It tends to occur around 30 to 60 minutes after feeding, leaving the baby hungry despite the vomiting. In some cases, there may be blood in the vomit. Other clinical features include persistent hunger, dehydration, weight loss, and constipation. An enlarged pylorus, often described as olive-shaped, can be felt in the right upper quadrant or epigastric in approximately 95% of cases. This is most noticeable at the beginning of a feed.

The typical acid-base disturbance seen in this condition is hypochloremic metabolic alkalosis. This occurs due to the loss of hydrogen and chloride ions in the vomit, as well as decreased secretion of pancreatic bicarbonate. The increased bicarbonate ions in the distal tubule of the kidney lead to the production of alkaline urine. Hyponatremia and hypokalemia are also commonly present.

Ultrasound scanning is the preferred diagnostic tool for infantile hypertrophic pyloric stenosis, as it is reliable and easy to perform. It has replaced barium studies as the investigation of choice.

Initial management involves fluid resuscitation, which should be tailored to the weight and degree of dehydration. Any electrolyte imbalances should also be corrected.

The definitive treatment for this condition is surgical intervention, with the Ramstedt pyloromyotomy being the procedure of choice. Laparoscopic pyloromyotomy is also an effective alternative if suitable facilities are available. The prognosis for infants with this condition is excellent, as long as there is no delay in diagnosis and treatment initiation.

Spontaneous bacterial peritonitis (SBP) is a serious infection that can occur in individuals with ascites, which is the accumulation of fluid in the abdominal cavity. In this case, the patient is a 42-year-old male intravenous drug user with a history of hepatitis C who has not received treatment. He presents to the emergency department with worsening abdominal distension, fever, and confusion.

To evaluate the patient, an abdominal paracentesis is performed, which involves removing a sample of the ascitic fluid for analysis. The findings from the ascitic fluid analysis can provide important information about the underlying cause of the patient’s symptoms.

In the given options, the finding that is indicative of spontaneous bacterial peritonitis (SBP) is an ascitic fluid absolute neutrophil count >250 cells/mm³. Neutrophils are a type of white blood cell that are typically elevated in the presence of infection. In SBP, there is an infection of the ascitic fluid, leading to an increase in neutrophils.

The other options provided do not specifically indicate SBP. An ascitic fluid absolute lymphocyte count >150 cells/mm³ may suggest a different type of infection or inflammation. An ascitic fluid absolute erythrocyte count >200 cells/mm³ may indicate bleeding into the ascitic fluid. An ascitic fluid albumin concentration of > 2.0 g/dL (20 g/L) and an ascitic fluid protein concentration of > 3.0 g/dL (30 g/L) may suggest liver disease or other causes of ascites, but they do not specifically indicate SBP.

Therefore, in this case, the presence of an ascitic fluid absolute neutrophil count >250 cells/mm³ is the finding that is indicative of spontaneous bacterial peritonitis (SBP).

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 ulnar nerve originates from the medial cord of the brachial plexus, specifically from the C8-T1 nerve roots. It may also carry fibers from C7 on occasion. This nerve has both motor and sensory functions.

In terms of motor function, the ulnar nerve innervates the muscles of the hand, excluding the thenar muscles and the lateral two lumbricals (which are supplied by the median nerve). It also innervates two muscles in the anterior forearm: the flexor carpi ulnaris and the medial half of the flexor digitorum profundus.

Regarding sensory function, the ulnar nerve provides innervation to the anterior and posterior surfaces of the medial one and a half fingers, as well as the associated palm and dorsal hand area. There are three sensory branches responsible for the cutaneous innervation of the ulnar nerve. Two of these branches arise in the forearm and travel into the hand: the palmar cutaneous branch, which innervates the skin of the medial half of the palm, and the dorsal cutaneous branch, which innervates the dorsal skin of the medial one and a half fingers and the associated dorsal hand. The third branch arises in the hand and is called the superficial branch, which innervates the palmar surface of the medial one and a half fingers.

When the ulnar nerve is damaged at the elbow, the flexor carpi ulnaris and the medial half of the flexor digitorum profundus muscles in the anterior forearm will be spared. However, if the ulnar nerve is injured at the wrist, these muscles will be affected. Additionally, when the ulnar nerve is damaged at the elbow, flexion of the wrist can still occur due to the intact median nerve, but it will be accompanied by abduction as the flexor carpi ulnaris adducts the hand. On the other hand, wrist flexion will be unaffected when the ulnar nerve is damaged at the wrist.

The sensory function also differs depending on the site of damage. When the ulnar nerve is damaged at the elbow, all three cutaneous branches will be affected, resulting in complete sensory loss in the areas innervated by the ulnar nerve. However, if the damage occurs at the wrist, the two branches that arise in the forearm may be spared.

Damage to the ulnar nerve at either the elbow or wrist leads to a characteristic claw hand appearance, characterized by hyperextension of the metacarpophalangeal joints and flexion of the distal and proximal interphalangeal joint of the little and ring fingers.

This infant is displaying prolonged jaundice and failure to thrive. Prolonged jaundice is defined as jaundice that persists beyond the first 14 days of life. Neonatal jaundice can be divided into two categories: unconjugated hyperbilirubinemia, which can be either physiological or pathological, and conjugated hyperbilirubinemia, which is always pathological.

Causes of prolonged unconjugated hyperbilirubinemia include breast milk jaundice, infections (particularly urinary tract infections), haemolysis (most commonly rhesus haemolytic disease), hypothyroidism, hereditary disorders (such as Crigler-Najjar syndrome), and galactosemia.

Causes of prolonged conjugated hyperbilirubinemia include biliary atresia, choledochal cysts, and neonatal hepatitis. Conjugated hyperbilirubinemia often presents with symptoms such as failure to thrive, easy bruising or bleeding tendency, dark urine, and pale, chalky stools.

In this case, the jaundice is clearly conjugated, and the only cause of prolonged conjugated hyperbilirubinemia listed is biliary atresia. To evaluate conjugated hyperbilirubinemia, an ultrasound of the bile ducts and gallbladder should be performed. If dilatation is observed, it may indicate the presence of choledochal cysts, which should be further investigated with a cholangiogram. If the bile ducts and gallbladder appear normal or are not visualized, a radionuclide scan is often conducted. The absence of excretion on the scan is consistent with biliary atresia.

Biliary atresia is a condition characterized by progressive destruction or absence of the extrahepatic biliary tree and intrahepatic biliary ducts. It is a rare condition, occurring in approximately 1 in 10-15,000 live births in the western world. Infants with biliary atresia typically exhibit jaundice early on, and their stools are pale while their urine is dark starting from the second day of life. If left untreated, the condition will progress to chronic liver failure, leading to portal hypertension and hepatosplenomegaly. Without treatment, death is inevitable.

Amiodarone is a medication that can have numerous harmful side effects, making it crucial to conduct a comprehensive clinical assessment before starting treatment with it. Some of the side effects associated with amiodarone include corneal microdeposits, photosensitivity, nausea, sleep disturbance, hyperthyroidism, hypothyroidism, acute hepatitis and jaundice, peripheral neuropathy, lung fibrosis, QT prolongation, and optic neuritis (although this is very rare). If optic neuritis occurs, immediate discontinuation of amiodarone is necessary to prevent the risk of blindness.

The majority of patients taking amiodarone experience corneal microdeposits, but these typically resolve after treatment is stopped and rarely affect vision. Amiodarone has a chemical structure similar to thyroxine and can bind to the nuclear thyroid receptor, leading to both hypothyroidism and hyperthyroidism. However, hypothyroidism is more commonly observed, affecting around 5-10% of patients.

Wernicke’s encephalopathy is a condition that is commonly associated with alcohol abuse and other causes of thiamine deficiency. It is characterized by a classic triad of symptoms, which include acute confusion, ophthalmoplegia (paralysis or weakness of the eye muscles), and ataxia (loss of coordination and balance). Additional possible features of this condition may include papilloedema (swelling of the optic disc), hearing loss, apathy, dysphagia (difficulty swallowing), memory impairment, and hypothermia. In the majority of cases, peripheral neuropathy (nerve damage) is also observed, typically affecting the legs.

The condition is marked by the presence of acute capillary haemorrhages, astrocytosis (abnormal increase in astrocytes, a type of brain cell), and neuronal death in the upper brainstem and diencephalon. These abnormalities can be visualized using MRI scanning, while CT scanning is not very useful for diagnosis.

If left untreated, most patients with Wernicke’s encephalopathy will go on to develop a Korsakoff psychosis. This condition is characterized by retrograde amnesia (difficulty remembering past events), an inability to memorize new information, disordered time appreciation, and confabulation (fabrication of false memories).

SSPE, also known as subacute sclerosing panencephalitis, is a serious and potentially deadly complication that can occur as a result of measles. While pneumonia and otitis media are commonly seen complications of measles, SSPE is much rarer. This condition involves inflammation of the brain and is believed to occur either due to the reactivation of the measles virus or an abnormal immune response to the virus.

Further Reading:

Measles is a highly contagious viral infection caused by an RNA paramyxovirus. It is primarily spread through aerosol transmission, specifically through droplets in the air. The incubation period for measles is typically 10-14 days, during which patients are infectious from 4 days before the appearance of the rash to 4 days after.

Common complications of measles include pneumonia, otitis media (middle ear infection), and encephalopathy (brain inflammation). However, a rare but fatal complication called subacute sclerosing panencephalitis (SSPE) can also occur, typically presenting 5-10 years after the initial illness.

The onset of measles is characterized by a prodrome, which includes symptoms such as irritability, malaise, conjunctivitis, and fever. Before the appearance of the rash, white spots known as Koplik spots can be seen on the buccal mucosa. The rash itself starts behind the ears and then spreads to the entire body, presenting as a discrete maculopapular rash that becomes blotchy and confluent.

In terms of complications, encephalitis typically occurs 1-2 weeks after the onset of the illness. Febrile convulsions, giant cell pneumonia, keratoconjunctivitis, corneal ulceration, diarrhea, increased incidence of appendicitis, and myocarditis are also possible complications of measles.

When managing contacts of individuals with measles, it is important to offer the MMR vaccine to children who have not been immunized against measles. The vaccine-induced measles antibody develops more rapidly than that following natural infection, so it should be administered within 72 hours of contact.

Every year in the UK, 5,000 individuals lose their lives to suicide. Shockingly, only 25% of these individuals were known to receive specialized mental health services. The demographic with the highest suicide rates is men aged between 30 and 60, but there is a concerning increase in rates among teenagers aged 15 to 19.

It is crucial for doctors to be able to identify and provide support to patients who suffer from severe depression or other mental health issues, as they are at a higher risk of suicide. Certain factors significantly increase the risk of suicide, including a history of self-harm, previous mental illness, being male, experiencing severe depression, and substance abuse. It is important to note that combinations of these risk factors are more significant than individual factors alone.

Despite the belief that hospital admission provides a safe environment, the risk of suicide remains high for inpatients. Additionally, the risk remains elevated in the months following discharge from the hospital.

On the other hand, there are protective factors that decrease the likelihood of suicide. These include having dependent children, having family members who would be deeply affected by the loss, and having religious beliefs.

The recommended target SpO2, which measures the percentage of oxygen saturation in the blood, following a cardiac arrest is 94-98%. This range ensures that the patient receives adequate oxygenation without the risk of hyperoxia, which is an excess of oxygen in the body.

Further Reading:

Cardiopulmonary arrest is a serious event with low survival rates. In non-traumatic cardiac arrest, only about 20% of patients who arrest as an in-patient survive to hospital discharge, while the survival rate for out-of-hospital cardiac arrest is approximately 8%. The Resus Council BLS/AED Algorithm for 2015 recommends chest compressions at a rate of 100-120 per minute with a compression depth of 5-6 cm. The ratio of chest compressions to rescue breaths is 30:2.

After a cardiac arrest, the goal of patient care is to minimize the impact of post cardiac arrest syndrome, which includes brain injury, myocardial dysfunction, the ischaemic/reperfusion response, and the underlying pathology that caused the arrest. The ABCDE approach is used for clinical assessment and general management. Intubation may be necessary if the airway cannot be maintained by simple measures or if it is immediately threatened. Controlled ventilation is aimed at maintaining oxygen saturation levels between 94-98% and normocarbia. Fluid status may be difficult to judge, but a target mean arterial pressure (MAP) between 65 and 100 mmHg is recommended. Inotropes may be administered to maintain blood pressure. Sedation should be adequate to gain control of ventilation, and short-acting sedating agents like propofol are preferred. Blood glucose levels should be maintained below 8 mmol/l. Pyrexia should be avoided, and there is some evidence for controlled mild hypothermia but no consensus on this.

Post ROSC investigations may include a chest X-ray, ECG monitoring, serial potassium and lactate measurements, and other imaging modalities like ultrasonography, echocardiography, CTPA, and CT head, depending on availability and skills in the local department. Treatment should be directed towards the underlying cause, and PCI or thrombolysis may be considered for acute coronary syndrome or suspected pulmonary embolism, respectively.

Patients who are comatose after ROSC without significant pre-arrest comorbidities should be transferred to the ICU for supportive care. Neurological outcome at 72 hours is the best prognostic indicator of outcome.

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, normal children:

Bodyweight:
– First 10 kg: Daily fluid requirement of 100 ml/kg and hourly fluid requirement of 4 ml/kg.
– Second 10 kg: Daily fluid requirement of 50 ml/kg and hourly fluid requirement of 2 ml/kg.
– Subsequent kg: Daily fluid requirement of 20 ml/kg and hourly fluid requirement of 1 ml/kg.

Based on this information, the hourly maintenance fluid requirements for this child can be calculated as follows:

– First 10 kg: 4 ml/kg = 40 ml
– Second 10 kg: 2 ml/kg = 20 ml
– Subsequent kg: 1 ml/kg = 5 ml

Therefore, the total hourly maintenance fluid requirement for this child is 65 ml.

Bell’s palsy is a condition characterized by a facial paralysis that affects the lower motor neurons. It can be distinguished from an upper motor neuron lesion by the inability to raise the eyebrow and the involvement of the upper facial muscles.

One distinctive feature of Bell’s palsy is the occurrence of Bell’s phenomenon, which refers to the upward and outward rolling of the eye on the affected side when attempting to close the eye and bare the teeth.

Approximately 80% of sudden onset lower motor neuron facial palsies are attributed to Bell’s palsy. It is believed that this condition is caused by swelling of the facial nerve within the petrous temporal bone, which is secondary to a latent herpesvirus, specifically HSV-1 and HZV.

Unlike some other conditions, Bell’s palsy does not lead to sensorineural deafness and tinnitus.

Treatment options for Bell’s palsy include the use of steroids and acyclovir.

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.

This woman is experiencing hypoglycemia, most likely due to her treatment with glibenclamide. Hypoglycemia is defined as having a blood glucose level below 3.0 mmol/l, and it is crucial to promptly treat this condition to prevent further complications such as seizures, stroke, or heart problems.

If the patient is conscious and able to swallow, a fast-acting carbohydrate like sugar or GlucoGel can be given orally. However, since this woman is unconscious, this option is not feasible.

In cases where intravenous access is available, like in this situation, an intravenous bolus of dextrose should be administered. The recommended doses are either 75 mL of 20% dextrose or 150 mL of 10% dextrose.

When a patient is at home and intravenous access is not possible, the preferred initial treatment is glucagon. Under these circumstances, 1 mg of glucagon can be given either intramuscularly (IM) or subcutaneously (SC).

It is important to note that immediate action is necessary to address hypoglycemia and prevent any potential complications.

Two types of tapeworms, Taenia solium and Taenia saginata, can infest humans. Infestation occurs when people consume meat from intermediate hosts that contain the parasite’s tissue stages. Tapeworms compete for nutrients and infestation is often without symptoms. However, in more severe cases, individuals may experience epigastric pain, diarrhea, and vomiting. Diagnosis involves identifying characteristic eggs in the patient’s stool.

Taenia solium infestation can also lead to a condition called cysticercosis. This occurs when larval cysts infiltrate and spread throughout the lung, liver, eye, or brain. Cysticercosis presents with neurological symptoms, seizures, and impaired vision. Confirmation of cysticercosis involves the presence of antibodies and imaging tests such as chest X-rays and CT brain scans.

The treatment for tapeworm infestation is highly effective and involves the use of medications like niclosamide or praziquantel. However, it is important to seek specialist advice when managing Taenia infections in the central nervous system, as severe inflammatory reactions can occur.

Hypomagnesaemia frequently occurs alongside hypokalaemia. It is important to note that potassium levels may not improve with supplementation until the magnesium deficiency is addressed.

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.

FAST scans consist of four standard views that are obtained to assess different areas of the body. These views include the right upper quadrant (RUQ), left upper quadrant (LUQ), pericardial sac, and the pelvis.

In the RUQ view, the focus is on the right flank or peri-hepatic area, which includes Morison’s pouch and the right costophrenic pleural recess.

The LUQ view examines the left flank or peri-splenic area, which includes the spleen-renal recess and the left costophrenic pleural space.

The pericardial sac is also assessed to evaluate any abnormalities in this area.

Lastly, the pelvis is examined in two planes to ensure a comprehensive evaluation.

In addition to these four standard views, an anterior pleural view is often performed alongside the others. This view used to be part of the extended FAST (eFAST) scan but is now commonly included routinely.

Further Reading:

Abdominal trauma can be classified into two categories: blunt trauma and penetrating trauma. Blunt trauma occurs when compressive or deceleration forces are applied to the abdomen, often resulting from road traffic accidents or direct blows during sports. The spleen and liver are the organs most commonly injured in blunt abdominal trauma. On the other hand, penetrating trauma involves injuries that pierce the skin and enter the abdominal cavity, such as stabbings, gunshot wounds, or industrial accidents. The bowel and liver are the organs most commonly affected in penetrating injuries.

When it comes to imaging in blunt abdominal trauma, there are three main modalities that are commonly used: focused assessment with sonography in trauma (FAST), diagnostic peritoneal lavage (DPL), and computed tomography (CT). FAST is a non-invasive and quick method used to detect free intraperitoneal fluid, aiding in the decision on whether a laparotomy is needed. DPL is also used to detect intraperitoneal blood and can be used in both unstable blunt abdominal trauma and penetrating abdominal trauma. However, it is more invasive and time-consuming compared to FAST and has largely been replaced by it. CT, on the other hand, is the gold standard for diagnosing intra-abdominal pathology and is used in stable abdominal trauma patients. It offers high sensitivity and specificity but requires a stable and cooperative patient. It also involves radiation and may have delays in availability.

In the case of penetrating trauma, it is important to assess these injuries with the help of a surgical team. Penetrating objects should not be removed in the emergency department as they may be tamponading underlying vessels. Ideally, these injuries should be explored in the operating theater.

In summary, abdominal trauma can be classified into blunt trauma and penetrating trauma. Blunt trauma is caused by compressive or deceleration forces and commonly affects the spleen and liver. Penetrating trauma involves injuries that pierce the skin and commonly affect the bowel and liver. Imaging modalities such as FAST, DPL, and CT are used to assess and diagnose abdominal trauma, with CT being the gold standard. Penetrating injuries should be assessed by a surgical team and should ideally be explored in the operating theater.

Thyroid storm, also known as thyrotoxic crisis, is a rare and dangerous complication of hyperthyroidism. The initial management of this condition involves the use of specific medications. These medications include a beta blocker, a corticosteroid, an antithyroid drug, and an iodine solution.

The beta blocker used is typically propranolol, which is administered intravenously at a dose of 1 mg over 1 minute. If a beta blocker is contraindicated, a calcium channel blocker such as diltiazem may be used instead, at a dose of 0.25 mg/kg over 2 minutes.

For corticosteroids, hydrocortisone is commonly used and given intravenously at a dose of 200 mg. Alternatively, dexamethasone can be used at a dose of 2 mg intravenously.

The antithyroid drug used is usually propylthiouracil, which is given orally, through a nasogastric tube, or rectally, at a dose of 200 mg.

An iodine solution, specifically Lugol’s iodine, is also part of the initial management. However, it should not be administered until at least 1 hour after the antithyroid drug has been given. This is because iodine can exacerbate thyrotoxicosis by stimulating thyroid hormone synthesis. Propylthiouracil, on the other hand, inhibits the normal interactions of iodine and peroxidase with thyroglobulin, preventing the formation of T4 and T3. Therefore, it is given first and allowed time to take effect before iodine is administered.

Further Reading:

The thyroid gland is an endocrine organ located in the anterior neck. It consists of two lobes connected by an isthmus. The gland produces hormones called thyroxine (T4) and triiodothyronine (T3), which regulate energy use, protein synthesis, and the body’s sensitivity to other hormones. The production of T4 and T3 is stimulated by thyroid-stimulating hormone (TSH) secreted by the pituitary gland, which is in turn stimulated by thyrotropin-releasing hormone (TRH) from the hypothalamus.

Thyroid disorders can occur when there is an imbalance in the production or regulation of thyroid hormones. Hypothyroidism is characterized by a deficiency of thyroid hormones, while hyperthyroidism is characterized by an excess. The most common cause of hypothyroidism is autoimmune thyroiditis, also known as Hashimoto’s thyroiditis. It is more common in women and is often associated with goiter. Other causes include subacute thyroiditis, atrophic thyroiditis, and iodine deficiency. On the other hand, the most common cause of hyperthyroidism is Graves’ disease, which is also an autoimmune disorder. Other causes include toxic multinodular goiter and subacute thyroiditis.

The symptoms and signs of thyroid disorders can vary depending on whether the thyroid gland is underactive or overactive. In hypothyroidism, common symptoms include weight gain, lethargy, cold intolerance, and dry skin. In hyperthyroidism, common symptoms include weight loss, restlessness, heat intolerance, and increased sweating. Both hypothyroidism and hyperthyroidism can also affect other systems in the body, such as the cardiovascular, gastrointestinal, and neurological systems.

Complications of thyroid disorders can include dyslipidemia, metabolic syndrome, coronary heart disease, heart failure, subfertility and infertility, impaired special senses, and myxedema coma in severe cases of hypothyroidism. In hyperthyroidism, complications can include Graves’ orbitopathy, compression of the esophagus or trachea by goiter, thyrotoxic periodic paralysis, arrhythmias, osteoporosis, mood disorders, and increased obstetric complications.

Myxedema coma is a rare and life-threatening complication of severe hypothyroidism. It can be triggered by factors such as infection or physiological insult and presents with lethargy, bradycardia, hypothermia, hypotension, hypoventilation, altered mental state, seizures and/or coma.

Epididymo-orchitis refers to the inflammation of the testis and epididymis caused by an infectious source. The most common way of infection is through local extension, often resulting from infections spreading from the urethra or bladder.

In individuals below the age of 35, sexually transmitted pathogens like Chlamydia trachomatis and Neisseria gonorrhoeae are the primary causes. On the other hand, in individuals over the age of 35, non-sexually transmitted infections caused by Gram-negative enteric organisms that lead to urinary tract infections are more common.

Typically, patients with epididymo-orchitis experience sudden onset of unilateral scrotal pain and swelling. The affected testis is tender to touch, and there is usually a noticeable swelling of the epididymis that starts at the lower pole of the testis and spreads towards the upper pole. The testis itself may also be affected, and there may be redness and/or swelling of the scrotum on the affected side. Patients may have a fever and may also have urethral discharge.

It is crucial to consider testicular torsion as the most important differential diagnosis. This should be taken into account for all patients with sudden testicular pain, as the testicle needs to be saved within 6 hours of onset. Torsion is more likely in men under the age of 20, especially if the pain is extremely acute and severe. Typically, torsion presents around four hours after onset. In this case, the patient’s age, longer history of symptoms, and the presence of fever are more indicative of epididymo-orchitis.

Osgood-Schlatter disease is commonly observed in active teenagers and is characterized by pain and tenderness in the tibial tuberosity. Rest is typically recommended as part of the treatment plan, and the diagnosis is made based on clinical evaluation.

Chondromalacia patella is most prevalent in teenage girls and is often accompanied by knee pain while going up and downstairs. Discomfort tends to worsen after prolonged periods of sitting. Treatment options include pain relief medication and physiotherapy.

Prepatellar bursitis, also known as housemaid’s knee, is linked to excessive kneeling.

Pseudogout is an inflammatory arthritis caused by the accumulation of pyrophosphate crystals. While the knees are frequently affected, it is unlikely to occur in this age group.

Still’s disease accounts for approximately 10% of cases of juvenile chronic arthritis. It typically involves multiple systems in the body and is often characterized by fever, rash, swollen lymph nodes, and joint pain.

Ketamine induces a distinct type of sedation known as dissociative sedation. This sedation state is unlike any other and is characterized by a trance-like, cataleptic condition. It provides deep pain relief and memory loss while still maintaining important protective reflexes for the airway, spontaneous breathing, and overall stability of the heart and lungs. Dissociative sedation with ketamine does not fit into the conventional categories of sedation.

Further Reading:

Procedural sedation is commonly used by emergency department (ED) doctors to minimize pain and discomfort during procedures that may be painful or distressing for patients. Effective procedural sedation requires the administration of analgesia, anxiolysis, sedation, and amnesia. This is typically achieved through the use of a combination of short-acting analgesics and sedatives.

There are different levels of sedation, ranging from minimal sedation (anxiolysis) to general anesthesia. It is important for clinicians to understand the level of sedation being used and to be able to manage any unintended deeper levels of sedation that may occur. Deeper levels of sedation are similar to general anesthesia and require the same level of care and monitoring.

Various drugs can be used for procedural sedation, including propofol, midazolam, ketamine, and fentanyl. Each of these drugs has its own mechanism of action and side effects. Propofol is commonly used for sedation, amnesia, and induction and maintenance of general anesthesia. Midazolam is a benzodiazepine that enhances the effect of GABA on the GABA A receptors. Ketamine is an NMDA receptor antagonist and is used for dissociative sedation. Fentanyl is a highly potent opioid used for analgesia and sedation.

The doses of these drugs for procedural sedation in the ED vary depending on the drug and the route of administration. It is important for clinicians to be familiar with the appropriate doses and onset and peak effect times for each drug.

Safe sedation requires certain requirements, including appropriate staffing levels, competencies of the sedating practitioner, location and facilities, and monitoring. The level of sedation being used determines the specific requirements for safe sedation.

After the procedure, patients should be monitored until they meet the criteria for safe discharge. This includes returning to their baseline level of consciousness, having vital signs within normal limits, and not experiencing compromised respiratory status. Pain and discomfort should also be addressed before discharge.

Calcium-channel blocker overdose is a serious condition that should always be taken seriously as it can be potentially life-threatening. The two most dangerous types of calcium channel blockers in overdose are verapamil and diltiazem. These medications work by binding to the alpha-1 subunit of L-type calcium channels, which prevents the entry of calcium into the cells. These channels play a crucial role in the functioning of cardiac myocytes, vascular smooth muscle cells, and islet beta-cells.

Significant toxicity can occur with the ingestion of more than 10 tablets of verapamil (160 mg or 240 mg immediate or sustained-release capsules) or diltiazem (180 mg, 240 mg or 360 mg immediate or sustained-release capsules). In children, even 1-2 tablets of immediate or sustained-release verapamil or diltiazem can be harmful. Symptoms usually appear within 1-2 hours of taking standard preparations, but with slow-release versions, the onset of severe toxicity may be delayed by 12-16 hours, with peak effects occurring after 24 hours.

The main clinical manifestations of calcium-channel blocker overdose include nausea and vomiting, low blood pressure, slow heart rate and first-degree heart block, heart muscle ischemia and stroke, kidney failure, pulmonary edema, and high blood sugar levels.

When managing a patient with calcium-channel blocker overdose, certain bedside investigations are crucial. These include checking blood glucose levels, performing an electrocardiogram (ECG), and obtaining an arterial blood gas sample. Additional investigations that can provide helpful information include assessing urea and electrolyte levels, conducting a chest X-ray to check for pulmonary edema, and performing an echocardiography.