The most common cause of infective endocarditis is Staphylococcus aureus, especially in acute presentations and among intravenous drug users. However, if the patient has undergone valve replacement surgery more than 2 months ago, the spectrum of organisms causing endocarditis returns to normal, making Staphylococcus epidermidis less likely. While Streptococcus bovis can also cause endocarditis, it is not as common as Staphylococcus aureus and is associated with colon cancer. Staphylococcus epidermidis is the most common cause of endocarditis within 2 months post-valvular surgery. On the other hand, Streptococcus mitis, a viridans streptococcus found in the mouth, is associated with endocarditis following dental procedures or in patients with poor dental hygiene.

Aetiology of Infective Endocarditis

Infective endocarditis is a condition that affects patients with previously normal valves, rheumatic valve disease, prosthetic valves, congenital heart defects, intravenous drug users, and those who have recently undergone piercings. The strongest risk factor for developing infective endocarditis is a previous episode of the condition. The mitral valve is the most commonly affected valve.

The most common cause of infective endocarditis is Staphylococcus aureus, particularly in acute presentations and intravenous drug users. Historically, Streptococcus viridans was the most common cause, but this is no longer the case except in developing countries. Streptococcus mitis and Streptococcus sanguinis are the two most notable viridans streptococci, commonly found in the mouth and dental plaque. Coagulase-negative Staphylococci such as Staphylococcus epidermidis are the most common cause of endocarditis in patients following prosthetic valve surgery.

Streptococcus bovis is associated with colorectal cancer, with the subtype Streptococcus gallolyticus being most linked to the condition. Non-infective causes of endocarditis include systemic lupus erythematosus and malignancy. Culture negative causes may be due to prior antibiotic therapy or infections caused by Coxiella burnetii, Bartonella, Brucella, or HACEK organisms (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella).

Inhibitory Postsynaptic Potentials (IPSPs)

Inhibitory postsynaptic potentials (IPSPs) are electrical charges generated in response to synaptic input that prevent the generation of additional action potentials in the postsynaptic neuron. This potential is generated after the postsynaptic action potential has fired, causing the membrane potential to become more negative, similar to the refractory period in the action potential sequence of events. IPSPs can be produced by the opening of chemical-gated potassium channels or GABA receptor chloride channels. The end result is a push of the membrane potential to a more negative charge, decreasing the likelihood of additional stimuli depolarizing it.

IPSPs are the opposite of excitatory postsynaptic potentials (EPSPs), which promote the generation of additional postsynaptic action potentials. It is important to note that only hyperpolarization of the postsynaptic membrane following neurotransmitter binding is correct. The other options are physiologically nonsensical.

The first-line treatment for syphilis is intramuscular benzathine penicillin, which is the correct management for the most likely diagnosis based on the patient’s symptoms of rash, lymphadenopathy, buccal ulcers, and condylomata, indicating secondary syphilis. The presence of a palmar rash is highly indicative of syphilis, although HIV should also be tested for as it can coexist with syphilis and present with similar symptoms. Cryotherapy is a treatment option for genital warts, but the flat white appearance of the wart-like lesions described here suggests they are more likely to be condylomata lata. The suggestion of no specific treatment except hydration and rest is incorrect, as this would only be appropriate for self-limiting viral illnesses such as Epstein-Barr virus, which is a potential differential diagnosis but less likely given the characteristic rash and history of the patient.

Management of Syphilis

Syphilis can be effectively managed with intramuscular benzathine penicillin as the first-line treatment. In cases where penicillin cannot be used, doxycycline may be used as an alternative. After treatment, nontreponemal titres such as rapid plasma reagin (RPR) or Venereal Disease Research Laboratory (VDRL) should be monitored to assess the response. A fourfold decline in titres is often considered an adequate response to treatment.

It is important to note that the Jarisch-Herxheimer reaction may occur following treatment. This reaction is characterized by fever, rash, and tachycardia after the first dose of antibiotic. Unlike anaphylaxis, there is no wheezing or hypotension. The reaction is thought to be due to the release of endotoxins following bacterial death and typically occurs within a few hours of treatment. However, no treatment is needed other than antipyretics if required.

In summary, the management of syphilis involves the use of intramuscular benzathine penicillin or doxycycline as an alternative. Nontreponemal titres should be monitored after treatment, and the Jarisch-Herxheimer reaction may occur but does not require treatment unless symptomatic.

The presence of fever, headache, and a focal neurological deficit, such as arm weakness, suggests a brain abscess as the correct diagnosis. Additionally, the patient’s history of seizures supports this diagnosis. However, diagnosing a brain abscess can be challenging, as the classic triad of symptoms is only present in a minority of cases. Epilepsy is unlikely due to the presence of fever and arm weakness, and the absence of a seizure history. Hypoglycemia is not the correct answer as the patient’s blood glucose level is within the normal range. Meningitis is a key differential diagnosis, but it is less likely to cause focal neurological abnormalities and tends to present with reduced consciousness or confusion in addition to fever and headache.

Understanding Brain Abscesses

Brain abscesses can occur due to various reasons such as sepsis from middle ear or sinuses, head injuries, and endocarditis. The symptoms of brain abscesses depend on the location of the abscess, with those in critical areas presenting earlier. Brain abscesses can cause a considerable mass effect in the brain, leading to raised intracranial pressure. Symptoms of brain abscesses include dull and persistent headaches, fever, focal neurology, nausea, papilloedema, and seizures.

To diagnose brain abscesses, doctors may perform imaging with CT scanning. Treatment for brain abscesses involves surgery, where a craniotomy is performed to remove the abscess cavity. However, the abscess may reform because the head is closed following abscess drainage. Intravenous antibiotics such as 3rd-generation cephalosporin and metronidazole are also administered. Additionally, intracranial pressure management with dexamethasone may be necessary.

Overall, brain abscesses are a serious condition that requires prompt medical attention. Understanding the symptoms and treatment options can help individuals seek medical help early and improve their chances of recovery.

Pack Year Calculation

Pack year calculation is a tool used to estimate the risk of tobacco exposure. It is calculated by multiplying the number of packs of cigarettes smoked per day by the number of years of smoking. One pack of cigarettes contains 20 cigarettes. For instance, if a person smoked half a pack of cigarettes per day for 30 years, their pack year history would be 15 (1/2 x 30 = 15).

The pack year calculation is a standardized method of measuring tobacco exposure. It helps healthcare professionals to estimate the risk of developing smoking-related diseases such as lung cancer, chronic obstructive pulmonary disease (COPD), and heart disease. The higher the pack year history, the greater the risk of developing these diseases. Therefore, it is important for individuals who smoke or have a history of smoking to discuss their pack year history with their healthcare provider to determine appropriate screening and prevention measures.

The likely diagnosis for this patient is hypercalcaemia, as indicated by their symptoms of polyuria, polydipsia, constipation, abdominal pain, depression, weakness, and fatigue. The main ECG abnormality associated with hypercalcaemia is a shortened QT interval. It is important to note that the presence of a J-wave is typically seen in hypothermia, not hypercalcaemia. Additionally, a prolonged QT interval is a feature of hypocalcaemia, not hypercalcaemia. Finally, tall tented T waves are characteristic of hyperkalaemia, not hypercalcaemia.

Hypercalcaemia: Symptoms and Signs

Hypercalcaemia is a medical condition characterized by high levels of calcium in the blood. The symptoms and signs of hypercalcaemia can be remembered by the phrase ‘bones, stones, groans and psychic moans’. This means that patients with hypercalcaemia may experience bone pain, kidney stones, constipation, and changes in mood or behavior. In addition, corneal calcification and a shortened QT interval on an electrocardiogram (ECG) may also be present. Hypertension, or high blood pressure, is another common feature of hypercalcaemia. It is important to seek medical attention if any of these symptoms are present, as hypercalcaemia can lead to serious complications if left untreated.

Pseudo-Obstruction and its Causes

Pseudo-obstruction is a condition that can be caused by various factors, including hypothyroidism, hypokalaemia, diabetes, uraemia, and hypocalcaemia. In the case of hypothyroidism, the slowness and hypothermia of the patient suggest that this may be the underlying cause of the pseudo-obstruction. However, other factors should also be considered.

It is important to note that pseudo-obstruction is a condition that affects the digestive system, specifically the intestines. It is characterized by symptoms that mimic those of a bowel obstruction, such as abdominal pain, bloating, and constipation. However, unlike a true bowel obstruction, there is no physical blockage in the intestines.

To diagnose pseudo-obstruction, doctors may perform various tests, including X-rays, CT scans, and blood tests. Treatment options may include medications to stimulate the intestines, changes in diet, and surgery in severe cases.

Overall, it is important to identify the underlying cause of pseudo-obstruction in order to provide appropriate treatment and management of the condition.

If initial treatment for dyspepsia with either a PPI or ‘test and treat’ approach fails, the other approach should be tried next. NICE guidelines recommend prescribing a full-dose PPI for 1 month or testing for H. pylori infection and prescribing eradication therapy if positive. If symptoms persist, switch to the alternative strategy. Referral for routine upper GI endoscopy is not indicated at this stage.

Management of Dyspepsia and Referral for Possible Cancer

Dyspepsia is a common symptom that can be caused by various factors, including medication and lifestyle choices. However, it can also be a sign of underlying conditions such as stomach or oesophageal cancer. The 2015 NICE guidelines provide updated advice on when urgent referral for endoscopy is necessary. Patients with dysphagia or an upper abdominal mass consistent with stomach cancer should be referred urgently. Patients aged 55 years or older with weight loss and upper abdominal pain, reflux, or dyspepsia should also be referred urgently. Non-urgent referrals include patients with haematemesis or those with treatment-resistant dyspepsia, upper abdominal pain with low haemoglobin levels, or raised platelet count with other symptoms.

For patients with undiagnosed dyspepsia, a step-wise approach is recommended. First, medications should be reviewed for possible causes. Lifestyle advice should also be given. If symptoms persist, a trial of full-dose proton pump inhibitor for one month or a ‘test and treat’ approach for H. pylori can be tried. If symptoms persist after either approach, the alternative should be attempted. Testing for H. pylori infection can be done using a carbon-13 urea breath test, stool antigen test, or laboratory-based serology. If symptoms resolve following test and treat, there is no need to check for H. pylori eradication. However, if repeat testing is required, a carbon-13 urea breath test should be used.

The patient’s symptoms indicate a life-threatening severity of asthma, as evidenced by their inability to complete full sentences and a PEFR measurement within the severe range. This is further supported by their normal pCO2 levels, which confirm the severity classification. The classification of moderate severity is incorrect in this case.

Management of Acute Asthma

Acute asthma is classified by the British Thoracic Society (BTS) into three categories: moderate, severe, and life-threatening. Patients with any of the life-threatening features should be treated as having a life-threatening attack. A fourth category, Near-fatal asthma, is also recognized. Further assessment may include arterial blood gases for patients with oxygen saturation levels below 92%. A chest x-ray is not routinely recommended unless the patient has life-threatening asthma, suspected pneumothorax, or failure to respond to treatment.

Admission criteria include a previous near-fatal asthma attack, pregnancy, an attack occurring despite already using oral corticosteroid, and presentation at night. All patients with life-threatening asthma should be admitted to the hospital, and patients with features of severe acute asthma should also be admitted if they fail to respond to initial treatment. Oxygen therapy should be started for hypoxaemic patients. Bronchodilation with short-acting beta₂-agonists (SABA) is recommended, and all patients should be given 40-50 mg of prednisolone orally daily. Ipratropium bromide and IV magnesium sulphate may also be considered for severe or life-threatening asthma. Patients who fail to respond require senior critical care support and should be treated in an appropriate ITU/HDU setting. Criteria for discharge include stability on discharge medication, checked and recorded inhaler technique, and PEF levels above 75% of best or predicted.

If serum transaminase levels remain consistently 3 times higher than the upper limit of the reference range, treatment with statins must be stopped.

Statins are drugs that inhibit the action of an enzyme called HMG-CoA reductase, which is responsible for producing cholesterol in the liver. However, they can cause some adverse effects such as myopathy, which includes muscle pain, weakness, and damage, and liver impairment. Myopathy is more common in lipophilic statins than in hydrophilic ones. Statins may also increase the risk of intracerebral hemorrhage in patients who have had a stroke before. Therefore, they should be avoided in these patients. Statins should not be taken during pregnancy and should be stopped if the patient is taking macrolides.

Statins are recommended for people with established cardiovascular disease, those with a 10-year cardiovascular risk of 10% or more, and patients with type 2 diabetes mellitus. Patients with type 1 diabetes mellitus who were diagnosed more than 10 years ago, are over 40 years old, or have established nephropathy should also take statins. It is recommended to take statins at night as this is when cholesterol synthesis takes place. Atorvastatin 20 mg is recommended for primary prevention, and the dose should be increased if non-HDL has not reduced for 40% or more. Atorvastatin 80mg is recommended for secondary prevention. The graphic shows the different types of statins available.