The rate-limiting enzyme in hepatic cholesterol synthesis, HMG-CoA reductase, is inhibited by statins.

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 20mg is recommended for primary prevention, and the dose should be increased if non-HDL has not reduced for 40% or more. Atorvastatin 80 mg is recommended for secondary prevention. The graphic shows the different types of statins available.

Investigating Coeliac Disease

Coeliac disease is a condition caused by sensitivity to gluten, which can lead to villous atrophy and malabsorption. It is often associated with other conditions such as dermatitis herpetiformis and autoimmune disorders. Diagnosis of coeliac disease is made through a combination of serology and endoscopic intestinal biopsy. The gold standard for diagnosis is the biopsy, which should be performed in all patients with suspected coeliac disease to confirm or exclude the diagnosis. The biopsy traditionally takes place in the duodenum, but jejunal biopsies are also sometimes performed. Findings supportive of coeliac disease include villous atrophy, crypt hyperplasia, an increase in intraepithelial lymphocytes, and lamina propria infiltration with lymphocytes. Serology tests for coeliac disease include tissue transglutaminase antibodies and endomyseal antibodies, while anti-gliadin antibodies are not recommended. Patients who are already on a gluten-free diet should reintroduce gluten for at least six weeks prior to testing. Rectal gluten challenge is not widely used. A gluten-free diet can reverse villous atrophy and immunology in patients with coeliac disease.

Understanding Dehydration in Children: Symptoms and Management

Dehydration is a common concern in children, especially when they are suffering from illnesses like gastroenteritis. It is important to recognize the different levels of dehydration and manage them accordingly.

Clinical dehydration is characterized by symptoms such as restlessness and decreased urine output. Signs of clinical dehydration include irritability, sunken eyes, dry mucous membranes, tachycardia, and normal capillary refill time (CRT).

Children with no clinically detectable dehydration do not show any signs or symptoms of dehydration and can be managed with oral fluids until the illness subsides.

Clinical shock is a severe form of dehydration that requires immediate medical attention. Symptoms of clinical shock include a decreased level of consciousness, pale or mottled skin, cold extremities, tachycardia, tachypnea, hypotension, weak peripheral pulses, and a prolonged CRT. Children with clinical shock require admission and rehydration with intravenous fluids and electrolyte supplementation.

A euvolemic child, on the other hand, has a normal general appearance, normal eyes, a moist tongue, and present tears. They have a normal CRT and are not tachycardic.

It is important to recognize the signs and symptoms of dehydration in children and manage it accordingly to prevent further complications. Fluid overload is also a concern, but in cases of gastroenteritis-induced dehydration, rehydration is necessary.

Sulfasalazine: A DMARD for Inflammatory Arthritis and Bowel Disease

Sulfasalazine is a type of disease modifying anti-rheumatic drug (DMARD) that is commonly used to manage inflammatory arthritis, particularly rheumatoid arthritis, as well as inflammatory bowel disease. This medication is a prodrug for 5-ASA, which works by reducing neutrophil chemotaxis and suppressing the proliferation of lymphocytes and pro-inflammatory cytokines.

However, caution should be exercised when using sulfasalazine in patients with G6PD deficiency or those who are allergic to aspirin or sulphonamides due to the risk of cross-sensitivity. Adverse effects of sulfasalazine may include oligospermia, Stevens-Johnson syndrome, pneumonitis/lung fibrosis, myelosuppression, Heinz body anaemia, megaloblastic anaemia, and the potential to color tears and stain contact lenses.

Despite these potential side effects, sulfasalazine is considered safe to use during pregnancy and breastfeeding, making it a viable option for women who require treatment for inflammatory arthritis or bowel disease. Overall, sulfasalazine is an effective DMARD that can help manage the symptoms of these conditions and improve patients’ quality of life.

Immunisation is the process of administering vaccines to protect individuals from infectious diseases. The Department of Health has provided guidance on the safe administration of vaccines in its publication ‘Immunisation against infectious disease’ in 2006. The guidance outlines general contraindications to immunisation, such as confirmed anaphylactic reactions to previous doses of a vaccine containing the same antigens or another component contained in the relevant vaccine. Vaccines should also be delayed in cases of febrile illness or intercurrent infection. Live vaccines should not be administered to pregnant women or individuals with immunosuppression.

Specific vaccines may have their own contraindications, such as deferring DTP vaccination in children with an evolving or unstable neurological condition. However, there are no contraindications to immunisation for individuals with asthma or eczema, a history of seizures (unless associated with fever), or a family history of autism. Additionally, previous natural infections with pertussis, measles, mumps, or rubella do not preclude immunisation. Other factors such as neurological conditions like Down’s or cerebral palsy, low birth weight or prematurity, and patients on replacement steroids (e.g. CAH) also do not contraindicate immunisation.

The treatment for life-threatening C. difficile infection involves administering vancomycin orally and metronidazole intravenously.

Clostridioides difficile is a type of bacteria that is commonly found in hospitals. It is a Gram positive rod that produces an exotoxin which can cause damage to the intestines, leading to a condition called pseudomembranous colitis. This bacteria usually develops when the normal gut flora is suppressed by broad-spectrum antibiotics, with second and third generation cephalosporins being the leading cause of C. difficile. Other risk factors include proton pump inhibitors. Symptoms of C. difficile include diarrhea, abdominal pain, and a raised white blood cell count. The severity of the infection can be determined using the Public Health England severity scale, which ranges from mild to life-threatening.

To diagnose C. difficile, a stool sample is tested for the presence of C. difficile toxin (CDT). Treatment for a first episode of C. difficile infection typically involves oral vancomycin for 10 days, with fidaxomicin or a combination of oral vancomycin and IV metronidazole being used as second and third-line therapies. Recurrent infections occur in around 20% of patients, increasing to 50% after their second episode. In such cases, oral fidaxomicin is recommended within 12 weeks of symptom resolution, while oral vancomycin or fidaxomicin can be used after 12 weeks. For life-threatening C. difficile infections, oral vancomycin and IV metronidazole are used, and surgery may be considered with specialist advice. Other therapies, such as bezlotoxumab and fecal microbiota transplant, may also be considered for preventing recurrences in certain cases.

Antiretroviral therapy (ART) for HIV involves a combination of at least three drugs, typically two nucleoside reverse transcriptase inhibitors (NRTI) and either a protease inhibitor (PI) or a non-nucleoside reverse transcriptase inhibitor (NNRTI). Entry inhibitors, NRTIs, NNRTIs, PIs, and integrase inhibitors are all used to manage HIV. The 2015 BHIVA guidelines recommend starting ART as soon as a patient is diagnosed with HIV. Each drug has its own side effects, and some of the common ones include peripheral neuropathy, renal impairment, osteoporosis, diabetes, hyperlipidemia, and P450 enzyme interaction.

Pulmonary fibrosis is a potential side effect of bleomycin, a cytotoxic antibiotic commonly prescribed for metastatic germ cell cancer, squamous cell carcinoma, and non-Hodgkin’s lymphoma. The severity of this adverse effect is directly proportional to the dosage administered.

Cytotoxic agents are drugs that are used to kill cancer cells. There are several types of cytotoxic agents, each with their own mechanism of action and adverse effects. Alkylating agents, such as cyclophosphamide, work by causing cross-linking in DNA. However, they can also cause haemorrhagic cystitis, myelosuppression, and transitional cell carcinoma. Cytotoxic antibiotics, like bleomycin, degrade preformed DNA and can lead to lung fibrosis. Anthracyclines, such as doxorubicin, stabilize the DNA-topoisomerase II complex and inhibit DNA and RNA synthesis, but can also cause cardiomyopathy. Antimetabolites, like methotrexate, inhibit dihydrofolate reductase and thymidylate synthesis, leading to myelosuppression, mucositis, liver fibrosis, and lung fibrosis. Fluorouracil (5-FU) is a pyrimidine analogue that induces cell cycle arrest and apoptosis by blocking thymidylate synthase, but can also cause myelosuppression, mucositis, and dermatitis. Cytarabine is a pyrimidine antagonist that interferes with DNA synthesis specifically at the S-phase of the cell cycle and inhibits DNA polymerase, but can also cause myelosuppression and ataxia. Drugs that act on microtubules, like vincristine and vinblastine, inhibit the formation of microtubules and can cause peripheral neuropathy, paralytic ileus, and myelosuppression. Docetaxel prevents microtubule depolymerisation and disassembly, decreasing free tubulin, but can also cause neutropaenia. Topoisomerase inhibitors, like irinotecan, inhibit topoisomerase I which prevents relaxation of supercoiled DNA, but can also cause myelosuppression. Other cytotoxic drugs, such as cisplatin, cause cross-linking in DNA and can lead to ototoxicity, peripheral neuropathy, and hypomagnesaemia. Hydroxyurea (hydroxycarbamide) inhibits ribonucleotide reductase, decreasing DNA synthesis, but can also cause myelosuppression.

Appropriate Investigations for Suspected Urinary Tract Infection

When a patient presents with symptoms suggestive of a urinary tract infection or pyelonephritis, the most appropriate investigation to arrange is urinary microscopy and culture. It is important to obtain a sample before starting empirical antibiotics, as this can guide subsequent antibiotic choice if the patient does not respond to the initial course. Recurrent episodes may require further investigation or referral to secondary care. Blood tests may be useful if the patient is unwell or has evidence of sepsis. However, a computed tomography of the kidneys, ureters, and bladder (CTKUB) would not be useful in this situation. Cystoscopy may be indicated for recurrent infections or unexplained bleeding, but not for a first episode. An urgent ultrasound of the renal tract may be useful to look for obstruction or anatomical abnormalities, but is not necessary for treatment. Inflammatory markers can be helpful, but urinary microscopy and culture are more appropriate in this situation.

The CHA2DS2-VASc score is utilized for assessing the necessity of anticoagulation in patients with atrial fibrillation. The HAS-BLED score estimates the likelihood of major bleeding in patients receiving anticoagulation for atrial fibrillation. The DRAGON score predicts the 3-month outcome in patients with ischemic stroke who are treated with tissue plasminogen activator (tPA). The ABCD2 score is employed to determine the risk of stroke in patients who have experienced a suspected TIA.

Common Scoring Systems in Medicine

In medicine, there are various scoring systems used to assess and determine the severity of different conditions. These scoring systems help healthcare professionals make informed decisions about treatment options and patient care. Some of the most commonly used scoring systems include the CHA2DS2-VASc for anticoagulation in atrial fibrillation, the ABCD2 for risk stratifying patients who have had a suspected TIA, and the NYHA for assessing heart failure severity.

Other scoring systems include the DAS28 for measuring disease activity in rheumatoid arthritis, the Child-Pugh classification for assessing the severity of liver cirrhosis, and the Wells score for estimating the risk of deep vein thrombosis. The MMSE is used to assess cognitive impairment, while the HAD and PHQ-9 are used to assess the severity of anxiety and depression symptoms. The GAD-7 is a screening tool for generalized anxiety disorder, and the Edinburgh Postnatal Depression Score is used to screen for postnatal depression.

Other scoring systems include the SCOFF questionnaire for detecting eating disorders, the AUDIT and CAGE for alcohol screening, and the FAST for identifying the symptoms of a stroke. The CURB-65 is used to assess the prognosis of a patient with pneumonia, while the Epworth Sleepiness Scale is used in the assessment of suspected obstructive sleep apnea. The IPSS and Gleason score are used to indicate prognosis in prostate cancer, while the APGAR assesses the health of a newborn immediately after birth. The Bishop score is used to help assess whether induction of labor will be required, and the Waterlow score assesses the risk of a patient developing a pressure sore. Finally, the FRAX is a risk assessment tool developed by WHO which calculates a patient’s 10-year risk of developing an osteoporosis-related fracture.