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Question 1
Incorrect
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What is the most likely diagnosis for a 45-year-old woman who has had severe itching for three weeks and presents to your clinic with abnormal liver function tests and a positive anti-TPO antibody?
Your Answer: Addison’s disease
Correct Answer: Primary biliary cholangitis
Explanation:Autoimmune Diseases and Hepatic Disorders: A Comparison of Symptoms and Diagnostic Findings
Primary biliary cholangitis is characterized by severe itching, mild jaundice, and elevated levels of alkaline phosphatase, ALT, and AST. Anti-mitochondrial antibody is positive, and LDL and TG may be mildly elevated. Patients may also exhibit microcytic anemia and elevated anti-TPO levels, as seen in Hashimoto’s thyroiditis. In contrast, primary sclerosing cholangitis affects men and is associated with colitis due to inflammatory bowel disease. Anti-mitochondrial antibody is often negative, and p-ANCA is often positive. Addison’s disease is characterized by fatigue, weakness, weight loss, hypoglycemia, and hyperkalemia, and may coexist with other autoimmune diseases. Autoimmune hepatitis is characterized by elevated levels of ANA, anti-smooth muscle antibody, anti-mitochondrial antibody, and anti-LKM antibody, with normal or slightly elevated levels of alkaline phosphatase. Chronic viral hepatitis is indicated by elevated levels of HBs antigen and anti-HBC antibody, with anti-HBs antibody indicating a history of prior infection or vaccination.
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This question is part of the following fields:
- Gastroenterology
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Question 2
Correct
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Sarah is a 19-year-old woman who was admitted with a fever and disseminated rash. She had not been previously vaccinated and was in contact with her 2-year-old cousin who had developed a fever and disseminated blisters and vesicles containing clear fluid. After 2 weeks, she began to have a fever and flu-like symptoms. Similar clear-fluid filled vesicles and blisters developed 3 days later and she was admitted for further observation.
After 3 days of observation, Sarah noticed that one of the lesions on her thigh appeared to be red and becoming hot to touch. An area of skin approximately 3x3cm was erythematosus. The skin was marked and she was commenced on IV flucloxacillin. Over the coming 12 hours, the erythema around this lesion continued to spread. The pain around her leg increased in intensity, requiring morphine to take the edge off the pain. A blueish discolouration began to develop around the rash.
What is the likely organism that has caused the complication?Your Answer: β- haemolytic Group A Streptococcus
Explanation:Chickenpox and Necrotizing Fasciitis
Chickenpox can increase the risk of developing invasive group A streptococcal soft tissue infections, including necrotizing fasciitis. Symptoms of chickenpox include the development of fevers, blisters, and vesicles, which can be milder in children but cause significant morbidity in adults. If a rapidly evolving rash with significant pain out of proportion to the rash is observed, along with blueish discoloration of the skin, it could be indicative of necrotizing fasciitis. In such cases, immediate surgical review should be sought.
Invasive group A Streptococcus is a β-haemolytic Streptococcus that is often the cause of necrotizing fasciitis in patients with chickenpox. Broad-spectrum antibiotics are initially used, with the choices tailored to bacterial sensitivities when known. Staphylococcus aureus can also cause necrotizing fasciitis, but it is more commonly associated with patients who have other underlying medical conditions like diabetes. Enterococcus faecalis is not known to cause skin infections and is often associated with infections like endocarditis. Streptococcus bovis is a gamma-haemolytic Streptococcus that is most often associated with colorectal cancer-associated endocarditis and is not associated with skin infections. Clostridium perfringens can cause necrotizing fasciitis and presents as gas gangrene, which is characterized by crepitus under the skin, a symptom not seen in chickenpox-related necrotizing fasciitis.
Chickenpox: Causes, Symptoms, and Management
Chickenpox is a viral infection caused by the varicella zoster virus. It is highly contagious and can be spread through respiratory droplets. The virus can also reactivate later in life, causing shingles. Chickenpox is most infectious four days before the rash appears and until five days after the rash first appears. The incubation period is typically 10-21 days. Symptoms include fever, an itchy rash that starts on the head and trunk before spreading, and mild systemic upset.
Management of chickenpox is supportive and includes keeping cool, trimming nails, and using calamine lotion. School exclusion is recommended during the infectious period. Immunocompromised patients and newborns with peripartum exposure should receive varicella zoster immunoglobulin (VZIG). If chickenpox develops, IV acyclovir may be considered. Secondary bacterial infection of the lesions is a common complication, which may be increased by the use of NSAIDs. In rare cases, invasive group A streptococcal soft tissue infections may occur, resulting in necrotizing fasciitis. Other rare complications include pneumonia, encephalitis, disseminated haemorrhagic chickenpox, arthritis, nephritis, and pancreatitis.
Radiographic Findings in Varicella Pneumonia
Varicella pneumonia is a rare complication of chickenpox that can occur in immunocompromised patients or adults. Radiographic findings of healed varicella pneumonia may include miliary opacities throughout both lungs, which are of uniform size and dense, suggesting calcification. There is typically no focal lung parenchymal mass or cavitating lesion seen. These findings are characteristic of healed varicella pneumonia.
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This question is part of the following fields:
- Paediatrics
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Question 3
Incorrect
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A 28-year-old male is brought to the emergency department following a car accident that caused severe thoracic injuries. Upon arrival, the patient's pulses cannot be detected and an ECG reveals asystole. CPR is initiated with a chest compression to rescue breath ratio of 30:2. What is the most appropriate next step in managing this patient?
Your Answer: 0.5ml 1 in 1,000 adrenaline delivered via intravenous (IV) injection
Correct Answer: 10ml 1 in 10,000 adrenaline delivered via intravenous (IV) injection
Explanation:Understanding Adrenaline and Its Indications
Adrenaline is a type of sympathomimetic amine that has both alpha and beta adrenergic stimulating properties. It is commonly used in emergency situations such as anaphylaxis and cardiac arrest. For anaphylaxis, the recommended adult life support adrenaline dose is 0.5ml 1:1,000 IM, while for cardiac arrest, it is 10ml 1:10,000 IV or 1ml of 1:1000 IV.
Adrenaline is responsible for the fight or flight response and is released by the adrenal glands. It acts on α 1 and 2, β 1 and 2 receptors, and causes vasoconstriction in the skin and kidneys, resulting in a narrow pulse pressure. It also increases cardiac output and total peripheral resistance, while causing vasodilation in skeletal muscle vessels.
When adrenaline acts on α adrenergic receptors, it inhibits insulin secretion by the pancreas and stimulates glycogenolysis in the liver and muscle. On the other hand, when it acts on β adrenergic receptors, it stimulates glucagon secretion in the pancreas, stimulates ACTH, and stimulates lipolysis by adipose tissue.
In case of accidental injection, the management involves local infiltration of phentolamine. Understanding the indications and actions of adrenaline is crucial in emergency situations, and proper administration can help save lives.
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This question is part of the following fields:
- Pharmacology
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Question 4
Incorrect
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A 30-year-old nulliparous patient presents to the Gynaecology Clinic with complaints of severe menstrual pain and pain during intercourse. She reports that the symptoms have been progressively worsening. An ultrasound of the pelvis reveals a 4-cm cyst in the right ovary. The serum CA-125 level is 225 (0–34 iu/ml). What is the probable diagnosis?
Your Answer: Granulosa cell tumour of the right ovary
Correct Answer: Ectopic endometrial tissue
Explanation:The patient is likely suffering from endometriosis, which is the presence of endometrial tissue outside of the uterus. This condition can cause subfertility, chronic pelvic pain, dysmenorrhoea, and dyspareunia. It may also lead to an increase in serum CA-125 levels and the development of ovarian deposits known as chocolate cysts. Acute appendicitis and ovarian neoplasms are unlikely causes of the patient’s symptoms, while mittelschmerz only causes mid-cycle pain and does not explain the elevated CA-125 levels. Granulosa cell tumors of the ovary typically secrete inhibin and estrogen, making endometriosis a more likely diagnosis. Symptoms of ovarian cancer are often vague and include abdominal discomfort, bloating, back and pelvic pain, irregular menstruation, loss of appetite, fatigue, and weight loss. Risk factors for ovarian cancer include not having children, early first menstruation and last menopause, hormone replacement therapy, endometriosis, and the BRCA genes. In this age group, germ cell tumors are the most likely ovarian carcinoma.
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This question is part of the following fields:
- Gynaecology
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Question 5
Incorrect
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A 65-year-old man presents with weakness and a skin rash on his upper eyelids. He also complains of a cough which has been present for 3 months. He has a 50 pack-year smoking history. On examination he is noted to have symmetrical proximal muscle weakness.
What is the most appropriate test from the options below?Your Answer: Anti-CCP (cyclic citrullinated peptide) antibody
Correct Answer: Anti-Jo 1 antibody
Explanation:The symptoms indicate the possibility of dermatomyositis, and the presence of anti-Jo 1 antibody can aid in confirming the diagnosis.
Dermatomyositis is a condition that causes inflammation and muscle weakness, as well as distinct skin lesions. It can occur on its own or be associated with other connective tissue disorders or underlying cancers, particularly ovarian, breast, and lung cancer. Screening for cancer is often done after a diagnosis of dermatomyositis. Polymyositis is a variant of the disease that does not have prominent skin manifestations.
The skin features of dermatomyositis include a photosensitive macular rash on the back and shoulders, a heliotrope rash around the eyes, roughened red papules on the fingers’ extensor surfaces (known as Gottron’s papules), extremely dry and scaly hands with linear cracks on the fingers’ palmar and lateral aspects (known as mechanic’s hands), and nail fold capillary dilation. Other symptoms may include proximal muscle weakness with tenderness, Raynaud’s phenomenon, respiratory muscle weakness, interstitial lung disease (such as fibrosing alveolitis or organizing pneumonia), dysphagia, and dysphonia.
Investigations for dermatomyositis typically involve testing for ANA antibodies, which are positive in around 80% of patients. Approximately 30% of patients have antibodies to aminoacyl-tRNA synthetases, including antibodies against histidine-tRNA ligase (also called Jo-1), antibodies to signal recognition particle (SRP), and anti-Mi-2 antibodies.
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This question is part of the following fields:
- Musculoskeletal
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Question 6
Incorrect
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A 9-month-old infant is experiencing feeding difficulties accompanied by a cough and wheeze, leading to a diagnosis of bronchiolitis. What is a triggering factor that can cause a more severe episode of bronchiolitis, rather than just an increased likelihood of developing the condition?
Your Answer: Aged between 3-6 months
Correct Answer: Underlying congenital heart disease
Explanation:Bronchiolitis can be more severe in individuals with congenital heart disease, particularly those with a ventricular septal defect. Fragile X is not associated with increased severity, but Down’s syndrome has been linked to worse episodes. Formula milk feeding is a risk factor for bronchiolitis, but does not affect the severity of the disease once contracted. While bronchiolitis is most common in infants aged 3-6 months, this age range is not indicative of a more severe episode. However, infants younger than 12 weeks are at higher risk. Being born at term is not a risk factor, but premature birth is associated with more severe episodes.
Bronchiolitis is a condition where the bronchioles become inflamed, and it is most commonly caused by respiratory syncytial virus (RSV). This virus is responsible for 75-80% of cases, with other causes including mycoplasma and adenoviruses. Bronchiolitis is most prevalent in infants under one year old, with 90% of cases occurring in those aged 1-9 months. The condition is more serious in premature babies, those with congenital heart disease or cystic fibrosis. Symptoms include coryzal symptoms, dry cough, increasing breathlessness, and wheezing. Hospital admission is often necessary due to feeding difficulties associated with increasing dyspnoea.
Immediate referral is recommended if the child has apnoea, looks seriously unwell, has severe respiratory distress, central cyanosis, or persistent oxygen saturation of less than 92% when breathing air. Clinicians should consider referral if the child has a respiratory rate of over 60 breaths/minute, difficulty with breastfeeding or inadequate oral fluid intake, or clinical dehydration. Immunofluorescence of nasopharyngeal secretions may show RSV, and management is largely supportive. Humidified oxygen is given via a head box if oxygen saturations are persistently low, and nasogastric feeding may be necessary if children cannot take enough fluid/feed by mouth. Suction may also be used for excessive upper airway secretions. NICE released guidelines on bronchiolitis in 2015 for more information.
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This question is part of the following fields:
- Paediatrics
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Question 7
Incorrect
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A 32-year-old female presents with stiff and swollen joints. She reports that the joints are especially stiff in the morning for the first few hours of the day. Her mother and sister have a history of rheumatoid arthritis (RA). On examination, she has symmetrical polyarthritis affecting the small joints of the hand. Rheumatoid factor antibody, anti-nuclear antibody, and anti-dsDNA are all negative.
Which of the following tests is the most suitable?Your Answer: Serum uric acid levels
Correct Answer: Anti-CCP (cyclic citrullinated peptide) antibody
Explanation:Rheumatoid arthritis can be diagnosed clinically, which is considered more important than using specific criteria such as those defined by the American College of Rheumatology. However, the college has established classification criteria for rheumatoid arthritis that require patients to have at least one joint with definite clinical synovitis that cannot be explained by another disease. The criteria also include scoring based on joint involvement, serology (RF and ACPA), acute-phase reactants (CRP and ESR), and duration of symptoms. A score of 6 out of 10 is needed for a definite diagnosis of rheumatoid arthritis.
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This question is part of the following fields:
- Musculoskeletal
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Question 8
Incorrect
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A 55 year old man visits his doctor complaining of a swollen scrotum. Although he had no discomfort, his wife urged him to seek medical attention. Upon examination, there is a swelling on the left side of the scrotal sac that is painless and fully transilluminates. The testicle cannot be felt. What is the probable cause of this condition?
Your Answer: Epididymo-orchitis
Correct Answer: Hydrocele
Explanation:The male patient has a swelling in his scrotal sac that is painless and allows light to pass through. The only possible diagnosis based on these symptoms is a hydrocele, which is a buildup of clear fluid around the testicles. This condition makes it difficult to feel the testes.
Causes and Management of Scrotal Swelling
Scrotal swelling can be caused by various conditions, including inguinal hernia, testicular tumors, acute epididymo-orchitis, epididymal cysts, hydrocele, testicular torsion, and varicocele. Inguinal hernia is characterized by inguinoscrotal swelling that cannot be examined above it, while testicular tumors often have a discrete testicular nodule and symptoms of metastatic disease. Acute epididymo-orchitis is often accompanied by dysuria and urethral discharge, while epididymal cysts are usually painless and occur in individuals over 40 years old. Hydrocele is a non-painful, soft fluctuant swelling that can be examined above, while testicular torsion is characterized by severe, sudden onset testicular pain and requires urgent surgery. Varicocele is characterized by varicosities of the pampiniform plexus and may affect fertility.
The management of scrotal swelling depends on the underlying condition. Testicular malignancy is treated with orchidectomy via an inguinal approach, while torsion requires prompt surgical exploration and testicular fixation. Varicoceles are usually managed conservatively, but surgery or radiological management can be considered if there are concerns about testicular function or infertility. Epididymal cysts can be excised using a scrotal approach, while hydroceles are managed differently in children and adults. In children, an inguinal approach is used to ligate the underlying pathology, while in adults, a scrotal approach is preferred to excise or plicate the hydrocele sac.
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This question is part of the following fields:
- Surgery
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Question 9
Correct
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A 45-year-old man has been experiencing left shoulder pain for the last five years. Recently, this pain has become more severe, and he has been advised to undergo a left shoulder replacement surgery. The patient has a history of diabetes and high blood pressure, but no other medical conditions. During his preoperative evaluation, the patient inquires about eating and drinking before the surgery, as he will not be staying overnight and will be arriving at the hospital on the day of the procedure.
What is the appropriate information to provide to this patient regarding fasting times for elective surgery?Your Answer: You can eat solids up to six hours before, clear fluids two hours before and carbohydrate-rich drinks two hours before
Explanation:Pre-Operative Fasting Guidelines: What You Need to Know
When it comes to preparing for surgery, there are certain guidelines that patients must follow regarding their food and drink intake. Contrary to popular belief, patients do not always need to fast for extended periods of time before their procedure.
According to recent studies, prolonged fasting may not be necessary to prepare for the stress of surgery. However, there are still some important guidelines to follow. Patients should stop eating solid foods six hours before their operation, and most patients having morning surgery are made nil by mouth from midnight. Clear fluids can be consumed up to two hours before the procedure, but carbohydrate-rich drinks should be stopped two hours before surgery.
Carbohydrate-rich drinks are often used in enhanced recovery programs to increase energy stores postoperatively and aid in recovery and mobilization. It is important to note that eating solids two hours before the procedure can increase the risk of residual solids in the stomach at induction of anesthesia.
In summary, patients should follow these guidelines: stop eating solids six hours before surgery, stop consuming carbohydrate-rich drinks two hours before surgery, and continue clear fluids up until two hours before the procedure. By following these guidelines, patients can ensure a safe and successful surgery.
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This question is part of the following fields:
- Surgery
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Question 10
Correct
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A 75-year-old man is taking warfarin for paroxysmal atrial fibrillation. He has been referred to the Medical Admissions Unit from the Community Warfarin Clinic with an INR of 9.0. He has recently finished a course of antibiotics prescribed by his GP.
Which antibiotic is the most probable cause of the elevated INR?Your Answer: Clarithromycin
Explanation:Impact of Antibiotics on Warfarin Metabolism
Antibiotics can have varying effects on the metabolism of warfarin, a commonly prescribed blood thinner. Clarithromycin, a macrolide antibiotic, inhibits the cytochrome P450 system and can lead to an accumulation of warfarin, resulting in a raised INR. On the other hand, broad-spectrum antibiotics like amoxicillin may alter warfarin metabolism through their impact on gut flora, but the effect is likely to be less significant. Trimethoprim and nitrofurantoin are not known to affect warfarin metabolism. Rifampicin, however, induces the cytochrome P450 system and may increase the first-pass metabolism of warfarin, leading to a reduction in INR levels. It is important for healthcare providers to be aware of these potential interactions when prescribing antibiotics to patients taking warfarin.
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This question is part of the following fields:
- Pharmacology
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Question 11
Incorrect
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A 79-year-old man comes to you with a complaint of weight loss and fatigue that has been going on for 3 months. He reports upper abdominal discomfort that worsens after eating and lying down. He has also noticed that his stool has become pale in color and his son has observed that he appears very yellow. Additionally, he has had high blood glucose levels on two separate occasions. What tumour marker would you order next?
Your Answer: CA 125
Correct Answer: CA 19–9
Explanation:Tumour Markers and their Associated Cancers
Tumour markers are substances produced by cancer cells that can be detected in the blood. They are used to aid in the diagnosis and monitoring of cancer. Here are some common tumour markers and the cancers they are associated with:
– CA 19-9: This marker is associated with pancreatic cancer.
– CEA: This marker is associated with colorectal cancer.
– PSA: This marker is associated with prostate cancer.
– CA 125: This marker is associated with ovarian cancer.
– AFP: This marker is associated with hepatocellular carcinoma.It is important to note that tumour markers are not always specific to one type of cancer and can also be elevated in non-cancerous conditions. Therefore, they should always be used in conjunction with other diagnostic tests and clinical evaluations.
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This question is part of the following fields:
- Oncology
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Question 12
Incorrect
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A 75-year-old woman presents to a respiratory outpatient clinic with a dry cough and shortness of breath that has been ongoing for 6 months. Despite being a non-smoker, her husband is a pigeon breeder. Upon examination, she has an SpO2 of 95% on room air and clubbing is present. Chest examination reveals symmetrical and bilateral reduced chest expansion with fine end-inspiratory crepitations. A chest radiograph shows increased interstitial markings in the lower zones of both lungs. High-resolution computed tomography (HRCT) confirms these findings and also shows bibasal honeycombing. There is no lymphadenopathy present on CT. What is the most likely diagnosis?
Your Answer: Sarcoidosis
Correct Answer: Idiopathic pulmonary fibrosis (usual interstitial pneumonia)
Explanation:Differential Diagnosis for Interstitial Lung Disease: A Case Study
Interstitial lung disease (ILD) is a group of lung disorders that affect the interstitium, the tissue and space surrounding the air sacs in the lungs. Idiopathic pulmonary fibrosis (IPF) is the most common type of ILD, characterized by chronic inflammation of the lung interstitium with lower zone predominance. This article discusses the differential diagnosis for ILD, using a case study of a patient presenting with subacute dry cough, exertional dyspnea, and general malaise and fatigue.
Idiopathic Pulmonary Fibrosis (IPF)
IPF is characterized by chronic inflammation of the lung interstitium with lower zone predominance. Patients present with subacute dry cough, exertional dyspnea, and general malaise and fatigue. Clinical examination reveals fine end-inspiratory crepitations throughout the chest with lower zone predominance. Radiological findings include reduced lung volumes and bilateral increased interstitial markings with lower zone predominance on chest X-ray (CXR), and honeycombing and microcyst formation in the lung bases on high-resolution CT (HRCT). Lung transplantation is the only definitive treatment, while steroids are not indicated.Tuberculosis
Tuberculosis presents with chronic cough, haemoptysis, fever, and night sweats. Imaging shows cavitating lesions ± lymphadenopathy.Bronchiectasis
Bronchiectasis presents with productive cough, recurrent chest infections, and haemoptysis. CXR findings are often non-specific, but dilated, thick-walled (ectatic) bronchi are easily seen on HRCT.Hypersensitivity Pneumonitis (Extrinsic Allergic Alveolitis)
Hypersensitivity pneumonitis may be caused by airborne irritants to lung parenchyma, such as pigeon breeding. Changes are classically found in lung apices, making it less likely than IPF/UIP.Sarcoidosis
End-stage sarcoidosis may present with lung fibrosis, but this does not spare the apices and typically affects the middle and upper zones of the lung.In conclusion, the differential diagnosis for ILD includes IPF, tuberculosis, bronchiectasis, hypersensitivity pneumonitis, and sarcoidosis. Accurate diagnosis is crucial for appropriate treatment and management of these conditions.
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This question is part of the following fields:
- Respiratory
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Question 13
Correct
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A 35-year-old woman in her second pregnancy has been diagnosed with pre-eclampsia and is taking labetalol twice daily. She presents to the Antenatal Assessment Unit with abdominal pain that began earlier this morning, followed by a brown discharge. The pain is constant and radiates to the back. During the examination, the uterus is hard and tender, and there is a small amount of dark red blood on the pad she presents to you. Which investigation is more likely to diagnose the cause of this patient's antepartum bleeding?
Your Answer: Transabdominal ultrasound scan
Explanation:When a patient presents with symptoms that suggest placental abruption, a transabdominal ultrasound scan is the most appropriate first-line investigation. This is especially true if the patient has risk factors such as pre-eclampsia and age over 35. The ultrasound scan can serve a dual purpose by assessing the position of the placenta and excluding placenta praevia, as well as assessing the integrity of the placenta and detecting any blood collection or haematoma that may indicate placental abruption. However, in some cases, the ultrasound scan may be normal even in the presence of placental abruption. In such cases, a magnetic resonance imaging (MRI) scan may be necessary for a more accurate diagnosis.
Before performing a bimanual pelvic examination, it is essential to rule out placenta praevia, as this can lead to significant haemorrhage and fetal and maternal compromise. A full blood count is also necessary to assess the extent of bleeding and anaemia, but it is not diagnostic of placental abruption.
An abdominal CT scan is not used as a first-line investigation for all women with antepartum haemorrhage, as it exposes the fetus to a significant radiation dose. It is only used in the assessment of pregnant women who have suffered traumatic injuries. Urinalysis is important in the assessment of women with antepartum haemorrhage, as it can detect genitourinary infections, but it does not aid in the diagnosis of placental abruption.
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This question is part of the following fields:
- Obstetrics
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Question 14
Incorrect
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A 60-year-old man with a long history of diabetes arrives at the emergency department complaining of excruciating pain around his 'rear end', inability to defecate due to the pain, and spiking temperatures. During the examination, the patient is unable to tolerate an anal examination, but the anus appears red and inflamed. What is the most probable cause of this man's symptoms?
Your Answer: Anal fissure
Correct Answer: Perianal abscess
Explanation:Understanding Perianal Abscesses
A perianal abscess is a type of anorectal abscess that occurs when pus collects within the subcutaneous tissue surrounding the anal sphincter. It is the most common form of anorectal abscess, accounting for around 60% of cases, and is more prevalent in men with an average age of 40 years. Symptoms include pain around the anus, hardened tissue in the anal region, and pus-like discharge from the anus. In some cases, patients may also experience systemic infection.
Perianal abscesses are typically caused by gut flora such as E. coli, although those caused by Staph. aureus are more likely to be a skin infection. Diagnosis can be made through inspection of the anus and digital rectal examination, with further investigations such as colonoscopy and blood tests used to determine underlying causes. Imaging such as MRI and transperineal ultrasound may also be used in complicated cases.
Treatment for perianal abscesses involves surgical incision and drainage under local anaesthetic, with the wound either packed or left open to heal over several weeks. Antibiotics may be used in cases of systemic infection, but are not typically used for wound healing. It is important to note that perianal abscesses are just one type of anorectal abscess, with others classified by the layers and planes they occupy, such as ischiorectal, supralevator, intersphincteric, and horseshoe abscesses.
Overall, understanding perianal abscesses and their causes, symptoms, and treatment options is important for proper diagnosis and management of this common condition.
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This question is part of the following fields:
- Surgery
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Question 15
Incorrect
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You are on your general practice placement, and a pregnant woman attends for a routine antenatal check-up. You examine her abdomen and find that her abdomen is distended up to her umbilicus. Your general practitioner asks you how many weeks you think she is, but you do not have a measuring tape.
How many weeks would you estimate her gestation to be if she was in her mid-30s?Your Answer: 18
Correct Answer: 20
Explanation:Measuring Uterine Growth During Pregnancy
During pregnancy, the size of the uterus can be used to estimate the gestational age of the fetus. At around 20 weeks, the uterus reaches the level of the umbilicus. This can be measured using the symphysio-fundal height (SFH), which is usually equal to the number of weeks of gestation (± 2 cm). To measure the SFH, the fundus of the uterus is first palpated and the tape measure is placed at this point. The tape measure is then rolled over the longitudinal axis of the uterus until it reaches the pubic symphysis, and the length in centimeters is recorded.
At 16 weeks, the uterus would not be palpable at the level of the umbilicus. The fundus of the uterus can be palpated at the midpoint between the umbilicus and the pubic symphysis. Similarly, at 18 weeks, the uterus would not be palpable at the level of the umbilicus.
By 22 weeks, the uterus would be past the level of the umbilicus. And by 24 weeks, the uterus would be higher in the abdomen than the umbilicus. Regular measurement of the SFH can help monitor fetal growth and ensure that the pregnancy is progressing normally.
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This question is part of the following fields:
- Obstetrics
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Question 16
Incorrect
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A 57-year-old woman visits her doctor complaining of fatigue and difficulty standing up from her chair for the past four weeks. She reports experiencing eyelid swelling and feeling generally unwell for the past two months, and now has trouble walking and grooming herself. Upon examination, the doctor observes reduced strength in her hips and shoulders, a heliotrope rash around her eyes, and a thick red rash on her knuckles. The doctor suspects a rheumatological condition and refers her for further testing. What urgent additional investigation is required, given the probable diagnosis?
Your Answer: Fundoscopy
Correct Answer: Malignancy screen
Explanation:Patients who are newly diagnosed with dermatomyositis require an urgent screening for malignancy. The presence of proximal muscle weakness, heliotrope rash, and Gottron’s papules are indicative of dermatomyositis. It is important to investigate for underlying cancer, with common malignancies including lung, breast, ovarian, prostate, and colorectal. A malignancy screen may involve a chest x-ray, mammography, CA-125, pelvic ultrasound (in females), prostate-specific antigen (in males), faecal occult blood testing, and potentially a CT chest/abdomen/pelvis. Basic blood tests such as serum corrected calcium and LFTs should also be done as a quick screen for bone and liver metastases. Fundoscopy is not necessary in the absence of ocular symptoms. A pregnancy test is not required for this patient due to her age. A renal biopsy is only necessary if there is rheumatological renal disease or if systemic lupus erythematosus is suspected. However, the patient’s symptoms are more consistent with dermatomyositis.
Dermatomyositis is a condition that causes inflammation and muscle weakness, as well as distinct skin lesions. It can occur on its own or be associated with other connective tissue disorders or underlying cancers, particularly ovarian, breast, and lung cancer. Screening for cancer is often done after a diagnosis of dermatomyositis. Polymyositis is a variant of the disease that does not have prominent skin manifestations.
The skin features of dermatomyositis include a photosensitive macular rash on the back and shoulders, a heliotrope rash around the eyes, roughened red papules on the fingers’ extensor surfaces (known as Gottron’s papules), extremely dry and scaly hands with linear cracks on the fingers’ palmar and lateral aspects (known as mechanic’s hands), and nail fold capillary dilation. Other symptoms may include proximal muscle weakness with tenderness, Raynaud’s phenomenon, respiratory muscle weakness, interstitial lung disease (such as fibrosing alveolitis or organizing pneumonia), dysphagia, and dysphonia.
Investigations for dermatomyositis typically involve testing for ANA antibodies, which are positive in around 80% of patients. Approximately 30% of patients have antibodies to aminoacyl-tRNA synthetases, including antibodies against histidine-tRNA ligase (also called Jo-1), antibodies to signal recognition particle (SRP), and anti-Mi-2 antibodies.
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This question is part of the following fields:
- Musculoskeletal
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Question 17
Incorrect
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A 30-year-old male visits his general practitioner (GP) complaining of swelling in his testicles. He reports a soft sensation on the top of his left testicle but denies any pain or issues with urination or erections. The GP orders an ultrasound, and the results show a mild varicocele on the left side without other abnormalities detected. What is the recommended next step in managing this patient?
Your Answer: Percutaneous embolisation of the varicocoele
Correct Answer: Reassure and observe
Explanation:Common Scrotal Problems and Their Features
Epididymal cysts, hydroceles, and varicoceles are the most common scrotal problems seen in primary care. Epididymal cysts are usually found posterior to the testicle and are separate from the body of the testicle. They may be associated with conditions such as polycystic kidney disease, cystic fibrosis, and von Hippel-Lindau syndrome. Diagnosis is confirmed by ultrasound, and management is usually supportive, although surgical removal or sclerotherapy may be attempted for larger or symptomatic cysts.
Hydroceles, on the other hand, describe the accumulation of fluid within the tunica vaginalis. They may be communicating or non-communicating, and may develop secondary to conditions such as epididymo-orchitis, testicular torsion, or testicular tumors. Hydroceles are usually soft, non-tender swellings of the hemi-scrotum that transilluminate with a pen torch. Diagnosis may be clinical, but ultrasound is required if there is any doubt about the diagnosis or if the underlying testis cannot be palpated. Management depends on the severity of the presentation, with infantile hydroceles generally repaired if they do not resolve spontaneously by the age of 1-2 years.
Varicoceles, on the other hand, are abnormal enlargements of the testicular veins that are usually asymptomatic but may be associated with subfertility. They are much more common on the left side and are classically described as a bag of worms. Diagnosis is confirmed by ultrasound with Doppler studies, and management is usually conservative, although surgery may be required if the patient is troubled by pain. There is ongoing debate regarding the effectiveness of surgery to treat infertility.
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This question is part of the following fields:
- Surgery
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Question 18
Correct
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A 60-year-old woman undergoes cardiac catheterisation. A catheter is inserted in her right femoral vein in the femoral triangle and advanced through the iliac veins and inferior vena cava to the right side of the heart so that right chamber pressures can be recorded.
What two other structures pass within the femoral triangle?Your Answer: Femoral artery, femoral nerve
Explanation:Anatomy of the Femoral Triangle
The femoral triangle is a triangular area on the anterior aspect of the thigh, formed by the crossing of various muscles. Within this area, the femoral vein, femoral artery, and femoral nerve lie medial to lateral (VAN). It is important to note that the inguinal lymph nodes and saphenous vein are not part of the femoral triangle. Understanding the anatomy of the femoral triangle is crucial for medical professionals when performing procedures in this area.
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This question is part of the following fields:
- Cardiology
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Question 19
Incorrect
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A 55-year-old woman comes to her doctor complaining of wheezing, chest tightness, cough, and difficulty breathing for the past three days. She reports that this started shortly after being exposed to a significant amount of hydrogen sulfide at work. She has no prior history of respiratory issues and is a non-smoker. What would be the most suitable initial management approach to alleviate her symptoms?
Your Answer: Inhaled corticosteroids
Correct Answer: Inhaled bronchodilators
Explanation:Management of Reactive Airway Dysfunction Syndrome (RADS)
Reactive airway dysfunction syndrome (RADS) is a condition that presents with asthma-like symptoms within 24 hours of exposure to irritant gases, vapours or fumes. To diagnose RADS, pre-existing respiratory conditions must be absent, and symptoms must occur after a single exposure to high concentrations of irritants. A positive methacholine challenge test and possible airflow obstruction on pulmonary function tests are also indicative of RADS.
Inhaled bronchodilators, such as salbutamol, are the first-line treatment for RADS. Cromolyn sodium may be added in select cases, while inhaled corticosteroids are used if bronchodilators are ineffective. Oral steroids are not as effective in RADS as they are in asthma. High-dose vitamin D may be useful in some cases, but it is not routinely recommended for initial management.
In summary, the management of RADS involves the use of inhaled bronchodilators as the first-line treatment, with other medications added in if necessary. A proper diagnosis is crucial to ensure appropriate management of this condition.
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This question is part of the following fields:
- Respiratory
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Question 20
Correct
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A 27-year-old woman arrives at the emergency department accompanied by her father. After a heated argument, the patient ingested a packet of her father's depression medication and locked herself in her room. When the door was forced open, she was found lying on the floor in a drowsy state. As part of her evaluation, an electrocardiogram was performed, revealing a sinus rhythm with a heart rate of 98 beats per minute, PR interval of 100ms, QRS of 150ms, and QTc interval of 420ms. What is the most appropriate course of action based on these findings?
Your Answer: IV sodium bicarbonate
Explanation:In tricyclic overdose, the QRS complex widens and can lead to ventricular tachycardia. IV sodium bicarbonate can be given to achieve cardiac stability. SSRIs do not widen the QRS but prolong the QT. DC cardioversion is not appropriate in this case. IV dextrose is not useful in reversing toxicity. IV lorazepam is used for seizures but not needed currently. Flecainide is contraindicated in tricyclic overdose.
Tricyclic overdose is a common occurrence in emergency departments, with particular danger associated with amitriptyline and dosulepin. Early symptoms include dry mouth, dilated pupils, agitation, sinus tachycardia, and blurred vision. Severe poisoning can lead to arrhythmias, seizures, metabolic acidosis, and coma. ECG changes may include sinus tachycardia, widening of QRS, and prolongation of QT interval. QRS widening over 100ms is linked to an increased risk of seizures, while QRS over 160 ms is associated with ventricular arrhythmias.
Management of tricyclic overdose involves IV bicarbonate as first-line therapy for hypotension or arrhythmias. Other drugs for arrhythmias, such as class 1a and class Ic antiarrhythmics, are contraindicated as they prolong depolarisation. Class III drugs like amiodarone should also be avoided as they prolong the QT interval. Lignocaine’s response is variable, and it should be noted that correcting acidosis is the first line of management for tricyclic-induced arrhythmias. Intravenous lipid emulsion is increasingly used to bind free drug and reduce toxicity. Dialysis is ineffective in removing tricyclics.
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This question is part of the following fields:
- Pharmacology
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Question 21
Incorrect
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A 24-year-old woman presents to the labour suite after being admitted 45 minutes ago. She is unsure of her gestational age but believes she is around 8 months pregnant based on her positive pregnancy test. She has not received any antenatal care and is currently homeless due to a violent relationship. The patient has been experiencing contractions for the past 3 hours and her waters broke 5 hours ago. Upon examination, her cervix is soft, anterior, 90% effaced, and dilated to 7 cm. The foetus is in a breech position with the presenting part at station 0 and engaged. What is the most appropriate course of action?
Your Answer: Put out a 2222 call and prepare for a crash category 1 caesarean section
Correct Answer: Arrange caesarean section within 75 minutes
Explanation:A category 2 caesarean section is the best management for a woman with an undiagnosed breech birth in labour who is not fully dilated. The decision to perform the caesarean section should be made within 75 minutes and the procedure should be arranged accordingly. Adopting an all-fours position or attempting external cephalic version with enhanced monitoring are not appropriate in this case. McRoberts manoeuvre is also not the correct management for breech birth.
Caesarean Section: Types, Indications, and Risks
Caesarean section, also known as C-section, is a surgical procedure that involves delivering a baby through an incision in the mother’s abdomen and uterus. In recent years, the rate of C-section has increased significantly due to an increased fear of litigation. There are two main types of C-section: lower segment C-section, which comprises 99% of cases, and classic C-section, which involves a longitudinal incision in the upper segment of the uterus.
C-section may be indicated for various reasons, including absolute cephalopelvic disproportion, placenta praevia grades 3/4, pre-eclampsia, post-maturity, IUGR, fetal distress in labor/prolapsed cord, failure of labor to progress, malpresentations, placental abruption, vaginal infection, and cervical cancer. The urgency of C-section may be categorized into four categories, with Category 1 being the most urgent and Category 4 being elective.
It is important for clinicians to inform women of the serious and frequent risks associated with C-section, including emergency hysterectomy, need for further surgery, admission to intensive care unit, thromboembolic disease, bladder injury, ureteric injury, and death. C-section may also increase the risk of uterine rupture, antepartum stillbirth, placenta praevia, and placenta accreta in subsequent pregnancies. Other complications may include persistent wound and abdominal discomfort, increased risk of repeat C-section, readmission to hospital, haemorrhage, infection, and fetal lacerations.
Vaginal birth after C-section (VBAC) may be an appropriate method of delivery for pregnant women with a single previous C-section delivery, except for those with previous uterine rupture or classical C-section scar. The success rate of VBAC is around 70-75%.
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This question is part of the following fields:
- Obstetrics
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Question 22
Incorrect
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A 25-year-old woman is brought to the hospital by air ambulance due to dyspnoea and severe chest pain after being thrown from a horse and trampled during an event.
Upon examination, there is a decrease in breath sounds on the left side of the chest with hyper-resonant percussion, and the apex beat is shifted to the right. Additionally, the patient's right arm appears to have a closed humeral fracture.
Considering the examination results, which medication should be used with caution?Your Answer: Morphine
Correct Answer: Nitrous oxide
Explanation:When treating a patient with a pneumothorax, caution should be exercised when using nitrous oxide. This is because nitrous oxide has a tendency to diffuse into air-filled spaces, including pneumothoraces, which can worsen cardiopulmonary impairment. In contrast, desflurane may be safely administered to patients with pneumothoraces as it does not diffuse into gas-filled airspaces as readily as nitrous oxide. Ketamine and morphine are also safe options for pain control in patients with traumatic pneumothoraces, with ketamine not being associated with cardiorespiratory depression and morphine being considered first-line due to its predictable effects and reversibility with naloxone. Neither ketamine or morphine are listed as a ‘caution’ for pneumothoraces in the BNF.
Overview of General Anaesthetics
General anaesthetics are drugs used to induce a state of unconsciousness in patients undergoing surgical procedures. There are two main types of general anaesthetics: inhaled and intravenous. Inhaled anaesthetics, such as isoflurane, desflurane, sevoflurane, and nitrous oxide, are administered through inhalation. These drugs work by acting on various receptors in the brain, including GABAA, glycine, NDMA, nACh, and 5-HT3 receptors. Inhaled anaesthetics can cause adverse effects such as myocardial depression, malignant hyperthermia, and hepatotoxicity.
Intravenous anaesthetics, such as propofol, thiopental, etomidate, and ketamine, are administered through injection. These drugs work by potentiating GABAA receptors or blocking NDMA receptors. Intravenous anaesthetics can cause adverse effects such as pain on injection, hypotension, laryngospasm, myoclonus, and disorientation. However, they are often preferred over inhaled anaesthetics in cases of haemodynamic instability.
It is important to note that the exact mechanism of action of general anaesthetics is not fully understood. Additionally, the choice of anaesthetic depends on various factors such as the patient’s medical history, the type of surgery, and the anaesthetist’s preference. Overall, general anaesthetics play a crucial role in modern medicine by allowing for safe and painless surgical procedures.
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This question is part of the following fields:
- Surgery
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Question 23
Correct
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A 35-year-old woman comes to her General Practitioner complaining of sudden onset of complete right-sided facial weakness that started yesterday. There are no other neurological symptoms observed during the examination. The patient denies any hearing loss and reports only drooling of saliva. Other than that, she is healthy and has no other complaints. An ear examination reveals no abnormalities.
What is the probable diagnosis?Your Answer: Bell's Palsy
Explanation:Understanding Bell’s Palsy and Differential Diagnoses
Bell’s palsy is a sudden, unexplained facial nerve paralysis that affects one side of the face. It is more common in individuals with certain risk factors, such as diabetes, obesity, and upper respiratory tract infections. Symptoms include facial muscle weakness, drooling, speech difficulties, dry mouth, numbness, and ear pain. Treatment focuses on preventing complications, such as eye irritation, and can include eye ointment, lubricating drops, sunglasses, and a soft-food diet. Recovery typically occurs within a few weeks to several months.
Differential diagnoses for Bell’s palsy include stroke, acoustic neuroma, Ramsay-Hunt syndrome, and neurosarcoidosis. Stroke typically spares the forehead muscles, while acoustic neuroma presents with hearing loss, tinnitus, and balance problems. Ramsay-Hunt syndrome is a complication of shingles and includes a vesicular rash, fever, and hearing loss. Neurosarcoidosis is rare and associated with systemic disease. A thorough evaluation is necessary to differentiate these conditions from Bell’s palsy.
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This question is part of the following fields:
- Neurology
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Question 24
Incorrect
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The arterial blood gas results are as follows: pH of 7.6 (normal range: 7.35-7.45), pO2 of 13.3 kPa (normal range: 10.5-13.5 kPa), pCO2 of 5.6 kPa (normal range: 4.6-6.0 kPa), HCO3 of 32 mmol/l (normal range: 24-30 mmol/l), and SaO2 of 97% on room air. Based on these results, which clinical scenario is the most likely explanation for these findings?
Your Answer: Hyperventilation
Correct Answer: Pyloric stenosis
Explanation:Understanding Acid-Base Imbalances in Various Medical Conditions
Pyloric Stenosis:
Pyloric stenosis causes projectile vomiting due to the inability of stomach contents to pass into the duodenum, resulting in metabolic alkalosis. Respiratory compensation may occur, leading to a raised pCO2.Septic Shock:
Septic shock leads to metabolic acidosis due to poor tissue perfusion and increased anaerobic respiration. Respiratory compensation may occur, leading to an increased respiratory rate.Pneumothorax:
A pneumothorax typically causes respiratory alkalosis, but if associated with fractured ribs, respiratory acidosis may occur. In the acute setting, there is unlikely to be any metabolic compensation.Hyperventilation:
Hyperventilation leads to respiratory alkalosis as the patient exhales excess CO2. There is unlikely to be metabolic compensation in the acute setting.Bowel Ischaemia:
Bowel ischaemia leads to metabolic acidosis due to anaerobic respiration in the affected tissue. Respiratory compensation may occur, leading to an increased respiratory rate. -
This question is part of the following fields:
- Clinical Biochemistry
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Question 25
Correct
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A 72-year-old man is admitted to the hospital by his wife who reports that he has been experiencing distressing visual hallucinations of animals in their home. You suspect that he may be suffering from Charles-Bonnet syndrome. What are some potential risk factors that could make him more susceptible to this condition?
Your Answer: Peripheral visual impairment
Explanation:Peripheral visual impairment is a risk factor for Charles-Bonnet syndrome, which is a condition characterized by visual hallucinations in individuals with eye disease. The most frequent hallucinations include faces, children, and wild animals. This syndrome is more common in older individuals, without significant difference in occurrence between males and females, and no known increased risk associated with family history.
Understanding Charles-Bonnet Syndrome
Charles-Bonnet syndrome (CBS) is a condition characterized by complex hallucinations, usually visual or auditory, that occur in clear consciousness. These hallucinations persist or recur and are often experienced by individuals with visual impairment, although this is not a mandatory requirement for diagnosis. People with CBS maintain their insight and do not exhibit any other significant neuropsychiatric disturbance. The risk factors for CBS include advanced age, peripheral visual impairment, social isolation, sensory deprivation, and early cognitive impairment. The syndrome is equally distributed between sexes and does not show any familial predisposition. The most common ophthalmological conditions associated with CBS are age-related macular degeneration, glaucoma, and cataract.
Well-formed complex visual hallucinations are experienced by 10-30% of individuals with severe visual impairment. The prevalence of CBS in visually impaired people is estimated to be between 11 and 15%. However, around a third of people with CBS find the hallucinations unpleasant or disturbing. A large study published in the British Journal of Ophthalmology found that 88% of people had CBS for two years or more, and only 25% experienced resolution at nine years. Therefore, CBS is not generally a transient experience.
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This question is part of the following fields:
- Psychiatry
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Question 26
Incorrect
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A 6-year-old boy is brought to the Emergency Department with episodes of cyanosis during physical activity. He was born at term via normal vaginal delivery, without complications during pregnancy. The child has been healthy, but recently started experiencing bluish skin during physical activity.
After examination, the child is diagnosed with Fallot's tetralogy.
What is a common association with a patient diagnosed with Fallot's tetralogy?Your Answer: A continuous murmur throughout systole and diastole
Correct Answer: Ventricular septal defect (VSD)
Explanation:Common Heart Conditions and Their Characteristics
Ventricular Septal Defect (VSD), Pulmonary Stenosis, Right Ventricular Outflow Tract (RVOT) Obstruction, Right Ventricular Hypertrophy, and Overriding of the VSD by the Aorta are all characteristics of Fallot’s Tetralogy, the most common form of cyanotic congenital heart disease. This condition presents with cyanotic episodes, typically at 1-2 months of age. Atrial Septal Defect (ASD) is not associated with Fallot’s Tetralogy. Pulmonary Regurgitation is not seen in Fallot’s Tetralogy, but rather Pulmonary Stenosis. A Continuous Murmur throughout Systole and Diastole is a characteristic of Patent Ductus Arteriosus (PDA). Hypoplastic Right Ventricle is not associated with Fallot’s Tetralogy, but rather Right Ventricular Hypertrophy.
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This question is part of the following fields:
- Paediatrics
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Question 27
Incorrect
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A 1-day-old child is found to have absent femoral pulses and a systolic ejection murmur over the left side of their chest and back upon their routine examination. Their brachial pulses are strong. They appear pale and are tachypnoeic. They have not managed to eat much solid food, as they become distressed.
Which of the following statements about their condition is true?Your Answer: If diagnosed antenatally, the baby should be given a prostaglandin inhibitor after birth to encourage closure of the ductus arteriosus
Correct Answer: May be treated by balloon angioplasty with or without stenting
Explanation:Coarctation of the Aorta: Diagnosis and Treatment Options
Coarctation of the aorta is a congenital condition that causes narrowing of the aorta, most commonly at the site of insertion of the ductus arteriosus. Diagnosis can be made antenatally or after birth upon newborn examination. Treatment options include surgical repair or balloon angioplasty and/or stenting. If diagnosed antenatally, prostaglandin is given to encourage the ductus arteriosus to remain patent until repair is performed. Less severe cases can present in older children with symptoms such as leg pain, tiredness, dizzy spells, or an incidental finding of a murmur. Following repair, there are rarely any long-term complications, but re-coarctation can occur. Balloon angioplasty, with or without stenting, can be used in some circumstances, rather than surgical reconstruction. It is important to monitor for hypertension and/or premature cardiovascular or cerebrovascular disease in adults with a previous history of coarctation of the aorta.
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This question is part of the following fields:
- Paediatrics
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Question 28
Correct
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A 16-year-old woman is admitted surgically with acute-onset lower abdominal pain. On examination, she has a tender left iliac fossa.
Which of the following is the most appropriate next test?Your Answer: Pregnancy test (ß-hCG)
Explanation:Investigations for Abdominal Pain in Women of Childbearing Age
When a woman of childbearing age presents with abdominal pain, it is important to consider the possibility of gynaecological problems, including ectopic pregnancy. The first step in investigation should be to ask about the patient’s last menstrual period and sexual history, and to perform a pregnancy test measuring β-human chorionic gonadotrophin (β-hCG) levels in urine or serum.
Proctoscopy is unlikely to be beneficial in the absence of specific gastrointestinal symptoms. Ultrasonography may be useful at a later stage to assess the location and severity of an ectopic pregnancy, but transvaginal ultrasound is preferable to transcutaneous abdominal ultrasound.
Specialist gynaecological opinion should only be sought once there is a high index of suspicion for a particular diagnosis. Laparoscopy is not indicated at this point, as less invasive tests are likely to yield the diagnosis. Exploratory laparoscopy may be considered if other investigations are inconclusive.
Investigating Abdominal Pain in Women of Childbearing Age
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This question is part of the following fields:
- Gynaecology
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Question 29
Correct
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A 68-year-old woman presents to the emergency department after collapsing at home. She has a medical history of COPD, recurrent urinary tract infections, hypertension, and hypercholesterolemia. Recently, she visited her general practitioner for a chest infection and was prescribed antibiotics and medications for symptom control. Additionally, she started taking medications for newly diagnosed hypertension. During her examination, there were no notable findings. However, her twelve lead ECG revealed a significantly prolonged QTc interval of 560ms. Which of the following medications is the most likely cause of this ECG abnormality?
Your Answer: Clarithromycin
Explanation:Macrolides have the potential to cause prolongation of the QT interval, which may have been a contributing factor to the marked QT interval prolongation observed in this patient following recent use of clarithromycin. Cyclizine, doxycycline, and lercanidipine are not known to affect the QT interval.
Macrolides: Antibiotics that Inhibit Bacterial Protein Synthesis
Macrolides are a class of antibiotics that include erythromycin, clarithromycin, and azithromycin. They work by blocking translocation, which inhibits bacterial protein synthesis. While they are generally considered bacteriostatic, their effectiveness can vary depending on the dose and type of organism being treated.
Resistance to macrolides can occur through post-transcriptional methylation of the 23S bacterial ribosomal RNA. Adverse effects of macrolides include prolongation of the QT interval and gastrointestinal side-effects, with nausea being less common with clarithromycin than erythromycin. Cholestatic jaundice is also a potential risk, although using erythromycin stearate may reduce this risk. Additionally, macrolides are known to inhibit the cytochrome P450 isoenzyme CYP3A4, which can cause interactions with other medications. For example, taking macrolides concurrently with statins significantly increases the risk of myopathy and rhabdomyolysis. Azithromycin is also associated with hearing loss and tinnitus.
Overall, macrolides are a useful class of antibiotics that can effectively treat bacterial infections. However, it is important to be aware of their potential adverse effects and interactions with other medications.
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This question is part of the following fields:
- Pharmacology
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Question 30
Correct
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A 60-year-old man presents to his doctor with a 5-month history of frequent urination, urgency, and weak stream. Upon urinalysis, blood is detected. Following a multiparametric MRI, it is confirmed that the patient has prostate cancer. To treat his condition, he is prescribed the GnRH agonist goserelin and the anti-androgen cyproterone acetate. The patient is advised on the importance of taking cyproterone acetate. What is the purpose of cyproterone acetate in this treatment plan?
Your Answer: Prevent paradoxical increase in symptoms with GnRH agonists
Explanation:GnRH agonists used in the treatment of prostate cancer may lead to a ‘tumour flare’ when initiated, resulting in symptoms such as bone pain and bladder obstruction. To prevent this paradoxical increase in symptoms, anti-androgens are used. GnRH agonists initially cause an increase in luteinizing hormone secretion, which stimulates the production of testosterone by Leydig cells in the testicles. Testosterone promotes the growth and survival of prostate cancer cells, leading to an increase in symptoms. Anti-androgens work by blocking androgen receptors, preventing testosterone from binding to them and suppressing luteinizing hormone secretion, thereby reducing testosterone levels and preventing ‘tumour flare’. Anti-androgens do not directly affect tumour growth rate.
Management of Prostate Cancer
Localised prostate cancer (T1/T2) can be managed through various treatment options depending on the patient’s life expectancy and preference. Conservative approaches such as active monitoring and watchful waiting can be considered, as well as radical prostatectomy and radiotherapy (external beam and brachytherapy). On the other hand, localised advanced prostate cancer (T3/T4) may require hormonal therapy, radical prostatectomy, or radiotherapy. However, patients who undergo radiotherapy may develop proctitis and are at a higher risk of bladder, colon, and rectal cancer.
For metastatic prostate cancer, the primary goal is to reduce androgen levels. A combination of approaches is often used, including anti-androgen therapy, synthetic GnRH agonist or antagonists, bicalutamide, cyproterone acetate, abiraterone, and bilateral orchidectomy. GnRH agonists such as Goserelin (Zoladex) may result in lower LH levels longer term by causing overstimulation, which disrupts endogenous hormonal feedback systems. This may cause a rise in testosterone initially for around 2-3 weeks before falling to castration levels. To prevent a rise in testosterone, anti-androgen therapy is often used initially. However, this may result in a tumour flare, which stimulates prostate cancer growth and may cause bone pain, bladder obstruction, and other symptoms. GnRH antagonists such as degarelix are being evaluated to suppress testosterone while avoiding the flare phenomenon. Chemotherapy with docetaxel may also be an option for the treatment of hormone-relapsed metastatic prostate cancer in patients who have no or mild symptoms after androgen deprivation therapy has failed, and before chemotherapy is indicated.
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This question is part of the following fields:
- Surgery
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