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Question 1
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You are in charge of the care of a 23-year-old man who has come for a military medical evaluation. Based on his symptoms, you suspect that he has type 1 diabetes and has been secretly administering insulin. What clinical methods can you use to evaluate his endogenous insulin production?
Your Answer: C-peptide
Explanation:C-peptide is a reliable indicator of insulin production as it is secreted in proportion to insulin. It is often used clinically to measure endogenous insulin production.
Insulin is a hormone produced by the pancreas that plays a crucial role in regulating the metabolism of carbohydrates and fats in the body. It works by causing cells in the liver, muscles, and fat tissue to absorb glucose from the bloodstream, which is then stored as glycogen in the liver and muscles or as triglycerides in fat cells. The human insulin protein is made up of 51 amino acids and is a dimer of an A-chain and a B-chain linked together by disulfide bonds. Pro-insulin is first formed in the rough endoplasmic reticulum of pancreatic beta cells and then cleaved to form insulin and C-peptide. Insulin is stored in secretory granules and released in response to high levels of glucose in the blood. In addition to its role in glucose metabolism, insulin also inhibits lipolysis, reduces muscle protein loss, and increases cellular uptake of potassium through stimulation of the Na+/K+ ATPase pump.
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This question is part of the following fields:
- Endocrine System
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Question 2
Correct
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A 82-year-old man visits the urology department complaining of a painful swelling in his left testicle that has been present for the past month. Upon examination, it is diagnosed as a left varicocele. Further CT scans reveal enlarged lymph nodes obstructing the venous drainage in the middle portion of his abdomen. Which vein is most likely to be compressed?
Your Answer: Left renal vein
Explanation:The left renal vein collects venous blood from the left testis through the left testicular/gonadal vein.
Both the left and right testes are drained by their respective testicular/gonadal veins. The right testicular vein empties directly into the inferior vena cava, while the left testicular vein drains into the left renal vein before joining the inferior vena cava.
Anatomy of the Inferior Vena Cava
The inferior vena cava (IVC) originates from the fifth lumbar vertebrae and is formed by the merging of the left and right common iliac veins. It passes to the right of the midline and receives drainage from paired segmental lumbar veins throughout its length. The right gonadal vein empties directly into the cava, while the left gonadal vein usually empties into the left renal vein. The renal veins and hepatic veins are the next major veins that drain into the IVC. The IVC pierces the central tendon of the diaphragm at the level of T8 and empties into the right atrium of the heart.
The IVC is related anteriorly to the small bowel, the first and third parts of the duodenum, the head of the pancreas, the liver and bile duct, the right common iliac artery, and the right gonadal artery. Posteriorly, it is related to the right renal artery, the right psoas muscle, the right sympathetic chain, and the coeliac ganglion.
The IVC is divided into different levels based on the veins that drain into it. At the level of T8, it receives drainage from the hepatic vein and inferior phrenic vein before piercing the diaphragm. At the level of L1, it receives drainage from the suprarenal veins and renal vein. At the level of L2, it receives drainage from the gonadal vein, and at the level of L1-5, it receives drainage from the lumbar veins. Finally, at the level of L5, the common iliac vein merges to form the IVC.
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This question is part of the following fields:
- Cardiovascular System
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Question 3
Correct
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A 12-year-old male patient has been diagnosed with Friedreich's ataxia, an autosomal recessive genetic disease that causes difficulty walking, a loss of sensation in the arms and legs and impaired speech that worsens over time. What condition should this patient be screened for as a result of having this disease?
Your Answer: Hypertrophic obstructive cardiomyopathy
Explanation:Friedreich’s ataxia is a genetic disorder caused by a deficiency of the frataxin protein, which can lead to cardiac neuropathy and hypertrophic obstructive cardiomyopathy. This condition is not associated with haemophilia, coarctation of the aorta, streptococcal pharyngitis, Kawasaki disease, or coronary artery aneurysm. However, Group A streptococcal infections can cause acute rheumatic fever and chronic rheumatic heart disease, which are autoimmune diseases that affect the heart.
Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic disorder that affects muscle tissue and is inherited in an autosomal dominant manner. It is caused by mutations in genes that encode contractile proteins, with the most common defects involving the β-myosin heavy chain protein or myosin-binding protein C. HOCM is characterized by left ventricle hypertrophy, which leads to decreased compliance and cardiac output, resulting in predominantly diastolic dysfunction. Biopsy findings show myofibrillar hypertrophy with disorganized myocytes and fibrosis. HOCM is often asymptomatic, but exertional dyspnea, angina, syncope, and sudden death can occur. Jerky pulse, systolic murmurs, and double apex beat are also common features. HOCM is associated with Friedreich’s ataxia and Wolff-Parkinson White. ECG findings include left ventricular hypertrophy, non-specific ST segment and T-wave abnormalities, and deep Q waves. Atrial fibrillation may occasionally be seen.
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This question is part of the following fields:
- Cardiovascular System
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Question 4
Incorrect
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Sophie, a 5-year-old girl, visits her doctor with her mother, complaining of a lump in her groin that appears and disappears. The lump is easily reducible.
The doctor suspects an indirect inguinal hernia, although it is difficult to differentiate between femoral, direct inguinal, and indirect inguinal hernias in such a young patient.
Sophie's mother is curious about the cause of her daughter's hernia. What is the pathology of an indirect inguinal hernia?Your Answer: Protrusion through a weakness of abdominal wall musculature
Correct Answer: Protrusion through the failure of the processus vaginalis to regress
Explanation:Indirect inguinal hernias are caused by the failure of the processus vaginalis to regress, resulting in a protrusion through the deep inguinal ring and into the inguinal canal. In males, it may progress into the scrotum, while in females, it may enter the labia. This type of hernia is located lateral to the epigastric vessels.
On the other hand, direct inguinal hernias are usually caused by weakening in the abdominal musculature, which occurs with age. The protrusion enters the inguinal canal through the posterior wall, which is medial to the epigastric vessels. It may exit through the superficial inguinal ring.
The tunica vaginalis is a layer that surrounds the testes and contains a small amount of serous fluid, reducing friction between the scrotum and the testes. Meanwhile, the tunica albuginea is a layer of connective tissue that covers the ovaries, testicles, and corpora cavernosa of the penis.
Understanding Inguinal Hernias
Inguinal hernias are the most common type of abdominal wall hernias, with 75% of cases falling under this category. They are more prevalent in men, with a 25% lifetime risk of developing one. The main symptom is a lump in the groin area, which disappears when pressure is applied or when the patient lies down. Discomfort and aching are also common, especially during physical activity. However, severe pain is rare, and strangulation is even rarer.
The traditional classification of inguinal hernias into indirect and direct types is no longer relevant in clinical management. Instead, the current consensus is to treat medically fit patients, even if they are asymptomatic. A hernia truss may be an option for those who are not fit for surgery, but it has limited use in other patients. Mesh repair is the preferred method, as it has the lowest recurrence rate. Unilateral hernias are usually repaired through an open approach, while bilateral and recurrent hernias are repaired laparoscopically.
After surgery, patients are advised to return to non-manual work after 2-3 weeks for open repair and 1-2 weeks for laparoscopic repair. Complications may include early bruising and wound infection, as well as late chronic pain and recurrence. It is important to seek medical attention if any of these symptoms occur.
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This question is part of the following fields:
- Gastrointestinal System
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Question 5
Incorrect
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During an on-call shift, you are reviewing the blood results of a 72-year-old man. He was admitted with abdominal pain and has a working diagnosis of acute cholecystitis. He is currently on intravenous cefuroxime and metronidazole, awaiting further surgical review. His blood results are as follows:
Hb 115 g/L : (115 - 160)
Platelets 320* 109/L (150 - 400)
WBC 18.2* 109/L (4.0 - 11.0)
Na+ 136 mmol/L (135 - 145)
K+ 6.9 mmol/L (3.5 - 5.0)
Urea 14.8 mmol/L (2.0 - 7.0)
Creatinine 225 µmol/L (55 - 120)
CRP 118 mg/L (< 5)
Bilirubin 15 µmol/L (3 - 17)
ALP 410 u/L (30 - 100)
ALT 32 u/L (3 - 40)
Albumin 39 g/L (35 - 50)
You initiate treatment with intravenous calcium gluconate, salbutamol nebulisers, and furosemide. On discussion with the renal team, they recommend additional treatment with calcium resonium.
What is the mechanism of action of calcium resonium?Your Answer: It stabilises the cardiac membrane
Correct Answer: It increases potassium excretion by preventing enteral absorption
Explanation:The correct answer is that calcium resonium increases potassium excretion by preventing enteral absorption. This is achieved through cation ion exchange, where the resin exchanges potassium for Ca++ in the body. The onset of action is usually 2-12 hours when taken orally and longer when administered rectally. It is important to note that calcium resonium does not act on the Na+/K+-ATPase pump, which is the mechanism of action for drugs like digoxin. Additionally, it does not shift potassium from the extracellular to the intracellular compartment, which is the mechanism of action for salbutamol nebulisers. Lastly, calcium resonium does not stabilise the cardiac membrane, which is the action of calcium gluconate.
Managing Hyperkalaemia: A Step-by-Step Guide
Hyperkalaemia is a serious condition that can lead to life-threatening arrhythmias if left untreated. To manage hyperkalaemia, it is important to address any underlying factors that may be contributing to the condition, such as acute kidney injury, and to stop any aggravating drugs, such as ACE inhibitors. Treatment can be categorised based on the severity of the hyperkalaemia, which is classified as mild, moderate, or severe based on the patient’s potassium levels.
ECG changes are also important in determining the appropriate management for hyperkalaemia. Peaked or ‘tall-tented’ T waves, loss of P waves, broad QRS complexes, and a sinusoidal wave pattern are all associated with hyperkalaemia and should be evaluated in all patients with new hyperkalaemia.
The principles of treatment modalities for hyperkalaemia include stabilising the cardiac membrane, shifting potassium from extracellular to intracellular fluid compartments, and removing potassium from the body. IV calcium gluconate is used to stabilise the myocardium, while insulin/dextrose infusion and nebulised salbutamol can be used to shift potassium from the extracellular to intracellular fluid compartments. Calcium resonium, loop diuretics, and dialysis can be used to remove potassium from the body.
In practical terms, all patients with severe hyperkalaemia or ECG changes should receive emergency treatment, including IV calcium gluconate to stabilise the myocardium and insulin/dextrose infusion to shift potassium from the extracellular to intracellular fluid compartments. Other treatments, such as nebulised salbutamol, may also be used to temporarily lower serum potassium levels. Further management may involve stopping exacerbating drugs, treating any underlying causes, and lowering total body potassium through the use of calcium resonium, loop diuretics, or dialysis.
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This question is part of the following fields:
- Renal System
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Question 6
Incorrect
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A 50-year-old man suffers a major head trauma and undergoes craniotomy. The bleeding is from the sigmoid sinus, what is the structure it drains into?
Your Answer: Straight sinus
Correct Answer: Internal jugular vein
Explanation:The internal jugular vein receives drainage from the sigmoid sinus and the inferior petrosal sinus after they merge.
Overview of Cranial Venous Sinuses
The cranial venous sinuses are a series of veins located within the dura mater, the outermost layer of the brain. Unlike other veins in the body, they do not have valves, which can increase the risk of sepsis spreading. These sinuses eventually drain into the internal jugular vein.
There are several cranial venous sinuses, including the superior sagittal sinus, inferior sagittal sinus, straight sinus, transverse sinus, sigmoid sinus, confluence of sinuses, occipital sinus, and cavernous sinus. Each of these sinuses has a specific location and function within the brain.
To better understand the topography of the cranial venous sinuses, it is helpful to visualize them as a map. The superior sagittal sinus runs along the top of the brain, while the inferior sagittal sinus runs along the bottom. The straight sinus connects the two, while the transverse sinus runs horizontally across the back of the brain. The sigmoid sinus then curves downward and connects to the internal jugular vein. The confluence of sinuses is where several of these sinuses meet, while the occipital sinus is located at the back of the head. Finally, the cavernous sinus is located on either side of the pituitary gland.
Understanding the location and function of these cranial venous sinuses is important for diagnosing and treating various neurological conditions.
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This question is part of the following fields:
- Neurological System
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Question 7
Incorrect
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A 68-year-old man visits the clinic with a complaint of persistent hiccups that have been ongoing for 5 days. During the consultation, he mentions feeling increasingly fatigued over the past 7 months. Apart from these issues, he reports no other health concerns. After conducting some blood tests, you discover that he is experiencing renal failure, and his potassium levels are at 6.2 (normal range is 3.5-5 mmol/l). You urgently advise him to go to the hospital, and upon arrival, the medical team requests an ECG to check for signs of hyperkalaemia. What is an ECG indication of hyperkalaemia?
Your Answer: Prominent U waves
Correct Answer: Wide QRS complexes
Explanation:Hyperkalaemia can be identified on an ECG by the presence of broad QRS complexes, which may appear bizarre and form a sinusoidal waveform. Other signs include tall-tented T waves and small or absent P waves. Asystole can also occur as a result of hyperkalaemia.
On the other hand, hypokalaemia can be identified by ECG signs such as small or inverted T waves, ST segment depression, and prominent U waves. A prolonged PR interval and long QT interval may also be present, although a short PR interval may suggest pre-excitation or an AV nodal rhythm.
In the case of a patient presenting with hiccups, persistent hiccups may indicate uraemia, which can be caused by renal failure. Fatigue is another common symptom of renal failure, which is also a common cause of hyperkalaemia.
Hyperkalaemia is a condition where there is an excess of potassium in the blood. The levels of potassium in the plasma are regulated by various factors such as aldosterone, insulin levels, and acid-base balance. When there is metabolic acidosis, hyperkalaemia can occur as hydrogen and potassium ions compete with each other for exchange with sodium ions across cell membranes and in the distal tubule. The ECG changes that can be seen in hyperkalaemia include tall-tented T waves, small P waves, widened QRS leading to a sinusoidal pattern, and asystole.
There are several causes of hyperkalaemia, including acute kidney injury, drugs such as potassium sparing diuretics, ACE inhibitors, angiotensin 2 receptor blockers, spironolactone, ciclosporin, and heparin, metabolic acidosis, Addison’s disease, rhabdomyolysis, and massive blood transfusion. Foods that are high in potassium include salt substitutes, bananas, oranges, kiwi fruit, avocado, spinach, and tomatoes.
It is important to note that beta-blockers can interfere with potassium transport into cells and potentially cause hyperkalaemia in renal failure patients. In contrast, beta-agonists such as Salbutamol are sometimes used as emergency treatment. Additionally, both unfractionated and low-molecular weight heparin can cause hyperkalaemia by inhibiting aldosterone secretion.
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This question is part of the following fields:
- Renal System
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Question 8
Incorrect
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At 28 years old, Gwen seeks pre-conception advice from her haematologist regarding her Von Willebrand Disease (VWD). She is concerned about the potential risks of bleeding during pregnancy and childbirth, as well as the likelihood of passing on her condition to her child. Gwen is a carrier of VWD, while her partner Dylan does not have the condition. What is the probability of their child inheriting VWD?
Your Answer: 25%
Correct Answer: 50%
Explanation:The offspring of Gwen and Dylan will have the Vv allele combination, resulting in inheriting VWD with a probability of 50%.
Autosomal Dominant Inheritance: Characteristics and Complicating Factors
Autosomal dominant diseases are genetic disorders that are inherited in an autosomal dominant pattern. This means that both homozygotes and heterozygotes manifest the disease, and there is no carrier state. Both males and females can be affected, and only affected individuals can pass on the disease. The disease is passed on to 50% of children, and it normally appears in every generation. The risk remains the same for each successive pregnancy.
However, there are complicating factors that can affect the inheritance of autosomal dominant diseases. One of these factors is non-penetrance, which refers to the lack of clinical signs and symptoms despite having an abnormal gene. For example, 40% of individuals with otosclerosis may not show any symptoms. Another complicating factor is spontaneous mutation, which occurs when there is a new mutation in one of the gametes. This means that 80% of individuals with achondroplasia have unaffected parents.
In summary, autosomal dominant inheritance is characterized by certain patterns of inheritance, but there are also complicating factors that can affect the expression of the disease. Understanding these factors is important for genetic counseling and for predicting the risk of passing on the disease to future generations.
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This question is part of the following fields:
- General Principles
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Question 9
Correct
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A 65-year-old female presents to the emergency department with a three-week history of gradual-onset left knee pain. She has a known history of hyperparathyroidism, but is not on any regular medications.
Upon examination, there are no visible changes to the joint and the temperature over the knee is normal. However, she experiences tenderness over passive and active movement, but no restriction of joint movement.
A joint radiograph reveals no fracture but chondrocalcinosis. Further, a joint aspiration under polarised light shows positively birefringent rhomboid-shaped crystals.
What is the underlying pathology, given the likely diagnosis?Your Answer: Calcium pyrophosphate dihydrate deposition
Explanation:The most probable diagnosis for this patient is pseudogout, which is characterized by the deposition of calcium pyrophosphate dihydrate crystals in the synovium, resulting in pain during movement. The knee joint is commonly affected, and the presence of rhomboid-shaped crystals that are positively birefringent in polarised-light microscopy of joint aspirate confirms the diagnosis. Radiography may also reveal chondrocalcinosis.
A fracture would require a history of trauma and would be visible on the radiograph, neither of which is present in this case, making it an unlikely diagnosis.
Reactive arthritis is associated with immune-mediated destruction of the joint, but there is no recent history of diarrhoea, coryza, conjunctivitis, or urethritis, which are commonly associated with this condition. The light microscopy of joint aspirate and radiography findings do not support this diagnosis.
Joint infection typically presents with a hot, swollen joint that rapidly develops after a history of trauma. The joint aspirate would be expected to contain turbid fluid and grow organisms. However, none of these features are present in this patient, making joint infection an unlikely diagnosis.
Understanding Pseudogout
Pseudogout, also known as acute calcium pyrophosphate crystal deposition disease, is a type of microcrystal synovitis that occurs when calcium pyrophosphate dihydrate crystals are deposited in the synovium. This condition is commonly associated with increasing age, but younger patients who develop pseudogout usually have an underlying risk factor such as haemochromatosis, hyperparathyroidism, low magnesium or phosphate levels, acromegaly, or Wilson’s disease.
The knee, wrist, and shoulders are the most commonly affected joints in pseudogout. Diagnosis is made through joint aspiration, which reveals weakly-positively birefringent rhomboid-shaped crystals, and x-rays, which show chondrocalcinosis. In the knee, linear calcifications of the meniscus and articular cartilage can be seen.
Management of pseudogout involves joint fluid aspiration to rule out septic arthritis, followed by treatment with NSAIDs or intra-articular, intra-muscular, or oral steroids, similar to the treatment for gout. Understanding the risk factors and symptoms of pseudogout can help with early diagnosis and effective management of this condition.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 10
Correct
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A 67-year-old man with a history of atrial fibrillation presents with an embolus in his lower leg. The medical team decides to perform an embolectomy using a trans popliteal approach. Upon incising the deep fascia, what will be the first structure encountered by the surgeons as they explore the central region of the popliteal fossa?
Your Answer: Tibial nerve
Explanation:The inferior aspect of the popliteal fossa houses the tibial nerve, which is positioned above the vessels. Initially, the nerve is located laterally to the vessels in the upper part of the fossa, but it eventually moves to a medial position by passing over them. The popliteal artery is the most deeply situated structure in the popliteal fossa.
Anatomy of the Popliteal Fossa
The popliteal fossa is a diamond-shaped space located at the back of the knee joint. It is bound by various muscles and ligaments, including the biceps femoris, semimembranosus, semitendinosus, and gastrocnemius. The floor of the popliteal fossa is formed by the popliteal surface of the femur, posterior ligament of the knee joint, and popliteus muscle, while the roof is made up of superficial and deep fascia.
The popliteal fossa contains several important structures, including the popliteal artery and vein, small saphenous vein, common peroneal nerve, tibial nerve, posterior cutaneous nerve of the thigh, genicular branch of the obturator nerve, and lymph nodes. These structures are crucial for the proper functioning of the lower leg and foot.
Understanding the anatomy of the popliteal fossa is important for healthcare professionals, as it can help in the diagnosis and treatment of various conditions affecting the knee joint and surrounding structures.
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This question is part of the following fields:
- Cardiovascular System
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Question 11
Correct
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A 40-year-old woman has just been diagnosed with HIV and is now taking a drug regimen that includes multiple medications. One of these drugs is designed to inhibit the virus from integrating its DNA into cells.
What drug is most likely being taken by this patient?Your Answer: Raltegravir
Explanation:Integrating HIV drugs that end with -gravir is significant because they are integrase inhibitors, while enfuvirtide functions as an entry inhibitor.
Antiretroviral therapy (ART) is a treatment for HIV that involves a combination of at least three drugs. This combination typically includes two nucleoside reverse transcriptase inhibitors (NRTI) and either a protease inhibitor (PI) or a non-nucleoside reverse transcriptase inhibitor (NNRTI). ART reduces viral replication and the risk of viral resistance emerging. The 2015 BHIVA guidelines recommend that patients start ART as soon as they are diagnosed with HIV, rather than waiting until a particular CD4 count.
Entry inhibitors, such as maraviroc and enfuvirtide, prevent HIV-1 from entering and infecting immune cells. Nucleoside analogue reverse transcriptase inhibitors (NRTI), such as zidovudine, abacavir, and tenofovir, can cause peripheral neuropathy and other side effects. Non-nucleoside reverse transcriptase inhibitors (NNRTI), such as nevirapine and efavirenz, can cause P450 enzyme interaction and rashes. Protease inhibitors (PI), such as indinavir and ritonavir, can cause diabetes, hyperlipidaemia, and other side effects. Integrase inhibitors, such as raltegravir and dolutegravir, block the action of integrase, a viral enzyme that inserts the viral genome into the DNA of the host cell.
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This question is part of the following fields:
- General Principles
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Question 12
Incorrect
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A 16-year-old boy undergoes an emergency splenectomy for trauma and is discharged home after making a full recovery. After eight weeks, his general practitioner performs a full blood count with a blood film. What is the most likely finding?
Your Answer: Myofibroblasts
Correct Answer: Howell-Jolly bodies
Explanation:After a splenectomy, the blood film may show the presence of Howell-Jolly bodies, Pappenheimer bodies, target cells, and irregular contracted erythrocytes due to the absence of the spleen’s filtration function.
Blood Film Changes after Splenectomy
After undergoing splenectomy, the body loses its ability to remove immature or abnormal red blood cells from circulation. This results in the appearance of cytoplasmic inclusions such as Howell-Jolly bodies, although the red cell count remains relatively unchanged. In the first few days following the procedure, target cells, siderocytes, and reticulocytes may be observed in the bloodstream. Additionally, agranulocytosis composed mainly of neutrophils is seen immediately after the operation, which is then replaced by a lymphocytosis and monocytosis over the next few weeks. The platelet count is typically elevated and may persist, necessitating the use of oral antiplatelet agents in some patients.
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This question is part of the following fields:
- Gastrointestinal System
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Question 13
Incorrect
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A 28-year-old male comes to the Emergency Department complaining of a severely painful, reddened right-eye that has been going on for 6 hours. He also reports experiencing haloes around light and reduced visual acuity. The patient has a history of hypermetropia. Upon examination, the right-eye appears red with a fixed and dilated pupil and conjunctival injection.
What is the most probable diagnosis?Your Answer: Vitreous haemorrhage
Correct Answer: Acute closed-angle glaucoma
Explanation:The correct diagnosis is acute closed-angle glaucoma, which is characterized by an increase in intra-ocular pressure due to impaired aqueous outflow. Symptoms include a painful red eye, reduced visual acuity, and haloes around light. Risk factors include hypermetropia, pupillary dilatation, and age-related lens growth. Examination findings typically include a fixed dilated pupil with conjunctival injection. Treatment options include reducing aqueous secretions with acetazolamide and increasing pupillary constriction with topical pilocarpine.
Anterior uveitis is an incorrect diagnosis, as it refers to inflammation of the anterior portion of the uvea and is associated with systemic inflammatory conditions. Ophthalmoscopy findings include an irregular pupil.
Central retinal vein occlusion is also an incorrect diagnosis, as it causes acute blindness due to thromboembolism or vasculitis in the central retinal vein. Ophthalmoscopy typically reveals severe retinal haemorrhages.
Infective conjunctivitis is another incorrect diagnosis, as it is characterized by sore, red eyes with discharge. Bacterial causes typically result in purulent discharge, while viral cases often have serous discharge.
Acute angle closure glaucoma (AACG) is a type of glaucoma where there is a rise in intraocular pressure (IOP) due to a blockage in the outflow of aqueous humor. This condition is more likely to occur in individuals with hypermetropia, pupillary dilation, and lens growth associated with aging. Symptoms of AACG include severe pain, decreased visual acuity, a hard and red eye, haloes around lights, and a semi-dilated non-reacting pupil. AACG is an emergency and requires urgent referral to an ophthalmologist. The initial medical treatment involves a combination of eye drops, such as a direct parasympathomimetic, a beta-blocker, and an alpha-2 agonist, as well as intravenous acetazolamide to reduce aqueous secretions. Definitive management involves laser peripheral iridotomy, which creates a tiny hole in the peripheral iris to allow aqueous humor to flow to the angle.
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This question is part of the following fields:
- Neurological System
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Question 14
Correct
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As a medical student on a general surgical team, I am currently treating an 82-year-old female who is scheduled for a mastectomy due to breast cancer. Can you inform me of the most prevalent form of breast cancer?
Your Answer: Invasive ductal carcinoma
Explanation:Breast Cancer Pathology: Understanding the Histological Features
Breast cancer pathology involves examining the histological features of the cancer cells to determine the underlying diagnosis. The invasive component of breast cancer is typically made up of ductal cells, although invasive lobular cancer may also occur. In situ lesions, such as DCIS, may also be present.
When examining breast cancer pathology, several typical changes are seen in conjunction with invasive breast cancer. These include nuclear pleomorphism, coarse chromatin, angiogenesis, invasion of the basement membrane, dystrophic calcification (which may be seen on mammography), abnormal mitoses, vascular invasion, and lymph node metastasis.
To grade the primary tumor, a scale of 1-3 is used, with 1 being the most benign lesion and 3 being the most poorly differentiated. Immunohistochemistry for estrogen receptor and herceptin status is routinely performed to further understand the cancer’s characteristics.
The grade, lymph node stage, and size are combined to provide the Nottingham prognostic index, which helps predict the patient’s prognosis and guide treatment decisions. Understanding the histological features of breast cancer is crucial in determining the best course of treatment for patients.
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This question is part of the following fields:
- Haematology And Oncology
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Question 15
Incorrect
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Samantha, a 23-year-old female, arrives at the emergency department after falling on her outstretched hand during a volleyball game. She reports experiencing pain in her left shoulder.
After assessing her neurovascular status, the attending physician orders an x-ray which reveals a surgical neck fracture of the left humerus.
Which muscles are expected to have decreased movement based on the nerve most likely affected by this fracture?Your Answer: Teres minor, trapezius and deltoid
Correct Answer: Teres minor and deltoid
Explanation:The axillary nerve is responsible for supplying the teres minor and deltoid muscles. It is composed of nerve fibers from C5 and C6 of the brachial plexus and originates in the axilla. The nerve exits the axilla through the quadrangular space, located at the lower border of the subscapularis muscle. It then travels medially to the surgical neck of the humerus, making it vulnerable to injury in cases of surgical neck fractures. Other muscles innervated by the axillary nerve include the teres major and trapezius, which are supplied by the lower subscapular and accessory nerves, respectively.
Upper limb anatomy is a common topic in examinations, and it is important to know certain facts about the nerves and muscles involved. The musculocutaneous nerve is responsible for elbow flexion and supination, and typically only injured as part of a brachial plexus injury. The axillary nerve controls shoulder abduction and can be damaged in cases of humeral neck fracture or dislocation, resulting in a flattened deltoid. The radial nerve is responsible for extension in the forearm, wrist, fingers, and thumb, and can be damaged in cases of humeral midshaft fracture, resulting in wrist drop. The median nerve controls the LOAF muscles and can be damaged in cases of carpal tunnel syndrome or elbow injury. The ulnar nerve controls wrist flexion and can be damaged in cases of medial epicondyle fracture, resulting in a claw hand. The long thoracic nerve controls the serratus anterior and can be damaged during sports or as a complication of mastectomy, resulting in a winged scapula. The brachial plexus can also be damaged, resulting in Erb-Duchenne palsy or Klumpke injury, which can cause the arm to hang by the side and be internally rotated or associated with Horner’s syndrome, respectively.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 16
Correct
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What is the carrier rate of cystic fibrosis in the United Kingdom?
Your Answer: 1 in 25
Explanation:Understanding Cystic Fibrosis
Cystic fibrosis is a genetic disorder that causes thickened secretions in the lungs and pancreas. It is an autosomal recessive condition that occurs due to a defect in the cystic fibrosis transmembrane conductance regulator gene (CFTR), which regulates a chloride channel. In the UK, 80% of CF cases are caused by delta F508 on chromosome 7, and the carrier rate is approximately 1 in 25.
CF patients are at risk of colonization by certain organisms, including Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia (previously known as Pseudomonas cepacia), and Aspergillus. These organisms can cause infections and exacerbate symptoms in CF patients. It is important for healthcare providers to monitor and manage these infections to prevent further complications.
Overall, understanding cystic fibrosis and its associated risks can help healthcare providers provide better care for patients with this condition.
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This question is part of the following fields:
- Respiratory System
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Question 17
Incorrect
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A 39-year old male visits the GP complaining of nipple discharge. Upon examination, it is found that his serum prolactin levels are significantly high. Besides prolactin releasing hormone, which other hypothalamic hormone can stimulate the secretion of prolactin?
Your Answer: Somatostatin
Correct Answer: Thyrotropin releasing hormone (TRH)
Explanation:Understanding Prolactin and Its Functions
Prolactin is a hormone that is produced by the anterior pituitary gland. Its primary function is to stimulate breast development and milk production in females. During pregnancy, prolactin levels increase to support the growth and development of the mammary glands. It also plays a role in reducing the pulsatility of gonadotropin-releasing hormone (GnRH) at the hypothalamic level, which can block the action of luteinizing hormone (LH) on the ovaries or testes.
The secretion of prolactin is regulated by dopamine, which constantly inhibits its release. However, certain factors can increase or decrease prolactin secretion. For example, prolactin levels increase during pregnancy, in response to estrogen, and during breastfeeding. Additionally, stress, sleep, and certain drugs like metoclopramide and antipsychotics can also increase prolactin secretion. On the other hand, dopamine and dopaminergic agonists can decrease prolactin secretion.
Overall, understanding the functions and regulation of prolactin is important for reproductive health and lactation.
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This question is part of the following fields:
- Endocrine System
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Question 18
Correct
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A 50-year-old motorcyclist is seeking treatment at your clinic after a bike accident that occurred 10 months ago. The patient suffered a significant pelvic fracture, which has since healed. However, he is worried about the persistent numbness in his right leg. During the examination, he experiences difficulty in adducting his right hip against resistance and has reduced sensation around the medial aspect of his right thigh. Which nerve is most likely to have been affected?
Your Answer: Obturator
Explanation:The patient is experiencing decreased sensation in the inner thigh and weakened adductor muscles, which are both controlled by the obturator nerve.
Meanwhile, the femoral nerve is responsible for providing sensation to the front of the thigh, while the sciatic nerve is responsible for sensation in the back of the thigh.
Additionally, the ilio-inguinal nerve is responsible for sensation in certain areas of the genital region, and the tibial nerve controls the movement of ankle muscles.
Anatomy of the Obturator Nerve
The obturator nerve is formed by branches from the ventral divisions of L2, L3, and L4 nerve roots, with L3 being the main contributor. It descends vertically in the posterior part of the psoas major muscle and emerges from its medial border at the lateral margin of the sacrum. After crossing the sacroiliac joint, it enters the lesser pelvis and descends on the obturator internus muscle to enter the obturator groove. The nerve lies lateral to the internal iliac vessels and ureter in the lesser pelvis and is joined by the obturator vessels lateral to the ovary or ductus deferens.
The obturator nerve supplies the muscles of the medial compartment of the thigh, including the external obturator, adductor longus, adductor brevis, adductor magnus (except for the lower part supplied by the sciatic nerve), and gracilis. The cutaneous branch, which is often absent, supplies the skin and fascia of the distal two-thirds of the medial aspect of the thigh when present.
The obturator canal connects the pelvis and thigh and contains the obturator artery, vein, and nerve, which divides into anterior and posterior branches. Understanding the anatomy of the obturator nerve is important in diagnosing and treating conditions that affect the medial thigh and pelvic region.
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This question is part of the following fields:
- Neurological System
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Question 19
Incorrect
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A 13-year-old girl is brought to the first-seizure clinic by her parents after experiencing multiple seizures in the past two weeks. According to her parents, the girl loses consciousness, becomes rigid, and falls to the ground while shaking for about two minutes during each episode. They also report that she has been experiencing urinary incontinence during these seizures.
The specialist decides to prescribe an antiepileptic medication.
What is the likely diagnosis for this patient, and what is the mechanism of action of the prescribed drug?Your Answer: Carbamazepine - inhibits sodium channels
Correct Answer: Sodium valproate - inhibits sodium channels
Explanation:The patient in this scenario is experiencing a classic case of tonic-clonic seizures, which is characterized by unconsciousness, stiffness, and jerking of muscles. The first-line treatment for males with tonic-clonic seizures is sodium valproate, which is believed to work by inhibiting sodium channels and suppressing the excitation of neurons in the brain. Lamotrigine or levetiracetam is recommended for females due to the teratogenic effects of sodium valproate. Carbamazepine, which is a second-line treatment for focal seizures, would not be prescribed in this case. Ethosuximide, which is used to treat absence seizures, works by partially antagonizing calcium channels in the brain.
Treatment Options for Epilepsy
Epilepsy is a neurological disorder that affects millions of people worldwide. Treatment for epilepsy typically involves the use of antiepileptic drugs (AEDs) to control seizures. The decision to start AEDs is usually made after a second seizure, but there are certain circumstances where treatment may be initiated after the first seizure. These include the presence of a neurological deficit, structural abnormalities on brain imaging, unequivocal epileptic activity on EEG, or if the patient or their family considers the risk of having another seizure to be unacceptable.
It is important to note that there are specific drug treatments for different types of seizures. For generalized tonic-clonic seizures, males are typically prescribed sodium valproate, while females may be given lamotrigine or levetiracetam. For focal seizures, first-line treatment options include lamotrigine or levetiracetam, with carbamazepine, oxcarbazepine, or zonisamide used as second-line options. Ethosuximide is the first-line treatment for absence seizures, with sodium valproate or lamotrigine/levetiracetam used as second-line options. For myoclonic seizures, males are usually given sodium valproate, while females may be prescribed levetiracetam. Finally, for tonic or atonic seizures, males are typically given sodium valproate, while females may be prescribed lamotrigine.
It is important to work closely with a healthcare provider to determine the best treatment plan for each individual with epilepsy. Additionally, it is important to be aware of potential risks associated with certain AEDs, such as the use of sodium valproate during pregnancy, which has been linked to neurodevelopmental delays in children.
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This question is part of the following fields:
- Neurological System
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Question 20
Incorrect
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A 9-year-old boy presents to the paediatric outpatient clinic with a history of duodenal atresia, clinodactyly, a wide nasal bridge, and a large tongue. What malignancy is he at an elevated risk for?
Your Answer: Nephroblastoma
Correct Answer: Acute leukaemias
Explanation:Down’s Syndrome and Associated Conditions
Down’s syndrome, also known as trisomy 21, is characterized by several physical features such as a wide, flat nasal bridge, macroglossia, and clinodactyly. Other common features include a round face, hypothyroidism, a sandal gap between the toes, and a single palmar crease. Individuals with Down’s syndrome are predisposed to certain conditions such as Alzheimer’s disease and acute leukaemias. However, nephroblastomas, primary bone malignancies, soft tissue tumours, and solid CNS tumours are not directly related to Down’s syndrome. Nephroblastomas are associated with an absent iris, while primary bone malignancies have few predisposing factors except for rare cancer syndromes. Soft tissue tumours, such as rhabdomyosarcomas, are linked to familial retinoblastoma, while solid CNS tumours are increased in cancer syndromes like Li-Fraumeni. the associated conditions of Down’s syndrome can aid in early detection and treatment of these conditions.
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This question is part of the following fields:
- Haematology And Oncology
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