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Question 1
Incorrect
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A 29-year-old woman visits her family physician with complaints of vaginal discomfort and grayish discharge for the past two days. She is sexually active with her husband and has never been pregnant. The physician confirms the presence of thin, grayish discharge with a fishy odor but finds no inflammation. The patient has no history of multiple sexual partners or illicit drug use, and a pregnancy test is negative. The doctor prescribes clindamycin for treatment and advises that the patient's husband does not need to be treated. What are the correct microscopic and biochemical findings for the pathogenic agent responsible for this patient's condition?
Your Answer: Motile trichomonads with a discharge pH less than 4.5
Correct Answer: Clue cells with a discharge of pH greater than 4.5
Explanation:The patient displayed symptoms consistent with bacterial vaginosis, which is characterized by a non-inflamed vagina and a thin, white or grayish discharge. In contrast, candida vulvovaginitis presents with an inflamed vagina and a thick, white, cheese-like discharge, while trichomonas vaginitis is associated with an inflamed vagina and a pH greater than 4.5. Bacterial vaginosis is caused by Gardnerella vaginalis and can be treated with metronidazole or clindamycin, without the need for partner treatment. Trichomonas vaginitis, on the other hand, requires partner treatment and is treated with metronidazole.
Bacterial vaginosis (BV) is a condition where there is an overgrowth of anaerobic organisms, particularly Gardnerella vaginalis, in the vagina. This leads to a decrease in the amount of lactobacilli, which produce lactic acid, resulting in an increase in vaginal pH. BV is not a sexually transmitted infection, but it is commonly seen in sexually active women. Symptoms include a fishy-smelling vaginal discharge, although some women may not experience any symptoms at all. Diagnosis is made using Amsel’s criteria, which includes the presence of thin, white discharge, clue cells on microscopy, a vaginal pH greater than 4.5, and a positive whiff test. Treatment involves oral metronidazole for 5-7 days, with a cure rate of 70-80%. However, relapse rates are high, with over 50% of women experiencing a recurrence within 3 months. Topical metronidazole or clindamycin may be used as alternatives.
Bacterial vaginosis during pregnancy can increase the risk of preterm labor, low birth weight, chorioamnionitis, and late miscarriage. It was previously recommended to avoid oral metronidazole in the first trimester and use topical clindamycin instead. However, recent guidelines suggest that oral metronidazole can be used throughout pregnancy. The British National Formulary (BNF) still advises against using high-dose metronidazole regimes. Clue cells, which are vaginal epithelial cells covered with bacteria, can be seen on microscopy in women with BV.
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This question is part of the following fields:
- General Principles
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Question 2
Correct
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Following a car crash, a 25-year-old male is brought to the hospital and needs a blood transfusion. He has B negative blood type. Which of the following blood types would be the best match?
Your Answer: O rhesus negative
Explanation:The ideal blood type for the patient would be B rhesus negative, but it is not available. Among the available options, rhesus positive blood is not recommended for a woman of reproductive age as it may lead to haemolytic disease in newborns. A-type blood would also cause hemolysis in this patient. The only suitable option is O rhesus negative, which is the universal donor.
Blood product transfusion complications can be categorized into immunological, infective, and other complications. Immunological complications include acute haemolytic reactions, non-haemolytic febrile reactions, and allergic/anaphylaxis reactions. Infective complications may arise due to transmission of vCJD, although measures have been taken to minimize this risk. Other complications include transfusion-related acute lung injury (TRALI), transfusion-associated circulatory overload (TACO), hyperkalaemia, iron overload, and clotting.
Non-haemolytic febrile reactions are thought to be caused by antibodies reacting with white cell fragments in the blood product and cytokines that have leaked from the blood cell during storage. These reactions may occur in 1-2% of red cell transfusions and 10-30% of platelet transfusions. Minor allergic reactions may also occur due to foreign plasma proteins, while anaphylaxis may be caused by patients with IgA deficiency who have anti-IgA antibodies.
Acute haemolytic transfusion reaction is a serious complication that results from a mismatch of blood group (ABO) which causes massive intravascular haemolysis. Symptoms begin minutes after the transfusion is started and include a fever, abdominal and chest pain, agitation, and hypotension. Treatment should include immediate transfusion termination, generous fluid resuscitation with saline solution, and informing the lab. Complications include disseminated intravascular coagulation and renal failure.
TRALI is a rare but potentially fatal complication of blood transfusion that is characterized by the development of hypoxaemia/acute respiratory distress syndrome within 6 hours of transfusion. On the other hand, TACO is a relatively common reaction due to fluid overload resulting in pulmonary oedema. As well as features of pulmonary oedema, the patient may also be hypertensive, a key difference from patients with TRALI.
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This question is part of the following fields:
- Haematology And Oncology
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Question 3
Incorrect
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A 25-year-old male presents with a recent onset of vomiting and diarrhoea. Upon further inquiry, he reports consuming undercooked meat at a barbecue three days ago. What is the probable pathological mechanism responsible for his diarrhoea?
Your Answer: Endotoxins causing cell death and leakage of intracellular contents into intestinal lumen
Correct Answer: Endotoxins stimulating secretion of electrolytes into intestinal lumen
Explanation:Two Main Pathological Processes that Cause Diarrhoea
There are two main pathological processes that typically cause diarrhoea: secretory diarrhoea and osmotic diarrhoea. Secretory diarrhoea is often caused by bacteria such as E. coli and V. cholerae, which produce A-B type endotoxins that activate and increase cyclic AMP. This leads to an increase in the amounts of Na+, K+, bicarbonate, and nutrients into the apical side of the lumen, which in turn draws water into the lumen as well. On the other hand, osmotic diarrhoea occurs when osmotically active nutrients within the lumen pull water in through osmotic gradients. This is often seen in patients with pancreatic insufficiency or coeliac disease.
Laxatives work in the same manner as osmotic diarrhoea, as they increase the water content in the large bowel by exerting osmotic effects. However, in this case, laxative use is unlikely as it does not fit with the clinical history. It is important to note that diarrhoea is defined as 200 ml of water per daily excrement. the underlying pathological processes that cause diarrhoea can help in the diagnosis and treatment of this common condition.
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This question is part of the following fields:
- Infectious Diseases
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Question 4
Correct
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A 72-year-old woman is brought to the general practice by her son. The son reports that his mother has been experiencing increasing forgetfulness and appears less alert. She has also been having repeated incidents of urinary incontinence and walks with a shuffling gait. A CT head scan is ordered, which reveals bilateral dilation of the lateral ventricles without any blockage of the interventricular foramina. What is the space that the interventricular foramen allows cerebrospinal fluid to flow from each lateral ventricle into?
Your Answer: Third ventricle
Explanation:The third ventricle is the correct answer as it is a part of the CSF system and is located in the midline between the thalami of the two hemispheres. It connects to the lateral ventricles via the interventricular foramina and to the fourth ventricle via the cerebral aqueduct (of Sylvius).
CSF flows from the third ventricle to the fourth ventricle through the cerebral aqueduct (of Sylvius) and exits the fourth ventricle through one of four openings. These include the median aperture (foramen of Magendie), either of the two lateral apertures (foramina of Luschka), and the central canal at the obex.
The lateral ventricles do not communicate directly with each other and drain into the third ventricle via individual interventricular foramina.
The patient in the question is likely suffering from normal pressure hydrocephalus, which is characterized by gait abnormality, urinary incontinence, and dementia. This condition is caused by alterations in the flow and absorption of CSF, leading to ventricular dilation without raised intracranial pressure. Lumbar puncture typically shows normal CSF pressure.
Cerebrospinal Fluid: Circulation and Composition
Cerebrospinal fluid (CSF) is a clear, colorless liquid that fills the space between the arachnoid mater and pia mater, covering the surface of the brain. The total volume of CSF in the brain is approximately 150ml, and it is produced by the ependymal cells in the choroid plexus or blood vessels. The majority of CSF is produced by the choroid plexus, accounting for 70% of the total volume. The remaining 30% is produced by blood vessels. The CSF is reabsorbed via the arachnoid granulations, which project into the venous sinuses.
The circulation of CSF starts from the lateral ventricles, which are connected to the third ventricle via the foramen of Munro. From the third ventricle, the CSF flows through the cerebral aqueduct (aqueduct of Sylvius) to reach the fourth ventricle via the foramina of Magendie and Luschka. The CSF then enters the subarachnoid space, where it circulates around the brain and spinal cord. Finally, the CSF is reabsorbed into the venous system via arachnoid granulations into the superior sagittal sinus.
The composition of CSF is essential for its proper functioning. The glucose level in CSF is between 50-80 mg/dl, while the protein level is between 15-40 mg/dl. Red blood cells are not present in CSF, and the white blood cell count is usually less than 3 cells/mm3. Understanding the circulation and composition of CSF is crucial for diagnosing and treating various neurological disorders.
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This question is part of the following fields:
- Neurological System
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Question 5
Correct
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A 30-year-old man visits the sexual health clinic with complaints of dysuria and penile discharge. He is concerned about having a sexually transmitted infection due to engaging in unprotected sex with multiple partners in the past month. During the examination, the clinician takes an urethral swab, smears it on a slide, and performs a gram stain. Upon examining the slide under the microscope, the clinician informs the man that he has probably contracted gonorrhoeae.
What would be the appearance of this organism when viewed under the microscope?Your Answer: Gram-negative diplococci
Explanation:Gram-negative diplococci can be used to identify Neisseria gonorrhoeae on gram staining.
Streptococcus pneumonia is a type of bacterium that appears as gram-positive diplococci.
Gram-positive cocci in clusters are characteristic of Staphylococcus aureus.
The Acinetobacter group and the Haemophilus group are examples of gram-negative coccobacilli.
Understanding gonorrhoeae: Causes, Symptoms, and Treatment
gonorrhoeae is a sexually transmitted infection caused by the Gram-negative diplococcus Neisseria gonorrhoeae. It can occur on any mucous membrane surface, including the genitourinary tract, rectum, and pharynx. Symptoms in males include urethral discharge and dysuria, while females may experience cervicitis leading to vaginal discharge. However, rectal and pharyngeal infections are usually asymptomatic. Unfortunately, immunisation is not possible, and reinfection is common due to antigen variation of type IV pili and Opa proteins.
If left untreated, gonorrhoeae can lead to local complications such as urethral strictures, epididymitis, and salpingitis, which may result in infertility. Disseminated infection may also occur, with gonococcal infection being the most common cause of septic arthritis in young adults. The pathophysiology of disseminated gonococcal infection is not fully understood but is thought to be due to haematogenous spread from mucosal infection.
Management of gonorrhoeae involves the use of antibiotics. Ciprofloxacin used to be the treatment of choice, but there is now increased resistance to it. Cephalosporins are now more widely used, with a single dose of IM ceftriaxone 1g being the new first-line treatment. If sensitivities are known, a single dose of oral ciprofloxacin 500mg may be given. Disseminated gonococcal infection and gonococcal arthritis may also occur, with symptoms including tenosynovitis, migratory polyarthritis, and dermatitis.
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This question is part of the following fields:
- General Principles
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Question 6
Incorrect
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A 65-year-old man presents to the vascular clinic with bilateral buttock claudication that spreads down the thigh and erectile dysfunction. The vascular surgeon is unable to palpate his left femoral pulse and the right is weakly palpable. The patient is diagnosed with Leriche syndrome, which is caused by atherosclerotic occlusion of blood flow at the abdominal aortic bifurcation. He has been consented for aorto-iliac bypass surgery and is currently awaiting the procedure.
What is the vertebral level of the affected artery that requires bypassing?Your Answer: T12
Correct Answer: L4
Explanation:The aorta is a major blood vessel that carries oxygenated blood from the heart to the rest of the body. At different levels along the aorta, there are branches that supply blood to specific organs and regions. These branches include the coeliac trunk at the level of T12, which supplies blood to the stomach, liver, and spleen. The left renal artery, at the level of L1, supplies blood to the left kidney. The testicular or ovarian arteries, at the level of L2, supply blood to the reproductive organs. The inferior mesenteric artery, at the level of L3, supplies blood to the lower part of the large intestine. Finally, at the level of L4, the abdominal aorta bifurcates, or splits into two branches, which supply blood to the legs and pelvis.
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This question is part of the following fields:
- Cardiovascular System
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Question 7
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A 28-year-old rugby player complains of polyuria and polydipsia. He reports being hospitalized 5 months ago due to a head injury sustained while playing rugby. Central diabetes insipidus is confirmed through biochemistry and a water-deprivation test. A pituitary MRI reveals a thickened pituitary stalk, supporting the diagnosis. What is the appropriate medication for this patient?
Your Answer: Desmopressin
Explanation:Desmopressin is an effective treatment for central diabetes insipidus, which is a rare condition caused by damage or dysfunction of the posterior pituitary gland resulting in a lack of ADH production. Carbimazole is used to treat hyperthyroidism, while goserelin is used to treat prostate cancer. Indapamide, a thiazide-like diuretic, is used to manage hypertension and heart failure.
Diabetes insipidus is a medical condition that can be caused by either a decreased secretion of antidiuretic hormone (ADH) from the pituitary gland (cranial DI) or an insensitivity to ADH (nephrogenic DI). Cranial DI can be caused by various factors such as head injury, pituitary surgery, and infiltrative diseases like sarcoidosis. On the other hand, nephrogenic DI can be caused by genetic factors, electrolyte imbalances, and certain medications like lithium and demeclocycline. The common symptoms of DI are excessive urination and thirst. Diagnosis is made through a water deprivation test and checking the osmolality of the urine. Treatment options include thiazides and a low salt/protein diet for nephrogenic DI, while central DI can be treated with desmopressin.
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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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A 67-year-old male is referred to a neurologist for a complete evaluation of a 6-month history of anosmia. The patient denies any other symptoms except for anosmia and occasional headaches. An MRI scan reveals a small brain tumor, which is suspected to be the underlying cause of the symptoms.
What is the most probable location of this lesion?Your Answer: Occipital lobe
Correct Answer: Frontal lobe
Explanation:Anosmia, or loss of smell, can be caused by lesions in the frontal lobe of the brain. In addition to anosmia, frontal lobe lesions may also cause Broca’s aphasia, personality changes, and loss of motor function. Cerebellar lesions, on the other hand, may present with the DANISH symptoms, which include dysdiadochokinesia, ataxia, intention tremor, nystagmus, and hypotonia. Lesions in the occipital lobe can cause visual loss, while lesions in the parietal lobe may cause sensory problems, body awareness issues, and language development weakening. Finally, lesions in the temporal lobe may cause Wernicke’s aphasia, memory loss, emotional changes, and a superior quadrantanopia.
Brain lesions can be localized based on the neurological disorders or features that are present. The gross anatomy of the brain can provide clues to the location of the lesion. For example, lesions in the parietal lobe can result in sensory inattention, apraxias, astereognosis, inferior homonymous quadrantanopia, and Gerstmann’s syndrome. Lesions in the occipital lobe can cause homonymous hemianopia, cortical blindness, and visual agnosia. Temporal lobe lesions can result in Wernicke’s aphasia, superior homonymous quadrantanopia, auditory agnosia, and prosopagnosia. Lesions in the frontal lobes can cause expressive aphasia, disinhibition, perseveration, anosmia, and an inability to generate a list. Lesions in the cerebellum can result in gait and truncal ataxia, intention tremor, past pointing, dysdiadokinesis, and nystagmus.
In addition to the gross anatomy, specific areas of the brain can also provide clues to the location of a lesion. For example, lesions in the medial thalamus and mammillary bodies of the hypothalamus can result in Wernicke and Korsakoff syndrome. Lesions in the subthalamic nucleus of the basal ganglia can cause hemiballism, while lesions in the striatum (caudate nucleus) can result in Huntington chorea. Parkinson’s disease is associated with lesions in the substantia nigra of the basal ganglia, while lesions in the amygdala can cause Kluver-Bucy syndrome, which is characterized by hypersexuality, hyperorality, hyperphagia, and visual agnosia. By identifying these specific conditions, doctors can better localize brain lesions and provide appropriate treatment.
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This question is part of the following fields:
- Neurological System
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Question 9
Incorrect
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What characteristic could serve as a reliable indicator of prognosis for a patient who has recently been diagnosed with acute lymphoblastic leukemia (ALL)?
Your Answer: Age <10 years
Correct Answer:
Explanation:Prognostic Factors in Acute Lymphoblastic Leukemia
Younger patients with acute lymphoblastic leukemia (ALL) have a better prognosis than older patients. In fact, the cure rate in children is around 90%, while it is less than 40% in adults. Additionally, male patients tend to fare worse than females, and they require a longer maintenance dose of chemotherapy (3 years versus 2 years). Interestingly, the Philadelphia chromosome, which is an effective treatment target in chronic myeloid leukemia, is actually a poor prognostic marker in ALL. Finally, higher white cell counts are associated with adverse outcomes, particularly if the count exceeds 100 ×106/ml.
Overall, these prognostic factors can help clinicians predict the likelihood of a successful outcome in patients with ALL. By taking these factors into account, healthcare providers can tailor treatment plans to each patient’s individual needs and improve their chances of a positive outcome.
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This question is part of the following fields:
- Haematology And Oncology
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Question 10
Correct
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A 55-year-old man with a recent diagnosis of essential hypertension and prescribed ramipril has returned for a follow-up appointment after 6 weeks. He has a medical history of osteoarthritis and benign prostate hypertrophy. Despite being compliant with his medication, his blood pressure reading is 145/90 mmHg, which is higher than his previous readings at home. What could be the reason for his inadequate blood pressure control despite medical treatment?
Your Answer: Ibuprofen
Explanation:The patient with osteoarthritis is likely taking NSAIDs, which can diminish the effectiveness of ACE inhibitors in controlling hypertension. Additionally, NSAIDs can worsen the hyperkalemic effects of ACE inhibitors, contributing to the patient’s uncontrolled blood pressure. It is important to note that alcohol can also exacerbate the hypotensive effects of ACE inhibitors. Nitrates, on the other hand, are useful in managing hypertension.
Angiotensin-converting enzyme (ACE) inhibitors are commonly used as the first-line treatment for hypertension and heart failure in younger patients. However, they may not be as effective in treating hypertensive Afro-Caribbean patients. ACE inhibitors are also used to treat diabetic nephropathy and prevent ischaemic heart disease. These drugs work by inhibiting the conversion of angiotensin I to angiotensin II and are metabolized in the liver.
While ACE inhibitors are generally well-tolerated, they can cause side effects such as cough, angioedema, hyperkalaemia, and first-dose hypotension. Patients with certain conditions, such as renovascular disease, aortic stenosis, or hereditary or idiopathic angioedema, should use ACE inhibitors with caution or avoid them altogether. Pregnant and breastfeeding women should also avoid these drugs.
Patients taking high-dose diuretics may be at increased risk of hypotension when using ACE inhibitors. Therefore, it is important to monitor urea and electrolyte levels before and after starting treatment, as well as any changes in creatinine and potassium levels. Acceptable changes include a 30% increase in serum creatinine from baseline and an increase in potassium up to 5.5 mmol/l. Patients with undiagnosed bilateral renal artery stenosis may experience significant renal impairment when using ACE inhibitors.
The current NICE guidelines recommend using a flow chart to manage hypertension, with ACE inhibitors as the first-line treatment for patients under 55 years old. However, individual patient factors and comorbidities should be taken into account when deciding on the best treatment plan.
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This question is part of the following fields:
- Cardiovascular System
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