Clinical Medicine Exam III

Psychosis is not one of the cardinal features of Parkinson's disease. The four cardinal features of Parkinson's disease are bradykinesia (slowness of movement), tremor (involuntary shaking), postural instability (balance problems), and muscular rigidity (stiffness of muscles). Psychosis refers to a loss of contact with reality and is not considered one of the primary symptoms of Parkinson's disease.

PET scans utilize a positron-labeled molecule that becomes associated with metabolically active tissues. This is because metabolically active tissues have a higher demand for energy and glucose, which results in increased uptake of the positron-labeled molecule. This allows PET scans to detect areas of the body that are metabolically active, such as areas of cancer, inflammation, or brain activity.

The patient in this case is experiencing a bilateral focal dystonia of the orbicularis oculi, which refers to involuntary muscle contractions in the muscles around the eyes. The treatment for this condition is an injection of Botulinum toxin, which helps to relax the muscles and reduce the spasms. Therefore, the correct disorder that the patient has is Blepharospasm, which specifically refers to involuntary contractions of the muscles around the eyes.

Iodinated CT contrast is commonly associated with the serious problem of renal dysfunction. The contrast can cause damage to the kidneys, leading to impaired kidney function. This can result in decreased urine output, increased levels of waste products in the blood, and potential kidney failure. It is important to assess the patient's renal function before administering contrast and to monitor them closely for any signs of renal dysfunction after the procedure.

During sleep, humans spend the longest portion in Stage 2. This stage is characterized by the presence of spindles and K-complexes, which are brief bursts of brain activity. Stage 2 is a transitional stage between light sleep (Stage 1) and deep sleep (Stages 3 and 4). It is during Stage 2 that the brain starts to produce sleep spindles, which are rapid bursts of brain waves, and K-complexes, which are large, slow waves. These characteristics make Stage 2 the correct answer.

The superchiasmatic nucleus is responsible for the regulation of melatonin secretion from the pineal gland. This nucleus is located in the hypothalamus and acts as the master clock for the circadian rhythm. It receives input from the retina, which helps in synchronizing the internal body clock with the external light-dark cycle. The superchiasmatic nucleus controls the timing of melatonin release, which plays a crucial role in regulating sleep-wake cycles and other physiological processes influenced by the circadian rhythm.

Streptococcus pneumoniae is responsible for the majority of bacterial meningitis cases in the United States of America. This bacterium is a common cause of pneumonia and can also cause other infections such as sinusitis and ear infections. It is a leading cause of meningitis, particularly in young children and older adults. Streptococcus pneumoniae can spread through respiratory droplets and can cause severe illness if it enters the bloodstream and reaches the brain and spinal cord, resulting in meningitis.

Narcolepsy is commonly associated with abnormally low or absent levels of hypocretin. Hypocretin is a neurotransmitter that helps regulate wakefulness and sleep. In individuals with narcolepsy, there is a deficiency of hypocretin, leading to excessive daytime sleepiness, sudden sleep attacks, and disrupted sleep patterns. This condition can greatly impact a person's daily functioning and quality of life.

Cytomegalovirus (CMV) is the most common virus transmitted to the fetus. CMV can be transmitted to the fetus during pregnancy if the mother becomes infected. It can cause various complications in the fetus, including hearing loss, vision problems, developmental delays, and even death. CMV is commonly transmitted through bodily fluids, such as saliva, urine, and blood. It is important for pregnant women to take precautions to prevent CMV infection, such as practicing good hygiene and avoiding close contact with individuals who have active CMV infections.

The goal for door to needle time for the administration of IV recombinant-tissue plasminogen activator should occur within 60 minutes upon arrival of the ischemic stroke patient at the emergency room. This means that the medication should be administered within one hour of the patient's arrival. Administering the medication within this time frame is crucial as it helps to improve outcomes and minimize the risk of complications associated with ischemic stroke.

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The combination of Ampicillin, 3rd generation cephalosporin, and vancomycin is considered the empirical treatment for suspected cases of bacterial meningitis until cultures are obtained. This combination covers a broad spectrum of bacteria that are commonly responsible for meningitis, including Streptococcus pneumoniae, Neisseria meningitidis, and Listeria monocytogenes. Ampicillin covers Listeria monocytogenes, while 3rd generation cephalosporin covers Streptococcus pneumoniae and Neisseria meningitidis. Vancomycin is added to cover methicillin-resistant Staphylococcus aureus (MRSA) and penicillin-resistant Streptococcus pneumoniae.

A vascular lacunar infarct refers to a small stroke that occurs in the deep structures of the brain. The basal ganglia are a group of structures located deep within the brain that are responsible for various functions, including movement control. Damage to the basal ganglia can result in motor deficits such as weakness or difficulty with coordination. Therefore, a vascular lacunar infarct is most commonly associated with damage to the basal ganglia.

Epidural hematoma is the most commonly associated brain injury with a skull fracture. This occurs when there is bleeding between the dura mater (the tough, outermost layer of the meninges) and the skull. A skull fracture can damage the middle meningeal artery, leading to bleeding and the formation of a hematoma. The hematoma can put pressure on the brain, causing symptoms such as headache, confusion, and loss of consciousness. Prompt medical intervention is necessary to relieve the pressure and prevent further damage.

MRI operates via the use of signals received as protons releasing energy. Protons in the body align with a strong magnetic field during an MRI scan. When a radiofrequency pulse is applied, the protons absorb energy and become excited. As the protons return to their original alignment, they release energy in the form of signals. These signals are detected by the MRI machine and used to create detailed images of the body.

Bacterial meningitis is most commonly caused by bacteria entering the bloodstream (hematogenous route) and then spreading to the meninges, which are the protective membranes surrounding the brain and spinal cord. This can occur through various means such as respiratory or gastrointestinal infections. Head trauma, direct extension via otitis media or sinusitis, and genetic cribiform plate malformation are not the most common routes of infection for bacterial meningitis.

The correct answer is Lyme disease. The patient's recent history of camping in the northeast, along with the presence of periventricular white matter lesions on MRI, is consistent with Lyme disease. Lyme disease is caused by the bacterium Borrelia burgdorferi, which is transmitted through the bite of infected black-legged ticks. It can lead to various neurological symptoms, including cognitive problems and peripheral ataxia. The presence of white matter lesions on MRI is a common finding in Lyme disease. Systemic lupus, multiple sclerosis, leptomeningitis, and brain abscess would have different clinical presentations and imaging findings.

Bell's palsy is commonly associated with infection with Borrelia burgdorferi. This microorganism is the causative agent of Lyme disease, which is known to cause facial paralysis or Bell's palsy as one of its manifestations. Other microorganisms listed in the options are not typically associated with Bell's palsy.

The correct answer is 45 minutes. This time interval is crucial because prompt interpretation of a CT scan is necessary to determine the extent and location of the ischemic stroke. This information is vital for making treatment decisions and assessing the eligibility for thrombolytic therapy, which should ideally be administered within 4.5 hours of symptom onset. Delaying the interpretation beyond 45 minutes may lead to delays in treatment and potentially worsen the patient's outcome.

The patient's difficulty in reaching and grasping objects with his right hand, but not with his left hand, suggests a focal neurological deficit. Cerebellar tremor is a type of focal tremor that is caused by damage or dysfunction in the cerebellum, which is responsible for coordinating movements. This type of tremor typically affects one side of the body and can cause difficulties with fine motor tasks such as reaching and grasping objects. Therefore, the patient's symptoms are consistent with a diagnosis of cerebellar tremor.

40% of brain abscesses can be attributed to nasopharyngeal infections. This means that out of all the cases of brain abscesses, 40% are caused by infections in the nasopharynx. This suggests that nasopharyngeal infections are a significant contributing factor to the development of brain abscesses.

The use of recombinant-tissue plasminogen activator (rt-PA) is contraindicated in stroke patients who present more than 4.5 hours after symptom onset. This is because rt-PA is most effective when administered within the first few hours after stroke symptoms begin. Therefore, a presentation 5 hours post symptom onset would contraindicate the use of rt-PA in this patient. The other options, such as a normal CT scan, elevated blood pressure, and a history of head surgery, are not contraindications for the use of rt-PA in stroke patients.

The tubomammary nucleus is responsible for the production of histamine. Histamine promotes wakefulness by transmitting signals to the entire central nervous system.

Tardive dyskinesia is a disorder that manifests with both choreoform (involuntary, rapid, jerky movements) and dystonic (involuntary muscle contractions causing abnormal postures) symptoms. It is commonly seen as a side effect of long-term use of antipsychotic medications. Huntington's disease is characterized by choreoform movements, Parkinson's disease primarily presents with tremors and rigidity, myoclonus is characterized by sudden, brief muscle contractions, and Wilson's disease primarily affects the liver and brain. Therefore, the correct answer is Tardive dyskinesia.

The initial evaluation of an ischemic stroke patient should be made within 10 minutes upon arrival at the emergency room. This is because time is crucial in treating ischemic strokes, as the sooner treatment is initiated, the better the chances of minimizing brain damage and improving outcomes. Prompt evaluation allows medical professionals to assess the patient's condition, confirm the diagnosis, and determine the appropriate course of treatment, such as administering clot-busting medication or performing a mechanical thrombectomy.

The symptoms described in the question, including altered consciousness, slurred speech, clonic-jerky movements of all four limbs, and subsequent bilateral total ophthalmoplegia, no verbal output, and total quadriplegia, are consistent with a vertebrobasilar artery syndrome. This syndrome occurs due to a blockage or occlusion in the vertebrobasilar artery, which supplies blood to the brainstem and posterior parts of the brain. The symptoms described suggest a severe and extensive impairment of blood supply to these areas, resulting in the neurological deficits observed.

Seizures are not one of the four most common presenting symptoms of meningitis. The four most common symptoms are headache, fever, meningismus (neck stiffness), and altered sensorium (changes in consciousness or mental status). Seizures may occur in some cases of meningitis, but they are not as common or characteristic as the other symptoms listed.

Diffusion-weighted MRI would be the best imaging modality to accurately and rapidly detect a possible ischemic stroke that may have occurred. Ischemic stroke occurs due to a blockage in the blood vessels supplying the brain, leading to a lack of blood flow and oxygen. Diffusion-weighted MRI is highly sensitive in detecting early signs of ischemic stroke by measuring the movement of water molecules in the brain. It can identify areas of restricted diffusion, indicating the presence of ischemic tissue. This imaging modality is particularly useful in the acute setting, allowing for prompt diagnosis and initiation of appropriate treatment.

A CT scan should be made within 25 minutes upon arrival of the ischemic stroke patient at the emergency room. This is because a CT scan is crucial in determining the type of stroke and guiding the appropriate treatment. Time is of the essence in stroke cases, as early intervention can significantly improve outcomes. A prompt CT scan allows healthcare professionals to quickly assess the extent of brain damage and make informed decisions about the most suitable treatment options for the patient.

Huntington's chorea is a genetic disorder characterized by involuntary movements (chorea), cognitive decline, and psychiatric symptoms. The progressive destruction of the substantia nigra is not a clinically diagnostic feature of Huntington's chorea. The substantia nigra is primarily associated with Parkinson's disease, not Huntington's chorea.

The combination of Penicillin G, 3rd generation cephalosporin, and metronidazole is considered the empirical treatment for a brain abscess until cultures are obtained. This combination covers a broad spectrum of bacteria that are commonly associated with brain abscesses, including aerobic and anaerobic organisms. Penicillin G and the 3rd generation cephalosporin provide coverage against gram-positive bacteria, while metronidazole covers anaerobic bacteria. This combination is chosen to provide effective initial treatment while awaiting culture results to guide further therapy.

In cerebrospinal fluid analysis, elevated white blood cell count, elevated eosinophils, and hypoglycorrhachia are commonly observed in encephalitis due to parasitic infection. However, normal protein levels are not typically indicative of parasitic encephalitis.

Patients with disorders that decrease B-lymphocyte function are particularly susceptible to meningitis caused by pneumococcus. B-lymphocytes play a crucial role in the immune response, including the production of antibodies. Pneumococcus is a bacteria that commonly causes meningitis, and without functioning B-lymphocytes, the body's ability to mount an effective immune response against the bacteria is compromised. This makes patients with B-lymphocyte disorders more susceptible to pneumococcal meningitis. Streptococcus, Listeria, Escherichia, and Cryptococcus may also cause meningitis, but they are not specifically associated with decreased B-lymphocyte function.

The stroke team should be notified within 15 minutes upon arrival of the ischemic stroke patient at the emergency room. This is because timely notification allows the stroke team to quickly assess and provide appropriate treatment to the patient. Early intervention is crucial in ischemic stroke cases to minimize brain damage and improve the chances of recovery. Therefore, notifying the stroke team within 15 minutes ensures that the patient receives prompt and effective care.

Streptococcus agalactae is the most responsible organism for bacterial meningitis in newborns. This bacterium is commonly found in the vaginal and gastrointestinal tracts of healthy women. During childbirth, it can be transmitted to the newborn, leading to infection. Newborns are particularly vulnerable to this type of meningitis due to their underdeveloped immune systems. Prompt diagnosis and treatment are crucial to prevent severe complications and long-term neurological damage.

Post-T1-weighted MRI is the most useful imaging modality for visualizing pathology of the meninges. This technique provides high contrast between different tissues, allowing for detailed visualization of the meninges and any associated abnormalities. It is particularly effective in detecting meningeal enhancement, which can be indicative of inflammation or infection. CT with contrast can also be helpful, but it is not as sensitive or specific as post-T1-weighted MRI in visualizing meningeal pathology. Post-T2-weighted MRI, CT without contrast, and PET scans are less useful for evaluating the meninges specifically.

The most likely diagnosis for the patient's symptoms and history is a ruptured intracerebral aneurysm. This is indicated by the sudden onset of severe headache, the patient's history of hypertension, and the presence of a dilated left pupil. A ruptured intracerebral aneurysm can cause a sudden and severe headache, often described as the worst headache of one's life. The high blood pressure may have contributed to the rupture of the aneurysm. The dilated pupil suggests involvement of the third cranial nerve, which can occur with aneurysmal rupture.

Patients with T-lymphocyte defects are at greater risk of developing CNS infections. Cryptococcus neoformans is the most likely organism responsible for a patient with a T-lymphocyte defect presenting with meningitis. Cryptococcus neoformans is an opportunistic fungal pathogen that commonly causes meningitis in immunocompromised individuals, including those with T-lymphocyte defects. Other organisms listed, such as Herpes simplex virus, Toxoplasma gondii, Cytomegalovirus, and Aspergillus niger, may also cause CNS infections in immunocompromised individuals, but Cryptococcus neoformans is the most likely in this specific scenario.

The basal ganglia are a common location for hypertensive hemorrhage. Hypertensive hemorrhage refers to bleeding that occurs in the brain due to high blood pressure. The basal ganglia are a group of structures located deep within the brain that play a role in motor control and movement. Hypertensive hemorrhage in the basal ganglia can lead to symptoms such as weakness, paralysis, and loss of coordination. This pathology is often associated with long-standing hypertension and can result in significant neurological deficits.

The patient having an abnormal CT 12 hours later would support the diagnosis of a recent transient ischemic attack. A transient ischemic attack (TIA) is a temporary episode of neurological dysfunction caused by a disruption in blood flow to the brain. The symptoms described by the patient, slurred speech and left arm weakness, are consistent with a TIA. The fact that the patient's blood pressure remains high in the emergency room and that the initial MRI and CT are normal do not rule out the possibility of a TIA. However, the abnormal CT 12 hours later suggests that there may be ongoing vascular issues or complications related to the TIA.

Tonsillar herniation, also known as tonsillar herniation or tonsillar ectopia, occurs when the cerebellar tonsils herniate through the foramen magnum, the opening at the base of the skull. This condition is most commonly caused by increased pressure within the skull, which can be a result of a hemorrhagic stroke. Hemorrhagic stroke refers to bleeding in the brain, which can lead to increased intracranial pressure and subsequent tonsillar herniation. Other conditions listed, such as physical trauma, ischemic stroke, brain abscess, and multiple sclerosis, may also cause increased intracranial pressure, but hemorrhagic stroke is the most common cause of tonsillar herniation.

Toxoplasma gondii is the leading cause of focal central nervous system disease in AIDS patients. This parasite can cause severe brain infection, leading to symptoms such as confusion, seizures, and headaches. AIDS patients are particularly susceptible to this infection due to their weakened immune system. Cryptococcus neoformans is another opportunistic pathogen that can cause central nervous system disease in AIDS patients, but it is not the leading cause. Treponema pallidum is the bacterium responsible for syphilis, which can also affect the central nervous system but is not specific to AIDS patients. Herpes simplex virus VI and cytomegalovirus can cause central nervous system disease in AIDS patients, but they are not the leading cause compared to Toxoplasma gondii.

Radiologic enhancement of the temporal/parietal meninges is a specific radiological diagnostic indicator of brain abscess secondary to otitis media that occurs in nearly all cases. This enhancement refers to the increased contrast uptake in the meninges, which is indicative of inflammation and infection. This finding is commonly seen in brain abscesses caused by otitis media, helping to differentiate it from other conditions. Displacement of the lateral ventricles, contralateral cerebral edema, and retinal papilledema may also be seen in brain abscesses, but they are not as specific or consistent as radiologic enhancement of the meninges.

The patient's presentation of seizures, cognitive loss, alcohol smell, and skin lesions suggests a possible brain abscess. The negative radiological imaging for mass lesions and the findings of neutrophils, increased protein, and hypoglycorrhachia in the lumbar puncture indicate an infectious process. Coagulase positive Staphylococcus aureus is a common cause of brain abscesses, especially in patients with a history of alcohol abuse and skin infections. Therefore, coagulase positive Staphylococcus aureus is the likely offending organism in this case.

Displaced lateral ventricles can be a contraindication to performing a lumbar puncture because it indicates increased intracranial pressure. Performing a lumbar puncture in such cases can cause herniation of the brain due to the pressure difference between the intracranial and intraspinal spaces. This can lead to serious complications and is therefore not recommended.