June 2020 Flashcards
AIDS is currently managed with highly active anti-retroviral therapy, combining a series of medication to overwhelm the virus and minimize its ability to form resistance. Which of the following is a non-competetive reverse transcriptase inhibitor? A.) Lamivudine B.) Didanosine C.) Nevirapine D.) Saquinavir E.) Zidovudine
C.) Nevirapine is a NNRTI. It functions by binding to the reverse transcriptase enzyme and acting as a noncompetetive inhibitor.
Olga a 50-year-old comes to the clinic for follow-up appointament complaning of weight gain two weeks after beginning a new medication for her refractory schizophrenia. Labs show a low WBC count, and low absolute neutrophil count. The rest of labs were within normal limits. Which of the following drug therapies did the patient most like begin two weeks ago? A.) Penicillin B.) Clozapine C.) Cloramphenicol D.) Polymyxins E.) Metronidazole
B.) Clozapine is an atypicak antipsychotic used to primarily treat schizophrenia. The patient is experiencing agranulocytosis which is an adverse effect of clozapine. Aside from this weight gain, hypotension and mild sedation are some of the other side effects.
A 60-year-old male with type II diabetes is taking glyburide for his disease but is not maintaining adequate glycemic control with
an HbA1c level of 7.3%. You elect to add rosiglitazone to his medications. This drug acts to:
A.) Increase insulin sensitivity in adipose and muscle
B.) Increase insulin secretion from β-cells
C.) Decrease somatostatin release from δ-cells
D.) Decrease glucose absorption in the small intestine
E.) Increase insulin receptors
A.) The major mechanism of action of thiazolidinediones is increasing sensitivity to insulin in adipose, skeletal muscle, and liver. Several classes of hypoglycemic drugs act to increase insulin release from the pancreas including the sulfonylureas, incretins, and DPP-IV antagonists. The α-glucosidase inhibitors inhibit intestinal hydrolysis of complex saccharides and thereby reduce glucose absorption.
Hypoxemia produces hyperventilation by a direct effect on the:
A.) Phrenic nerve
B.) J receptors
C.) Lung stretch receptors
D.) Medullary chemoreceptors
E.) Carotid and aortic body chemoreceptors
E.) Hypoxemia stimulates breathing by a direct effect on the peripheral chemoreceptors in the carotid and aortic bodies. Central (medullary) chemoreceptors are stimulated by CO2 (or H+). The J receptors and lung stretch receptors are not chemoreceptors. The phrenic nerve innervates the diaphragm, and its activity is determined by the output of the brainstem breathing center.
You are handling a patient who reports of having hyperthyroidism. Which of the following will you most likely NOT see in the presentation of this patient?
A.) Increase thermogenesis and sweating
B.) Increased cardiac output
C.) Increased rate and depth of respiration
D.) Increased mean arterial pressure
E.) Increased utilisation of carbohydrates, fats, and proteins
D.) Thyroid hormone causes increased cardiac output and reduced peripheral vascular resistance. Due to this, systolic arterial pressure is elevated and diastolic arterial pressure is reduced. As a result, pulse pressure is increased, while there is usually NO change in mean arterial pressure.
Complete transection of the spinal cord at the level of T1 would most likely result in:
A.) temporary loss of stretch reflexes below the lesion
B.) temporary loss of conscious proprioception below the lesion
C.) permanent loss of voluntary control of movement above the lesion
D.) permanent loss of consciousness above the lesion
A.) Transection of the spinal cord causes “spinal shock” and loss of all reflexes below the level of the lesion. These reflexes, which are local circuits within the spinal cord, will return with time or become hypersensitive. Proprioception is permanently (rather than temporarily) lost because of the interruption of sensory nerve fibers. Fibers above the lesion are intact.
During a domestic dispute, a 16 year old boy receives a deep stab wound around the superior angle of the scapula near the medial border, which injures both the dorsal scapular and spinal accessory nerves. Such an injury could result in paralysis or weakness of which muscles?
A.) Trapezius and serratus posterior superior
B.) Rhomboid major and trapezius
C.) Rhomboid minor and latissimus dorsi
D.) Splenius cervicis and sternocleidomastoid
E.) Levator scapulae and erector spinae
B.) The dorsal scapular nerve innervates the levator scapulae and rhomboid muscles, where as the accessory nerve innervates the trapezius and SCM. The serratus posterior superior is innervated by ventral primary rami of the spinal nerves, whereas the splenius cervicis and erector spinae are innervated by the dorsal primary rami of the spinal nerves.
Coronary angiographs of a 44-year-old male patient reveal an occlusion of the circumflex branch of the left coronary artery. This patient has been suffering from myocardial infarction in which of the following areas? A.) Right and left ventricles B.) Right and left atria C.) Interventricular septum D.) Apex of the heart E.) Left atrium and ventricle
E.) Left atrium and ventricle. The left atrium and ventricle receive blood from the circumflex branch of the left coronary artery. The interventricular septum and the apex of the heart are supplied by the anterior interventricular branch of the left coronary artery. The right ventricle receives blood from the anterior interventricular artery and the marginal branch of the right coronary artery. The right atrium receives blood from the right coronary artery.
The tentorial notch is the opening in the tentorium cerebelli for the brainstem. If the patient was diagnosed with a tumor in the supratentorial compartment that causes part of the adjacent temporal lobe of the brain to herniate through the tentorial notch, what is most likely his presentation?
A.) Patient complains of mydriasis
B.) Patient’s eye adopts a position termed as ‘down and out’
C.) Patient’s pupils are equal and briskly reactive to light
D.) Patient tends to tilt the head for better vision
E.) Patient lateral gaze is affected
B.) Patient’s eye may adopt a position known as ‘down and out’. During tentorial herniation, the temporal lobe may be lacerated by the tough tentorium cerebellum, and the oculomotor nerve (CNIII) may be stretched, compressed, or both. Oculomotor lesions may produce paralysis of the extrinsic eye muscles supplied by CN III.
50-year-old patient presents with a necrotizing fasciitis accompanied by fever. Later on, this rapidly progresses to shock and multiorgan failure. Blood culture shows β-hemolytic discoid colonies after growth overnight on a 10-cm plate with 5% sheep blood agar. Which of the following toxin/enzyme is most likely responsible for the eventual demise of the patient? A.) Hyaluronidase B.) Streptolysin O C.) SpeA D.) Catalase E.) Exfoliative toxin A
C.) SpeA. SpeA stands for streptococcal pyrogenic exotoxin A. The causative agent is S. pyogenes. The patient presented with Streptococcal toxic shock syndrome, which is directly caused by this toxin. It acts as a superantigen, which stimulates T cells to mediate shock and tissue injury. From the blood agar findings, the most likely causative agents can be narrowed down to S. pyogenes and S. agalactiae, which eliminates Choice D and E (Both are Catalase negative; Exfoliative Toxin A is found in S. aureus). Hyaluronidase is mainly a spreading factor that helps in the dissemination of microorganisms. Streptolysin O is also found in S. pyogenes, however it is a hemolysin that is not directly involved in the pathogenesis of toxic shock syndrome.
A 35 year-old male was rushed to the emergency room due to severe burn injuries. Several days after, the burn injuries were noted to have a blue-green pus. Also noted were skin lesions composed of hemorrhagic vesicles or pustules that evolve into necrotic ulcers with a tender erythematous border. This hemorrhagic necrosis of the skin is classically associated with an organism with which of the following characteristics?
A.) Gram positive bacilli, oxidase positive
B.) Gram negative bacilli, oxidase positive
C.) Gram negative bacilli, oxidase negative
D.) Gram positive bacilli, oxidase negative
E.) NOTA
B.) Gram negative bacilli, oxidase positive. The lesion is called ecthyma gangrenosum and it is classically associated with Pseudomonas aeruginosa bacteremia. Pseudomonas spp are gram negative bacilli, oxidase positive. Growth in 42 deg C helps differentiate Pseudomonas aeruginosa from other Pseudomonas spp. Pseudomonas can also cause meningitis when introduced via lumbar puncture or during a neurosurgical procedure. It can also cause UTI when introduced by catheters and instruments or in irrigating solutions.
A 54-year-old man develops a pyogenic infection along the suture line after knee surgery. The laboratory gives a preliminary report of a beta-hemolytic, catalase-positive, coagulase-positive, Gram-positive coccus. The most likely causative agent is: A.) Moraxella catarrhalis B.) Staphylococcus aureus C.) Staphylococcus epidermidis D.) Streptococcus agalactiae E.) Streptococcus pyogenes
B.) Staphylococcus aureus. Of the answer choices, only streptococci and staphylococci are Gram positive. The streptococci are catalase negative and staphylococci are catalase positive. Of the two staphylococci, Staphylococcus aureus is the beta-hemolytic, coagulase-positive organism.
The body operates in a delicate balance. Every little thing operates in a small range of normalcy. A little above or below this threshold could result in pathology. How would you describe then the state of a 32 year-old female with type 1 diabetes who was rushed to the ER unconscious after a night of binge drinking following a really stressful workday where she skipped most of her meals? A.) Metabolic acidosis B.) Metabolic alkalosis C.) Diabetic ketoacidosis D.) Diabetic ketoalkalosis E.) None of the above
C.) Diabetic ketoacidosis is often seen in cases of uncontrolled type 1 diabetes mellitus. The rate of ketone bodies formation is greater than the rate of their use, increasing ketone body concentration in both blood and urine. “Each ketone body loses a proton (H+) as it circulates in the blood, which lowers the pH.” Glucosuria coupled with faster ketone body formation results in dehydration which further lowers pH into an acidotic state – also seen in cases of prolonged fasting and excessive ethanol consumption.
Anion Gap Metabolic Acidosis MUDPILES Methanol Uremia DKA Paraldehyde Iron, Isoniazid Lactic Acidosis Ethylene glycol Salicylates
You encounter an infant who presents with vomiting, poor feeding, and with severe CNS defects. Upon further examination, you notice that his urine smells like burnt sugar or maple syrup. You recall that the pathophysiology of this condition involves the blocked degradation of branched amino acids. Which amino acid is NOT associated with this condition? A.) Isoleucine B.) Valine C.) Glycine D.) Leucine
C.) Remember the mnemonic I LoVe maple syrup (Isoleucine, Leucine, Valine). In Maple Syrup Urine Disease (MSUD), there is blocked degradation of these AA due to decreased branched-chain alpha-ketoacid dehydrogenase (B1). This causes an increase of alpha-ketoacids in the blood, causing CNS defects, intellectual disability and death. This is an autosomal recessive condition.
In times of fasting where your body needs glucose but there is lack of intake in glucose, your body adapts by releasing its own stored glucose from glycogen in a process called glycogenolysis. Which of the following pairs are the correct enzymes for you to properly unbranch and utilize the glucose kept in glycogen?
A.) Debranching Enzyme, Phosphofructokinase
B.) Debranching Enzyme, Glucose synthase
C.) Glycogen Phosphorylase, Glucose synthase
D.) Glycogen Phosphorylase, Debranching Enzyme
E.) Phosphoglucomutase, G6P translocase
D.) Glycogen phosphorylase and Debranching enzyme are the two quintessential enzymes needed to shorten and unbranch glycogen stores to produce glucose 1-phosphate which can be converted in the cytosol to glucose 6-phosphate by phosphoglucomutase. This then enters the hepatic ER via the G6P translocase to be converted into glucose using the glucose 6-phosphatase (the same enzyme used in the last step of gluconeogenesis).
A 5-year-old boy presents with mild fever and redness of the eyes, tearing, coryza, and cough. 4 days later, the patient develops an erythematous maculopapular eruption that started at the hairline, spreading downward. Which pathognomonic sign is missing from this case presentation that can confirm the diagnosis?
A.) Discrete red lesions with bluish white spots in the center at the level of the premolars
B.) Inflammation of the Stensen duct
C.) Ulceration of the erythematous maculopapular rash
D.) Whitish spots on the tongue
E.) Black spots on the sclerae
A.) Discrete red lesions with bluish-white spots on the level of the premolars. These are known as Koplik spots. These are pathognomonic for measles, which typically present with 4 C’s - cough, coryza, conjunctivitis, and C(K)oplik.
A 15-day old newborn was rushed to the ER due to generalized tonic-clonic seizure, which abated when she was given calcium chloride. Upon further inspection, she had short philtrum, hypertelorism, and low-set notched ears. Which of the following would you expect in this newborn?
A.) Congenital Heart Disease
B.) Thymic hypoplasia
C.) Cleft palate
D.) All of the above
- D.) All of the above. The newborn presented with hypocalcemic seizure (as suggested when it abated with calcium chloride). Together with the physical findings, this case suggests DiGeorge Syndrome. Mnemonic for DiGeorge: CATCH-22 (cardiac, abnormal facies, thymic hypoplasia, cleft palate, hypocalcemia, 22q11.2 deletion). Thus, all of the choices can be expected in the newborn.
An 8 year old kid had erythematous facial flushing, which was followed by diffuse macular erythematous rash in the trunk. The rashes in the trunk eventually cleared in the center, leaving a reticular appearance. This type of rash is commonly caused by which etiologic agent?
A.) Rubeola virus B.) Rubella virus C.) Parvovirus B19 D.) Streptococcus pyogenes E.) HHV-6
C.) Parvovirus B19. This is a case of erythema infectiosum, or the fifth disease, which is caused by Parvovirus B19. Its characteristic rash appears in three stages. First, the child will have an erythematous facial flushing, creating the slapped-cheek appearance. Next, the rashes will appear in the trunk as diffuse macular erythema. Finally, the rashes in the trunk will have a central clearing, making it look like lacy, reticulated rash. The rash is more prominent in extensor surface and it often fades without desquamation.
