MDS PREP
What is the target INR range for a patient on warfarin therapy to undergo minor oral surgery?
(1) Less than 2
(2) 2-3
(3) 3-4
(4) Less than 1.5
For a patient on warfarin therapy, the target INR (International Normalized Ratio) for undergoing minor oral surgery is typically 2-3. This range provides adequate thromboprophylaxis while minimizing the risk of excessive bleeding. However, the decision to proceed with surgery should be made on a case-by-case basis, considering the patient's overall health and surgical risks.
Which of the following is a characteristic of the rash seen in scarlet fever?
(1) Small, flat, red spots that are not elevated.
(2) Small, raised, red bumps that feel like sandpaper.
(3) Large, fluid-filled blisters.
(4) Thin, red streaks that spread out from the central lesion.
The rash in scarlet fever is characterized by small, raised, red bumps that feel like sandpaper when touched. These bumps, known as "Pastia lines," are particularly prominent in skin folds. The rash is caused by the exotoxins produced by Streptococcus pyogenes and typically occurs with a strep throat infection.
What is the primary cellular defect caused by HIV infection leading to AIDS?
(1) Depletion of CD8 cells
(2) Depletion of CD4 cells
(3) Overproduction of CD8 cells
(4) Overproduction of CD4 cells
The primary cellular defect caused by HIV infection is the depletion of CD4+ T-helper cells, which are essential for a properly functioning immune system. This leads to a compromised immune system that is susceptible to opportunistic infections.
What is the primary function of the mitral valve in the heart?
1) To prevent backflow of blood from the aorta into the left ventricle during diastole
2) To prevent backflow of blood from the pulmonary artery into the right ventricle during systole
3) To prevent backflow of blood from the left atrium into the left ventricle during systole
4) To prevent backflow of blood from the vena cava into the right atrium during systole
The mitral valve is crucial in preventing the backflow of blood from the left atrium to the left ventricle during systole, ensuring that blood flows in the correct direction through the heart during the cardiac cycle.
What is the common mode of action of antifungal agents like nystatin and clotrimazole in treating oral candidiasis?
(1) Binding to bacterial cell walls
(2) Inhibition of bacterial protein synthesis
(3) Inhibition of fungal ergosterol synthesis
(4) Inhibition of fungal DNA synthesis
Nystatin and clotrimazole work by binding to ergosterol in the fungal cell membrane, increasing permeability and allowing the leakage of intracellular components. This leads to the death of the affected fungal cell.
In a patient with suspected acute coronary syndrome, which of the following ECG changes is most indicative of an ST-elevation myocardial infarction (STEMI)?
1) ST depression in leads II, III, and aVF
2) ST elevation in leads I and aVL
3) ST elevation in leads V1-V4 with reciprocal depression in leads II, III, and aVF
4) ST elevation in leads II, III, and aVF
In a patient with a suspected STEMI, the characteristic ECG findings include ST elevation in the anterolateral leads (I, aVL, V1-V6) and reciprocal ST depression in the inferior leads (II, III, aVF). The pattern of ST elevation in the anterolateral leads with reciprocal depression in the inferior leads is most indicative of a STEMI affecting the anterolateral wall of the heart.
How is chronic hepatitis typically defined?
(1) Asymptomatic with biochemical evidence of liver disease for less than 6 months
(2) Asymptomatic with histologically documented inflammation for less than 6 months
(3) Asymptomatic with serological evidence of hepatic disease for less than 6 months
(4) Asymptomatic with biochemical or serological evidence of liver disease for more than 6 months
Chronic hepatitis is characterized by the persistent presence of liver inflammation and damage, typically lasting for more than 6 months. It can be caused by various factors, including viral infections, alcohol abuse, autoimmune diseases, and metabolic disorders. The diagnosis is often made based on a combination of clinical symptoms, laboratory tests, and liver biopsy findings.
In a patient with nephrotic syndrome, which of the following is true regarding plasma cholesterol levels?
(1) Plasma cholesterol levels are decreased due to increased LDL receptors in the liver.
(2) Plasma cholesterol levels are increased due to the loss of cholesterol in urine.
(3) Plasma cholesterol levels are normal as the condition is unrelated to lipid metabolism.
(4) Plasma cholesterol levels are decreased due to increased hepatic synthesis of bile salts.
Nephrotic syndrome is associated with hyperlipidemia, particularly increased levels of LDL and cholesterol. The underlying mechanism involves the loss of albumin in the urine, which leads to hypoalbuminemia. This causes an increased synthesis of very low-density lipoproteins (VLDL) by the liver to compensate for the loss of oncotic pressure. Additionally, the loss of proteins that normally bind to cholesterol in the blood, such as lipoproteins, results in decreased clearance of LDL.