MDS PREP
A patient with severe nausea and vomiting is prescribed metoclopramide. What is the primary mechanism of action of metoclopramide?
(1) Antihistaminic action
(2) Dopamine antagonism in the CNS
(3) Muscarinic receptor antagonism
(4) 5-HT3 receptor antagonism
Metoclopramide acts primarily as a dopamine D2 receptor antagonist in the chemoreceptive trigger zone in the brain and in the gastrointestinal tract, which helps to reduce nausea and vomiting by decreasing gastric emptying and increasing gastric tone.
Which of the following is a potential complication of chronic glucocorticoid therapy?
(1) Hypocalcemia
(2) Hypercalcemia
(3) Hyponatremia
(4) Hypokalemia
Chronic glucocorticoid therapy can lead to a condition known as Cushing's syndrome, which includes various endocrine and metabolic disturbances. One of the common complications is hypercalcemia due to increased bone resorption and impaired calcium excretion in the kidneys. Additionally, glucocorticoids can cause a mild increase in serum phosphorus levels, leading to hyperphosphatemia in some cases.
Which of the following is NOT a common behavioral symptom in early Huntington's disease?
(1) Depression
(2) Apathy
(3) Hyperactivity
(4) Social withdrawal
In early Huntington's disease, common behavioral symptoms include depression, apathy, irritability, and social withdrawal. Hyperactivity is not a typical early symptom; rather, the disease is more associated with a decline in motor function and increased involuntary movements (chorea).
What is the primary mechanism of action of amphotericin B in treating systemic fungal infections?
(1) Inhibition of fungal cell wall synthesis
(2) Inhibition of fungal DNA replication
(3) Inhibition of fungal protein synthesis
(4) Alteration of fungal membrane potential
Amphotericin B is an antifungal agent that works primarily by binding to ergosterol in the fungal cell membrane, leading to increased permeability and cell death. It is effective against a wide range of fungi and is often used to treat severe systemic infections.
What is the most commonly damaged heart valve in rheumatic heart disease?
1) Aortic valve
2) Mitral valve
3) Tricuspid valve
4) Pulmonary valve
Rheumatic heart disease is most commonly associated with damage to the mitral valve, which is situated between the left atrium and left ventricle of the heart.
Which of the following is a true statement about amylase levels in pleural fluid?
(1) High amylase levels in pleural fluid indicate a pancreatic origin of the effusion
(2) High amylase levels in pleural fluid are always due to esophageal rupture
(3) High amylase levels in pleural fluid can be seen in both pancreatic and esophageal rupture
(4) High amylase levels in pleural fluid are diagnostic of pulmonary tuberculosis
High amylase levels in pleural fluid can indicate either a pancreatic or an esophageal origin of the effusion. It is not specific to one condition and further diagnostic tests are needed to determine the source.
What is the typical age of onset for Huntington's disease?
(1) Childhood
(2) Fourth or fifth decade
(3) Seventh or eighth decade
(4) Second or third decade
Huntington's disease typically begins in the fourth or fifth decade of life. It is an autosomal dominant disorder that affects both men and women, and the symptoms include chorea, behavioral disturbances, and cognitive decline. While there is a wide range in age of onset, the average age of symptom manifestation is around 30 to 50 years.
What is the genetic basis of neurofibromatosis type 1?
(1) Autosomal recessive inheritance, gene located on chromosome 13
(2) Autosomal dominant inheritance, gene located on chromosome 17
(3) Autosomal dominant inheritance, gene located on chromosome 22
(4) Autosomal recessive inheritance, gene located on chromosome 17
Neurofibromatosis type 1 is an autosomal dominant disorder caused by a mutation in the NF1 gene, which produces neurofibromin. The gene is located on chromosome 17.