Deficiencies in cyanocobalamin (B12) can result in

Correct Answer: B

Rationale: Cyanocobalamin, or vitamin B12, is essential for red blood cell production and neurological function, and its deficiency directly leads to pernicious anemia, a condition characterized by large, immature red blood cells due to impaired DNA synthesis. This occurs because B12 is crucial for folate metabolism and erythropoiesis, and without it, anemia develops, often accompanied by neurological symptoms like numbness or tingling. Pellagra, however, results from niacin (vitamin B3) deficiency, manifesting as dermatitis, diarrhea, and dementia-unrelated to B12's role. Rickets stems from vitamin D deficiency, causing bone deformities due to poor calcium absorption, not a B12 issue. Scurvy arises from vitamin C deficiency, leading to collagen breakdown and symptoms like bleeding gums, distinct from B12's hematological effects. Pernicious anemia stands out as the correct outcome because B12 deficiency disrupts bone marrow function, and it often requires pharmacotherapy, such as B12 injections, especially if absorption is impaired (e.g., due to lack of intrinsic factor). This specificity eliminates other conditions, highlighting B12's unique role in blood and nerve health.

Correct Answer: A

Rationale: A side effect of a medication is an unintended or undesired effect that occurs in addition to the desired therapeutic effect. Bloody stools can be a serious side effect of certain medications, indicating potential gastrointestinal bleeding. It is important to monitor for this side effect and report it to a healthcare provider promptly if observed, as it may require immediate medical attention. Changes in stomach pH, thirst, and constipation are also potential side effects of medications, but bloody stools indicate a more severe issue that should be addressed promptly.

Correct Answer: B

Rationale: Enteric-coated aspirin reduces GI irritation, an accurate statement for pain management. High doses are for anticoagulation, not pain. Herbs increase bleeding risk, not inflammation relief. Low doses prevent clotting, not inflammation. B enhances safety, making it correct.

Correct Answer: C

Rationale: Amitriptyline, a tricyclic antidepressant, has anticholinergic effects, including urinary retention , a medical emergency risking bladder damage or infection, needing immediate intervention. Dry mouth and constipation are common, manageable side effects. Drowsiness is expected with its sedative action. Urinary retention's severity'potential for acute retention'sets it apart, requiring rapid reporting or catheterization. This aligns with amitriptyline's blockade of muscarinic receptors, where bladder dysfunction can escalate fast, making C the finding demanding urgent attention over chronic annoyances.

Correct Answer: A

Rationale: ACE (Angiotensin-Converting Enzyme) inhibitors are known to act on the Renin-Angiotensin-Aldosterone System (RAAS) by blocking the conversion of angiotensin I to the active angiotensin II. Angiotensin II is a potent vasoconstrictor and also stimulates the release of aldosterone, leading to increased blood pressure. By inhibiting ACE, ACE inhibitors help to lower blood pressure and reduce the secretion of aldosterone, thereby decreasing the overall vasoconstriction and volume expansion effects of the RAAS. Examples of ACE inhibitors include medications such as lisinopril, enalapril, and captopril.

Correct Answer: D

Rationale: In a patient who is severely anemic, the primary goal is to raise the hemoglobin and hematocrit levels. Packed red blood cells (PRBCs) contain a concentrated dose of red blood cells and are given to increase oxygen-carrying capacity in cases of significant anemia. Fresh frozen plasma, albumin, and whole blood do not specifically address the issue of low hemoglobin levels, making them less appropriate choices for this scenario.

Correct Answer: D

Rationale: Emesis risk depends on chemotherapeutic emetogenicity. Cisplatin, dacarbazine, doxorubicin, and mustine are highly emetogenic, triggering vomiting via chemoreceptor zones. Vincristine, a vinca alkaloid, is least emetogenic, causing neuropathy instead, making it the exception. This lower risk reduces antiemetic needs, easing patient burden during treatment.

Correct Answer: C

Rationale: Hair loss is a known but temporary side effect of azathioprine, an immunosuppressant used to treat autoimmune conditions. It occurs due to the drug's impact on rapidly dividing cells, including hair follicles. While distressing, this side effect is usually reversible once the medication is discontinued or the body adjusts to it. Hair loss is not typically a sign of toxicity, and reassuring the client about its temporary nature can help alleviate anxiety.

Correct Answer: B

Rationale: Cyanocobalamin, or vitamin B12, is essential for red blood cell production and neurological function, and its deficiency directly leads to pernicious anemia, a condition characterized by large, immature red blood cells due to impaired DNA synthesis. This occurs because B12 is crucial for folate metabolism and erythropoiesis, and without it, anemia develops, often accompanied by neurological symptoms like numbness or tingling. Pellagra, however, results from niacin (vitamin B3) deficiency, manifesting as dermatitis, diarrhea, and dementia-unrelated to B12's role. Rickets stems from vitamin D deficiency, causing bone deformities due to poor calcium absorption, not a B12 issue. Scurvy arises from vitamin C deficiency, leading to collagen breakdown and symptoms like bleeding gums, distinct from B12's hematological effects. Pernicious anemia stands out as the correct outcome because B12 deficiency disrupts bone marrow function, and it often requires pharmacotherapy, such as B12 injections, especially if absorption is impaired (e.g., due to lack of intrinsic factor). This specificity eliminates other conditions, highlighting B12's unique role in blood and nerve health.