How are Type IV hypersensitivity reactions different from all other types (I, II, or III) of hypersentivity reactions?
The usual types of reactions are mediated by antibodies.
B-lymphocytes produce the offending substances.
They typically occur with the first exposure to an antigen.
Delayed reactions are characterized by cytokine release.
The Correct Answer is A
A) The usual types of reactions are mediated by antibodies:
Correct. Types I, II, and III hypersensitivity reactions are mediated by antibodies (IgE, IgG, or IgM) that bind to antigens and trigger immune responses. In contrast, Type IV hypersensitivity reactions are T-cell mediated and do not involve antibodies.
B) B-lymphocytes produce the offending substances:
This statement is incorrect. B-lymphocytes are involved in antibody-mediated immune responses (types I, II, and III hypersensitivity reactions), not Type IV hypersensitivity reactions, which are primarily mediated by T-lymphocytes.
C) They typically occur with the first exposure to an antigen:
This statement is incorrect. Type IV hypersensitivity reactions usually require sensitization upon initial exposure to an antigen, and subsequent exposures elicit the delayed hypersensitivity response. This is similar to types I, II, and III hypersensitivity reactions, which also involve sensitization upon initial exposure.
D) Delayed reactions are characterized by cytokine release:
This statement is partially correct. Type IV hypersensitivity reactions are characterized by a delayed onset (typically 24 to 72 hours after exposure) and involve the release of cytokines from activated T-lymphocytes, leading to inflammation and tissue damage. However, other types of hypersensitivity reactions may also involve cytokine release, so this feature alone does not differentiate Type IV from other types of reactions.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Polycystic kidney disease (PKD) is a genetic disorder characterized by the formation of multiple fluid-filled cysts in the kidneys. One of the complications associated with PKD is hypertension, which often occurs due to activation of the renin-angiotensin-aldosterone system (RAAS). Here's how the pathophysiological process of the RAAS contributes to the client's elevated blood pressure:
A) Intravascular fluid deficit:
In polycystic kidney disease, the development of multiple cysts in the kidneys can impair renal function and lead to decreased filtration and reabsorption capacity. However, this impairment typically leads to fluid retention rather than intravascular fluid deficit, contributing to hypertension rather than hypotension.
B) Renin angiotensin mechanism:
Correct. In PKD, the cysts disrupt normal kidney architecture and function, leading to activation of the renin-angiotensin-aldosterone system (RAAS). Reduced renal blood flow and glomerular filtration rate (GFR) stimulate the release of renin from the juxtaglomerular cells of the kidneys. Renin acts on angiotensinogen to convert it into angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme (ACE). Angiotensin II is a potent vasoconstrictor that increases peripheral vascular resistance, leading to elevated blood pressure. Additionally, angiotensin II stimulates the secretion of aldosterone, which promotes sodium and water retention, further contributing to hypertension.
C) Inflammatory process of bladder mucosa:
This option is not directly related to the pathophysiological process of hypertension in polycystic kidney disease. Flank pain and hematuria in PKD are often associated with cyst rupture or hemorrhage within the cysts rather than an inflammatory process of the bladder mucosa.
D) Mineral precipitation in urine:
Mineral precipitation in urine, such as the formation of kidney stones, can occur in polycystic kidney disease but is not directly associated with hypertension. Kidney stones may contribute to flank pain and hematuria but do not typically cause systemic hypertension.
Correct Answer is C
Explanation
A. Myocardial infarction:
Myocardial infarction (MI) typically presents with severe and prolonged chest pain or discomfort that is not relieved by rest or nitroglycerin. MI is characterized by myocardial necrosis due to prolonged ischemia, often resulting from the occlusion of a coronary artery by a thrombus or plaque rupture. While chest pressure and breathlessness are symptoms commonly associated with MI, the transient nature of the symptoms described by the client, as well as their relief after rest, is more indicative of stable angina rather than MI.
B. Unstable angina:
Unstable angina is characterized by new-onset angina, increasing frequency, or worsening intensity of angina symptoms. It is considered a medical emergency as it may precede a myocardial infarction. However, unstable angina typically presents with symptoms at rest or with minimal exertion and is not usually relieved by rest or nitroglycerin. The client's symptoms, which are relieved by rest, are more consistent with stable angina.
C. Stable angina:
Stable angina is characterized by predictable chest pain or discomfort that occurs with exertion or stress and is relieved by rest or nitroglycerin. The symptoms described by the client, including chest pressure and breathlessness that improve with rest, are consistent with stable angina. Stable angina occurs due to transient myocardial ischemia caused by an imbalance between myocardial oxygen supply and demand, often related to coronary artery disease.
D. Prinzmetal angina:
Prinzmetal angina, also known as variant angina, is characterized by chest pain or discomfort that occurs at rest, often in the early morning hours, and is typically caused by coronary artery spasm rather than fixed atherosclerotic lesions. While Prinzmetal angina can present with transient symptoms similar to those described by the client, it is less common than stable angina and is often associated with transient ST-segment elevation on electrocardiogram (ECG), which is not mentioned in the scenario.
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