A nurse is caring for a client who has a traumatic brain injury.
Which of the following should the nurse understand as a consequence of a traumatic brain injury?

Choice A rationale

The humoral immune response is primarily mediated by B-lymphocytes, not T-lymphocytes. B-cells differentiate into plasma cells, which produce antibodies that target specific antigens circulating in body fluids. T-lymphocytes are central to cell-mediated immunity, directly destroying infected cells or regulating other immune cells.

Choice B rationale

Cell-mediated immunity, primarily involving T-lymphocytes, defends against a broad range of intracellular pathogens, including viruses, fungi, parasites, and some bacteria, not exclusively viral infections. It also plays a crucial role in tumor surveillance and rejection of transplanted tissues.

Choice C rationale

Cell-mediated immunity involves various immune cells, but phagocytic natural killer cells are distinct. While natural killer cells are part of the innate immune system and can lyse infected or tumor cells, the core of adaptive cell-mediated immunity relies on antigen-specific T-lymphocytes (cytotoxic T cells and helper T cells).

Choice D rationale

Anaphylactic reactions to blood transfusions, particularly in individuals with IgA deficiency, can occur when pre-existing anti-IgA antibodies in the recipient react with IgA present in the transfused blood product. This antigen-antibody complex formation triggers mast cell degranulation and subsequent release of potent inflammatory mediators, leading to systemic anaphylaxis.

Choice A rationale

A myasthenic crisis is a life-threatening exacerbation of myasthenia gravis characterized by severe muscle weakness, particularly affecting the respiratory muscles. This can lead to impending or actual respiratory failure, necessitating immediate intervention with mechanical ventilation to support breathing and prevent hypoxemia and hypercapnia.

Choice B rationale

A vasoconstrictor would elevate blood pressure by constricting blood vessels. Myasthenic crisis primarily involves profound muscle weakness, not typically hypotensive states requiring vasoconstrictors. Administering a vasoconstrictor would not address the underlying respiratory compromise or muscle weakness.

Choice C rationale

Pursed-lip breathing is a technique used to prolong exhalation and improve ventilation in individuals with obstructive lung diseases like COPD. While it can help with dyspnea, it is insufficient to manage the severe respiratory muscle weakness seen in a myasthenic crisis and would not prevent respiratory failure.

Choice D rationale

Sedatives depress the central nervous system and can further impair respiratory drive and muscle function, which would be detrimental in a myasthenic crisis. The client's respiratory status is already compromised, and sedation would exacerbate hypoventilation and increase the risk of respiratory arrest.