A 5-year-old male presents with low-set ears, a fish-shaped mouth, and involuntary rapid muscular contraction. Laboratory testing reveals decreased calcium levels. Which of the following diagnoses is most likely?

Correct Answer: B

Rationale: The correct answer is B: T cell deficiency. The symptoms described in the case, including low-set ears, a fish-shaped mouth, involuntary rapid muscular contraction, and decreased calcium levels, are indicative of DiGeorge syndrome. This syndrome is characterized by T cell deficiency due to thymic hypoplasia. B cell deficiency (Choice A), combined immunodeficiency (Choice C), and complement deficiency (Choice D) do not align with the clinical presentation and laboratory findings provided in the case. Therefore, T cell deficiency is the most likely diagnosis in this scenario.

Correct Answer: C

Rationale: The correct answer is C: PH 7.40, PaCO2 40 mm Hg, PaO2 90 mm Hg, HCO3 24 mEq/L. These values represent a balanced state for arterial blood gas. Choice A has lower than normal PH and HCO3 levels and higher PaCO2 and lower PaO2 levels. Choice B has higher than normal PH and HCO3 levels, lower PaCO2, and a normal PaO2 level. Choice D has a significantly lower PH and PaO2 level, normal HCO3 level, and low PaCO2 level, indicating an acidic state with impaired oxygenation.

Correct Answer: D

Rationale: The correct answer is D. Cerebral palsy involves irreversible damage to the brain that occurs before, during, or shortly after birth, impacting movement and coordination. Choices A, B, and C are incorrect because cerebral palsy is not reversible with cognitive therapy or physical therapy, does not resolve in adulthood, and does not manifest in adulthood after regular childhood activities.

Correct Answer: B

Rationale: Bones store electrolytes and act as a reservoir, maintaining a balance of essential minerals like calcium and phosphate. The correct pair in this context is 'Bone - Nails.' Choices A, C, and D are incorrect because the brain, kidneys, liver, and pancreas perform other functions in the body and are not primarily responsible for storing electrolytes.

Correct Answer: A

Rationale: Vascular spasm is the initial step in hemostasis, where blood vessels constrict to reduce blood flow to the injured area. This constriction helps limit blood loss until further steps like platelet plug formation and coagulation can take place. Platelet plug formation and coagulation occur after the vascular spasm, making them incorrect choices. Dissolution of the clot happens much later in the healing process, after the injury has sufficiently healed.