The recommended children's dosage of Keflex is 25 to 50 mg/kg/day in divided doses. The maximum daily safe dosage for a child weighing 42 lb is: Round to the nearest tenth.

(Number Only, do not enter mg, kg, or day with your answer)

The correct answer is choice B. First stage.

Choice A rationale:

There is no fourth stage of Lyme disease. Lyme disease typically progresses through three stages: early localized, early disseminated, and late disseminated. The symptoms mentioned in the question are more indicative of earlier stages of the disease.

Choice B rationale:

The child is likely exhibiting symptoms of the first stage of Lyme disease, known as early localized Lyme disease. This stage is characterized by the appearance of small annular (circular) lesions known as erythema migrans. These lesions are often red and have a clear center, resembling a "bull's-eye" pattern. This stage occurs within days to weeks after a tick bite and is usually accompanied by flu-like symptoms.

Choice C rationale:

There is no third stage of Lyme disease. The third stage is considered the late disseminated stage, which occurs months to years after the initial infection. It typically involves more severe symptoms, such as arthritis, neurological issues, and cardiac abnormalities.

Choice D rationale:

There is no second stage of Lyme disease. The second stage is the early disseminated stage, which occurs weeks to a few months after the tick bite. It involves the spread of the bacteria to other parts of the body, leading to symptoms such as multiple erythema migrans lesions, flu-like symptoms, fatigue, and muscle and joint pain.

The correct answers are choices A, C, and D: Tachycardia, Hyperthermia, and Vomiting.

Choice A rationale:

Tachycardia. Tachycardia, an abnormally fast heart rate, is a classic manifestation of thyroid storm. In this life-threatening condition, there is an excessive release of thyroid hormones, leading to increased metabolic rate and subsequent cardiovascular effects such as tachycardia.

Choice B rationale:

Constipation. This choice is incorrect for thyroid storm. Hyperthyroidism typically leads to increased bowel motility and can cause diarrhea rather than constipation.

Choice C rationale:

Hyperthermia. This is a correct choice. Thyroid storm is associated with severe hyperthermia due to the increased metabolic rate caused by excessive thyroid hormones. The body's temperature regulation is disrupted, leading to dangerously high body temperatures.

Choice D rationale:

Vomiting. This is a correct choice. Gastrointestinal symptoms, including vomiting and nausea, can occur in thyroid storm due to the heightened metabolic state. Thyroid storm affects various systems, including the gastrointestinal system, leading to symptoms like vomiting.

Choice E rationale:

Hypotension. This choice is incorrect for thyroid storm. Thyroid storm is more likely to cause hypertension rather than hypotension due to the increased cardiac output and sympathetic stimulation.