A nurse is caring for a child who has pertussis. The child's parent asks the nurse what the common name for this disease is. The nurse should
respond with which of the following common names?

Choice A reason: Failure to thrive is not a likely condition, as it is a term used to describe inadequate growth or weight gain in children. The infant has a low weight percentile, but not below the 5th percentile, which is the usual cutoff for failure to thrive. The infant's length and head circumference are within the normal range, which also does not indicate failure to thrive.

Choice B reason: Microcephaly is not a probable condition, as it is a condition where the head size is much smaller than normal for the age and sex of the child. The infant has a high head circumference percentile, which is the opposite of microcephaly. Microcephaly can be caused by genetic disorders, infections, or brain damage.

Choice C reason: Hydrocephalus is a possible condition, as it is a condition where excess cerebrospinal fluid accumulates in the brain, causing increased pressure and enlargement of the head. The infant has a high head circumference percentile, which can indicate hydrocephalus. The infant also has a low weight percentile, which can be a result of poor feeding or vomiting due to increased intracranial pressure. T

Choice D reason: Macrocephaly is not a definite condition, as it is a term used to describe a head size that is much larger than normal for the age and sex of the child. The infant has a high head circumference percentile, but not above the 97th percentile, which is the usual cutoff for macrocephaly. Macrocephaly can be caused by genetic factors, benign familial macrocephaly, or other conditions, such as hydrocephalus.

Choice A reason: This test measures the level of antibodies that the body produces against the streptolysin O enzyme, which is produced by some strains of streptococcal bacteria. A high level of ASO titer indicates that the child had a recent streptococcal infection, which may trigger rheumatic fever in some cases.

Choice B reason: This test does not directly indicate if the child has rheumatic fever. Rheumatic fever is a complication of untreated or inadequately treated streptococcal infection, which causes inflammation of the heart, joints, skin, and brain. The diagnosis of rheumatic fever is based on clinical criteria, such as the presence of carditis, polyarthritis, chorea, erythema marginatum, or subcutaneous nodules.

Choice C reason: This test does not confirm if the child has immunity to streptococcal bacteria. Immunity is the ability of the body to resist or fight off an infection. A high level of ASO titer does not mean that the child is immune to streptococcal bacteria, but rather that the child was exposed to them recently.

Choice D reason: This test does not indicate if the child has a therapeutic blood level of an aminoglycoside. Aminoglycosides are a class of antibiotics that are used to treat serious bacterial infections, such as endocarditis or septicemia. The blood level of an aminoglycoside is measured by a different test, called a peak and trough level, which determines the effectiveness and safety of the drug.