Pediatric Problem Solving-Case21

Pediatric Problem Solving – Case 21
A 10 week old infant develops fever (38.5 C), vomiting, and irritability. His heart rate is 170/m and respiratory rate is 40/m. the infant's anterior fontanel is full, but there is no neck rigidity. The rest of the examination is unremarkable.
What is the most appropriate diagnostic test?
A. CSF examination

B. Complete blood count and ESR.

C. X- ray skull

D. chest x-ray

Explanation of the case:
Tachycardia is proportionate to fever.
Full anterior fontanel indicates increase of intra cranial tension.
Absence of neck rigidity don't exclude meningitides as it's not a dependent sign in children due to
open fontanel, which offer a relief of increased tension
Fever, vomiting, irritability are signs of infection.
choice (A): right choice: From the above cerebrospinal fluid examination is the most appropriate diagnostic test for meningitis as it indicates turbidity of CSF and confirm meningitis

Choice (B): point against. It will be done later as this is not a specific diagnostic test as it will show increase in WBCS count indicating infection but doesn’t detect the type of infection.

Choice (C): point against: it is useless in this case as it will show nothing and the infant will be exposed to X-ray without important reason.

Choice (D): the respiratory rate is normal and there is no symptoms suggesting any chest problems.