1. A well-appearing, 6 month-old girl has a 104 fever and has had two seizures on the day of presentation to the ED. Do you perform an LP?
A February 2011 AAP guideline on children with simple febrile seizures makes it pretty clear that a lumbar puncture is not necessarily needed in a well-appearing child, who is sufficiently immunized against Strep. pneumo and H. influenzae, and has not received any recent antibiotics (raising the question of partial treatment). Prior to this, the dogma was that all children under 18 months with their first simple febrile seizure required an LP.
However, many would not classify this child as having a “simple” febrile seizure, because there were two seizures in less than 24 hours. In a case like this, the decision not to LP is a bit more hazy. Seltz, et al., 2009, looked at 390 episodes of complex febrile seizures in patients from 2002-2006, and found seven positive LPs, six Strep pneumo, one HSV. ALL seven children found in this retrospective study had abnormal mental status in the ED. This has led some commentators to suggest that well-appearing children with complex febrile seizures, who meet the AAP guidelines (no abx, immunizations UTD), may not need an LP.
2. A 22 day old presents with a fever of 101.9, a WBC count of 17,000, and negative urine and CXR. You are unable, in spite of repeated attempts, to get the LP. What antibiotics do you give the child?
Regardless of the tap, this hot little neonate needs to be covered broadly and empirically for serious bacterial illness (SBI). The most common cause of SBI in neonates are Group B strep, E. coli and gram negative rods, Strep. pneumo, H. flu, and Listeria. Ampicillin (for Listeria) and gentamicin, or ampicillin and cefotaxime, are the standard regimens for this situation. The question of adding acyclovir to the regimen often comes up, especially when the LP is an issue. Critical consensus dictates acyclovir should not be used in all neonates, except those that are ill-appearing, seize, have vesicles anywhere suggestive of HSV, or eye redness/irritation. Elevated LFTs, thrombocytopenia, or CSF pleocytosis, can also be signs of early disseminated HSV: most would strongly consider starting acyclovir in such a case. When the LP is a dry tap, and the patient does not meet any of the above criteria, it is reasonable to skip the acyclovir.
3. A 4 month old has had a fever to 102 for five days. The exam is notable only for a well-appearing child with the omnipresent nasal crusties and a mildly red oropharynx. The influenza swab is positive. What else would you do before discharging this patient?
Unfortunately, just because the flu swab is positive doesn’t mean you’re quite off the hook. You’re still going to need to go hunting for pyelo, with a cath urine (sorry, kids). About 16% of girls under 2 years, and ~8% of boys under 1 year of age, with fever without a source, will have a UTI. These are the axiomatic age cut offs to get urine, generally, for children with a fever (2 for girls, 1 for boys, 6 months for circumcised boys). In those over 2 months of age, Kupperman, et al., 1997, found that 2% of kids with RSV bronchiolitis also had a UTI. Krief, et al, 2009, found that in children 2 months and under, those with influenza still had a 2-3% UTI rate.
Secondly: does this child need to be treated with antivirals? Their efficacy greater than 48 hours out is doubtful. Most experts suggest saving the neuraminidase inhibitors for children who are getting hospitalized, are seriously and progressively getting sicker, or are at high risk of complication from influenza. For outpatient cases, the CDC currently recommends treating in children under 2 months, and in those at risk of complication due to a co-morbidity.
4. Do you do bag urines? In what scenarios? When do you go straight to a catheterized specimen?
In the un-toilet-trained, catheterization is the preferred method for getting the pee. Up to 85% of positive cultures from bag urine specimens are false positives. Bag urine is only helpful if the culture is negative. Some physicians use bag urines to screen for those requiring a cath for culture (i.e., if the bag urine urinalysis is positive, I’ll cath for the culture). This is a bad idea, as children can often have a normal urinalysis (due to their constant urination and lack of in-bladder stasis time) and a positive culture. Most recommend bagging the bag.
References and Further Reading
American Academy of Pediatrics. Herpes simplex. In: Red Book: 2009 Report of the Committee on Infectious Diseases, 28th ed, Pickering, LK (Ed), American Academy of Pediatrics, Elk Grove Village, IL, 2009. p.363.