Written by Clay Smith
Serious infection was rare among infants ≤60 days with hypothermia (2.6% prevalence). The three infants with serious infection all had hypothermia plus some other red flag, but be very careful how you use this in practice.
Why does this matter?
Hypothermia (rectal temperature ≤36.0°C) in young infants may be a sign of sepsis, especially infection caused by HSV, but it may simply be from exposure to a cool environment. Should we consider hypothermia alone as a reason to initiate a sepsis workup, as we do fever (≥38.0°C)?
Oh, that’s cool!
This was a single center retrospective study of 4,797 infant ≤60 days over ~3 years who presented to the ED for any reason. Of these, 116 were hypothermic. Prevalence of a serious infection, defined as urinary tract infection (UTI), bacteremia, meningitis, pneumonia, or herpes infection, was 2.6% (3/116) among hypothermic infants; prevalence was 15.2% (61/401) among febrile infants. The three hypothermic infants with serious infection all had other clinical features in addition to hypothermia, such as, “prematurity, apnea, poor feeding, lethargy, ill-appearance, and respiratory signs.” No infants with isolated hypothermia had serious infection, that the authors could detect. Here is a major caveat – just 33/116 (28.4%) of the hypothermic infants had any workup for serious infection, and not all (91.4%) could be followed up. Clearly, the emergency physicians treated hypothermia as benign 72% of the time and did not perform a workup. And the three infants with serious infection (that we know about) all had hypothermia plus something else that indicated the infant had something more serious. However, we should not view this study as definitive, since the sample size is relatively small, most of the hypothermic infants did not have infectious workup, and some were lost to follow up. Generally, this affirms my practice. In a healthy appearing infant ≤60 days with hypothermia, I may not do a full sepsis workup, especially if there is a reasonable explanation – blanket fell off, cold room, etc. But if there is one thing I take away, it is that hypothermia plus any other red flag means that child should get a full workup for serious infection.
Hypothermia: A Sign of Sepsis in Young Infants in the Emergency Department? Pediatr Emerg Care. 2021 Mar 1;37(3):e124-e128. doi: 10.1097/PEC.0000000000001539.