2019 May 23. pii: S1695-4033(18)30548-4. doi: 10.1016/j.anpedi.2018.07.017. [Epub ahead of print]

[Pyogenic sacroiliitis: Lessons learned from an atypical case series].

[Article in Spanish]



Pyogenic sacroiliitis (PSI) is a rare condition that amounts to 1% to 2% of all joint infections in the paediatric age group. Its diagnosis is often difficult and delayed due to its nonspecific signs, symptoms and physical findings. Also, the identification of the causative microorganism is frequently challenging due to a high proportion of negative blood cultures and the risks involved in joint aspiration in this site.


We performed a retrospective review of the health records of all patients aged less than 18 years admitted to a tertiary children’s hospital due to PSI between 2008 and 2016.


We identified 6 cases of paediatric PSI. The blood cultures were negative, and the identification of the causative agent required joint fluid aspiration in one patient with infection by Aggregatibacter aphrophilus, and specific screening tests for less frequent agents in the other patients: Kingella kingae (n=2), Brucella melitensis (n=1) and Bartonella henselae (n=1). The patients were treated with specific antimicrobial regimens, and all had favourable clinical outcomes and were free from sequelae during the follow-up.


Despite the small sample size, our study evinced the low effectiveness of blood cultures for diagnosis of paediatric PSI. It also highlights the need for a high level of suspicion for atypical agents and the early use of adequate diagnostic methods, including imaging and serological testing or polymerase chain-reaction (PCR) analysis of blood samples, as well as prescription of effective antimicrobial therapy.



Pyogenic sacroiliitis = puss forming joint infection in the sacroiliac joint.


Brucella melitensisa gram negative rod-shaped bacteria, is a human pathogen (Malta fever), B.abortus (Bang’s disease), and in rare cases, B. suis and B. canis. Transmission occurs through animal contact (birth) or animal products, inhalation of infected particles, STD, breastfeeding, bone marrow transplants, blood products, and yes, ticks.  Pathogens are found in macrophages which are transported to lymph nodes, then spread throughout the body.  Treatment consists of doxycycline, rifampicin, & gentamicin.  Also, Ciprofloxin 500mg twice a day for 7-14 days. It has been found in eggs, larvae and engorged females of Dermacentor marginatus ticks (that bite humans)

Hosts are most mammals including humans.

Symptoms are very non-specific:  Actually the best information is found here.

And…according to the CDC:

*Three types of the bacteria that cause brucellosis – Brucella abortusBrucella melitensis and Brucella suis – are designated as select agents. This means that they have the potential to be developed as bioterrorism agents due to their ability to undergo aerosolization.

Oh goody, another potential bioweaponized agent spread by ticks.

For more on the history of brucella as a bioweapon:  Acute Lyme arthritis in the hip mimicking acute pyogenic arthritis in 5-year old girl.  Bartonella & all sorts of rheumatic symptoms in patients from Lyme endemic regions with histories of cat, dog, mosquitoes, ticks, fleas, and biting fly exposure.

Staph is usually the culprit, but this case report highlights that Lyme, Bartonella, Brucella, and mycoplasma should be tested for as well.  Things to watch for in children/babies – pain with diaper changes, limping, fever, irritability, decreased range of motion in the pelvic area.  This review stated the highest incidence was in adolescents:, but that it’s an under recognized entity in infants with an unidentified bacterial source.  Could this be a manifestation of congenital Lyme/MSIDS that’s flying under the radar?