Recurrent iliacus abscess with sacroiliac septic arthritis & osteomyelitis - how is resolution typically confirmed before stopping IV antibiotics?
My husband is currently being treated for right iliacus abscess (originally 9.6 cm), recurrent iliacus abscess, right sacroiliac septic arthritis, and osteomyelitis of the right sacrum and iliac bone. I’m looking for opinions on whether his current treatment plan is appropriate and, more importantly, how to make sure this infection is truly eradicated before antibiotics are stopped. We are terrified of this happening a third time.
His initial diagnosis was a 9.6 cm iliacus muscle abscess. Unfortunately, there was a delay in diagnosis that progressed to septic shock, and he nearly died. He underwent CT-guided drainage and was hospitalized for about a week and a half.
Initially, he continued having extremely high fevers (up to 106°F), worsening blood cultures, abnormal inflammatory labs, and remained unable to walk despite drainage and IV antibiotics. Infectious Disease was eventually consulted, changed his antibiotics based on culture and sensitivity results because the original antibiotics were ineffective, and a repeat CT with contrast found a second approximately 5 cm abdominal wall abscess. They attempted to drain it, but it collapsed during the procedure. His original drain also had to be corrected because it wasnt draining.
He completed IV antibiotics through a PICC line for about two weeks after discharge. A CT with contrast reportedly showed the iliacus abscess had resolved, his drain was removed, and once his CBC normalized, his PICC was removed and antibiotics were stopped.
About one month later, he was in sepsis again, but it did not progress into septic shock. Initially they searched for another source of infection (heart, abdominal organs, etc.), but those were negative. MRI with contrast ultimately showed that the iliacus abscess was still present, along with septic arthritis of the right SI joint and osteomyelitis involving the right sacrum and iliac bone. He is now being treated with a PICC line and is expected to receive at least 6-8 weeks of IV antibiotics. They have not placed another drain because they felt the remaining collection was too small.
My questions are:
- Given this history of abscess not being resolved after treatment was stopped, is 6-8 weeks of IV antibiotics alone the standard approach, or would you expect additional intervention?
- Before stopping antibiotics this time, what imaging would give the highest confidence that the infection has truly resolved? Wouldnt MRI with contrast generally be preferred over CT with contrast for evaluating a deep iliacus abscess and associated osteomyelitis, or is CT sufficient? From my understanding, MRI with contrast can see small abscesses better than CT?
- Is it common for a CT with contrast to appear reassuring while residual infection is still present and later identified on MRI?
- Are there any additional tests, labs, or imaging that you would want before discontinuing antibiotics in a case like this?
We fully understand no one can give medical advice over Reddit, but after he nearly died once and then was in sepsis again a month after treatment ended, we’re trying to make sure everything possible is done before his antibiotics are discontinued again.