Discussion
Initial symptoms of STSS are fever, pain and swelling of extremities,
with rapid clinical deterioration leading to multiple organ failure,
including acute respiratory distress syndrome, DIC and renal
disturbance, with extremely high mortality [2].
While group A Streptococcus (GAS)
is a major cause of STSS, cases of group B Streptococcus and GGS-induced
STSS have recently increased [3,4]. Among GGS, SDSE infection is
most frequent in humans [5]. While STSS due to GAS can occur in
patients without underlying conditions [6], STSS due to GGS tends to
occur in elderly patients and those with underlying conditions, such as
diabetes mellitus, cardiovascular diseases, malignancies, cirrhosis,
immunosuppressive conditions, or skin diseases [5,7,8]. In our case,
the causative bacterium of STSS was not GAS, but SDSE of GGS. While GGS
is a normal inhabitant of the nasopharyngeal cavity, skin and perineal
area [5], it can cause erysipelas, cellulitis, necrotizing
fasciitis, STSS, pneumonia, arthritis, osteomyelitis, meningitis,
encephalitis, endocarditis, and sepsis, with clinical presentations
similar to GAS. Both group C Streptococcus and GGS were previously not
considered pathogenic bacteria. However, invasive infection caused by
SDSE has been recently recognized, and thus, merits special attention
[9,10].
When STSS is suspected, prompt diagnosis and early initiation of
treatment with whole-body management, antibiotic administration and
surgical intervention are critical [7]. The primary antibiotic for
STSS treatment is penicillin, to which GGS is highly sensitive.
Combination therapy with CLDM, which has anti-exotoxin effects with high
tissue penetration properties, is also effective [5,11]. Reportedly,
CLDM also suppresses penicillin-binding protein synthesis, resulting in
enhancement of the penicillin effect in addition to suppression of
exotoxin production [12]. Early debridement is important in cases
with necrosis [7]. Although we did not administer immunoglobulin
therapy in our case, it might also be effective for STSS treatment
[5,13].
We used CHDF and PMX-DHP in addition to hemodynamic management and
infection control. CHDF functions as an artificial kidney, removing
various mediators of shock. In our case, we used an AN69ST membrane to
absorb cytokines. The AN69ST membranes absorb
high mobility group box protein 1
(HMGB-1), which is a late mediator of septic shock [14]. Previous
reports have shown that absorption of HMGB-1 has beneficial clinical
effects in patients with septic shock [15,16].
PMX-DHP removes intrinsic cannabinoids, which are critical mediators in
the early stages of septic shock, and is effective in the treatment of
severe sepsis [17]. In our case, fluid therapy and high doses of
noradrenaline were ineffective for treating the shock state, and PMX-DHP
and CHDF enabled the tapering of noradrenaline administration,
suggesting that hypercytokinemia might contribute to hemodynamic
disruption. We speculate that absorption and removal of cytokines by
blood purification therapy using both PMX-DHP and CHDF resulted in
hemodynamic stabilization and the positive outcome in our patient.
Since necrotic tissue has a poor blood supply, penetration of necrotic
tissue by antibiotics is generally low. Therefore, early surgical
resection of the necrotic tissue to prevent progression of tissue
necrosis is prioritized in STSS with comorbid necrotic fasciitis
[7,18,19]. Misiakos et al. reported that the mean interval between
diagnosis of necrotizing fasciitis and debridement should be not more
than approximately 12 hours, since a prolonged duration >
12 hours worsens mortality [20]. Bilton et al. reported that the
mortality of patients with necrotic fasciitis who received early and
adequate debridement was 4.2%, whereas delayed debridement increased
the mortality to 38% [21]. In addition, necrotizing fasciitis
causes persistent damage to surrounding tissues via exotoxin secreted by
bacteria after establishment of the necrosis, which requires recurrent
debridement [18-20]. Our patient underwent emergency debridement
within several hours after admission. Furthermore, in our case, daily
debridement of necrotic tissue reduced symptoms of infection and
successfully preserved the affected leg. With progression of infection,
the leg might require amputation. In particular, necrotizing fasciitis
cases with comorbid diabetes mellitus have a higher risk of progression
of symptoms, requiring amputation of the leg [22,23].
Here, we reported a case of STSS with necrotizing fasciitis and septic
shock. Early multidisciplinary treatment resulted in a favorable outcome
despite her advanced age.