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Acute Kidney Injury in a Case of Purpura Fulminans Developing Secondary to Antithrombin 3 Deficiency

Purpura fulminans associated with antithrombin 3 (AT 3) deficiency is very rare in adults and neonates. It can be categorized into three principal forms neonatal, idiopathic and acute infectious. Purpura fulminans has been reported to cause cardiac, pulmonary and renal damage in rare cases. We describe an adult case of purpura fulminans developing in association with AT 3 deficiency without infection following a surgical procedure, and acute kidney injury (AKI) developing secondary to rhabdomyolysis and disseminated intravascular coagulation (DIC). To the best of our knowledge there have been no previous cases of purpura fulminans and AKI developing in association with acquired AT 3 deficiency without infection after surgery. (J Nippon Med Sch 2018; 85: 56―59)


Introduction
Purpura fulminans is characterized by intravascular thrombosis, collapse in cutaneous vessels and rapidly progressing hemorrhagic infarction and disseminated intravascular coagulation (DIC) 1 . Purpura fulminans can be categorized into three principal forms -neonatal, idiopathic and acute infectious 2 . All three forms present and are treated differently. Protein C, protein S and AT 3 deficiency are implicated in the etiology of purpura fulminans, resulting in DIC and purpura progressing to gangrenous lesions 3 . Idiopathic purpura fulminans frequently emerges after a latent period following a febrile infection, and DIC and multiorgan dysfunction subsequently develop 4 . The acute infectious form generally develops following meningococcal or Varicella zoster virus infection 5 .
We describe an adult case of purpura fulminans developing in association with AT 3 deficiency without infection following a surgical procedure, acute kidney injury (AKI) developing secondary to rhabdomyolysis and DIC, and the successful treatment thereof. The rarity of this case makes it particularly interesting.

Case Presentation
A 32-year-old male patient, undergoing surgery in an external center due to acute appendicitis, presented to our emergency department on the 7 th day postoperatively due to lethargy, hematuria, decreased urine output and eruptions on his lower extremities. On physical examination, he was confused, and orientation and cooperation were weak. His blood pressure was 90/60 mm/Hg, heart rate was 120 beats per minute, body temperature was 37.2°C, and partial pressure of oxygen was 70%. Diffuse purpura were present on both lower extremities, pulses were palpable bilaterally and a right lower quadrant abdominal scar secondary to an operation was visible. The patient's general condition was poor, and his oxygenation was low. He was intubated and transferred to the intensive care unit. The patient was extubated on the 2 nd day after admission. Biochemistry, complete blood count and coagulation values are shown in Table 1. No bacterial growth was determined in his blood or urine cultures. At follow-up, his urine output was 160 mL/day and his creatinine was 6.4 mg/dL, and hemodialysis was   . 1). Arterial thrombosis was not suspected. ANA and anti-dsDNA were negative, Protein C was 113% (70 130%), and AT 3 activity was 23% (80 120) at tests performed for the purpuric lesions with a preliminary diagnosis of vasculitis and purpura fulminans. A punch biopsy was taken from the purpuric lesions. The pathology result was compatible with purpura fulminans (Fig. 2).

Discussion
Purpura fulminans is a disease that is frequently seen in newborns but rarely in adults, in whose etiology gram negative bacteria are frequently involved, and that presents with cutaneous vascular collapse, edema, necrosis and gangrene 1 3 . In our patient, purpura fulminans was diagnosed after a punch biopsy from eruptions emerging following an appendectomy. AT 3 deficiency was determined from the known etiological factors.
AT 3 is a natural anticoagulant. AT 3 deficiency can be congenital or acquired. Congenital forms occur as a result of antithrombin gene mutations, while acquired forms can also accompany conditions such as liver disease or warfarin therapy in which AT 3 production decreases, nephrotic syndrome in which loss worsens, or acute thrombosis or DIC in which consumption increases 6 8 . AT 3 deficiency may rarely be observed following major surgery 9 . Although the low AT3 level after surgery cannot be fully explained, it may perhaps be due to consumption associated with the process arising from tissue trauma in the surgical procedure 10 . In our case, we think that AT 3 deficiency developed secondary to sur- Compatibly with the presentation, gangrenous lesions were present in the lower extremities, particularly the toes. Cardiac, hepatic and renal damage have rarely been reported in purpura fulminans in previous studies 5 . We considered that the development of acute kidney injury together with eruptions in our case was secondary to purpura fulminans-associated DIC and rhabdomyolysis.
Previous cases have been reported of acute kidney injury developing following purpura fulminans and/or rhabdomyolysis secondary to various infections 12 14 . In the adult age group, purpura fulminans associated with protein C and S, and antithrombin 3 deficiency generally emerges with the development of antibodies to these coagulation proteins after an infection. However, we determined no infectious agent in our patient. Only an appendectomy before presentation to our hospital was present in his history. This distinguishes this case from others in the literature. To the best of our knowledge, this is the first case of acute kidney injury and purpura fulminans developing in association with AT 3 deficiency after surgery.
The recommended treatment of purpura fulminans in the guidelines involves treatment of sepsis with appropriate antibiotics, adjustment of coagulation with requisite replacements, debridement of gangrenous lesions in the extremities under suitable conditions, and even amputation 15 . We determined no infection in our patient. No further hemodialysis was required on the 5 th day of heparinization. Our patient is still being followed-up and treated with no cutaneous lesions or organ dysfunction following warfarin therapy.
In conclusion, antithrombin 3 deficiency may constitute a rare cause of purpura fulminans, purpura fulminans can be triggered following a surgical procedure in adults with AT 3 deficiency, and rhabdomyolysis should not be overlooked in the development of acute kidney injury in such cases.

Conflict of Interest:
We report no conflicts of interest.