Pyomyositis as a focus of infection in hematological disorders: a report of 3 cases

Ultrasound-Guided Conservative Treatment of Pyomyositis Due to Metamizole-Induced Agranulocytosis

Metamizole-induced agranulocytosis is a rare adverse drug reaction with common infectious complications. In this context, pyomyositis of the extremities has not yet been described. Usually, pyomyositis is treated with a combination of antibiotics and surgical intervention. Sonography is described as diagnostic tool for pyomyositis but without defined concrete characteristics for follow-up. This case report describes a widespread pyomyositis due to a metamizole-induced agranulocytosis, which was treated conservatively, using sonography for surveillance.

Pyomyositis caused by Streptococcus pneumoniae after allogeneic hematopoietic stem cell transplantation

Pyomyositis is classified into two main types: tropical and non-tropical. Non-tropical pyomyositis occurs among various immunocompromised patients, and Staphylococcus aureus has been reported as the most common pathogen. Pyomyositis caused by Streptococcus pneumoniae is uncommon, and has not been previously reported after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Here, we report a unique case with pyomyositis caused by S. pneumoniae in the bilateral erector spinae muscles 34 months after allo-HSCT. The patient had an initial clinical response following the administration of intravenous benzylpenicillin potassium for 4 weeks. Although S. pneumoniae bacteremia is a rare bacterial infection after HSCT, the possibility of pyomyositis must be considered when a recipient develops S. pneumoniae bacteremia. Accurate diagnosis and the selection of appropriate antibiotics are necessary for the treatment of pyomyositis.

Pyomyositis at the surgical site in a patient with chronic myeloid leukemia: a case report and literature review

BACKGROUND

Pyomyositis is a rare, subacute, deep pyogenic infection of the muscle tissue. This disease has been previously described in patients that were immunocompromised due to a hematological malignancy.

CASE PRESENTATION

A 68-year-old man with a history of chronic myeloid leukemia was treated with imatinib. He was diagnosed with ascending colon cancer and underwent curative surgery. His postoperative course was uneventful, and he was healthy at 6 months after surgery, allowing for reinitiation of imatinib therapy. After the reinitiation of therapy, a computed tomography (CT) scan revealed a mass shadow in the right iliopsoas muscle. This lesion was clinically diagnosed as recurrent colon cancer with an abscess, which was resected surgically. A pathological examination uncovered both edema and inflammation. Two months after the second surgery, imatinib therapy was reinitiated; however, he again developed painful swelling and erythema in his right thigh. A CT scan revealed a similar shadow as described previously. He was then diagnosed with pyomyositis; he underwent incisional drainage and was administered linezolid. Following the treatment for pyomyositis, there was no cancer recurrence or evidence of any recurrent pyomyositis.

CONCLUSIONS

Findings from this case suggest that both undergoing surgery and receiving imatinib therapy may modulate an individual's immune response, whereby the surgical site becomes more prone to infection and may predispose an individual to pyomyositis. The case report is followed by a discussion of the literature regarding this disease, including potential risk factors and the underlying pathogenesis.

Bilateral hip pain caused by adductor pyomyositis as the initial presentation of chronic myeloid leukemia in a 17-year-old child

Pyomyositis is a pyogenic muscular tissue infection mainly occurring in immunocompromised patients. Chronic myeloid leukemia (CML) accounts for only 2-3% of cases of childhood leukemia. Herein, we report on a 17-year-old male with bilateral hip pain caused by adductor pyomyositis before beginning the treatment course of CML. CML was diagnosed by bone marrow chromosome study and was treated initially with imatinib but switched to hydroxyurea 5 days later because of poor cytoreduction response. Subsequently, white blood cell counts decreased gradually; however, the hyperleukocytosis condition resolved very slowly again until we switched back to imatinib use on the 40(th) day of hospitalization. Pyomyositis was diagnosed by magnetic resonance imaging. Oxacillin was administered to cover Staphylococcus aureus, the most common pathogen of pyomyositis. Bilateral hip pain improved within 72 hours after antibiotic usage, but follow-up magnetic resonance imaging after 15 days of treatment revealed well-defined abscess and osteomyelitis of both femoral heads. Abscess incision and drainage were performed, and cultures of the drained pus grew no microorganisms. The patient completed 5 weeks of oxacillin treatment after the operation and recovered with a full range of motion of both hips. There was no residual disability. This is the first report of bilateral hip pain caused by pyomyositis as the initial presentation of CML. Pyomyositis needs to be considered in the differential diagnosis of hip pain in pediatric patients.

Pyomyositis associated with hematological malignancy: case report and review of the literature

Pyomyositis occurs most commonly in patients with various immunosuppressive diseases. However, the association of pyomyositis with an underlying hematological malignancy has not been reviewed. We present herein a relevant case and also review the available literature regarding the association of non-tropical pyomyositis and hematological malignancies. The case patient, a 46-year old female, had non-tropical pyomyositis of the iliopsoas and obturator muscles due to Staphylococcus aureus and underlying Hodgkin's disease. Forty-four patients with pyomyositis and an associated hematological malignant disease have been reported in the literature. The most common types of hematological oncology diseases found were acute lymphocytic leukemia (present in 11/44 patients (25%)) and multiple myeloma (7/44 patients (15.9%)). Staphylococcus aureus was the most common cause of pyomyositis (26 out of 44 patients (59.1%)). The muscles of the thigh were most commonly affected (18/44 patients (40.9%)). Medical therapy with antibiotics and surgical drainage were employed in 25/44 (56.8%) of the patients. Thirty out of 44 (68.2%) of the patients had a successful outcome. Death occurred in 5/44 (11.4%) patients. In cases of pyomyositis, the physician should consider an underlying hematological malignancy.

Community-acquired methicillin-resistant Staphylococcus aureus pyomyositis in an intravenous drug user

Pyomyositis is a disease of abscess formation deep within large striated muscles. Outside of the tropics it is a rare disease which occurs mainly in certain patient populations such as the immunosuppressed or intravenous drug users (IDUs). A case of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) pyomyositis in an IDU is described. The incidence of both CA-MRSA and pyomyositis is currently increasing. To the authors' knowledge this is the first reported case of CA-MRSA pyomyositis in the UK. Cases of CA-MRSA pyomyositis are likely to increase and it may be necessary to empirically treat certain patients with glycopeptides.

Piomiosite tropical

Piomiosite tropical é infecção bacteriana do músculo esquelético, mais freqüente em homens e que se apresenta com edema e hiperestesia na área afetada. Staphylococcus aureus é o agente prevalente. É relatado caso de homem com piomiosite de músculo gastrocnêmio, secundário a pioderma gangrenoso em membro inferior direito. Ultra-sonografia demonstrou coleção de líquido permeando feixes musculares. A drenagem cirúrgica e antibioticoterapia prolongada levaram à resolução do quadro.