Post-meningococcal splenic infarction

Case contributed by Dr Anass Benomar

Presentation

Fever, headache, confusion, and LUQ abdominal pain for 24 hours.

Patient Data

Age: 30 years
Gender: Male

Head CT

CT

Mild third ventricle dilation, along with a visibility of the temporal horns, but without transependymal resorption; suggesting early hydrocephalus. There is a partial effacement of sulci bilaterally, more than expected for the patient's young age. There is no hyperdense sulcus, nor any sign of acute ischemia. Note the heterogeneous hyperdense content filling the left sphenoid sinus, suggesting chronic sinusitis with proteinaceous or mucinous content.

Abdominal CT with contrast

CT

Despite the poor quality of this exam (due to the patient's confusion and movements during acquisition), we can appreciate a diffusely hypodense aspect of the spleen, as compared to the liver.

Abdominal US (6 days after Head and Body CT scans)

Ultrasound

There is a hypoechoic, bean-shaped, anterosuperior splenic lesion, along with a markedly heterogeneous aspect of the residual parenchyma. Numerous bright band signs are also noted.

Case Discussion

The patient's clinical and radiological findings triggered ER physicians to perform a lumbar puncture and a blood culture, both of which were positive for Neisseria meningitidis; confirming the diagnosis of pyogenic meningitis.

In addition to the diffusely hypodense aspect of the spleen on the abdominal CT, the diagnosis of splenic infarction was further ascertained by the presence of multiple bright band signs 2.

Splenic infarction following meningococcal infection can occur by two main mechanisms 1disseminated intravascular coagulation (DIC) and abscess formation. This patient had low platelet count, high d-dimer, and low fibrinogen; in keeping with DIC. Moreover, no enhancing peripheral splenic capsule was seen on the abdominal CT to suggest the presence of an abscess.

The patient evolved favorably after administration of IV ceftriaxone, receiving his hospital leave 6 days after admission. Prophylactic vaccination against encapsulated bacterias, as well as preventive splenectomy (due to the high risk of abscess formation), were scheduled.

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