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Inside Out: Bone Marrow Necrosis and Fat Embolism

 

Reconstruction images from CT of the abdomen and pelvis show femoral head osteonecrosis.

Reconstruction images from CT of the abdomen and pelvis show femoral head osteonecrosis.

Neurologic symptoms initially attributed to infection were ultimately the result of a devastating hematologic condition. The patient, a 57-year-old woman, was rushed to the emergency department for somnolence and slurred speech. She had experienced low back pain during the preceding week. Her medical history was notable for a ventriculoperitoneal shunt placed several years ago after spontaneous intracranial hemorrhage.

Assessment

On examination, the patient was difficult to arouse and was emergently intubated for airway protection. She was febrile to 39.3°C with a heart rate of 144 beats/min. An oxygen saturation was not recorded. Her physical examination results were otherwise unremarkable. The electrocardiogram revealed sinus tachycardia and T-wave inversions in the anterior and lateral leads.

Laboratory investigation revealed a white blood cell count of 11.1 × 103/μL, hemoglobin of 11.2 g/dL, and platelet count of 148 × 103/μL. Basic metabolic panel disclosed normal renal function with creatinine of 1.0 mg/dL. Troponin I and liver function results were mildly elevated (Table).

A chest radiograph showed diffuse bilateral lung opacities, worse in the bases, consistent with a combination of pulmonary edema and basilar pneumonia. Computed tomography (CT) of the head without contrast revealed no acute process. The ventriculoperitoneal shunt catheter placement was appropriate. CT of the abdomen showed no fluid collection or pseudocyst associated with the ventriculoperitoneal shunt catheter. Extension of the image into the chest revealed patchy opacities in both lower lobes, and extension into the pelvis identified bilateral femoral head osteonecrosis. Magnetic resonance imaging of the brain was significant for innumerable punctate foci of restricted diffusion predominantly in the bilateral cerebral subcortical and deep white matter (Figure 1).

Lumbar puncture was attempted but unsuccessful because of the patient’s body habitus. Arrangements were made to obtain cerebrospinal fluid via the ventriculoperitoneal shunt. In the interim, treatment was started for possible meningoencephalitis and pneumonia with vancomycin, cefepime, ampicillin, and acyclovir.

The patient’s ventriculoperitoneal shunt was accessed on day 2 with only 2 mL of fluid obtained. The white blood cell count was 23/μL (29% neutrophils, 50% lymphocytes, 17% monocytes). Protein and glucose were within normal limits at 108 mg/dL and 83 mg/dL, respectively. Cultures of the cerebrospinal fluid and blood remained negative for bacterial, viral, and fungal organisms, including herpes simplex virus, cytomegalovirus, and Cryptococcus. Tracheal aspirate culture grew methicillin-sensitive Staphylococcus aureus. The patient was continued on antimicrobial therapy without mental status improvement.

On day 2, the patient remained febrile and tachycardic with a heart rate of 120 beats/min. Her troponin increased to a peak of 2.01 ng/mL while liver function began to normalize (Table). Her creatinine increased to 3.4 mg/dL and platelet count decreased rapidly to 30.7 × 103/μL. Her hemoglobin also decreased to 6.3 g/dL. The combination of encephalopathy, fever, and acute renal failure with anemia and thrombocytopenia raised concern for thrombotic thrombocytopenic purpura. However, serum haptoglobin and indirect bilirubin were within normal limits and the peripheral smear did not show schistocytes, indicating an absence of hemolysis that characterizes thrombotic thrombocytopenic purpura (not shown).

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-Jori May, MD, Joseph C. Sullivan, MD, Daniel LaVie, MD, Katherine LaVie, MD, Marisa B. Marques, MD

This article originally appeared in the December 2016 issue of The American Journal of Medicine.

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