Skull osteomyelitis from a infected pilar cyst

J.Sales-Llopis

Neurosurgery Service, Alicante University General Hospital, Alicante, Spain.

The patient is an 86-year-old male with a history of high blood pressure, dyslipidemia, and chronic ischemic heart disease. He was taking rivaroxaban for deep vein thrombosis. Additionally, he has been experiencing complications related to a supposedly infected trichilemmal cyst in the occipital region of the scalp for the past 5 months. The cyst was drained, but there has been ongoing bleeding and pus discharge from the wound, with a lack of continuity in the skull cap at the surgical site.

On CT imaging, a subcutaneous extracranial lesion is observed on the right occipital level, exhibiting heterogeneity with air presence and loss of skin integrity. The lesion has caused erosion of the underlying bone and is similar in size to a previous study.Skull osteomyelitis. No signs of hemorrhage or space-occupying lesions are noted. However, there is diffuse hypodensity of the periventricular white matter, indicating moderate/severe chronic small vessel ischemic disease. The patient also exhibits increased ventricular size, possibly suggestive of normal pressure hydrocephalus, which should be clinically evaluated. The midline is centered, and basal cisterns are clear.

In addition, the patient's exudate shows the presence of Proteus mirabilis, pending confirmation of its resistance to ertapenem. The organism is susceptible to amoxicillin/clavulanate, meropenem, amikacin, and quinolones. Klebsiella oxytoca is also present, which is susceptible to amoxicillin/clavulanate, cefotaxime, carbapenems, quinolones, and trimethoprim/sulfamethoxazole. The patient is currently receiving a combination of cloxacillin and ceftazidime antibiotics, with an urgent meropenem dose scheduled.

Furthermore, the patient's bloodwork shows macrocytosis, indicating the presence of abnormally large red blood cells.