Case 3:
A five-month-old boy was presented to the pediatric department as his
parents had noticed a progressive swelling and erythema on the left
thigh from one month ago. On physical examination vital signs were
stable. There was a swelling sized 4*4 cm on the left thigh and the site
was warm. No deformity, discharge, or tenderness was detected. The
general physical examinations including lung and heart auscultation,
abdominal examination, and the examination of lymph nodes were normal.
He had received oral Metronidazole and Amoxicillin-Clavulanic acid for
one week without any improvement. The patient had an appropriate growth
and developmental history with no prenatal or perinatal difficulties and
he had received the routine vaccination for Iranian children. The lab
results were as follows: WBC: 39000/μl, Hemoglobin: 9.8 gr/dl, Platelet:
510000, and ESR: 21 mm/h. BUN and Cr were normal. Ultrasound results
demonstrated a hypo-echoic lesion with internal septations (46*37*47 mm,
approximately 42 ml, 10 mm under the skin). X-ray imaging was otherwise
normal. Open surgical drainage was done and samples were sent for gram
staining, acid-fast staining, culture, and PCR examination of various
mycobacterium types. Clindamycin was administered after admission to
cover possible causes of abscess and due to inappropriate response, it
was changed to Vancomycin and Cefotaxime. Gram staining and routine
culture were negative. Acid-fast staining and culture on Loewenstein
Jensen culture media were both positive for mycobacterium. The PCR test
result was positive for Mycobacterium Bovis. TST was done and showed 0
mm induration. Isoniazid and Rifampin were administered after the
diagnosis of the mycobacterial cold abscess was confirmed. During the
next two weeks, regarding the thigh swelling and possible pus
re-accumulation, ultrasound examination of thigh soft tissue was
repeated and showed an abscess (approximately 9 ml, 19 mm under the
skin), so the patient underwent surgical drainage and debridement of the
lesion for the second time. Isoniazid and Rifampin were continued for
the next six months. The patient had good growth and development with no
further re-accumulation of pus or any other remarkable health problem
during the follow-up.