3-in-1: bilateral subcutaneous leg abscesses and liver abscess from Klebsiella pneumoniae

Background

Hypervirulent strains of Klebsiella pneumoniae cause liver abscesses and other metastatic infections. Not yet reported is the occurrence of bilateral subcutaneous leg abscesses. Since he also had an incidentally discovered liver abscess, the occurrence of three distant abscesses in one patient, hence ‘3-in-1,’ makes this case worth reporting.

Case presentation

A 51-year-old man consulted for bilateral leg pains which started to be severe and activity limiting 1 month prior to admission.

He was known to have type 2 diabetes and hypertension for the past 6 years but was not compliant with medications and had irregular follow-up with his physician. He was previously prescribed with oral medications for diabetes and has been on insulin for the past 2 years. He reported unintentional weight loss, fatigue, polyuria and nocturia. He also mentioned dysuria and dribbling of urine.

He was a ballet dancer and choreographer. Whenever he got tired, he often experienced leg pains which he attributed to his occupation. He now reports severe leg pains very different from what he usually feels, difficulty in standing up from a sitting position and even walking. There was no antecedent trauma to both legs.

He has not had receptive and insertive anal intercourse with other men, but has engaged in oral intercourse. He denied recent wading in flood waters.

On physical examination, vital signs were as follows: blood pressure 130/80 mm Hg, heart rate 90 beats/min, temperature 36.6°C. He had anicteric sclerae and there is no conjunctival erythema. There was no goitre and no enlarged neck nodes. There were no crackles. Heart rhythm was regular and there were no murmurs. The abdomen was flat with no tenderness. The liver and spleen were not enlarged.

The pertinent findings were centred on the lower extremities. There was erythema of the skin overlying the right knee and left ankle with warmth and tenderness. Pain was elicited on flexion of both knees. There was direct tenderness of both calves even if there was no induration or overlying erythema. Slight pressure on both calves was enough for the patient to wince in pain. There were no enlarged inguinal nodes.

Investigations

Capillary blood glucose on admission was 267 mg/dL.

Complete blood count showed leucocytosis with segmenter predominance (white blood cell (WBC) 23.60×10⁹/mL, 92% polymorphonuclear leucocytes (PMNs)), with normal haemoglobin and platelet count. Serum creatinine and electrolytes were normal. Urinalysis showed +4 glucosuria, no albuminuria, no ketones, WBC 5/hpf and red blood cell 0/hpf. HbA1c was 9.0%.

Serum creatine kinase total and the MB isoform turned out to be normal, hence the attending physicians thought that myositis was unlikely.

After 3 days of empirical antibiotics, there was reduction in leg pain and tenderness from numerical rating scale of 10/10 to 6/10, and reduction in WBC to 11.20 (from 23.60) ×10⁹/mL, with 88% PMNs (from 92%). Initial blood culture at this time already showed Gram-negative bacilli after 10 hours of incubation. Urine culture did not reveal any growth.

Ultrasound of the abdomen revealed an enlarged prostate with an approximate volume of 38.3 cc, urinary retention of 63.9% (pre-void volume 909 cc, post-void volume 581 cc) and ureteropelvocaliectasia. There was an incidental finding of a heterogeneous predominantly hypoechoic focus in segments 6 and 7 of liver measuring 3.2×4.4×4.7 cm.

Though there was reduction in pain and tenderness, it was not completely relieved. This was when the attending medical doctors wanted to rule out an intramuscular abscess.

Contrast-enhanced CT scan of both lower extremities (figures 1 and 2) was performed. This revealed bilateral peripherally enhancing fluid collections confined to the subcutaneous regions of the legs, more extensive on the left. Small pockets of air were detected within these fluid collections. These fluid collections were mostly in the posterior aspect of the calves compressing on the gastrocnemius muscles. The osseous structures were intact for which intercurrent osteomyelitis was deemed unlikely. The left leg was swollen with associated subcutaneous fat stranding densities. These bilateral fluid collections were ascribed to subcutaneous abscesses with concomitant cellulitis in the left leg.

Figure 1

CT (axial view) of both legs shows collection of pus in the subcutaneous region delineated by green line.

Figure 2

CT (sagittal view) of leg shows collection of pus in the subcutaneous region delineated by red line.

To better characterise the liver nodule, triphasic CT of the abdomen (figure 3) was done and showed a peripherally enhancing hypodense lobulated mass in segments 6 and 7 of the liver measuring about 4.2×4.3×3.4 cm (craniocaudal× transverse× anteroposterior (CC×W×AP)), corresponding to the hypoechoic focus seen in the prior ultrasound which was interpreted as a hepatic abscess. No dilated biliary ducts or other mass lesions were seen in the rest of the liver. The prostate gland was enlarged, 2.6×2.8×2.3 cm (CC×W×AP). The urinary bladder wall was irregularly thickened and was ascribed to cystitis.

Figure 3

Triphasic CT of the abdomen shows a peripherally enhancing hypodense lobulated mass in segments 6 and 7 of the liver measuring about 4.2×4.3×3.4 cm (craniocaudal× transverse× anteroposterior), assessed to be a liver abscess.

Based on the ultrasound and CT scan findings plus a normal serum alpha-fetoprotein (0.33 ng/mL, normal: 0.74–7.3), the liver nodule was assessed to be a liver abscess. Since the liver abscess was less than 5 cm in greatest dimension, a decision to defer percutaneous drainage was made and close observation was planned.

Blood culture eventually grew K. pneumoniae ss pneumoniae, susceptible to ceftriaxone, cefazolin, cefoxitin, cefepime, ceftazidime, amikacin, meropenem, ertapenem, amoxicillin, piperacillin–tazobactam, cotrimoxazole and levofloxacin, but resistant to ampicillin.

Infective endocarditis was suspected on the basis of bacteremia and presence of abscesses in three non-contiguous sites (both legs and the liver). 2D-echocardiogram did not show any vegetations and there were no valvular abnormalities.

Initially, the patient did not consent for HIV screening but was convinced when told that he had three abscesses in separate sites. HIV screening turned out to be negative. Rapid plasma reagin, hepatitis B surface antigen and anti-HBs also turned out to be negative/non-reactive as well.

Differential diagnosis

Based on history and physical examination alone, initial impression was (1) cellulitis and myositis of both legs, (2) urinary tract infection, (3) possible prostate enlargement in a patient with (4) uncontrolled type 2 diabetes, with (4) HIV infection being suspected.

Leptospirosis was also considered as a possible cause of the bilateral calf pain since the patient presented during the Philippines’ rainy season. Cases of leptospirosis peak when there are floods brought about by monsoon rains. This, however, became less likely as the patient did not have recent wading in flood waters, did not have jaundice and conjunctival erythema.

Melioidosis, an infection due to Burkholderia pseudomallei, is also a differential since it can present with musculoskeletal infections, intra-abdominal abscesses and sepsis. It is of a significant burden in Southeast Asia and in the Philippines, in particular.1

Myositis and/or intramuscular abscess involving both gastrocnemius muscles was also considered.

Final diagnosis was bilateral subcutaneous leg abscesses, liver abscess and bacteremia from K. pneumoniae ss pneumoniae in a patient with uncontrolled type 2 diabetes, with prostate enlargement causing some urinary retention.

Treatment

On admission, the patient was empirically started on intravenous ceftriaxone and clindamycin, and basal-bolus insulin regimen using insulin degludec and aspart.

When symptoms were not improving and after demonstration of bilateral leg abscesses on CT scan, urgent incision and drainage of both legs was performed. Fifty cc of pus was drained from the right leg and 250 cc from the left (figure 4). There was immediate and near-complete resolution of pain and tenderness after incision and drainage was performed.

Figure 4

Pus draining from the left leg during incision and drainage.

Tissue culture collected intraoperatively from the legs also showed K. pneumoniae ss pneumoniae with the same antibiotic susceptibility.

Outcome and follow-up

Intravenous ceftriaxone and clindamycin for the leg abscesses were given for 14 days, while intravenous metronidazole, which was added for the liver abscess, was given for 9 days.

Surveillance blood culture done on the 8th hospital day did not anymore reveal any bacterial growth.

He was sent home 10 days after incision and drainage. On discharge, the antibiotic regimen was shifted to oral coamoxiclav 1 g two times per day for 4 weeks and metronidazole 500 mg every 6 hours for 5 more days. For the diabetes, he remained on insulin degludec and aspart while metformin was added. For the prostate enlargement, he was placed on dutasteride and tamsulosin.

On follow-up, the patient did not report any leg pains anymore and there were no dysuria and lower urinary tract symptoms. There was no jaundice nor abdominal pain. His capillary blood glucose levels were within target.

Serial ultrasound of the liver (figure 5) demonstrated a gradual decrease in the size and echogenicity of the cystic hepatic mass in segments 6 and 7 from a baseline measurement of 3.2×4.4×4.7 to 1.9×1.7×1.8 cm in the fourth ultrasound examination taken after a 44-day interval, indicating a resolving hepatic abscess.

Figure 5

Serial liver ultrasound demonstrating reduction in size and echogenicity of the liver abscess.

He was back to doing what he enjoys—dancing and teaching others how to dance.