Bhavik Patel

Therapeutic drug monitoring of beta-lactam antibiotics in burns patients-A one-year prospective study

Background Beta-lactams are first-line antibiotics for the management of superficial infections due to burn injury. There is sparse data available on therapeutic drug monitoring (TDM) in patients with burns in a ward setting. This study was conducted to evaluate the utility of a beta-lactam TDM program in a cohort of burn injury patients in a ward environment. Methods Steady-state blood samples were collected immediately before a scheduled dose. The therapeutic concentration targets assessed were (1) free antibiotic concentrations exceeding the minimum inhibitory concentration (MIC; fT > MIC) and (2) free concentrations ≥4× MIC of the known or suspected pathogen (fT > 4× MIC). The duration of therapy was also assessed. Results A total of 50 patients were included for TDM over a 12-month period. The mean (±SD) age was 49 ± 16 years. The mean percent total body surface area burn was 17 ± 13%. The mean serum creatinine concentration was 86 ± 20 &mgr;mole/L. Sixty percent of the patients did not achieve fT > MIC, and only 18% achieved the higher target of fT > 4× MIC. Although all the patients achieved a positive clinical outcome, the duration of antibiotic treatment was shorter in patients who achieved fT > MIC compared with those who did not (4.2 ± 1.1 versus 5.3 ± 2.3 days; P = 0.03). Conclusions We found TDM to be a reliable intervention for burn injury patients in a ward environment. This study supports pharmacokinetic data that burns patients may be at risk of subtherapeutic dosing, which may prolong the duration of antibiotic therapy.

Characteristics of bloodstream infections in burn patients: An 11-year retrospective study

AIMS The principal aim of this study was to describe infection related characteristics of blood stream infections (BSI) in patients with burns. We sought to determine the organisms that caused BSI and factors that could predict the outcome of BSI. METHODS Data was collected on admitted patients with burns from January 1998 to December 2008. Selected information from databases was analysed using SPSS version 17 (SPSS Inc., Chicago). Descriptive, univariate and multivariate analysis was undertaken to determine factors predictive of clinical outcome. The factors analysed by univariate analysis were selected on clinical plausibility. Multivariate analysis used a crosstabs procedure initially to estimate maximum likelihood. Factors that were associated with a p value <0.15 were entered into a binary logistic regression to detect which factors were independent predictors of mortality in BSI and outcome according to specific organisms. RESULTS Ninety-nine out of 2364 (4%) patients developed 212-documented BSI. The median time from burn to BSI was 7 (interquartile range 3-16) days. Gram-positive organisms, in particular Methicillin resistant Staphylococcus aureus and Coagulase negative Staphylococci, were the most common bacteria associated with BSI in the first week of hospital admission. The mortality rate for all admissions over the data collection period was 3%. Of the 99 patients with BSI, 13 died giving a mortality rate, in the presence of BSI, of 13%. Univariate analysis found that the factors predictive of P. aeruginosa mortality were inhalational injury, higher total body surface area burns, total days of antibiotic treatment and elevated Acute Physiological and Chronic Health Evaluation (APACHE) II scores. Multivariate analysis identified inhalational injury to be the only factor associated with BSI-related mortality. CONCLUSION Whilst the overall mortality in our cohort was low, the presence of BSI increased this four-fold. Whilst infections caused by Gram-positive pathogens occurred earlier in the patient stay than Gram-negative organisms, the highest mortality was associated with P. aeruginosa infections. This study highlights the negative effects of BSI on clinical outcomes in burn patients.

Laparoscopic pancreaticoduodenectomy in Brisbane, Australia: an initial experience.

The role of minimally invasive approach for pancreaticoduodenectomy has not yet been well defined in Australia. We present our early experience with laparoscopic pancreaticoduodenectomy (LPD) from Brisbane, Australia.

Revision gastric bypass after laparoscopic adjustable gastric band: a 10‐year experience at a public teaching hospital

In Australia, there is limited access to public revisional bariatric procedures. However, the need for such procedures is rising. We investigated the safety and efficacy of band‐to‐bypass procedures in our experience at a public teaching hospital over a period of 10 years.

Obturator nerve ganglion cyst: masquerading as groin hernia: Images for surgeons

A 59-year-old female patient was referred to our outpatient department for consideration of left inguinal hernia repair in the context of left groin pain and ultrasound-proven small indirect hernia containing fat. On further history, the patient complained of pain mostly in the groin region below the inguinal ligament radiating to inner thigh. On examination, there was no cough impulse noted and no hernias felt, but the patient was tender over the left femoral region. Due to inconsistencies in history and examination, multiphase computed tomography scan of the abdomen was performed (Fig. 1), which was suggestive of obturator neuroma. Magnetic resonance imaging (MRI) scan of the pelvis was performed (Fig. 2), which showed T2 hyperintense lesion in the left obturator canal with multiple thin internal septa but no solid nodule component. Both hip joints demonstrate normal trochanteric bursa. These MRI features were compatible with ganglion cyst within the obturator foramen abutting the obturator nerve. Radiologist commented that the cyst is not communicating with the hip joint and is running between the obturator internus and externus muscle and lying on the pectineus muscle. After multidisciplinary team discussion, the patient was offered surgical excision. Extraperitoneal approach with left lateral incision was done. Psoas muscle was identified and the obturator foramen approached medially. Lesion was identified encasing the obturator nerve. The cyst was stuck in the obturator foramen, so the wall was incised. Gelatinous fluid was suctioned, and the cyst was completely extirpated from the obturator nerve and foramen with preserving of the obturator nerve. Patient had follow-up MRI scan again in 6 months time and no cyst recurrence was noted. Patient was completely asymptomatic. Histological evaluation revealed a cystic lesion without epithelial lining. The surrounding tissue was fibrous with scattered large nerve bundles. There was focal myxoid degeneration, together with perivascular and perineural fibrosis and prominence of the connective tissue cell nuclei. There is no synovial lining involved in the cyst. The features were consistent with ganglion arising from the obturator nerve (Fig. 3). Groin pain with incidental finding of hernia on imaging is a common referral to general surgery outpatients at various hospitals. It is important to take a proper history with regards to the symptoms and to clinically examine this subset of patients. As depicted in our case, if we believed in the incidental finding, then our patient would have received an incorrect intervention and symptoms would have persisted in spite of a hernia operation. We hereby report a rare case of obturator ganglion cyst with symptoms masquerading as groin hernia, and have provided intraoperative, histological and radiological images. The differential diagnosis of lesion in the obturator foramen is limited and includes ganglion cyst, obturator neuroma and obturator hernia. Intraneural ganglion cysts arising from the peripheral nerve is a rare disorder. It presents as unilocular or septated cysts filled with translucent mucin. It causes motor weakness, sensory changes or pain due to compression of the affected nerve. Although intraneural ganglion cysts usually arise near the joints, cysts in the pelvic region involving the obturator nerve with a connection to the hip joint have been reported. In this case, a ganglion involving the obturator nerve was not connected to the hip joint.

Gastrointestinal mucormycosis in an immunocompromised host

A surgical consultation was requested for a 61-year-old immunocompromised male with worsening abdominal pain and increasing abdominal distension. This was in the setting of myelodysplastic syndrome treated with an allogenic haematopoietic stem cell transplant, complicated by graft versus host disease. There was no other surgical history. Upon review, the patient was haemodynamically stable and afebrile. A multiphase abdominal computed tomography scan was performed, which was suggestive of non-enhancing loops of distal ileum with associated mesenteric stranding and free fluid, concerning for ischaemia/infarction (Fig. 1). The remainder of small bowel was pathologically dilated, indicating obstruction. A laparoscopy was performed, which showed patchy necrosis of the small bowel and perforation of the distal ileum. A laparotomy was performed (Fig. 2) with resection of 110 cm of distal ileum; the ends were left stapled with a view to re-look in 48 h and reassess the remaining bowel to assure viability. At re-exploration, a further 50 cm of necrotic small bowel was resected and an end ileostomy and mucus fistula were fashioned. Histopathology revealed angioinvasive fungal organisms scattered amongst areas of necrotic bowel, with hyphae extending into the walls of regional blood vessels, with associated intestinal transmural infarction (Fig. 3). Tissue culture confirmed a diagnosis of mucormycosis secondary to Rhizopus species and amphotericin B was commenced. Two weeks following the operation, the patient developed worsening abdominal pain, vomiting and confusion. Computed tomography showed extensive small bowel ischemia, perforation and intra-abdominal free fluid. Given his complications from immunosuppression and the need for extensive bowel resection, the treating team and family decided against further surgical or therapeutic interventions. The patient was palliated and passed away several days later. We have reported a rare case of gastrointestinal mucormycosis, which clinically appeared to be ischaemic bowel, and have provided intraoperative, histological and radiological images. Risk factors, diagnosis and principles of treatment will be discussed. Mucormycosis refers to angioinvasive infections caused by fungi in the order of Mucorales. Of these, the most common genera are Rhizopus and Mucor, with Rhizopus oryzae being the most common pathogen accounting for more than 70% of cases. Mucormycosis is characterized by the invasion of blood vessels by fungal hyphae, leading to necrosis and infarction. Infection typically occurs in the presence of immunosuppression, including patients with haematological malignancies, uncontrolled diabetes and diabetic ketoacidosis, haematopoietic stem cell transplants and solid organ transplants. In haematopoietic stem cell transplants recipients, graft versus host disease and voriconazole therapy further increases the risk. Other predisposing factors include iron overload, especially those receiving desferrioxamine therapy; and wound contamination in the setting of penetrating trauma and blast injuries, which may present with a cutaneous manifestation of mucormycosis. Gastrointestinal involvement is rare and usually involves the stomach, colon or ileum. It is associated with a significant risk of mortality, which is up to 85%. Gastrointestinal cases may present with abdominal pain, gastrointestinal bleeding, perforation or unexplained sepsis. As this disease typically affects the

Case of mesenteric ischaemia secondary to triple occlusive arterial disease in a patient with protein C deficiency and radiation-induced vascular insufficiency.

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