A penetrating injury with a cocktail stick resulting in a spreading infection with Streptococcus milleri

Abstract

This case deals with a penetrating injury with a cocktail stick sustained to the right foot in a 72-year-old woman. Despite being discharged from the Accident and Emergency Department on empirical oral antibiotic therapy, she went on to develop a severe cellulitis, necessitating admission for intravenous antibiotics, multiple debridement procedures under general anaesthesia and eventual split thickness skin grafting to repair areas of necrosis. This case raises a number of important issues, including the potential hazards of apparently so trivial an injury with a common household item, the absence of any benefit of plain radiography in these injuries and the need for exploration and debridement early in the management, in the face of a refractory response to empirical antibiotics.

BACKGROUND

A number of reports in the literature have documented injuries sustained with cocktail sticks, including oesophageal and large bowel perforation, hepatic abscess formation and development of aortoenteric or duodenocaval fistulae, all following accidental ingestion.¹ There have also been cases of penetrating injuries of the extremities similar to the case presented here, however none quite so severe.²

CASE PRESENTATION

A 72-year-old woman attended the Accident and Emergency Department having stepped onto a cocktail stick that she had been using to clean interdentally following dinner at home. The cocktail stick had penetrated the plantar aspect of her right foot superficial to the medial cuneiform, passing obliquely through the foot, exiting on the dorsolateral aspect, between the fourth and fifth metatarsal heads. She had removed the stick before attending and only entry and exit wounds were visible on clinical examination. Neurological examination was unremarkable and all peripheral pulses were palpable.

Medically, she was fit and well, with a history of hypothyroidism and primary hypertension, both well controlled. At this first attendance, haemostasis had been easily achieved with local measures and she was discharged, following tetanus toxoid injection, on flucloxacillin 500 mg orally three times a day and ibuprofen 400 mg orally three times a day.

The patient returned 10 days post injury with increasing swelling and tenderness of the right foot, which was erythematous up to the midpoint of the calf. There was a necrotic area of skin surrounding the exit wound on the dorsal surface measuring 6 cm by 6 cm.

INVESTIGATIONS

Plain radiography revealed no foreign body to be present. Full blood count revealed a raised white blood cell (WBC) count of 23.3×10⁹/litre with a neutrophilia of 20.8×10⁹/litre. C-reactive protein (CRP) was 325 IU/litre and the patient was pyrexic with a temperature of 37.8°C.

DIFFERENTIAL DIAGNOSIS

A diagnosis of post-traumatic cellulitis was made and she was given flucloxacillin 2 g intravenously four times a day and penicillin G 1.2 g intravenously four times a day.

TREATMENT

At 14 days post injury she underwent formal exploration and debridement under general anaesthesia of the necrotic area and drainage of around 20 ml of pus from a collection on the plantar aspect of the foot. Following debridement on the dorsal surface of the foot, the area was dressed with proflavine and a melolin pad. Culture and sensitivity testing of the pus evacuated yielded a light growth of Streptococcus milleri sensitive to penicillin, erythromycin and tetracycline. Antibiotic therapy was changed to metronidazole 500 mg intravenously three times a day, benzyl penicillin 1.2g intravenously four times a day and flucloxacillin 1 g intravenously four times a day.

She underwent a further debridement at 16 days and dressing with jelonet and a crepe bandage to the necrotic area dorsolaterally. Subsequent to this, she developed a tense, fluctuant swelling along the medial longitudinal arch, necessitating a further general anaesthetic, during which an incision and drainage of the medial compartment was made under tourniquet control from the entry wound to the medial malleolus (fig 1) along with a further S-shaped incision below the lateral malleolus (fig 2). In all, 60 ml of pus was drained from the plantar aspect and a further 30 ml from the retromalleolar area medially. Yates drains were left in situ and the wound dressed with inadine dressing, velband, crepe bandage and plaster of Paris backslab. Further re-exploration and dressing of the wounds were carried out at days 18, 21, 23, 28 and 30 post injury. Preoperative vacuum-assisted closure (VAC) therapy was started on day 23 to the ulcerated area on the dorsolateral surface to reduce the dimensions of the necrotic areas and encourage healing.

Figure 1.

Incision extending along the medial longitudinal arch to behind the medial malleolus for formal exploration and drainage.

Figure 2.

S-shaped incision below the lateral malleolus and the debrided area surrounding the exit wound.

OUTCOME AND FOLLOW-UP

Repair of the ulcerated area at the exit wounds, and a new area of breakdown on the plantar aspect with fenestrated split skin grafts harvested from the left thigh, was finally undertaken at almost 2 months post injury (figs 3 and 4), following the resolution of infection and appearance of healthy-looking granulation tissue at the base of these defects.

Figure 3.

The outcome following split thickness skin grafting to the plantar aspect and primary closure of the exploratory incisions medially.

Figure 4.

Split thickness skin grafting to the dorsolateral wound.

DISCUSSION

A previous case series by Rand dealt with three cases of cocktail stick-related injuries, two to the foot and one to the hand, although none as severe or protracted as the case described here.² As in our case, in those discussed by Rand, patients had removed the cocktail stick prior to attending the Emergency Department and in all cases the medical staff had failed to establish the length of the stick and whether two pointed ends had been identified. Plain radiography is of little value as wood is radiolucent, and should infection continue to deteriorate after a penetrating injury then this is an indication to formally explore the wound and not to continue empirical antibiotics, which may mask the signs of a retained foreign body. Fortunately, in the case presented here, no retained fragments of the cocktail stick were found.

Antibiotics are of limited efficacy in the instance of a closed space infection, as in the case presented here, which warranted early surgical intervention. The decision to operate in this case was made on the basis of findings on clinical examination, however MRI might have provided additional information concerning the soft tissues and is being increasingly used in the evaluation of pedal infection, as it allows precise preoperative localisation of fluid collections.³ Requesting an MRI may well have caused an unnecessary delay in definitive treatment in the case presented here, however, due to the limited availability and large waiting lists for this investigation within the hospital.

In a study by Jacobs et al⁴ of the patients who developed more severe infections with bacteria of the S milleri group, the majority had underlying predisposing diseases, malignancy being the most common. Diabetes mellitus and collagen disorders such as Ehlers–Danlos syndrome may also impair host defences. The patient presented here had no such comorbidities that might have explained the severity of the infection. Speciation of the bacterium may have provided additional insight however, as while Streptococcus anginosus has been shown to be isolated more frequently than Streptococcus intermedius in infections involving the S milleri group, S intermedius is more commonly implicated in occult abscesses and the liability to develop closed space infections.^4,5 This information was not available for the case presented here.

VAC therapy has been shown to be of very real benefit in the management of traumatic wounds after debridement and was certainly an asset here. By removing oedema fluid from the extracellular space and improving local blood flow, microcirculatory embarrassment is reduced, and it is even postulated that the mechanical action encourages the formation of granulation tissue.⁶ Indeed, 84% of patients in one study of acute traumatic and infected soft tissue defects showed reduction in the dimensions of the initial wound.⁷ All these factors contribute to providing a healthy environment for elective split thickness skin grafting at a later date.

LEARNING POINTS

• Consider the source of the infection: in this case there was an argument for considering anaerobes and Streptococcus milleri earlier on, given that these are common oral commensals.

• Plain radiography is of little value when any foreign body is likely to be radiolucent.

• Should infection continue to deteriorate after a penetrating injury then this is an indication to formally explore the wound and not to continue empirical antibiotics, which may mask the signs of a retained foreign body.

• This case also serves to highlight the benefits of vacuum-assisted closure (VAC) therapy and delayed split thickness skin grafting.