MEDICAL HISTORY

On review of notes it was found that, in the 13 months before this admission, he had attended the emergency department three times and been admitted to hospital twice. He had also been seen in the orthopaedic outpatient department. His initial contact had been an admission, arranged by his general practitioner, when he had a left calf deep venous thrombosis and associated cellulitis. At that time, S aureus was isolated from blood cultures. He was treated with oral flucloxacillin and tinzaparine. He failed to attend for follow up.

Five months later he attended the emergency department with a temperature and low back pain. A diagnosis of psoas abscess was made and he was admitted to the acute medical ward. He absconded from the ward before being seen. The blood cultures that had been taken in the emergency department once again grew S aureus. Attempts made to contact the patient failed as he had lost touch with his family, his phone had been disconnected, and he was no longer registered with a general practitioner. It is interesting to note that the card from this attendance was missing from his emergency department notes, and the blood culture report was filed in the hospital notes only. This information was therefore not available to emergency department staff when he next attended.

Six weeks later he returned to the emergency department complaining of nausea, vomiting, and back pain. He was again admitted under the physicians with a provisional diagnosis of pyelonephritis with muscular back pain. At this stage his haemoglobin was 9.3 g/dl. He subsequently had a normal upper gastrointestinal endoscopy. Once again he developed a deep venous thrombosis. S aureus was again isolated on blood cultures. He was discharged prescribed trimethoprim, flucloxacillin, and warfarin.

After a further six weeks he re-presented to the emergency department with low back pain. His temperature was normal. A diagnosis of muscular pain was once again made. The following week he was seen in the orthopaedic outpatient department, having been referred by his general practitioner for investigation of the persistent low back pain. He was referred for physiotherapy and failed to attend for further follow up.

His next attendance five months later was the episode described initially.

DISCUSSION

Pyomyositis is a primary bacterial infection of skeletal muscle. It is common in the tropics (tropical pyomyositis), first being described by Scriba in 1885.¹ It was first reported in the USA in 1971,² when the term temperate pyomysitis was introduced. Between 1971 and 1986 fewer than 50 cases of temperate pyomyositis were reported.³ With the increasing prevalence of immunocompromised patients and injecting drug misusers it is becoming more widely recognised in temperate countries.⁴ It is commonly misdiagnosed in its initial stages.⁵ The most common muscle groups to be involved are iliopsoas (46%), gluteals (18%), and the thigh (18%).⁶S aureus is the most frequently isolated organism,^3,4,6 occurring in over 90% of patients in some series.⁴ Other organisms implicated include S pyogenes, S freundii, and E coli.^3,4,6 Recognised predisposing factors are trauma, HIV infection, diabetes mellitus, corticosteroid treatment, malignancy, and intramuscular injection.

Pyomyositis presents in three stages. Initially there is myositis and muscle oedema but no abscess formation. The patient presents with muscle pain and low grade fever. At this stage the condition may be cured by appropriate antibiotic therapy, but it is difficult to diagnose because of non-specific signs and symptoms.⁵ The most common stage at presentation is stage two, characterised by abscess formation, muscle pain, fever, tenderness, and leucocytosis. This picture is complicated in stage three disease by systemic toxicity. Treatment in the latter stages requires surgical drainage as well as appropriate antibiotics.⁶

This case highlights some of the difficulties posed in managing the health needs of drug misusers. It seems probable that the extensive abscesses seen in this patient had been developing over at least 13 months. In this time he had been seen in the hospital on no less than five separate occasions. A combination of factors contributed to the delay in diagnosis. As previously mentioned temperate pyomyositis is often misdiagnosed initially.⁵ Having been admitted, the patient absconded from the ward, failed to keep follow up appointments, had been removed from his GP’s list, and was at times uncontactable. However, some of the responsibility must rest with the medical teams involved in his care. Incomplete medical records and poor communication between medical specialties, surgical specialties, and the emergency department regarding inpatient investigations and blood cultures resulted in lost opportunities to reinstate appropriate inpatient care.

If the emergency department were to routinely receive and file copies of discharge letters for patients admitted through the department, we would have been aware that on his second admission a diagnosis of psoas abscess had been made, and S aureus had been isolated from blood cultures. This should have enabled him to be rapidly readmitted under the appropriate specialty.

Computer based records should reduce the incidence of notes “going missing” and enable all hospital and perhaps primary care staff to access investigations performed and treatment received by any patient.

It important for all medical staff who may come into contact with injecting drug misusers to be aware of the range of conditions with which they may present and receive adequate training in dealing with patients who refuse treatment. This should result in more timely and appropriate treatment, and ultimately reduce morbidity.