A Retrospective Study of Discitis : a Life-threatening Complication of Chronic Haemodialysis De Silva S T¹, Qurban S², Farrington K³ ¹Consultant Physician, Teaching Hospital, Kandy, formerly Clinical Fellow in Nephrology, ²Senior House Officer, and ³Consultant Nephrologist Department of Renal Medicine, Lister Hospital, Stevenage, UK

Infection & Haemodialysis Infection is the 2nd commonest cause of death in haemodialysis patients Discitis is rare but potentially life-threatening Discitis is an infection in an inter-vertebral disc in the spine Disc space infection is an infection of the intervertebral disc, that begins in one of the continguous end plates, and spreads to the disc secondarily.

Study Design Retrospective analysis of all episodes of discitis All patients on chronic haemodialysis from 1990-2005 3 Haemodialysis Centres attached to Renal Department, Lister Hospital, Stevenage, UK Using RenalPlus - database of all patients treated since inception of Unit Data from Renal Plus, a large data base of all patients treated at the Centre since its inception.

Objectives of Study Determine patient characteristics Determine outcome & prognosis

Results Total number of patients studied - 809 (on haemodialysis for >3 months) Fistula 2/3 & Line 1/3 10 radiologically proven episodes in 10 patients incidence - 1.24% 8 male Average age 71.3 years (range 57 – 83) Silastic cuffed catheters are tunneled through the skin and inserted into the jugular or subclavian vein. Age at time of episode

Haemodialysis (range 0.85 – 1.37) Average duration on all modes of dialysis - 43 months (range 14 – 96) Average duration on haemodialysis - 35.4 months (range 8 – 96) Access – 5 fistula 5 lines Dialysis adequacy (Kt/V) – 1.12 (range 0.85 – 1.37) All data at time of episode

Symptoms at Presentation Backache / neck pain 8 Fever 4 Rigors 4 Shoulder pain 2 Paraplegia 2 Dysphagia 1 Sensory level 1 Severe back pain that began insidiously was characteristic. The back pain was constant and there was no history of trauma. There was a lack of systemic symptoms ie fever in most, with neurological signs present in only 4 patients.

Symptoms at Presentation All 4 with neurology had fever/rigors & back/neck pain

Co-morbidity Commonest underlying renal disease was Diabetes Mellitus Commonest co-morbidity was Ischaemic Heart Disease (in 2) None were on immuno-suppressants Mixed bag for underlying disease with analgesic, renovascular, glom-neph, renovascular, amyloid, PCKD & unknown being other causes.

Previous Infections on Dialysis Line infections in 4 patients Staph aureus 3 CNS* 1 Average time before discitis episode was 22 months Fistula infection in 1 (Staph aureus) Time before discitis episode was 11 months PD peritonitis in 2 (organism unknown) Average time before discitis episode was 31 months *Coagulase Negative Staphylococci

Subsequent Infections 1 each of - no further infections - neutropenic sepsis ?origin (12 months) - Enterococcus line infection (21 months) - VRE* line infection (7 months) - MSSA** endocarditis (16 months) *Vancomycin Resistent Enterococci **Methycillin Sensitive Staph aureus

Investigations The laboratory study may be misleading, normal white blood cell counts are common, radiographs often show no abnormalities early in the course of the illness, and even more sensitive diagnostic tests such as bone scans may not become positive for a week. When the diagnosis is suspected, the MRI now seems to be the most reliable early confirmatory test, while elevations of the erythrocyte sedimentation rate are a valuable screening test.

Investigations MRI proven discitis - in ALL Blood cultures - negative in 3 MSSA¹ in 3 MRSA², CNS³, VRE* & Enterobacter in 1 each Fistula swab MSSA* - in 1 (BC negative) ¹Methycillin Sensitive Staph aureus ²Methycillin Resistent Staph aureus ³Coagulase Negative Staphylococci *Vancomycin Resistent Enterococci

Associated Diagnoses 4/10 had associated abscess 1 had osteomyelitis (paravertebral, extradural, epidural & retro-pharyngeal) 1 had osteomyelitis (lumbar) 1 had aortic valve endocarditis

Treatment Vancomycin + Fusidic acid 2/10 Vancomycin + Ciprofloxacin 2/10 Combinations 4/10 (of Vancomycin, Flucloxacillin, Ceftazidine, Teicoplanin, Amoxycillin, Linezolid) Single agent 2/10 (Co-amoxyclav, Clindamycin)

Outcome Mean duration of treatment was 6 weeks 5 patients died 5 patients recovered with NO neurological sequelae

Conclusions I Discitis must be suspected in haemodialysis patients presenting with backache & fever, even when neurological symptoms are absent Patients tend to be male, elderly & diabetic Patients are more likely to be line dependant & poorly dialysed

Conclusions II CRP was a good marker of infection MRI was the best technique for diagnosis MSSA was the commonest infecting organism Prolonged course of antibiotic therapy was required

Conclusions III Discitis was fatal in half the study population High degree of suspicion and early diagnosis with MRI are vital to prevent fatalities in the future

Relevance of Study Incidence of CKD increasing in Sri Lanka More patients likely to reach ESRD in future Most ESRD patients on chronic haemodialysis

Relevance of Study Rare but potentially life-threatening complications of chronic haemodialysis must be suspected early This study was done to increase awareness of one such complication - discitis

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