This case describes a 48-year-old woman presenting with suspected urosepsis. She reported several days of back pain and 2 days of UTI symptoms including rigors. Initial investigations showed elevated inflammatory markers. She was treated with IV gentamicin and oral trimethoprim but discharged with ongoing rigors. She was later readmitted with persistent rigors and vomiting, and urine and blood cultures grew E. coli. The presence of true rigors indicates a more serious infection requiring inpatient treatment and investigation until the patient has stabilized, rather than early discharge. Initial management could be improved by performing a renal ultrasound and ensuring clear documentation and follow-up plans.

1. Case presentation
Urosepsis

2. History
48 year old woman referred to ED with suspected urosepsis
Arrived 0900 hrs
• R sided back pain for several days, with UTI symptoms last 2 days
• Associated sweats and rigors
• Now feels unwell “like flu”
PH
Well Hypertension Rx Telmisartan
NKA
No history of UTIs

3. Initial examination
• “Not toxic” appearance
• Obs Temp 38.7 HR 110 BP 160/80 RR 14 O2 sat 99%
• Abdomen soft, non tender, and no renal angle tenderness noted

4. Investigations
• FBE Hb 117 WCC 9.4, normal diff Pla 291
• CRP 75
• U+Es normal
• Urine M+C+S
• Blood M+C+S
Assessment : “UTI”

5. Treatment
• IV Gentamicin 240mg
• Trimethoprim commenced orally
Disposition: “D/C”
Obs on discharge:
Temp 37.8 HR 103 BP 122/71 RR 16 O2 sat 97%

6. What do you think of therapy used and disposition in this patient?

7. Antibiotic Guidelines 1 - Introduction
• In patients with acute pyelonephritis, attempts should be made to define or
exclude any underlying anatomical or functional abnormality. In particular,
obstruction of the upper urinary tract should be excluded.
• It is imperative that adequate urine cultures are collected before the
administration of antibiotics. In hospitalised patients, blood cultures should also
be performed. The antibiotic susceptibilities of organisms should be used to guide
therapy. Therapy may need to be prolonged, high-dose, and often parenteral.
• Acute pyelonephritis is common in pregnancy where the special problems
associated with antibiotic use will need to be considered

8. Antibiotic Guidelines 2 – “Mild Pyelonephritis”
Mild cases (low-grade fever, no nausea or vomiting) may be treated by oral therapy alone.
For empirical therapy, while awaiting culture results, use:
amoxycillin+clavulanate 875+125 mg orally, 12-hourly for 10 days
OR
cephalexin 500 mg orally, 6-hourly for 10 days
OR
trimethoprim 300 mg orally, daily for 10 days.
If resistance to all the above drugs is proven or the causative organism is Pseudomonas aeruginosa, use:
norfloxacin 400 mg orally, 12-hourly for 10 days
PBS
Pregnancy
Breastfeeding
OR
ciprofloxacin 500 mg orally, 12-hourly for 10 days.
A follow-up urine culture at least 48 hours after the conclusion of therapy is advised.

9. Antibiotic Guidelines 3 – “Severe Pyelonephritis”
For patients with sepsis or vomiting, give parenteral treatment initially while awaiting culture results. Use:
gentamicin 4 to 6 mg/kg (see Table 2.24) (severe sepsis: 7 mg/kg) IV, for 1 dose, then determine dosing interval for a maximum of
either 1 or 2 further doses based on renal function (see Table 2.25)
PLUS
amoxy/ampicillin 2 g IV, 6-hourly.
In patients hypersensitive to penicillin (see Table 2.2), gentamicin alone will usually suffice.
If gentamicin is contraindicated (see Box 2.7), as a single drug, use:
ceftriaxone 1 g IV, daily
OR
cefotaxime 1 g IV, 8-hourly.
These regimens do not provide adequate cover for P. aeruginosa or enterococci.

10. • Subsequent treatment should be guided by susceptibility results and clinical
response, with early conversion to oral therapy. Other than for short-term
empirical use, gentamicin is no longer recommended except for directed therapy
in specific circumstances (see Dosing and monitoring of aminoglycosides).
• If susceptibility results are not available by 72 hours and empirical IV therapy is still
required, cease the gentamicin-containing regimen and use ceftriaxone or
cefotaxime as above.
• The total duration of therapy is usually 10 to 14 days, but may need to be
extended to 21 days in patients with delayed response.
• A follow-up urine culture at least 48 hours after the conclusion of therapy is
advised.

11. So what happened to this patient?

12. 2 days later
• Review of results – positive urine and blood cultures for E. Coli
Patient recalled for review
Slightly improved with decreased loin pain, but ongoing rigors and vomiting x 6
Exam: still well looking, afebrile, with slightly tender right loin
Repeat investigations: FBE normal, CRP 292
Renal US - normal
Treatment: IV Amoxicillin and Gentamicin
Admit PGMU

13. Course
IV Ampicillin continued for five days IV in total, patient afebrile and mostly
asymptomatic after first 24 hours
Discharged home on a further 10 days of oral Amoxycillin

14. Two questions for you
• What’s a rigor?
• Does a history of rigors have special importance?

15. Definition
• Rigor: derived from Latin for stiffness
• A feeling of coldness / chills accompanied by uncontrollable shaking / shivering

16. Importance
• Traditional medical teaching has associated true rigors (as distinct from simple
shivering) with bacteraemia and serious bacterial infection
• Higher risk for serious sepsis and thus morbidity / mortality
• Shakes may be caused by presence in blood of bacteria, bacterial fragments,
viruses or cytokines / interleukins

17. “Implications of chills”
Van Dissel et al The Lancet 1998

18. J Am Geriatric Soc. 1995 Mar;43(3):230-5.
Predicting bacteremia in older patients.
Pfitzenmeyer P, Decrey H, Auckenthaler R, Michel JP.
Source
University Geriatric Hospital, Geneva, Switzerland.
Abstract
OBJECTIVE:
To evaluate potential clinical predictors of bacteremia in hospitalized geriatric patients and to propose an individual risk score as an
alternative to "subjective" clinical judgment for a more efficient approach in early recognition and treatment of bacteremia.
DESIGN:
A 16-month prospective study.
SETTING:
The University Geriatric Hospital of Geneva, Switzerland.
PATIENTS:
Four hundred thirty-eight patients aged 62 years or older in whom 558 episodes of bacteremia were suspected.
MEASUREMENTS:
The unit of evaluation was the blood culture episode, which was defined as a 48-hour period beginning with the drawing of the first blood
for culture. An extensive precoded protocol, including clinical and biological data, was completed by the resident who requested the
blood cultures. For each episode, the resident also provided a subjective assessment of the probability of bacteremia. Odds ratios and
their variances were used to estimate the relative risks of potential predictors of bacteremia. The performance of a predictive clinical
model based on risk score threshold was evaluated by means of a receiver-operating characteristic analysis.
RESULTS:
Of the 558 potentially bacteremic episodes investigated, 46 (8.2%) yielded positive blood cultures. The bacteremia rate was strongly
associated with the type of episode: it reached 15.6% among the community-acquired (CA) episodes (those occurring within 48 hours of
hospital admission) and 6.0% only among the hospital-acquired (HA) episodes (those occurring after the first two days of hospitalization).
Predictors of bacteremia with highest relative risks included: bladder catheter removal, fever (> or = 38.5 degrees C), rigors, shock, total
band count > or = 1500/mm3, and lymphocyte count < or = 1000/mm3. When assessed by episode type, it appeared that bladder
catheter removal and rigors were good predictors of bacteremia in HA episodes only, whereas fever (> or = 38.5 degrees C) had a good
predictive value in CA episodes only. The performance of the clinical model was two times better than the physician's subjective ability to
predict bacteremia when the threshold of the risk score was fixed at two or more predictors per episode.
CONCLUSIONS:
These findings provide means to identify older hospitalized patients at high risk of bacteremia. Although the proposed predictive model
will need further validation and more precise evaluation of the potential benefits, it may nevertheless be of some help in early
recognition and treatment of bacteremia.

19. Eur J Pediatr. 1997 Jun;156(6):457-9.
The clinical significance of rigors in febrile children.
Tal Y, Even L, Kugelman A, Hardoff D, Srugo I, Jaffe M.
Source
Paediatric Department, Bnai Zion Medical Centre, Haifa, Israel.
Abstract
The objective of the study was to evaluate the significance of rigor as a predictor of bacterial infection in hospitalized febrile
infants and children. One hundred febrile children with rigor were studied and compared to 334 febrile matched controls
without rigor. All underwent clinical evaluation and appropriate laboratory investigations. The patients were then divided into
"bacterial" and "non bacterial" infection groups, as defined in the text. It was demonstrated that 66% of the patients with
rigor belonged to the bacterial infection group versus 50% in the non-rigor group (P < 0.005).
There was a significantly greater yield of positive blood cultures in the patients with rigor (P < 0.04), especially those over
the age of 1 year (P < 0.015).
The only laboratory examination of potential value as a predictor of bacterial infection in children with rigor was the band
count. An absolute band count of more than 1500/mm was significantly more frequent in the rigor group (P < 0.003), and
the combination of a rigor and band count of more than 1500 increased the relative risk for a bacterial infection by a factor
of 1.35. These data demonstrate that rigor in hospitalized febrile infants or children significantly increase the likelihood of
bacterial infection.
CONCLUSION: Although the absence of rigors in febrile children does not exclude bacterial aetiology, their presence
significantly increase the probability of an infection requiring appropriate workup and a reader institution of antibiotic
therapy.

20. “Early clinical clues to meningococcaemia”
Allen P Yung and Malcolm I McDonald
MJA 2003 178 (3): 134-137
True rigors
A rigor is a shaking chill that cannot be stopped voluntarily. Onset is sudden, and duration may be
10–20 minutes. It should be distinguished from a sensation of chill or shivers that lasts only for
seconds. Although rigors occur in some viral infections, they should generally be regarded as
indicators of significant sepsis, in conditions such as bacteraemia, pneumonia, abscesses,
endocarditis, cholangitis, and pyelonephritis.
We preach the "rigor rule" to our students: any patient, young or old, presenting with a rigor
should be admitted to hospital for observation and investigation. This rule has not been popular
with some colleagues in emergency departments.

21. Important learning points
A history of true rigors should lead to admission of the patient
(even if initial examination / investigations not concerning)
Initial investigation for Pyelonephritis should routinely include an early Renal US
Empiric therapy is IV Gentamicin and Amoxicillin initially
Documentation should be explicit, and adequately detailed about follow-up when
patients are discharged
Strong support by ID physicians at Cabrini Hospital for a “rigor rule” style approach to
disposition planning