Post-operative fever, or pyrexia, is common in surgical patients and can be caused by infection, non-infectious causes like drugs or blood transfusions, or unknown origins. The timing of the fever can indicate potential sources, such as respiratory issues within the first two days or urinary tract infections between days 3-5. Evaluation involves a septic screen with blood tests, urine and sputum cultures, and imaging. Treatment depends on identifying the source through investigations and providing targeted antibiotic therapy.

2. MANAGEMENT OF POST
OPERATIVE PYREXIA
DR.ARIFUL ISLAM
INTERN DOCTOR

3. INTRODUCTION
•Pyrexia (fever) refers to a raised body
temperature, typically greater than 37.5c. It is
common in surgical patients, either normal
immediate post-operative response or as feature of
a specific post-operative complication.

4. POST OPERATIVE FEVER

5. PATHOGENESIS

6. AETIOLOGY
•Infection
•The most common cause of pyrexia in the post-
operative patient is infection. The specific post-
operative day on which the fever develops may
indicate the source of the infection

7. •Day 1-2 – consider a respiratory source (or body’s
routine response to surgery)
•Day 3-5 – consider a respiratory or urinary tract
source
•Day 5-7 – consider a surgical site infection or
abscess/collection formation
•Any day post-operatively – consider infected IV
lines or central lines as a source

8. Other Causes of Pyrexia
Other causes of post-operative pyrexia include:
•Iatrogenic – which may include a drug-induced reaction
(e.g. antibiotics or anaesthetic agents) or from a transfusion
reaction
•Venous thromboembolism – although rare, a PE or DVT
can cause a low grade fever without any other overt clinical
features
•Secondary to prosthetic implantation – with any foreign
body, for example after an AAA repair, a low-grade fever
may be evident
•Pyrexia of Unknown Origin

9. INFECTIOUS CAUSES

10. NON INFECTIOUS

11. DRUG FEVER

12. EVALUATION

13. CLINICAL FEATURES
SYMPTOMS
• Fever
• Urinary frequency, urgency or
dysuria
• Productive cough,
dyspnea,hemoptysis, chest pain
• Calf pain
• Wound or cannula line pain
SINGNS
• Respiratory tract infections
• I/v line infections
• Wound infections
• Calf tenderness
• Examine the signs of specific complications
From operation e.g: signs of peritonism in an
anastomotic leak

14. INVESTIGATIONS
A septic screen is essential in investigating the surgical
patient with pyrexia.
•Blood tests – FBC, CRP, LFTs,
•Urine :Urine RE,CS
•Cultures – blood, urine, sputum, and wound swab
•Imaging – Plain film chest radiograph, specific CT imaging
If the source cannot be identified through the septic
screen, more detailed investigations may be required

15. TREATMENT
INFECTION SOURCE
• Lower respiratory tract
• Upper Urinary Tract Catheter
Association
• Surgical Site Infection
• Central line (or any vascular
catheter infection)
EMPIRICAL ANTIBIOTIC REGIME
• Co amoxiclav1.2gm IV +/- Amikacin
• Co-Amoxiclav 1.2g IV +/-
AmikacinNitrofurantoin 50mg PO +
Change of Catheter
• Flucloxacillin 1g IV
• Replace line (trial antibiotic line lock
with vancomycin if not able to replace
line)

16. Key Points
•Ensure to take an A to E approach for all
cases of pyrexia in the surgical patient
•Consider the time since operation and details
of the procedure to help focus your
investigations
•Not all cases of pyrexia are due to infection