Day to Day Causes of Post-Operative Fever

Postoperative fever is common in post-surgical patients. It is estimated that up to two third of the patients suffer from postoperative fever. Post-operative fever may occur due to infectious or non-infectious causes.

Non-Infection Causes of Post Operative Fever:

1. Surgical trauma to tissues itself is a strong stimulus of cytokines release. Interleukin 1 (IL 1), Interleukin 6 (IL 6), Tumor necrosis factor alpha and Interferon gamma, all may release after surgery. Release of these cytokines after surgical procedure results in fever.
2. Lung Atelectasis is another cause of post-operative fever.
3. Certain drugs also tend to increase temperature. For example, serotonergic drugs, antidopaminergic drugs (cause neuroleptic malignant syndrome), Sulfa antibiotics, Cocaine, Methamphetamine, Progesterone, Chemotherapeutics, anti-histamines, cimetidine among the many others may cause fever.
4. Transfusion reaction is yet another non-infectious cause of post-operative fever. Others are;
5. Deep venous thrombosis
6. Collagen vascular disease and
7. Cancer/Neoplasm

Infectious Causes of Post-operative fever:

1. Pneumonia
2. Wound cellulitis
3. Indwelling catheter infection
4. Urinary tract infection
5. Necrotizing fasciitis
6. Cholecystitis
7. Systemic bacteremia
8. Leaking anastomosis
9. Infected prosthetic material
10. Deep wound infection
11. Abscess
12. Infective diarrhoea

The 5Ws for Causes of Postoperative Fever

The 5 W approach is usually used by the physician to describe the causes of postoperative fever.

1. Wind

The word “wind” represents the lungs. Lung atelectasis is the most common cause of fever within the first 24 hours of surgery. Pneumonia or ventilator-associated pneumonia usually occurs several days after surgery.

2. Water

The word “water” represents the urinary tract. Urinary catheters are also a common cause of fever within 24 hours of surgery. Therefore these should be used for the shortest possible duration of time. They should be removed when the patient starts to move.

3. Wound

Wound infections, cellulitis, anastomosis leak, abscess, necrotizing fasciitis all include in this category.

4. Wings and Weins (Veins)

Wings/Weins represent limbs and intravenous access catheters. Intravenous access should be checked regularly for the signs of thrombophlebitis. Lower  Limbs should be examined for the signs of deep venous thrombosis.

5. Wonder Drugs

Certain drugs also cause fever. Moreover, fever that follows blood transfusion reaction also falls in this category.

Day to Day Causes of Post-Operative Fever

Postoperative Day 1 Causes of Fever

1. Cytokine-induced fever
2. Lung Atelectasis
3. Wound Cellulitis
4. UTI
5. Infection due to indwelling catheters
6. Post-transfusion reaction fever
7. Drug-induced fever
8. Thrombophlebitis
9. Complicated/complex surgery

Post operative Day 2 Causes of Fever

1. Respiratory infection/pneumonia
2. UTI
3. Wound Cellulitis
4. Necrotizing Fasciitis

Post operative Day 3 Causes of Fever

These include systemic causes;

1. 1. Thrombophlebitis
2. DVT
3. Wound infection
4. Acute Cholecystitis
5. Pancreatitis
6. Bacteremia or Viremia

Post operative Day 7 and on Causes of Fever

These includes surgical complications and un-diagnosed diseases

1. Leaking anastomosis after abdominal surgery
2. Infected prosthesis
3. Post-operative abscess
4. Infection of Deep wound
5. DVT
6. Thrombophlebitis
7. Collagen/vascular diseases
8. Infective diarrhea
9. Bacteremia
10. Tumor

In a nut shell, 27 to 58% of patients develop fever after surgery. Examine the wound and all the organ systems of the patients. If indicated then send urine culture, blood culture,erythrocyte sedimentation rate,  complete blood count, Liver function tests and Chest X-ray and in special cases duplex US of lower extremities or CT scan. Treatment include the elimination of the cause.