Differential Diagnosis For Postoperative Fever: Timing Of Fever

OVERVIEW

This page is dedicated to covering the differential diagnosis for postoperative fever. This differential will be organized by the timing of the fever.

How quickly the fever develops relative to the operation can dictate what causes should be considered in the differential (image source).
WHAT ARE THE MAJOR TIME FRAMES TO CONSIDER?

When thinking about the differential for postoperative fever the following timeframes should be distinguished:

  • Immediate: Onset during the operation or within hours after surgery
  • Acute: Onset within the first week after surgery (excluding immediate)
  • Subacute: Onset from one to four weeks following surgery
  • Delayed: Onset more than one month after surgery
CAUSES OF IMEEDIATE POSTOPERATIVE FEVER

Generally speaking, many of the causes of such a fever will relate to the medications or products that were administered during the case. Here is the differential to consider for a postoperative fever that begins immediately:

  • Medication administered preoperatively: a drug fever can be caused by an adverse reaction to medications
  • Blood product related: patients who are transfused with blood may have an immune mediated reaction to the blood products.
  • Trauma: either sustained prior to surgery or during the operation
  • Prior infection: patients with an infection prior to surgery may have a fever that results from it.
  • Malignant hyperthermia (rare): patient fever should present about 30 minutes after inhaled anesthetics (classically succinylcholine)
CAUSES OF ACUTE POSTOPERATIVE FEVER

Generally speaking, many of the causes of such a fever will be various types of infections. Here are some examples to consider:

  • Intravascular catheter associated infection: should be considered in any patient with an intravascular catheter or line. The infection can either be around the exit site o the catheter, or intravascularly.
  • Surgical site infection (SSI): generally this is more common in the subacaute setting, however it should be considered in this time frame as well.
  • Aspiration pneumonia: can be especially common in patients with an NG tube, decreased gag reflexes, and altered mental status, especially in the setting of recent anesthesia.
  • Ventilator acquired pneumonia (VAP): patients receiving mechanical ventilation either during and/or after surgery are at risk for VAP (the risk increases as the time on the ventilator increases).
  • Urinary tract infection (UTI): this is a frequent cause of infection in patients with indwelling foley catheters. The longer the catheter stays in place the higher the risk for infection.
  • Atelectasis: typically a diagnosis of exclusion correlated with X-ray findings.
  • Pancreatitis
  • Myocardial infarction
  • Pulmonary embolism
  • Alcohol withdrawal
  • Gout
CAUSES OF SUBACUTE POSTOPERATIVE FEVER

Here are some conditions to consider for a postoperative fever in this timeframe:

  • Surgical site infections: these are very common in this time window.
  • Intravascular catheter associated infection: should be considered in any patient with an intravascular catheter or line. The infection can either be around the exit site o the catheter, or intravascularly.
  • Antibiotic associated diarrhea (such as C. diff colitis): this should be considered for any patient on long term antibiotics.
  • Febrile drug reactions: beta-lactam antibiotics, sulfa drugs are more common,  H2-blockers, procainamide, phenytoin, and heparin are also possibilities.
  • Thrombophlebitis: seen in patients with impaired mobility
  • Deep vein thrombosis: more often seen in debilitated patients
  • Pulmonary embolism: more often seen in debilitated patients
  • Ventilator acquired pneumonia (VAP): patients receiving mechanical ventilation either during and/or after surgery are at risk for VAP (the risk increases as the time on the ventilator increases).
  • Urinary tract infection (UTI): this is a frequent cause of infection in patients with indwelling foley catheters. The longer the catheter stays in place the higher the risk for infection.
  • Sinusitis 
CAUSES OF DELAYTED POSTOPERATIVE FEVER

Most of these fevers are due to infection. Here are some conditions to consider for a postoperative fever in this timeframe:

  • Surgical site infections: these are possible causes of fever, generally resulting from more indolent organisms (such as coagulase-negative staph)
  • Infection associated with implanted hardware/devices: delayed fevers can be caused by infection associated with devices/hardware that was implanted into the patient during the operation.
  • Viral infections from blood products: cytomegalovirus (CMV), hepatitis viruses, and human immunodeficiency virus (HIV), can all arise from transfusions during the initial operation.
  • Parasitic infections from blood products: toxoplasmosis, babesiosis, malaria infection can also (rarely) be transmitted via transfusion.
  • Delayed cellulitis: can be caused by disrupted venous and lymphatic drainage from surgery.
  • Infective endocarditis: this can be caused by preoperative bactermeia
  • Postpericardiotomy: should only be considered in patients who have had cardiac surgery.

 

 

Page Updated: 03.02.2018