Urgent considerations
See Differentials for more details
There are a few general principles that should be followed for all patients regardless of the cause of the fever. Clinicians should refrain from routine use of antibiotics unless patients display signs of a systemic inflammatory response with organ dysfunction, are haemodynamically unstable, or are immunocompromised. Unnecessary vascular access devices should be removed. Potential fever-inducing medications should be discontinued. Antipyretic therapies such as paracetamol are useful as they provide analgesia and reduce the physiological demands of fever. These therapies should not be withheld because of concerns about masking fever as there is little evidence that masking fever worsens outcomes.[28]
Malignant hyperthermia
A rare adverse reaction to inhalation anaesthesia. It usually manifests immediately following the administration of a triggering anaesthetic or succinylcholine (suxamethonium), but symptoms can appear up to 1 hour after administration of these agents. Symptoms include tachycardia, hypercapnia and/or tachypnoea, elevated temperature, and muscle rigidity.[18] The fever is usually >40ºC (104ºF). If suspected, the inhalation anaesthetic should be discontinued and treatment with dantrolene initiated.
Transfusion reaction
Blood or blood products may cause a transfusion reaction, a serious complication which usually occurs during or immediately after the transfusion. Fever may be accompanied by headache, nausea, vomiting, anxiety, wheezing and/or pain in the chest, back, abdomen or infused extremity. Temperature, heart rate, and blood pressure should be checked 15 minutes after the start of a blood transfusion, and the transfusion should be stopped immediately if a reaction is suspected.[29]
Toxic shock syndrome
A rare complication of surgical and postpartum wound infections. Typical organisms are Staphylococcus aureus or group A beta-haemolytic Streptococcus. Patients present with fever, hypotension, and skin manifestations consisting of diffuse macular erythroderma. Shock and multi-organ system failure can complicate this infection so early recognition is important. Blood, wound and tissue cultures should be obtained and empiric antibiotic therapy given. This is one of the few infections that can present in the first 48 hours postoperatively.[14]
[Figure caption and citation for the preceding image starts]: Rash and subcutaneous oedema of the right hand due to toxic shock syndromeFrom the CDC and the Public Health Image Library [Citation ends].
Deep venous thrombosis and pulmonary embolism
Venous thromboembolism (VTE) occurs in <1% of surgical patients.[6] Longer duration of hospital stay, obesity, cancer, increasing age, and history of VTE all increase the risk of VTE.[30] Symptoms of deep venous thrombosis (DVT) include calf swelling (or, more rarely, swelling of the entire leg), localised pain along the deep venous system, oedema, or dilated superficial veins over the foot and leg. Symptoms may be very subtle, and patients can be asymptomatic.
[Figure caption and citation for the preceding image starts]: Deep vein thrombosis (DVT) of the right leg with associated swelling and rednessFrom the collection of James Heilman, MD. [Citation ends].
Patients with a high probability of DVT require further investigation with a duplex ultrasound of the lower limb. D-dimer is raised for at least one week postoperatively in patients without DVT, limiting its usefulness in this population.[31]
Pulmonary embolism (PE) carries a high mortality and clinicians should have a high index of suspicion of any patient with shortness of breath in the postoperative period, especially in the setting of tachycardia and fever. Suspicion for PE should prompt testing with a computed tomography (CT) pulmonary angiogram or ventilation/perfusion scan (for patients who have a contraindication to CT pulmonary angiogram).
Pseudomembranous colitis
Clostridium difficile is becoming more common due to the extensive use of antibiotics. If symptoms of C difficile infection are not recognised early, the initial mild diarrhoeal illness can progress to fulminant colitis.
Stool samples for C difficile toxins should be sent in the febrile patient with diarrhoea, especially in the face of a rapidly escalating white blood cell count.
The causative antibiotic should be discontinued as soon as possible.[32] If antibiotics cannot be withdrawn, an agent less likely to cause C difficile infection should be used instead.
Antibiotic therapy should be started empirically if there is likely to be a substantial delay (>48 hours) in laboratory confirmation or for fulminant infection. For other patients, antibiotic therapy may be started after diagnosis in order to limit the overuse of antibiotics. Recommended regimens are based on the severity of disease and whether the episode is an initial episode or a recurrence.
US guidelines recommend either oral vancomycin or fidaxomicin as a first-line agent for an initial episode of C difficileinfection. Previously, oral metronidazole was the antibiotic of choice; however, it is now only recommended in settings where access to first-line agents is limited.[32] International guidelines may still recommend metronidazole as a first-line agent for non-severe disease. Local guidance should be consulted.
Transplant rejection
Transplant rejection is a potentially life-threatening complication of transplantation. Fever is a key presenting sign and should prompt suspicion of rejection. Hyperacute rejection presents in the intraoperative and immediate postoperative period. Acute rejection usually presents in the second postoperative week, although it can present up to 6 months following transplantation.[33] Chronic rejection can present at any time after the fourth postoperative week.
Delirium tremens
Alcohol withdrawal typically presents 3 to 5 days after cessation of alcohol ingestion, although some symptoms such as tremulousness may begin in the first 48 hours. Uncommonly, alcohol withdrawal can present with life-threatening delirium tremens. Symptoms include confusion, agitation, paranoia, and visual and auditory hallucinations.[34] If a history of alcohol abuse is present, the possibility of postoperative alcohol withdrawal should be anticipated. Initiate prompt treatment with benzodiazepines to reduce symptoms and risk of seizures.
Fever in immunosuppressed patients
Any fever in an immunosuppressed patient requires urgent investigation, as these patients have increased susceptibility to bacterial and fungal infections that can be fatal. The risk of all postoperative infections is greatly increased, and additional infections caused by the endogenous flora of the gut and mucosa can occur at any time. The usual signs of inflammation may be absent or less obvious in this patient group. Empiric treatment with broad-spectrum antibiotics should be started as soon as possible after the appearance of fever.
Sepsis
Sepsis is a spectrum of disease, where there is a systemic and dysregulated host response to an infection.[35] Presentation ranges from subtle, non-specific symptoms (e.g., feeling unwell with a normal temperature, malaise, lethargy, nausea or vomiting) to severe symptoms with evidence of multi-organ dysfunction and septic shock. Patients may have signs of tachycardia, tachypnoea, hypotension, fever or hypothermia, poor capillary refill, mottled or ashen skin, cyanosis, newly altered mental state or reduced urine output.[36] Sepsis and septic shock are medical emergencies.
Risk factors for sepsis include:[36]
age under 1 year
age over 75 years
frailty, impaired immunity (due to illness or drugs)
recent surgery or other invasive procedures
any breach of skin integrity (e.g., cuts, burns)
intravenous drug misuse
indwelling lines or catheters and
pregnancy or recent pregnancy.
Early recognition of sepsis is essential because early treatment improves outcomes.[36][Evidence C][Evidence C][37] However, detection can be challenging because the clinical presentation of sepsis can be subtle and non-specific. A low threshold for suspecting sepsis is therefore important. The key to early recognition is the systematic identification of any patient who has signs or symptoms suggestive of infection and is at risk of deterioration due to organ dysfunction. Several risk stratification approaches have been proposed. All rely on a structured clinical assessment and recording of the patient’s vital signs.[36][38][39][40][41] It is important to check local guidance for information on which approach your institution recommends. The timeline of ensuing investigations and treatment should be guided by this early assessment.[41]
Treatment guidelines have been produced by the Surviving Sepsis Campaign and remain the most widely accepted standards.[37][42] Recommended treatment of patients with suspected sepsis is:
Measure lactate level, and remeasure lactate if initial lactate is elevated (>2 mmol/L [>18 mg/dL])
Obtain blood cultures before administering antibiotics
Administer broad-spectrum antibiotics (with methicillin-resistant Staphylococcus aureus [MRSA] coverage if there is high risk of MRSA) for adults with possible septic shock or a high likelihood for sepsis
For adults with sepsis or septic shock at high risk of fungal infection, empiric antifungal therapy should be administered
Begin rapid administration of crystalloid fluids for hypotension or lactate level ≥4 mmol/L (≥36 mg/dL). Consult local protocols.
Administer vasopressors peripherally if hypotensive during or after fluid resuscitation to maintain MAP ≥65 mmHg, rather than delaying initiation until central venous access is secured. Noradrenaline (norepinephrine) is the vasopressor of choice
For adults with sepsis-induced hypoxaemic respiratory failure, high flow nasal oxygen should be given.
Ideally these interventions should all begin in the first hour after sepsis recognition.[42]
For adults with possible sepsis without shock, if concern for infection persists, antibiotics should be given within 3 hours from the time when sepsis was first recognised.[37] For adults with a low likelihood of infection and without shock, antibiotics can be deferred while continuing to closely monitor the patient.[37]
For more information on sepsis, please see Sepsis in adults and Sepsis in children.
Use of this content is subject to our disclaimer