Thursday, February 28, 2019

Non-Infectious Causes of Fever

emDocs - February 25, 2019 - Author: Brubaker S
Edited by: Koyfman A; Long B and Montrief T
  • Most fevers are caused by infection. However, in fever of unknown origin, up to 70% of fevers have non-infectious etiology.
  • Some common medications that can cause fever: beta-lactam antibiotics, antiepileptics (phenytoin, carbamazepine), chemotherapeutic agents (paclitaxel, docetaxel), thyroxine.
  • Toxidromes with fever: anticholinergic, sympathomimetic, hallucinogenic.
  • Withdrawal syndromes with fever: alcohol, opioid, and barbiturate.
  • NMS (most common offending agent: 1st generation antipsychotics) and serotonin syndrome are associated with high mortality; have high suspicion for these diagnoses in patients with hyperpyrexia (temperature greater than 41°C (105.8°F)).
  • Workup for autoimmune disease can often be deferred to the outpatient setting; patients with known chronic inflammatory conditions are often immunocompromised, and infection must be ruled out before assuming a non-infectious fever.
  • “B symptoms” (fever, night sweats, weight loss) may indicate the presence of a neoplastic process; hematologic cancers (both lymphoma and leukemia) are more likely to cause fever than solid cancers.
  • Although infectious causes must be excluded first, non-infectious fevers are common in patients with intracranial pathology (hemorrhage, ischemia, hydrocephalus).
  • Thyroid storm and adrenal insufficiency are two metabolic conditions that can lead to fever. They have very high morbidity and mortality when they are not promptly recognized. They often co-occur with infective processes, so have a low threshold to administer antibiotics.
  • Other possible causes: environmental exposure (e.g. heat exhaustion, heat stroke), as well as thromboembolism (e.g. myocardial infarction, deep venous thrombosis, pulmonary embolism).
  • In the correct setting, fever can also be caused by transplant rejection (both acute and chronic) as well as transfusion reaction."