Differential Diagnosis for Fever and Bradycardia The combination of fever and bradycardia can be caused by various medical conditions. Here's a differential diagnosis, categorized for clarity:
Single Most Likely Diagnosis
- Hypothyardism: This condition, where the thyroid gland doesn't produce enough thyroid hormones, can lead to both fever and bradycardia. The reduced metabolic rate associated with hypothyardism can cause bradycardia, and the fever might be due to an underlying infection or inflammation that the body is less equipped to handle due to the metabolic slowdown.
Other Likely Diagnoses
- Infective Endocarditis: This infection of the heart valves can cause fever and, in some cases, bradycardia, especially if the infection leads to the formation of a large vegetation that interferes with the heart's conduction system.
- Typhoid Fever: Caused by Salmonella Typhi, this condition can present with fever, bradycardia (relative), and other systemic symptoms. The bradycardia in typhoid fever is often relative, meaning the heart rate is lower than expected for the degree of fever.
- Brusk Syndrome (Lyme Carditis): An early manifestation of Lyme disease, caused by Borrelia burgdorferi, can lead to fever and heart block, resulting in bradycardia.
Do Not Miss Diagnoses
- Severe Sepsis or Septic Shock: Although sepsis typically presents with tachycardia, in the elderly or those with severe sepsis, an inappropriate bradycardia response can occur. Missing this diagnosis can be fatal.
- Myocardial Infarmction: Especially in the elderly, myocardial infarction can present atypically with bradycardia and fever, rather than the classic chest pain and tachycardia.
- Neuronally Mediated Hypotension (NMH): Part of the dysautonomia spectrum, NMH can cause bradycardia and might be associated with fever in certain contexts, such as during a crisis.
Rare Diagnoses
- Factitious Disorder (Munchausen Syndrome): Although rare, factitious disorder can lead to presentations that mimic serious medical conditions, including fever and bradycardia, induced by the patient themselves.
- Pheochromocytoma: A rare tumor of the adrenal gland that can cause episodes of hypertension, tachycardia, but in some cases, due to its effect on the autonomic nervous system, might present with bradycardia and fever during a paroxysmal episode.
- Hypothermia: In severe cases, hypothermia can initially present with a feverish state due to the body's attempt to generate heat, followed by bradycardia as the body temperature drops. This is a rare but critical diagnosis to consider, especially in individuals exposed to cold environments.