Approach to a fever (over 2 months): Clinical sciences

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Introduction0:00–0:29

Fever is defined as a temperature of 38 degrees Celsius or 100.4 degrees Fahrenheit, or higher. It’s crucial to determine the source of fever in children over 2 months of age in order to promptly identify the cause of the fever and initiate appropriate treatment.
The most important underlying causes of fever include infection, malignancy, inflammatory conditions, and certain medications.If a child over 2 months of age presents with a fever, you should first perform an ABCDE assessment.

Unstable fever0:29–1:03

If the patient is unstable, stabilize the airway, breathing, and circulation. Next, obtain IV access, and consider starting IV fluids.
Finally, put your patient on continuous vital sign monitoring, including blood pressure, heart rate, and oxygen saturation, and provide supplemental oxygen if needed.

Stable Fever - H&P1:03–1:29

Okay, now let’s go back to the ABCDE assessment and look at stable patients. First, let’s start by obtaining a focused history and physical exam.
The presence of a temperature of 38 degrees Celsius or higher confirms a fever, so your next step is to assess signs and symptoms of a clinical infection.
First, let’s start with signs and symptoms that suggest a localized infection, such as a purulent middle ear effusion, tonsillar exudates, focal crackles on lung auscultation, or a history of dysuria with urinary urgency or frequency.

Localized infection1:29–2:21

If this is the case, consider ordering additional testing, like a urinalysis and urine culture, chest X-ray, rapid strep test, or throat culture.
If the confirmatory testing identifies a focus of infection, or if you’re able to make a clinical diagnosis based on exam findings alone, you can diagnose a focal infection.
Some common examples of focal bacterial infections in children include otitis media, urinary tract infection, pneumococcal pneumonia, and group A Strep pharyngitis.On the other hand, in some individuals, you might identify signs and symptoms suggesting a systemic infection, such as malaise, fatigue, weakness, chills, muscle or joint pain, and decreased appetite.

Systemic infection2:21–3:13

In this case, you can consider diseases like influenza, enterovirus, Lyme disease, blastomycosis, or malaria; and order additional tests to confirm the diagnosis, such as serology, nucleic acid amplification testing, or cultures.
If confirmatory testing identifies a cause of systemic infection, or if you are able to make a clinical diagnosis based on findings alone, you can diagnose systemic infection.Now, if you identify no signs or symptoms of infection, your next step is to assess your patient’s age and body temperature.If your patient is between 2 and 36 months of age, with a temperature of 39 degrees Celsius or higher, you should consider an occult bacterial infection.

No S/S of infection3:13–3:22

Occult bacterial infection3:22–5:09

Start by ordering labs, including a CBC, procalcitonin or CRP, and urinalysis. Additionally, consider obtaining blood and urine cultures, and depending on other patient factors, consider sending cerebrospinal fluid, or CSF, for analysis and culture.
Now, if there’s an occult bacterial infection, the CBC might reveal elevated WBCs with neutrophilia in combination with an elevated PCT or CRP.
The urinalysis may also reveal the presence of WBCs with a positive leukocyte esterase, and if obtained, the CSF analysis may show pleocytosis.
These findings are highly suggestive of a bacterial infection, so while you’re waiting for culture results, consider hospital admission and empiric treatment with antibiotics.
Next, review the culture results once they are available. If the CSF culture is positive, you can diagnose bacterial meningitis; if the urine culture is positive, diagnose UTI; and if the blood culture is positive, you can diagnose bacteremia.
Finally, if all cultures are negative, you should discontinue antibiotics and continue to look for an underlying cause of fever.
In this case, your next step is to assess for signs and symptoms of malignancy!Similarly, for febrile children over 36 months of age, and those between 2 and 36 months of age with a temperature between 38 and 39 degrees Celsius, you should assess for signs and symptoms of malignancy.Some important signs and symptoms suggesting malignancy include weight loss, fatigue, or night sweats, as well as pallor, hepatosplenomegaly, and lymphadenopathy.

Malignancy5:09–6:01

The presence of any of these findings in combination with fever should make you consider malignancy, such as leukemia and lymphoma.
In these individuals, your next step is to order labs, including a CBC with a peripheral smear; and obtain bone marrow or lymph node biopsy.
Finally, if your patient reports respiratory symptoms, consider ordering a chest X-ray. Patients with leukemia often report fatigue, bleeding, and bone pain; while the physical exam may be significant for pallor, bruising, or petechiae.

Leukemia6:01–6:38

The CBC usually demonstrates leukocytosis and anemia, while peripheral smear and bone marrow biopsy reveal the presence of immature blasts.
With these findings, you can diagnose leukemia.Meanwhile, individuals with lymphoma often report night sweats, weight loss, and occasionally, they may also have dyspnea or a cough; while the physical exam commonly reveals lymphadenopathy or hepatosplenomegaly.

Lymphoma6:38–7:27

A lymph node biopsy demonstrates the presence of malignant cells, while the chest X-ray may show a mediastinal mass. With these findings, you can diagnose lymphoma.Now here’s a clinical pearl to keep in mind!
In addition to leukemia and lymphoma, be sure to consider other malignancies or cancer-like conditions that can present with fever, including neuroblastoma, rhabdomyosarcoma, and Langerhans cell histiocytosis.Now let’s switch gears and discuss febrile children who have no signs or symptoms of malignancy.

Inflammatory conditions7:27–8:28

In this case, your next step should be to assess for signs and symptoms of inflammatory conditions, such as joint pain and swelling, rash, pallor, or lymphadenopathy.
This spectrum of findings should make you consider inflammatory conditions, like Kawasaki disease, systemic juvenile idiopathic arthritis, and systemic lupus erythematosus.Once you suspect that an inflammatory condition is the underlying cause of fever you should order labs, including a CBC, CRP, and urinalysis.
Additionally, check ANA, anti-double-stranded DNA, and anti-Smith antibodies, and rheumatoid factor. Finally, consider ordering an echocardiogram.First, let’s discuss Kawasaki disease.

Kawasaki disease8:28–9:20

Affected individuals report a fever lasting 5 or more days, and the physical exam will reveal bilateral nonexudative conjunctivitis, dry cracked lips with a “strawberry” tongue, and a polymorphic rash; as well as erythema and edema of the hands and feet.
You may also detect unilateral cervical lymphadenopathy. Meanwhile, lab results typically reveal an elevated CRP and thrombocytosis, while urinalysis shows sterile pyuria.
Finally, an echocardiogram may demonstrate the presence of coronary aneurysms. With these findings, you can diagnose Kawasaki disease.Next, let’s discuss systemic juvenile idiopathic arthritis.

SJIA9:20–10:10

These patients are less than 16 years old with 6 or more weeks of morning stiffness and arthritis that typically affects one or more joints.
Additionally, they may report a rash that appears salmon-pink on light skin tones, though it may appear different on darker skin tones.
Physical exam typically reveals hepatosplenomegaly and joint swelling, while CBC results may reveal elevated WBCs and platelets.
Other findings include negative ANA and rheumatoid factor. Based on these findings, you can diagnose systemic juvenile idiopathic arthritis.Finally, let’s discuss individuals with systemic lupus erythematosus, who often report skin photosensitivity or a malar rash in a classic butterfly pattern.

SLE10:10–11:21

The physical examination may reveal oral ulcers and joint swelling, often involving the small joints of the hands, while lab results include positive ANA, anti-double-stranded DNA, and anti-Smith antibodies.
The CBC may reveal cytopenia, while a urinalysis may demonstrate the presence of blood. With these findings, you can diagnose systemic lupus erythematosus.Now here’s a clinical pearl to keep in mind!
Other inflammatory conditions that are associated with fever include Crohn disease and ulcerative colitis, antibody-mediated thyroid conditions like subacute thyroiditis and Graves disease, as well as juvenile dermatomyositis, polyarteritis nodosa, sarcoidosis, and acute rheumatic fever.

Medication-induced fever11:21–11:47

Now, let’s go back and take a look at children that have no signs or symptoms suggesting an inflammatory condition. In this case, your next step is to assess for medication-induced fever, which may occur with the use of beta-lactams, sulfa-containing medications, diuretics, or antiepileptics.
If you identify a causative medication, diagnose a medication-induced fever. On the other hand, if you don’t identify a causative medication, then you should assess the duration of your patient’s fever.

FWS/FUO11:47–13:27

If the fever has been present for 8 days or less, diagnose fever without an identified source. On the other hand, if the fever has been present for more than 8 days, diagnose fever of unknown origin, which is most often caused by a common infectious or non-infectious process presenting with atypical or subtle signs and symptoms.Here’s one last clinical pearl to keep in mind!
Some unusual causes of fever in children include systemic autoinflammatory diseases, the most common example being periodic fever, aphthous stomatitis, pharyngitis, and adenitis syndrome, or PFAPA for short.
PFAPA commonly presents in preschool-age children with recurrent monthly fevers, along with pharyngitis, cervical adenopathy, and aphthous stomatitis of the buccal and pharyngeal mucosa.
Less common monogenic autoinflammatory diseases include familial Mediterranean fever and mevalonate kinase deficiency. Finally, there’s cyclic neutropenia, which is an autosomal dominant disorder of granulopoiesis characterized by oscillations in the absolute neutrophil count, with regularly occurring cycles of profound neutropenia.
These patients may experience oral ulcers, stomatitis, lymphadenopathy, and occasionally, serious infections.Alright, as a quick recap… Fever refers to a body temperature of 38 degrees Celsius or higher.

Review13:27–14:12

The most important underlying causes of fever include infections, which can be subdivided into localized, systemic, and occult.
Other important causes include malignancies, like leukemia and lymphoma, as well as inflammatory conditions, like Kawasaki disease, systemic juvenile idiopathic arthritis, and lupus.
Finally, if there's no underlying cause, assess the duration of the fever. Patients with a fever lasting eight days or less have a fever without an identifiable source, while children with more than eight days have a fever