10: 6-month-old female infant with a fever

Question 1

Inactivated, subunit, or toxoid vaccines (e.g. DTaP, PCV-13)

Answer 1

Inert vaccine components induce an immune response, with potential fever, within a few days of immunization.

Question 2

Live attenuated vaccines (e.g.) MMR, Varicella

Answer 2

Attenuated vaccine virus replicates, induces an immune response, with potential fever, 6-14 days after immunization.

Question 3

fever without source

Answer 3

• when a complete history has been obtained and a detailed physical examination performed, and there is no identified source of the child’s fever.
• m/c c/o fever without source in this age group is a viral syndrome.

Question 4

small minority of fever sans source may have serious bacterial illness (SBI)

Answer 4

• Urinary tract infection (UTI) - most common
• Meningitis
• Sepsis/Bacteremia
• Pneumonia
• Bacterial gastroenteritis Osteomyelitis
• Septic arthritis

Question 5

Management considerations for fever without a source

Answer 5

• Since the vast majority of immunized, immunocompetent 3-36-mo children presenting w/ fever without a source focus will not have bacteremia or SBI, a CBC and empiric treatment with abx are generally not necessary.
• A young febrile child who appears ill - even if immunized - should be evaluated carefully, b/c sepsis from non-vaccine pneumococcal serotypes and other bacteria still occurs- though rarely

Question 6

Signs of Meningitis in Infants

Answer 6

• Fever
• Hypothermia
• Bulging fontanelles
• Lethargy
• Irritability
• Restlessness
• Paroxysmal crying (crying when picked up)
• Poor feeding
• Vomiting and/or
• Diarrhea

Question 7

Recommendations for Empiric Antibiotic Treatment of Pyelonephritis: Ceftriaxone (parenteral abx)

Answer 7

• Provides excellent coverage against most gram-negative bacilli (the major exception being Pseudomonas aeruginosa)
• Not effective against enterococci
• Excellent safety profile in children
• Can be given once daily
• Calcium-containing medications cannot be given through the same IV line as they may interact with ceftriaxone to form precipitates in the lungs and kidneys

Question 8

Recommendations for Empiric Antibiotic Treatment of Pyelonephritis: (Parenteral Abx)

Answer 8

• Ampicillin/Gentamicin
• Ceftriaxone
• Meropenem
• Cipro

Question 9

Recommendations for Empiric Antibiotic Treatment of Pyelonephritis: (Oral Abx)

Answer 9

• Cephalexin (Keflex)
• –Provides good coverage for E.Coli and other enteric gram-negative rods
• –Inexpensive and well tolerated
• Trimethoprim/Sulfamethoxazole
• Nitrofurantoin
• –approved only for the treatment of cystitis, not pyelonephritis
• Amoxicillin/Clavunate (Augmentin)

Question 10

Testing for Fever Without Source: Urinalysis and urine culture

Answer 10

• Since the most likely cause of SBI is UTI, a UA and catheterized urine culture should be obtained.
• If the child has low likelihood of UTI, clinical followup without testing is sufficient.

Question 11

Testing for Fever Without Source: CBC with differential

Answer 11

• A CBC with differential may provide useful information in an ill-appearing infant with fever.
• Abnormalities in the WBC count and the differential (such as a “left shift” toward more immature forms) can increase the likelihood that the child has serious bacterial illness.
• A previously healthy child who looks well does not require a CBC.

Question 12

Testing for Fever Without Source: Blood culture

Answer 12

A culture is warranted when a young child is ill appearing or unimmunized/underimmunized.

Question 13

Testing for Fever Without Source: LP

Answer 13

indicated when a young child is ill-appearing, unimmunized/underimmunized, and when meningitis cannot be excluded by exam.

Question 14

traditional definition of pyuria

Answer 14

• -microscopic analysis, with > 5 WBCs per high-power field (hpf) in a centrifuged urine considered positive.
• -If a counting chamber is used, then > 10 WBCs per microliter in uncentrifuged urine is considered positive

Question 15

positive nitrite test

Answer 15

occurs when gram-negative bacteria, which can reduce urinary nitrate into nitrite, are present in the urine (esp. E. coli, Klebsiella, and Proteus spp) for an adequate amount of time (3-4 hours)

Question 16

positive nitrite on urinalysis is extremely helpful

Answer 16

highly specific for the presence of bacteria in the urine (few false positives).

Question 17

positive leukocyte esterase reaction

Answer 17

detects esterases released from broken-down leukocytes.

Question 18

Ultrasound study of the kidneys and bladder

Answer 18

• -Provides info about renal structure and dilatations in the collecting system
• -Has replaced the iv pyelogram for providing this info
• -Unless the illness is of unusual severity, or the child is not improving on abx, the US may be obtained at completion of the abx course.

Question 19

Renal technetium scan

Answer 19

Provides evidence of pyelonephritis

Not required in a patient who has responded well to treatment

Question 20

Voiding cystourethrogram (VCUG)

Answer 20

• -Demonstrates presence of vesicoureteral reflux, an important risk factor for recurrences of urinary tract infections
• -Should not be performed routinely in children after a first febrile UTI unless there are findings on the renal and bladder ultrasound that suggest high-grade vesicoureteral reflux, such as hydronephrosis.
• -Recommended after a second febrile UTI.

Question 21

Differential Diagnosis for Infant with a Fever: UTI (1/10)

Answer 21

• commonly presents as fever and no focus on PE and a relatively unremarkable ROS
• Fussiness and lack of appetite are common associated s/s.

Question 22

Differential Diagnosis for Infant with a Fever: PNA (2/10)

Answer 22

• Most kids with pna have cough, tachypnea, fever, rales, or low SaO2.
• Its unusual for a child with pna to have no s/s referable to the respiratory system.
• Current guidelines recommend a CXR if a child has respiratory findings and /or a WBC count > 20,000 cells x 103/μL.

Question 23

Differential Diagnosis for Infant with a Fever: Sepsis/Bacteremia (3/10)–medical emergency

Answer 23

• Bacteremia =bacteria in the bloodstream.
• Sepsis=a systemic response to an infectious agent, whether bacterial, viral, or fungal. Inflammation occurs in tissues throughout the body, resulting in: vasodilation, leukocyte accumulation, and increased capillary permeability.
• Fever is usually present; young infants may present with hypothermia.
• Children with sepsis generally do not look well.
• Early in sepsis an elevated HR may be the only vital sign abnormality. Late signs include evidence of end-organ hypoperfusion: poor perfusion (delayed capillary refill), low blood pressure, AMS and other evidence of organ failure.

Question 24

Differential Diagnosis for Infant with a Fever: Occult bacteremia (4/10)

Answer 24

• In contrast to sepsis , the term “occult bacteremia” is applied when there is a positive blood culture in a well-appearing child.
• The distinction is made because most children with occult bacteremia will NOT develop a serious bacterial illness (SBI), whereas a child with sepsis represents a medical emergency.

Question 25

Differential Diagnosis for Infant with a Fever: Bacterial meningitis (5/10)

Answer 25

• *This is one of the most worrisome diagnoses to consider.**
• Both viral and bacterial meningitis occur in children, but typically the symptoms of bacterial meningitis are more severe.
• Early in the illness, meningitis can present with fever and no other source of infection.
• Most common causes in children are S. pneumoniae and N. meningitidis; (conjugated pneumococcal vaccine protects against only 13 pneumococcal serotypes.)
• A fully immunized child 3-36 mo who appears well, has a nml fontanel, and no nuchal rigidity or other signs of meningismus, is very unlikely to have meningitis. Therefore, no LP is needed in this group.
• In very young children, the absence of meningismus cannot rule out this diagnosis.

Question 26

Differential Diagnosis for Infant with a Fever: Viral meningitis (6/10)

Answer 26

• -Symptoms typically less severe than with bacterial meningitis.
• -Commonly caused by enterovirus.
• -May be other symptoms such as loose stools, rashes, or upper respiratory symptoms.

Question 27

Differential Diagnosis for Infant with a Fever: Roseola (7/10)

Answer 27

• Common viral illness in children <2yo.
• Caused by human herpes virus 6 (HHV-6).
• A high fever is often the only symptom in the first few days of illness and typically lasts for 3 to 5 days.
• Some pts develop a rash as the fever resolves; the rash can persist from 1 to 4 days.
• management: reassure the family that no other therapy is indicated.

Question 28

Differential Diagnosis for Infant with a Fever: Primary HSV gingivostomatitis (8/10)

Answer 28

• Usually seen in young children 10 mo-3yo
• Estimated that only 10-30% of perioral HSV infections are symptomatic.
• Fever and irritability may be the initial symptoms, but oral lesions that start as vesicles and evolve to ulcerations are seen shortly after the onset of symptoms.

Question 29

Differential Diagnosis for Infant with a Fever: Otitis media (9/10)

Answer 29

• With an OM poor mobility and at least mild bulging of the tympanic membrane should be demonstrated. Without either of these signs, an OM cannot be diagnosed.
• A red TM by itself has no positive predictive value.

Question 30

Differential Diagnosis for Infant with a Fever: VIral Upper Resp Tract Infxn (10/10)

Answer 30

congestion, cough, rhinorrhea

Question 31

A 3-month-old male presents to the ED with a fever that started the previous day. Mother reports that he was fussy and had decreased oral intake. He had had five fewer diaper changes than usual. He had no vomiting, diarrhea, or respiratory difficulty. On physical exam his temperature is 101.6 F, pulse 110 bpm, RR 24 bpm, and BP 95/67 mmHg. The baby seems irritable and is not consolable by the parent. HEENT exam was significant for dry mucous membranes. Other than his irritability, the rest of the physical exam was unremarkable. CBC showed WBC 3.5, but was otherwise normal. BMP was within normal limits. Urinalysis showed positive leukocyte esterase, positive nitrite, and WBCs > 10/hpf. An LP was performed, and urine and CSF culture results are pending. The patient is placed on IV fluids and is started on cefotaxime. What is the next best step in evaluation?

Answer 31

This infant has a fever without other respiratory symptoms. Meningitis and UTI must be considered in patients with fever. The only way to rule out meningitis is by lumbar puncture. This patient has a low WBC, suspicious for sepsis, and a UA that is highly suggestive of UTI. Empiric therapy should be started to cover common organisms including E.coli, P. mirabilis, and Klebsiella. Cefotaxime is reasonable empiric therapy. Renal ultrasound is recommended for all infants with pyelonephritis to assess for renal structural abnormalities or signs of obstructive uropathy (hydronephrosis).

Question 32

A 10-day-old boy is brought to the ED by his mother because of “fever.” Mom describes that the baby has been “sleepy” and feeding less vigorously than in the previous two days. She believes his urine output has also decreased. His birth history is notable for prolonged membrane rupture (about 32 hours), and maternal fever at the time of delivery. Prenatal and neonatal ultrasound revealed bilateral hydronephrosis. On exam, the infant is sleepy with a temperature of 38.5 C. A blood sample is sent for CBC, BMP, and culture. Attempts are made to obtain CSF and urine for analysis and culture, but only very small volumes of these fluids are obtained. Volume resuscitation is begun. Chest x-ray is performed with indeterminate results. What is the most appropriate next step?

Answer 32

Given the presentation of fever in a neonate who presents with sleepiness and poor feeding, samples should be sent for culture and the baby started on empiric antimicrobial therapy. This infant is likely to have a urinary tract infection, and urosepsis is certainly a possibility, especially given his known urinary tract anoamlies. We have no way of ruling out meningitis from this presentation, so antibiotics should be initiated at meningitic dosing. In an infant younger than one month, fever with any suspicion of sepsis, whatever the source, requires immediate evaluation and initiation of antibiotic treatment. Because infants at this age have immature immune systems, they do not localize infections as well as older children. An infection of the urinary tract may lead to bacteremia, which in turn may lead to CNS infection. Only cultures will give us the information required to determine the appropriate type length of antimicrobial therapy.

Question 33

A 6-month-old female is brought into the pediatrician’s office for three days of high fever, fussiness, and decreased appetite. The patient has not had any upper respiratory tract symptoms, vomiting, diarrhea, or rash. On physical exam the patient is fussy, has a RR of 28 bpm and a pulse of 160 bpm. She is febrile to 102.8 F (rectal). The patient is alert and fully moving all extremities. Apart from her vital signs, no other significant exam findings are noted. A CBC demonstrates leukocytosis of 17.0 cells x 103 / µL with elevated bands. What diagnosis is most likely?

Answer 33

UTI, the most common bacterial illness in a female infant, is consistent with her high fever, fussiness, and decreased appetite. Her CBC suggests that she has a bacterial infection (leukocytosis and elevated bands). A sample of her urine should be obtained by catheterization and sent for urinalysis and culture.

Question 34

A 6-month-old female with normal birth and developmental history presents with fever for the past two days, fussiness, and decreased appetite. ROS is negative. No abnormalities are noted on the physical examination. A urinalysis from a bag specimen is positive for leukocytes and nitrite, which suggests the presence of a UTI; a culture from this sample is pending. The patient is ill-appearing, dehydrated, and unable to retain oral intake. She is hospitalized, receives a 20 cc/kg NS bolus and is placed on maintenance IV fluids with clinical improvement. What is the best next step for management of this patient?

Answer 34

Urinary catheterization is correct . It is the best method for obtaining a specimen for culture that has not been contaminated by perineal bacteria, and for this ill child, you must determine the cause of the fever with accuracy.