First Aid for the Pediatrics Clerkship, 3 Ed.

Infectious Disease

 

OCCULT BACTEREMIA

DEFINITION

Fever without obvious focus of infection (except otitis media) in a well-appearing child, and positive blood culture for a bacterial pathogen.

ETIOLOGY

Neonates

Image Group B streptococci

Image Escherichia coli

Image Listeria monocytogenes

Image Staphylococcus aureus

Image Coagulase-negative Staphylococcus (preterm infants, catheter-related)

Image Candida albicans (preterm infants, catheter-related)


Image

Group B strep is the most common cause of neonatal septicemia


Children

Image Streptococcus pneumoniae (most common)

Image Neisseria meningitidis

Image Salmonella typhimurium

Image S aureus

Image Group A streptococci

SIGNS AND SYMPTOMS

Image Fever

Image Leukocytosis

PREDISPOSING FACTORS

Image Loss of external defenses (burns, ulceration, catheter).

Image Inadequate immune function.

Image Impaired reticuloendothelial function.

Image Overwhelming inoculum.

TABLE 10-1. Age-Based Management of Possible Occult Bacteremia in a Low-Risk Infant—Full Term, Previously Healthy, with Negative Laboratory Screen (Normal WBC Count and Urinalysis)

Image

DIAGNOSTIC WORKUP

Image Blood and urine cultures.

Image Complete blood count (CBC): Normal WBC count is > 5000 and < 15,000 cells/cmL.

Image Lumbar puncture if < 60 days old.

TREATMENT

Image Treat to prevent progression to septicemia.

Image See Table 10-1 for age-based criteria.

SEPSIS

Image

A 3-month-old female is brought to the ED with fever, vomiting × 1, → activity, and poor breast-feeding of 1 day’s duration. Previous history is unremarkable. Physical examination shows the following: “ill appearing,” temperature of 101.1°F (38.4°C), HR 196 beats/min, and no identifiable focus of infection. Think: Sepsis.

Young infants are at ↑ risk for infection. Initial presentation may be nonspecific signs and symptoms, and young infants lack focal signs of infection.

DEFINITION

Image A systemic inflammatory response to infection that includes hemodynamic and metabolic derangements.

Image Hypoperfusion abnormalities include lactic acidosis, oliguria, an alteration of mental status, and an ↑ alveolar-arterial oxygen gradient.

DIAGNOSTIC CRITERIA

Manifested by ≥ 2 conditions:

Image Hyper- or hypothermia (≥ 101.2°F [38.4°C] or < 96.8°F [36°C]).

Image Tachycardia (heart rate: infant > 160 bpm, child > 150 bpm).

Image Tachypnea (respiratory rate: infant > 60, child > 50).

Image WBC count > 15,000 or < 5000 cells/L and bandemia.

ETIOLOGY

Same as for occult bacteremia above.

SIGNS AND SYMPTOMS

Image Remember, a sick-looking, listless, infant who is not eating in the first 3 months of life with a rectal temperature < 98°F (36.7°C) is hypothermic and thus septic.

Image Vomiting is usual symptom in any infant with fever.

DIAGNOSIS

Image Same as for occult bacteremia.

Image Ten percent will have negative cultures.

RISK FACTORS

Image Younger at greater risk.

Image Prematurity.

Image Immunodeficiency.

Image Catheters.

Image Contact with known N meningitidis or Haemophilus influenzae infection.

Septic Shock

DEFINITION

Shock associated with systemic inflammatory response syndrome (SIRS) is defined as “hypotension persisting despite adequate fluid resuscitation, along with the presence of hypoperfusion abnormalities or organ dysfunction.” Septic shock is defined as shock plus clinical evidence of infection.

DIAGNOSTIC CRITERIA

Clinical evidence of infection plus meets the criteria for SIRS, plus one of the following:

Image Hypoperfusion requiring > 40 mL/kg isotonic fluid (crystalloid or colloid) and/or inotropic support.

Image Hypotension.

Image More than one manifestation of organ hypoperfusion.

TREATMENT

Image IV broad-spectrum antibiotics.

Image Manage shock with supportive therapy to maintain blood pressure, perfusion, and oxygenation.

Meningococcemia (Figure 10-1)

Image

A 5-year-old boy presents with sudden onset of chills, fever, and listlessness. Physical examination shows a temperature of 103.5°F (39.7°C) and reddish-purple, palpable, nonblanching spots, mostly on the lower extremities and buttocks. He is rapidly progressing to shock. Think: Meningococcemia.

Typical presentation is sudden onset of fever, vomiting, headache, and lethargy. Most patients have petechiae on presentation. The infection can progress rapidly to profound shock and DIC.


Image

Meningococcemia

Image Fever

Image Purpura

Image Rapid progression


Image Presents nonspecifically but progresses rapidly (within hours).

Image Most progress to septic shock due to endotoxin.

Image First petechiae, then purpura, and finally eschar (one of the rashes seen on palms and soles).

Image Typical rash distribution: Buttocks and lower extremities.

Image Adrenal hemorrhage (Waterhouse-Friedrichsen syndrome) and insufficiency common.

Image Establish diagnosis by culture of blood, cerebrospinal fluid (CSF), and skin lesions.

Image

FIGURE 10-1. Meningococcemia.

(Reproduced, with permission, from Knoop KJ, Stack LB, Storrow AB, et al. Atlas of Emergency Medicine, 3rd ed. New York: McGraw-Hill, 2010: 423. Photo contributor: Richard Strait, MD.)

TREATMENT

Image IV ceftriaxone or cefotaxime is treatment of choice until sensitivities are available.

Image See Septic Shock.

HUMAN IMMUNODEFICIENCY VIRUS (HIV) IN THE CHILD

ETIOLOGY

Image Infants: Vertical transmission from mothers either perinatally or through breast milk (preventable with antiretroviral prophylaxis).

Image Adolescents: Sexual transmission or IV drug use.


Image

Perinatal HIV

Image Lymphadenopathy

Image Hepatosplenomegaly

Image Oral thrush

Image Failure to thrive


DIAGNOSIS

Image HIV screening is part of prenatal care.

Image In non-breast-feeding infants < 18 months of age and born to HIV -infected mothers, definitive exclusion of HIV-1 is based on:

Image At least two negative HIV-1 DNA or RNA virologic tests, both of which were obtained at ≥ 1 month of age and one of which was obtained at ≥ 4 months of age or

Image Two negative HIV-1 antibody test results from separate specimens obtained at ≥ 6 months of age and

Image No other laboratory or clinical evidence of HIV-1 infection, and no AIDS-defining condition for which there is no other underlying condition of immunosuppression.

Image In adolescents of > 13 years of age, rapid oral swab enzyme immunoassay (EIA) is an alternative method. If it is positive, confirmatory enzyme-linked immunosorbent assay (ELISA) and Western blot are required.

Image Suspect HIV infection in a child with failure to thrive, oral thrush after 3 months of age, generalized nontender lymphadenopathy, hepatosplenomegaly, and thrombocytopenia.


Image

Common presentation:

Infants: PCP

Children: ITP


Image Consider acute HIV syndrome in a sexually active adolescent with mononucleosis-like illness with fever, lymphadenopathy, and hepatosplenomegaly.

Image See Table 10-2 for clinical classifications.

TABLE 10-2. 1993 Centers for Disease Control and Prevention Clinical Classification of HIV Infection in Children < 13 years

Image

Image

TREATMENT

Image Three classes:

Image Nucleoside reverse transcriptase inhibitors (NRTIs).

Image Non-nucleoside reverse transcriptase inhibitors (NNRTIs).

Image Protease inhibitors.

Image HIV rapidly becomes resistant; therefore, multidrug therapy is necessary.

COMMON OPPORTUNISTIC INFECTIONS IN HIV

Toxoplasmosis

ETIOLOGY

Image Toxoplasma gondii (intracellular protozoan).

Image Cats excrete cysts in feces.

SIGNS AND SYMPTOMS

Image Mononucleosis syndrome including fever, lymphadenopathy, and hepatosplenomegaly.

Image Disseminated infection with T cell deficiency.

DIAGNOSIS

Serologic antibody tests, biopsy, visualization of parasites in CSF.

TREATMENT

Pyrimethamine and sulfadiazine used concurrently (both inhibit folic acid synthesis, so replace folic acid).

Cryptococcosis

DEFINITION

Image Fungal infection.

Image Primary infection in lungs.

Image Disseminates to brain, meninges, skin, eyes, and skeletal system in immune compromised.

SIGNS AND SYMPTOMS

Image Subacute or chronic meningitis is the most common presentation in AIDS.

Image Typically presents with fever, headache, and malaise.

Image Postinfectious sequelae commonly including hydrocephalus.

Image Change in visual acuity.

Image Deafness.

Image Cranial nerve palsies.

Image Seizures.

Image Ataxia.

DIAGNOSIS

Image Definitive diagnosis requires isolation of the organism from body fluid or tissue specimens: sputum, bronchopulmonary lavage, or CSF.

Image Niger seed (birdseed) can ↑ detection in sputum and urine.

Image The latex agglutination test and EIA for detection of cryptococcal capsular polysaccharide antigen in serum or CSF specimens are excellent rapid diagnostic tests.

Image Microscopy: Encapsulated yeast seen as white halos when CSF is mixed with India ink.

Image Can be grown in culture (takes up to 3 weeks).

Image May also see cryptococcomas on head CT.

TREATMENT

Image Treat with combination therapy using amphotericin B and flucytosine.

Image Relapse rate is very high. This is a reason for subsequent maintenance therapy with oral fluconazole.

Pneumocystis jiroveci Pneumonia

Formerly P carinii, now classified as a fungus.

EPIDEMIOLOGY

Image Peak incidence 3–6 months of age.

Image Highest mortality rate in infants.

SIGNS AND SYMPTOMS

Image Acute onset of fever, tachypnea, dyspnea, dry cough, and progressive hypoxemia.

Image Chest x-ray—diffuse bilateral interstitial infiltrates or alveolar disease, may have characteristic “ground glass” appearance.

DIAGNOSIS

Diagnosis by methenamine silver staining of bronchoalveolar fluid lavage (BAL) to identify cyst walls or Giemsa staining to identify nuclei of trophozoites. LDH > 500.

TREATMENT

Image First-line treatment with prednisone is trimethoprim-sulfamethoxazole (TMP-SMX) (TMP: 15–20 mg/kg/24 hr; SMX: 75–100 mg/kg/24 hr) q6h for 5–7 days.

Image Alternative regimens: Pentamidine, TMP-SMX plus dapsone, atovaquone.

PROPHYLAXIS

Starting at 6 weeks of age TMP-SMX if CD4 < 15%, or < 200 for age 6–12 years old and < 500 for age 1–5 years old. Risk displacement of bilirubin in neonate.

Atypical Mycobacterial Infections

ETIOLOGY

Image Mycobacterium avium complex (MAC).

Image Considered an AIDS-defining illnesses. Patients with CD4 counts < 50/mm3 are at highest risk.


Image

Rifabutin ↓ serum levels of zidovudine (ZDV) and clarithromycin.


SIGNS AND SYMPTOMS

Disseminated disease:

Image Fever.

Image Malaise.

Image Weight loss.

Image Night sweats.

Image May have gastrointestinal (GI) symptoms.


Image

Fluconazole can ↓ the level of rifabutin by 80%.


DIAGNOSIS

Diagnosis by culture from blood, bone marrow, or tissue.

TREATMENT

Two-drug regimen:

Image Either clarithromycin or azithromycin

Image Plus ethambutol, rifabutin, rifampin, ciprofloxacin, or amikacin.


Image

Rifabutin can color body secretions such as urine, sweat, and tears a bright orange


PROPHYLAXIS

For CD4 < 50: Azithromycin once a week.

Cytomegalovirus (CMV)

ETIOLOGY

Member of Herpesviridae family.

PATHOPHYSIOLOGY

Infection is lifelong, as with any other herpesvirus. It may be acquired early in life and stay latent until host becomes immunocompromised, years later. Lung, liver, kidney, GI tract, and salivary glands are most common organs infected.


Image

CMV is the most frequently transmitted virus to a child before birth.


SIGNS AND SYMPTOMS

Image Pneumonitis.

Image Esophagitis.

Image Retinitis (can cause blindness).

DIAGNOSIS

Image Reactivation may be associated with appearance of IgM in serum.

Image Detection of pp65 antigen in white blood cells is used to detect infection in immunocompromised hosts. Quantitative polymerase chain reaction (PCR) (viral load) in blood is available.

Image Urine shedding of virus is lifelong. Positive urine CMV culture does not indicate association with current disease.

TREATMENT

Image Gancyclovir. Addition of intraocular to systemic for retinitis.

Image IV foscarnet in gancyclovir-resistant infection.

FEVER AND RASH

Image Enanthema: Lesion(s) on mucosa.

Image Exanthema: Lesion(s) on the skin, rash.

Image Polymorphous rash: Consists of various primary elements.

Image Primary elements of rash:

Image Macule: Flat, pink blanching spot.

Image Papule: Small, raised spot.

Image Vesicle: Small, round fluid-filled lesion.

Image Pustule: Small, round pus-filled lesion.

Image Petechia: Pinpoint nonblanching purplish spot (extravasation).

Image Purpura: Small, raised, purplish nonblanching lesion (extravasation).

Image Erythroderma: Confluent redness of the skin.

Image Excoriation: Crust.

Image Eschar: Dead tissue (or ulcer) covered by dry, dark scab.

Image In order to recognize infection, keep in mind:

Image Primary element(s) of rash.

Image Distribution and/or pattern of the rash.

Image Sequence (timeline) of events.

Image Associated hallmarks of infection.

Image Vaccine-preventable infection is most likely to develop in an unvaccinated child, for example, in a new immigrant or in an adoptee.

Image Remember: Any rash may be itchy.

Image See Table 10-3.

Rubeola (Measles)

Image

A 6-year-old girl has a 1-day history of a rash. It started on her face and then spread to the trunk. Prior to developing the rash, she had a 4-day history of running nose, pink eyes with crusting, barking cough, and high fever. She was never immunized because of her parents’ beliefs. On exam, her temperature is 103°F (39.4°C), and there is a maculopapular rash most prominent on the trunk. There are three tiny whitish round spots on her buccal mucosa. Think: Measles.

Measles is characterized by high fever, an enanthem (Koplik’s spots), cough, conjunctivitis, and a maculopapular rash. The rash usually begins on the face and appears several days after the initial symptoms. Koplik’s spots precede the onset of rash.


Image

Rubeola classic findings:

Image Coryza

Image Cough

Image Conjunctivitis

Image Koplik spots


ETIOLOGY

Paramyxovirus (RNA virus).

SIGNS AND SYMPTOMS

Image Fever is high and, together with “3Cs” (see Table 10-3), precedes rash (3–5 days).

Image Conjunctivitis is exudative (yellow discharge).

Image Cough is croupy (barking, or “seal-like”).

Image Rash starts as faint macules on upper lateral neck, behind ears, along hairline, and on cheeks.

TABLE 10-3. Fever and Rash

Image

Image

Image Lesions become maculopapular and spread quickly downward (“shower distribution”), while the rash becomes confluent (erythrthroderma) starting from the top.

Image May have lymphadenopathy or splenomegaly.

Image Koplik spots (pathognomonic): Irregularly shaped spots with grayish white centers on buccal mucosa (see Figure 10-2).

DIAGNOSIS

Image Clinical.

Image Laboratory rarely needed.


Image

Children under the age of 6 months do not usually get measles due to passive immunity they still have from mother.


COMPLICATIONS

Image Otitis media.

Image Pneumonia: May be fatal in HIV patients.

Image Encephalitis.

TREATMENT

The World Health Organization recommends vitamin A for all children with measles, regardless of their country of residence.


Image

Vitamin A for measles.


VACCINE

Image Live attenuated vaccine included in measles-mumps-rubella (MMR) vaccine.

Image Generally given at 12–15 months with a booster given at 4–6 years.

Image

FIGURE 10-2. Koplik spots (rubeola).

(Reproduced, with permission, from Knoop KJ, Stack LB, and Storrow AB. Atlas of Emergency Medicine, 1st ed. New York: McGraw-Hill, 1997: 174.)

Rubella

Image

A 3-year-old girl develops a rash. She was recently adopted from Romania, and her immunization history is unknown. She is brought in because of a fever × 1 day. On physical examination, she is not sick-looking, her temperature is 100.4°F (38.0°C), there is a confluent maculopapular rash on her face and discrete rash on her trunk, and the suboccipital and posterior cervical lymph nodes are palpable. WBC 7.2. Think: Rubella.

The disease has a prodrome of low-grade fever, sore throat, red eyes, headache, malaise, and anorexia. Suboccipital or postauricular lymphadenopathy is common. Rash is usually the first symptom, which appears on the face and spreads centrifugally to the extremities.

Rubella is contagious from 1 week before the rash appears to 1 week after it fades.

ETIOLOGY

RNA virus.

SIGNS AND SYMPTOMS

Image Mild fever prodrome for 1–2 days.

Image Rash begins on face and spreads quickly to trunk (“shower distribution”). As it spreads to trunk, it clears on face.

Image Lymphadenopathy: Retroauricular, posterior cervical, and suboccipital.

Image Conjunctivitis may be present.

Image Polyarthritis common in adolescent females.

COMPLICATIONS

Image Progressive panencephalitis (very rare):

Image Insidious behavior change.

Image Deteriorating school performance.

Image Later, dementia and multifocal neurologic deficits.

Image Thrombocytopenia (rare).

TREATMENT

Image Supportive; usually lasts about 3 days.

Congenital Rubella Syndrome

Image The earlier in gestation rubella occurred, the higher is the risk—more than 80% in the first trimester, and 25% at the end of the second trimester.

Image Neonatal manifestations:

Image Intrauterine growth retardation.

Image Pneumonitis.

Image Radiolucent bone lesions.

Image Hepatosplenomegaly.

Image Thrombocytopenia.

Image “Blueberry muffin” rash (dermal erythropoiesis).

Image Eye: Cataracts, glaucoma, pigmentary retinopathy, microphthalmos.

Image Heart: Patent ductus arteriosus (PDA), peripheral pulmonary artery stenosis.

Image Sensorineural hearing impairment.

Image Neurologic: Meningoencephalitis → mental retardation.

VACCINE

Image Live attenuated vaccine included in MMR vaccine.

Image Generally given at 12–15 months with a booster given at 4–6 years.

Roseola

Image

An 11-month-old boy has had a fever 103–104°F (39.4–40°C) for 4 days and was seen in ED because of febrile seizures. He had no vomiting, did not look sick, and his neurologic examination was normal. The only finding at the time was small suboccipital lymph nodes. No workup was done. Three days later, the child’s fever has resolved, but now he has a maculopapular rash. Think: Roseola.

Typical history: Rash appears when the fever disappears. It is associated with high fever, and some children may develop a seizure. Mild cervical or occipital lymphadenopathy may be present.


Image

Peak age: 6–24 months


ETIOLOGY

Image Human herpesvirus types 6 and 7.

Image By the age of 4 years almost all are immune.

SIGNS AND SYMPTOMS

Image High fever.

Image Mild upper respiratory symptoms.

Image Cervical and suboccipital lymphadenopathy.

Image Maculopapular rash that spreads to the neck, face and proximal extremities.


Image

The high fever seen with roseola often triggers febrile seizures.


TREATMENT

Supportive (antipyretics, ↑ oral fluid intake, rest).

Fifth Disease (Erythema Infectiosum)

Image

An 8-year-old girl has a 4-day history of fever and bright red cheeks. Now she has rash everywhere and complains of knee pain. On examination, she is not sick-looking, her temperature is 100.8°F (38.2°C), and she has “slapped”-looking cheeks and a discrete macular rash on the trunk and extremities that looks lacy. Her joints look intact, with full range of motion. Think: Erythema infectiosum, Parvovirus B19.

Erythema infectiosum is a self-limiting exanthematous illness in children. Slapped-cheek appearance is classic presentation. In addition, lacy, reticulated appearance on the extremities is often present.

ETIOLOGY

Parvovirus B19.

PATHOPHYSIOLOGY

Image Attacks red blood cell precursors.

Image Transmitted in respiratory secretions.

SIGNS AND SYMPTOMS

Image Prodrome: 1 week of low-grade fever, headache, malaise, myalgia, and mild upper respiratory symptoms.

Image “Slapped cheeks,” circumoral pallor.

Image Rash spreads rapidly to trunk and extremities in ornamental “lacelike” pattern.

Image Arthritis (knee) rare in children.

DIAGNOSIS

Image Clinical (serum parvovirus B19 immunoglobulin M is available, eg, for arthritis cases).

Image Parvovirus B19 serology may be offered to women of childbearing age to determine their susceptibility to infection (teachers).

COMPLICATIONS

Image Transient aplastic crisis in patients with chronic hemolysis including sickle cell disease (SCD), thalassemia, hereditary spherocytosis, and pyruvate kinase deficiency.

Image Chronic anemia/pure red cell aplasia in immunocompromised hosts.

Image Hydrops fetalis: Generalized edema due to fetal congestive heart failure (caused by fetal anemia).

TREATMENT

Image Supportive (antipyretics, ↑ oral fluid intake, rest).

Image Intravenous immune globulin (IVIG) should be considered for immunocompromised patients.

Scarlet Fever

Image

A 7-year-old boy has a sore throat, fever, and rash. His classmate had similar symptoms 1 week ago. On examination, his temperature is 102°F (38.9°C). He has red tonsils; swollen, tender bilateral anterior cervical lymphatic nodes (2.5 cm); and a confluent red rash that feels “sandpaper-like.” He has circumoral pallor (nasolabial triangle and chin are spared). Think: Scarlet fever.

Scarlet fever has an abrupt onset, with fever, chills, malaise, and sore throat and a distinctive rash that begins on the chest. Circumoral pallor is often present. The rash has a rough, sandpaper-like texture.


Image

Scarlet fever common findings:

Image Sandpaper rash

Image Pastia lines

Image Desquamation


ETIOLOGY

Erythrogenic exotoxins of group A β-hemolytic Streptococcus (GAS).

SIGNS AND SYMPTOMS

Image Fever, often sore throat.

Image Confluent erythematous (erythroderma) sandpaper-like rash.

Image Nasolabial triangle and chin are spared: “Circumoral pallor.”

Image Accentuation of rash in a linear pattern in folds (Pastia lines).

Image Desquamation (peeling), starting with fingers, in the second week.

DIAGNOSIS

Image Clinical.

Image Throat culture, anti-streptolysin O (ASO), and deoxyribonuclease B titers.

COMPLICATIONS

Myocarditis.

TREATMENT

Penicillin.

Varicella (Chickenpox)

Image

A 5-year-old boy has had a fever for 3 days and an itchy rash that started yesterday. He is a recent immigrant from overseas. On examination, his temperature is 101.8°F (38.8°C) and he does not look sick. There are crops of papules, vesicles, pustules, and crusts on the face, trunk, and extremities. Think: Varicella.

Varicella is a highly contagious disease characterized by a generalized vesicular rash. There is centripetal distribution. In a patient with chickenpox, erythematous macules, papules, vesicles, and scabbed lesions are present at the same time.

DEFINITION

Highly contagious, self-limited viral infection characterized by multiple pruritic vesicles (Figure 10-3).

ETIOLOGY

Varicella-zoster virus (VZV), group of herpesviruses.

EPIDEMIOLOGY

Image Ninety percent of patients are < 10 years old.

Image Often, there is a history of exposure to infected individual.

Image Incidence is ↓ with introduction of vaccine.

PATHOPHYSIOLOGY

Image Transmitted by respiratory secretions and fluid from the skin lesions.

Image Virus replicates in respiratory tract.

Image Establishes lifelong infection in sensory ganglia cells.


Image

Herpes zoster (shingles) is the reactivation of VZV and occurs in dermatomal distribution.


SIGNS AND SYMPTOMS

Image Rash may be preceded by a prodrome of fever, malaise, anorexia, headache, and abdominal pain 24–48 hours before the onset of the rash.

Image

FIGURE 10-3. Varicella (chickenpox).

Note dewdrop appearance of lesion and that there are lesions in multiple stages of eruption.

Image “Dew drops on a rose petal” initially appear on face and spread to trunk and extremities, sparing palms and soles.

Image Within days, vesicles become turbid and then crusted (see Figure 10-3).

DIAGNOSIS

Image Clinical; Tzanck preparation is not used anymore.

Image PCR test of swab from the vesicle.


Image

Smallpox generally presents with all lesions in the same stage (versus chickenpox).


COMPLICATIONS

Image Skin lesions may be superinfected by bacteria (Streptococcus pyogenes or Staphylococcus aureus).

Image Pneumonia in immunocompromised or pregnant patients.

Image Encephalitis.

Image Reye syndrome (associated with aspirin use).

TREATMENT

Image For most immunocompetent children: Symptomatic for fever and pruritus.

Image For VZV pneumonia and for immunocompromised individuals: Acyclovir.

Congenital Varicella Syndrome

Caused by maternal varicella infection in first 20 weeks of pregnancy.


Image

Varicella zoster immune globulin (VZIG) is used for post-exposure prophylaxis in immunocompromised or newborns exposed to maternal varicella


SYMPTOMS

Image Cicatricial skin lesions (cutaneous scarring).

Image Limb hypoplasia.

Image Neurologic deficits.

Image Eye abnormalities.

VACCINE

Live attenuated vaccine, first dose given between 12 and 18 months of age, second dose age > 4 years.

Hand-Foot-Mouth Disease

ETIOLOGY

Enteroviruses: 71, coxsackievirus A16.

EPIDEMIOLOGY

Image Fecal-oral and respiratory routes.

Image Summer and fall seasonal pattern.

SIGNS AND SYMPTOMS

Image GI discomfort.

Image Ulcerative mouth lesions (small, superficial, round erosions).

Image Hand and foot lesions tender and vesicular.

Image Hands more commonly involved than feet.

Image May occur on palms and soles.

COMPLICATIONS

Image Aseptic meningitis

Image Encephalitis

Mumps

Image

An unvaccinated 14-year-old boy presented with fever of 100.9°F (38.3°C), bilateral facial swelling, and inability to eat normally because of pain when he tries to chew. On examination, he was active and had trismus (inability to open wide the mouth) and swelling in front of the earlobes. There was no redness or purulent discharge at Stenson duct openings. At follow-up visit 8 days later, parotid swelling is resolved, but now he has a swollen tender left testis. Think: Mumps orchitis.

Epididymo-orchitis is a common extra–salivary gland complication of mumps in postpubertal males. Many of these occur during the first week of parotitis. It is characterized by marked testicular swelling and severe pain and may be associated with fever, nausea, and headache. Testicular atrophy may follow, although sterility is not common.

ETIOLOGY

Paramyxovirus (RNA virus).

PATHOPHYSIOLOGY

Image Spread via respiratory secretions.

Image Incubation period of 14–24 days.

SIGNS AND SYMPTOMS

Image Rare viral prodrome.

Image Swelling and tenderness in one or both parotid glands.

Image Difficult to open mouth.

COMPLICATIONS

Image Meningoencephalomyelitis (rare).

Image Orchitis/oophoritis common after puberty.

Image Pancreatitis.

Image Arthritis.

Image Thyroiditis.

Image Deafness.

VACCINE

Image Live attenuated vaccine included in MMR vaccine.

Image Generally given at 12–15 months with a booster given at 4–6 years.

BACTERIAL INFECTIONS

Typhoid (Enteric) Fever

Image

An 8-year-old boy returns from Africa, and 5 days later develops fever that gets higher and higher, escalating in the next 7 days. He has abdominal pain and refuses to eat. His last bowel movement was normal and occurred prior to the onset of fever. On examination, his temperature is 103°F (39.4°C), HR 88 beats/min. There are fine pink spots on the abdomen and a palpable spleen (2.5 cm). Abdomen is soft, with mild, nonconstant tenderness and no guarding or rebound. WBC is 11.9, and blood smear shows no parasites. Think: Typhoid fever.

Typhoid fever is characterized by prolonged sustained fever, relative bradycardia, splenomegaly, rose spots, and leukopenia. It is due to S typhi.


Image

Typhoid fever:

Image Relative bradycardia

Image Rose spots

Image Hepatosplenomegaly


ETIOLOGY

Salmonella typhi.

PATHOPHYSIOLOGY

Image Fecal-oral transmission.

Image Incubation period of 7–14 days.

Image Time of incubation dependent on inoculum size.

SIGNS AND SYMPTOMS

Image Fever: Gradual rise in the first week, gradual → in the third week.

Image Malaise.

Image Anorexia.

Image Myalgia.

Image Headache.

Image Abdominal pain.

Image Diarrhea is a late symptom.

Image Transient rose-colored spots on trunk.

Image Hepatosplenomegaly.

COMPLICATIONS

Image Intestinal hemorrhage

Image Intestinal perforation

DIAGNOSIS

Image Culture of blood, urine, stool.

Image The sensitivity of blood culture is ~60%.

TREATMENT

Image Ceftriaxone.

Image Severe case with altered mental status: Dexamethasone is to be considered.

VACCINE

Available for travelers to endemic areas (not routinely recommended).

Tick-Borne Infections

LYME DISEASE

Image

A 6-year-old boy developed limping, swelling, and pain in his right knee; there was no fever. Two months ago he was hiking in Wisconsin. Physical examination shows temperature of 98.6°F and no distress. No rash/murmur/organomegaly. The right knee was swollen, warm, but not red, with ↓ range of motion due to pain on passive movement. Think: Lyme disease.


Image

Lyme disease:

Image Erythema migrans

Image Bell’s palsy

Image Heart block


Image

An 11-year-old girl presents with an enlarging erythematous, nonitchy spot on her left shoulder. She was camping in upstate New York 2 weeks ago. On examination, her temperature is 100.3°F (37.9°C), she is not sick-looking, and she has a flat annular lesion 7 cm in diameter on the left shoulder. No regional lymphadenopathy is noted. Think: Lyme disease.

Lyme disease is a tick-borne, inflammatory disorder due to the spirochete Borrelia burgdorferi. The most common manifestation of Lyme disease in children is erythema migrans rash and arthritis. Most case of Lyme disease are from the following states: New York, Pennsylvania, New Jersey, Massachusetts, Connecticut, Wisconsin, Maryland, Minnesota, and Delaware

DEFINITION

A multisystem disease transmitted by the bite of an Ixodes tick infected with a spirochetes.

ETIOLOGY

Borrelia burgdorferi.

EPIDEMIOLOGY

Image Patients are often unaware of the tick bite.

Image Incubation period: 2–31 days (see Table 10-4).

Image Keep in mind geography (presence of a vector) and season (see Table 10-5).

PATHOPHYSIOLOGY

Disseminated Lyme is due to a spirochetemia.

TABLE 10-4. Stages of Lyme Disease

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TABLE 10-5. Epidemiology of Tick-Borne Infections

Image

SIGNS AND SYMPTOMS

Image See Table 10-4.

Image Erythema migrans (EM):

Image Begins as a red macule or papule that gradually (over days to weeks) turns into an annular, erythematous lesion of 5–15 cm in diameter (Figure 10-4).

Image Sometimes there is partial central clearing (halo appearance).

Image May have vesicular or necrotic areas in its center and can be confused with cellulitis.

Image The lesion usually is painless and not pruritic.

Image May be located at the axilla or in the groin.

Image May be associated with acute onset of fever, chills, myalgia, weakness, headache, and photophobia.

Image Isolated facial palsy (CN VII, Bell’s palsy): Develops 3–5 weeks after exposure.

Image Treatment has no effect on resolution, but prevents late events (arthritis).

Image Self-limited.

DIAGNOSIS

Image Confirmed by serology.

Image During the first 4 weeks of infection, serologic tests are negative and therefore not recommended.

Image Immunoglobulins M and G (IgM and IgG) peak 4–6 weeks after exposure and are detected by EIA (screening, may be false positive) and Western immunoblot (confirmation).

Image False-positive results with other spirochetal infection and in patients with some autoimmune disorders (systemic lupus erythematosus [SLE], rheumatoid arthritis [RA]).

Image An elevated IgG titer in absence of an elevated IgM indicates prior exposure as opposed to recent infection.

Image PCR can detect spirochete DNA in CSF and synovial fluid.

Image Forty percent of skin biopsies reveal spirochetes.

Image

FIGURE 10-4. Erythema chronicum migrans rash characteristic of Lyme disease.

COMPLICATIONS

Sixty percent of untreated cases with disseminated infection develop arthritis (mediated by immune complex formation) 6 weeks following tick bite.

TREATMENT

Image Amoxicillin (cefuroxime) or doxycycline:

Image EM: 14–21days.

Image Multiple EM: 21 days.

Image Isolated facial palsy: 21–28 days.

Image Arthritis: 28 days.

Image Ceftriaxone or Penicillin IV: Carditis, meningitis, persistent/recurrent arthritis: 14–28 days.


Image

If untreated, lesions fade within 28 days. If delayed diagnosis, may have permanent neurologic or joint disabilities.


ROCKY MOUNTAIN SPOTTED FEVER (RMSF)

Image

An 8-year-old girl from North Carolina presents with fever, severe headache, and myalgia over 3 days in July. She attended a family picnic 1 week ago. On examination, she has a temperature of 102.9°F (39.4°C), HR 134 beats/min. She is complaining of headache and has a macular rash on the wrists, palms, ankles, and soles. There are no other significant findings. Her platelets are 68 and serum sodium is 129. Think: Rocky Mountain spotted fever.

RMSF is a systemic tick-borne illness caused by Rickettsia rickettsii. Rash is considered the hallmark of this disease, which characteristically involves the palm and soles. Severe frontal headache is common, although it occurs less frequently in children. Abdominal pain, splenomegaly, and conjunctivitis may also be present. RMSF should be considered in the following states: Oklahoma, North and South Carolina, Tennessee, and Pennsylvania. Highest incidence rates for RMSF are in North Carolina and Oklahoma. Since the classic triad of fever, rash, and a history of tick exposure occurs in a few patients, awareness of seasonality and geographic distribution of the disease is important to make the diagnosis. Laboratory abnormalities include hyponatremia, hypoalbuminemia, anemia, and thrombocytopenia.


Image

If treated adequately, lesions fade within days and the late manifestations are prevented.


DEFINITION

A potentially life-threatening disease following a tick bite.

ETIOLOGY

Rickettsia rickettsii.

EPIDEMIOLOGY

Keep in mind geography (presence of a vector) and season (see Table 10-5).

PATHOPHYSIOLOGY

Image An intracellular infection of the endothelial cells lining the small blood vessels, resulting in vascular necrosis and extravasation of blood.

Image Only 60% of patients report a history of a tick bite.

Image The incubation period is 2–14 days.

Image Rarely occurs in the Rocky Mountains.

Image Highest incidence in children aged 5–10 years old.

SIGNS AND SYMPTOMS

Image Sudden onset of high fever, myalgia, severe headache, rigors, nausea, and photophobia.

Image Fifty percent develop rash within 3 days. Another 30% develop the rash within 6 days.

Image Rash consists of 2- to 6-mm pink initially blanchable macules that first appear peripherally on wrists, forearms, ankles, palms, and soles.

Image Within 6–18 hours the exanthem spreads centrally to the trunk, proximal extremities, and face (centrifugal).

Image Within 1–3 days the macules evolve to deep red papules, and within 2–4 days the exanthem is hemorrhagic and no longer blanchable.

Image Up to 15% have no rash (“spotless”).

Image Many patients have exquisite tenderness of the gastrocnemius muscle.

Image Meningitis is common.

Image If untreated, myocarditis, disseminated intravascular coagulation (DIC), shock, fatality rate up to 25%.

DIAGNOSIS

Image Clinical.

Image Rash biopsy would demonstrate necrotizing vasculitis.

Image Indirect fluorescent antibody (IFA) assay: Titer > 1:64 is diagnostic.

Image

Image

TREATMENT

Image Doxycycline, irrespective of a patient’s age.

COMPLICATIONS

Image Fulminant infection in glucose-6-phosphate dehydrogenase (G6PD) deficiency.

Image Noncardiogenic pulmonary edema.

Image Meningoencephalitis.

Image Multiorgan damage due to vasculitis.


Image

RMSF is a clinical diagnosis. It is important not to delay treatment.


Toxic Shock Syndrome

DEFINITION

An acute, febrile, exanthematous illness that involves multiple systems with potential complications, including shock, renal failure, myocardial failure, and adult respiratory distress syndrome.

PATHOPHYSIOLOGY

Image A result of hematogenous dissemination of a toxin.

Image Toxins from Staphylococcus or Streptococcus (Table 10-6) act as superantigens activating T cells, resulting in massive release of cytokines, which has profound physiologic consequences (ie, fever, vasodilation, hypotension, and multisystem organ involvement).


Image

RMSF is one of the few current indications to use chloramphenicol. It is seldom used anymore due to potential for gray baby syndrome (aplastic anemia).


TABLE 10-6. Diagnostic Criteria of Toxic Shock Syndrome (TSS)

Image

SIGNS AND SYMPTOMS

Image Sick-looking patient—streptococcal TSS (group A Streptococcus [GAS]): Usually, there is evidence of soft tissue infection (Table 10-7), classically necrotizing fasciitis in a patient with varicella.

Image Less than half of staphylococcal TSS is associated with menstrual tampons. Source also may be nasal or wound packing, or an abscess.

Image Recovery in 7–10 days.

TREATMENT

Image Aggressive fluid replacement.

Image Eradication of source.

Image Parenteral β-lactamase-resistant antibiotic.

TABLE 10-7. Streptococcal versus Staphylococcal

Image

FUNGAL INFECTIONS

See Table 10-8 for a summary of endemic fungal infections.

TABLE 10-8. Summary of Endemic Fungal Infections

Image

Image

Coccidioidomycosis

Image

A 13-year-old girl develops fever, cough, and chest pain soon after she has visited relatives in Arizona, where they were outing in a desert quite often. On examination, her temperature is 102.5°F (39.2°C), RR 44 breaths/min, no hypoxemia, and rales are heard over her left lower lobe. There are symmetrical tender, red, shiny indurations on both shins. WBC: 16.8. Chest radiograph shows left lower lobe consolidation. Think: Coccidioidomycosis.

Coccidioidomycosis is an infectious disease caused by the fungus Coccidioides immitis. Also known as San Joaquin Valley fever, coccidioidomycosis should be considered in southwestern U.S. states (Arizona, California, New Mexico, Utah, Nevada, and Texas). Symptoms usually develop 1–3 weeks after exposure. Clinical features include dry cough, chest pain, myalgias, arthralgia, fever, anorexia, and weakness.

ETIOLOGY

Coccidioides immitis, the dimorphic fungus.

EPIDEMIOLOGY

Image Southwestern United States.

Image Black and Filipino, pregnant women, neonates, and immunocompromised people have higher risk of dissemination.

Image Person-to-person transmission does not occur.

Image Incubation period: 1–3 weeks.

Image Transmission: Inhalation of airborne spores.

Image Infection produces lifelong immunity.

SIGNS AND SYMPTOMS

Image Usually asymptomatic or self-limited: Influenza-like or pneumonia, with fever, headache, cough, malaise, myalgia, and chest pain.

Image Maculopapular rash, erythema multiforme, or erythema nodosum may be the only manifestations.

Image Dissemination is rare, mostly in infants: Skin, bones and joints, central nervous system (CNS), and lungs.

Image Night sweats and anorexia.

Image Meningitis almost invariably is fatal if untreated.

DIAGNOSIS

Image Residual coin-like pulmonary lesions may be present on chest x-ray.

Image Spherules with endospores in tissue or body fluid is pathognomonic.

Image Cultures are hazardous.

Image Elevated erythrocyte sedimentation rate (ESR) and alkaline phosphatase.

Image Marked eosinophilia.

TREATMENT

Image Same as for histoplasmosis below.

Image Surgery for chronic pulmonary coccidioidal disease that is unresponsive to IV azole or amphotericin B therapy.

Histoplasmosis

Image

A 6-year-old boy from Indiana develops fever, chest pain, and cough. He was playing in a cave 10 days ago and got scared of bats. Physical exam shows no distress, temperature of 100.7°F (38.2°C), RR 28 breaths/min, oxygen saturation 95%. Rhonchi are heard over the lung fields bilaterally. WBC: 14.9. Chest x-ray shows diffuse bilateral reticulonodular infiltrates and hilar lymph node. Think: Histoplasmosis.

It is the most common endemic mycosis causing human infection. Pneumonia is the most common presentation. Atypical pneumonia is usually the initial diagnosis. Initial chest x-ray may show patchy infiltrate, while diffuse reticulonodular infiltrates are present in a progressive disease. The presence of hilar or mediastinal lymphadenopathy ↑ the suspicion for fungal pneumonia.

ETIOLOGY

Histoplasma capsulatum.

EPIDEMIOLOGY

Image Endemic infection: Ohio and Mississippi River valleys.

Image History of exposure to bird or bat droppings.

Image Incubation period: 1–3 weeks.

Image Transmission: Inhalation of airborne spores.

Image Reinfection happens with large inoculum.

SIGNS AND SYMPTOMS

Image Generally asymptomatic

Image Flulike prodrome.

Image The more spores inhaled, the more symptoms.

Image Severe acute pulmonary infection: Diffuse nodular infiltrates, prolonged fever, fatigue, and weight loss.

Image Progressive disseminated histoplasmosis (PDH): In infants < 2 years of age and in immunosuppressed, often starts as prolonged “fever of unknown origin.”

DIAGNOSIS

Image Mediastinal adenitis or granuloma may be seen on chest x-ray.

Image Cultures: Sputum, blood, bone marrow; may be negative.

Image Histoplasma antigen assay: Cross-reaction with other endemic fungi.

TREATMENT

Image Uncomplicated infection in an immunocompetent child is self-limited, and does not require treatment.

Image Oral itraconazole for serious focal (pulmonary) infection.

Image IV amphotericin B for PDH.

In order to recognize endemic infection, keep in mind:

Image

PROTOZOAL INFECTIONS

Schistosomiasis

Image

A 16-year-old male presents with fever, arthralgia, cough, abdominal pain, and rash of 5 days’ duration. He went to Puerto Rico for a river rafting trip 3 weeks ago. On examination, his temperature is 102°F (38.9°C), there are scattered urticaria on the trunk and extremities that wax and wane, and his spleen is palpable 3 cm below the costal margin. WBC count is 6.1, with 23% eosinophils. Think: Schistosomiasis.

Schistosomiasis is transmitted in tropical and subtropical areas. Clinical presentations are chills, cough, abdominal pain, diarrhea, nausea, vomiting, headache, rash, and lymphadenopathy. Physical examination may show an enlarged, non-tender liver and an enlarged spleen. Eosinophilia is often prominent in schistosomiasis.

ETIOLOGY

Caused by trematodes (flukes). See Table 10-9.

TABLE 10-9. Schistosomiasis

Image

EPIDEMIOLOGY

Image Fecal or urine ova get into the snails and form larvae.

Image Larvae leave the snail into the fresh water and penetrate the skin.

Image Larvae travel to particular organs and tissues, and there develop into mature forms.

SIGNS AND SYMPTOMS

Image “Swimmer’s itch” transient, a few hours after water exposure, followed in 1–2 weeks by an intermittent pruritic, papular rash.

Image Invasive stage: Within weeks to months of exposure—fever, malaise, cough, abdominal pain, and nonspecific rash .

Image Ulceration of intestine and colon, abdominal pain, and bloody diarrhea (Schistosoma interclatum and Schistosoma mekongi).


Image

Pay attention to travel history and timing from return (incubation period from weeks to months).


DIAGNOSIS

Image Eggs in stool or urine.

Image Eosinophilia.

TREATMENT

Praziquantel.


Image

Exposure to fresh water (lake, river) at the endemic area: swimming, fishing, playing.


Visceral Larva Migrans

ETIOLOGY

Toxocara canis and Toxocara cati (roundworms of puppies or kittens).

EPIDEMIOLOGY

Image Fecal-oral transmission: Eggs in soil make their way into the mouth by getting onto hands or toys.

Image Role of pica—eating soil: Ingested eggs hatch and penetrate the GI tract, migrating to the liver, lung, eye, central nervous system, and heart, where they die and calcify.


Image

Differentiate eye lesions of visceral larva migrans from retinoblastoma.


SIGNS AND SYMPTOMS

Image Most individuals are asymptomatic.

Image Symptomatic in young children (under 4 years of age).

Image The more larvae, the more symptoms.

Image Visceral: Fever, cough, wheezing (pneumonitis), hepatomegaly.

Image Rare: Myocarditis, encephalitis (seizures).

Image Ocular: Endophthalmitis or retinal granulomas, usually in older children or adolescents.

DIAGNOSIS

Image Leukocytosis and hypereosinophilia.

Image Hypergammaglobulinemia and ↑ titers of isohemagglutinin to the A and B blood group antigens.

Image EIA for Toxocara antibodies. EIA is more sensitive in visceral than in ocular form of infection.

TREATMENT

Albendazole.


Image

A 4-year-old boy presents with fever and cough of 10 days’ duration. On exam, he has a temperature of 101.8°F (38.8°C) and hepatomegaly. He has leukocytosis, with 45% eosinophils. He likes to play with his puppy in a sandbox. What is the diagnosis? Visceral larva migrans.


TRAUMATIC INFECTIONS

Animal Bites/Scratches

Image Cleaning, debridement, and irrigation are most important treatment.

Image Antibiotic prophylaxis for human, cat, and dog bites (amoxicillin/clavulanate).

Image X-ray to check for bone involvement if deep wound.

Image Most wounds should not be sutured; if deep wounds, surgical consult is best.

Image Assess risk for rabies: Local epidemiological information.

Image Ensure tetanus immunization is up to date.


Image

Pathogens in bites:

Image Human: Eikenella corrodens

Image Cats: Pasteurella multocida

Image Dogs: Capnocytophagia canimorsus


Abrasions and Lacerations

Image

A 10-year-old boy steps on a dirty nail that punctures his foot through his sneaker. Two days later he presents with pain, swelling, and redness of the heel, with purulent drainage from a central pinpoint opening. He has no fever. WBC is 14.6. X-ray: no foreign body, no fracture, no gas in the soft tissue. Think: Wound likely to become infected with Pseudomonas. The association of Pseudomonas infection with puncture wounds to the foot is well recognized.

Image Cleaning, debridement, and irrigation are most important initial treatment. Suturing indicated if no obvious signs of infection.

Image If secondarily infected, debride and drain.

Image Initial antibiotic given based on most likely organism; Gram stain and culture to determine best antibiotic in chronic or complex wounds.

Image Staphylococcus and Streptococcus are the most common pathogens, so a first-generation cephalosporin such as cephalexin or clindamycin is commonly given as empiric treatment.


Image

In human bites, consider child abuse and risk for HIV and hepatitis B.


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