Infectious Disesae Flashcards
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Atypical Mycobacterial Infections
What are Atypical Mycobacterial Infections?
- Mycobacterium avium complex (MAC)
- Considered an AIDS-defining illness. Patients with CD4 counts <50/mm3 are at highest risk.
What are the signs and symptoms of Atypical Mycobacterial Infections?
- Disseminated disease:
- Fever
- Malaise
- Weight loss
- Night sweats
- May have gastrointestinal (GI) symptoms
How do we diagnose Atypical Mycobacterial Infections?
- Diagnosis by culture from blood, bone marrow, or tissue
How do we treat Atypical Mycobacterial Infections?
- Two Drug regimen:
- Either clarithromycin or azithromycin
- Plus ethambutol, rifabutin, rifampin, ciprofloxacin, or amikacin. (Fluconazole can decrease the level of rifabutin by 80%. Rifabutin can color body secretions such as urine, sweat, and tears bright orange.
Prophylaxis:
- For CD4 < 50: Azithromycin once a week
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Pinworms
What are pin worms?
- Humans are the only host of Enterobius vermicularis. There is a worldwide distribution, and children are more infected than adults
How are pinworms transmitted?
Mode of Transmission:
- Hand to mouth
- Infection is easily passed through hands, food, drink and fomites. The eggs are swallowed and hatch in the duodenum; larvae pass to the cecum and mature in 3-4 weeks. The life span is 30-45 days.
What are the signs and symptoms of pinworms?
- Many patients are asymptomatic
- Characteristic symptoms include perianal pruritus (crawling sensation that is worse at night), insomnia, weight loss, enuresis, and irritability. Examination at night may reveal worms in the anus or in the stool. Scratching causes excoriations and secondary skin infections (i.e., impetigo).
- Migration can cause vulvovaginitis, diverticulitis, appendicitis, cystitis, and granulomatous reactions.
How are pinworms diagnosed?
- Eggs can be captured on a piece of cellophane tape over the perianal skin; three tries over three consecutive nights yields a 90% success rate.
What is the treatment for pinworms?
- All members of the household should be treated concurrently.
- Albendazole or mebendazole or pyrantel pamoate 11 mg/kg (max dose, 1 g PO x 1)
- Hand washing after defecation and before meals must be stressed. Linens should be washed thoroughly
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EBV
What causes EBV?
- EBV is human herpes virus 4, a universal virus transmitted via saliva
- The most characteristic disease is mononucleosis (the “kissing disease”). EBV has also been implicated in Burkitt lymphoma, nasopharyngeal carcinoma, pediatric leiomyomas, collagen vascular diseases, and other disorders
What are the signs and symptoms of EBV?
- After the incubation period of several weeks, patients develop fever and sore throat. Oral lesions include exudative pharyngitis, tonsillitis, gingivitis, and soft palate petechiae. Severe infections also exhibit malaise, anorexia and myalgias.
- Lymph nodes, typically the posterior cervical nodes, are enlarged, discrete, and nonsuppurative, with minimal pain
- Splenomegaly is present in 50% of cases
- A maculopapular and occasionally petechial rash develops in 15% of cases; administration of amoxicillin raises the incidence of rash to 90%.
How is EBV diagnosed?
- Any clearly granulocytopenia is followed by a lymphocytic leukocytosis. Atypical lymphocytes appear as larger cells that stain darker and are frequently vacuolated
- Hemolytic anemia and thrombocytopenia may develop
- Heterophile antibodies and screening mononucleosis tests are usually positive within 4 weeks. A false positive syphilis test (Venereal Disease Research Laboratory [VDRL] or rapid plasma reagent [RPR]) occurs in 10% of infected patients.
- Increased hepatic aminotransferases, increased bilirubin, and decreased cryoglobulins also may be found.
What is the treatment for EBV?
- Treatment is symptomatic, with nonaspirin antipyretics and anti-inflammatories. Antivirals will decrease viral shedding but do not affect the course of the illness
- Patients with splenomegaly should avoid contact sports
- Steroids are indicated for thrombocytopenia, hemolytic anemia, or airway obstruction secondary to enlarged lymph nodes
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Herpes Simplex
What are the signs and symptoms of Herpes?
- There are three distinct patterns of the disease:
• Cutaneous disease: Involves the skin, mouth and eyes. Vesicular eruptions appear around 7-10 days of life, usually on presenting part. If not recognized promptly, can progress to disseminated disease - Encephalitic disease: Occurs at second to third week of life. Clinical signs include lethargy, irritability, poor suck, and seizures. Cutaneous lesions may be absent.
- Disseminated disease: sepsis-like picture (apnea, irritability, hypotonia, hypotension). Cutaneous lesions may be absent.
How do we diagnose HSV?
- HSV can be isolated in cell culture from skin lesions or nasopharyngeal swabs
- Polymerase chain reaction (PCR) is a sensitive tool for HSV detection
How is Herpes Simplex treated?
- Acyclovir is very effective in the treatment of HSV
- Course treatment is often prolonged (21 days) for encephalitic disseminated forms
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Influenza
What is influenza?
- Viral respiratory illness
- Influenza is an orthomyxovirus
- It is readily transmitted through droplet nuclei and occurs in epidemics and pandemics during the fall or winter
Etiology:
- Influenza A and B – epidemic disease: H1N1 (influenza A)
- Influenza C- sporadic
- Major change is a shift
- Minor change is a drift
What are the signs and symptoms of influenza?
- Incubation period: 1-3 days
- Sudden onset of fever, frequently with chills, headache, malaise, diffuse myalgia, and nonproductive cough
- Conjunctivitis, pharyngitis
- Typical duration of febrile illness is 2-4 days
- Complications include otitis media, pneumonia, myositis and myocarditis
- Diarrhea and vomiting (H1N1)
How do we diagnose influenza?
- Nasal swab or nasal washing
- During epidemic, clinical signs can be used to save test costs
- Diagnosis of influenza depends on epidemiologic and clinical consideration
How do we treat influenza?
- Symptomatic treatment is appropriate for healthy children- fluids, rest, acetaminophen
- Pregnant patients with H1N1 should receive a 5-day course of antiviral treatment
- Oseltamivir (Tamiflu) is preferred during pregnancy
- Avoid aspirin in children because of Reyes Syndrome- fatty liver with encephalopathy
What is the vaccine for influenza?
Intramuscular:
- Now recommended for all children over age of 6 months, with priority given to high-risk groups
- Best administered before the peak flu season
- Antibodies take up to 6 weeks to develop in children. Consider prophylaxis in high-risk children during this period
- Since the composition of influenza virus changes, the flu vaccine needs to be administered every year
- Vaccine is a killed virus and therefore cannot cause the flu
- Not approved for children < 6 months of age
Intranasal:
- Live, attenuated vaccine available for children > 5 years old
- Not licensed for children with reactive airway disease
- Contraindicated in immunosuppressed individuals
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Mumps
What is the most common complication in a pre-pubertal child with mumps?
Menningitis
What is the most common complication in a post-pubertal male with mumps?
Orchitis
What causes Mumps?
- Paramyxovirus (RNA virus)
What is the mode of transmission for mumps?
- Spread via respiratory secretions
- Incubation period of 14-24 days
What are the signs and symptoms of mumps?
- Rare viral prodrome
- Swelling and tenderness in one or both parotid glands
- Difficult to open mouth
What is the vaccine for mumps?
- Live attenuated vaccine in MMR vaccine
- Generally given at 12-15 months with booster given at 4-6 yrs
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Rubeola
What is rubeola?
Measles
What causes rubeola?
- Paramyxovirus (RNA virus)
- Children under the age of 6 months do not usually get measles due to passive immunity they still have from mother
What are the signs and symtpoms of rubeola?
- Fever is high and, together with “3Cs”, precedes rash (3-5 days)
- Conjunctivitis is exudative (yellow discharge)
- Cough is croupy (barking or seal-like)
- Rash starts as faint macules on upper lateral neck, behind ears, along hairline, and on cheeks
- Lesions become maculopapular and spread quickly downward (“shower distribution”), while the rash becomes confluent (erythrthroderma) starting from the top.
- Rash is face to extremities
- May have lymphadenopathy or splenomegaly
- Koplik spots (pathognomonic): irregularly shaped spots with grayish white centers on buccal mucosa.
How do we diagnose rubeola?
- Clinical
- Laboratory rarely needed
What are the complications associated with rubeola?
- Otitis media
- Pneumonia: may be fatal in HIV patients
- Encephalitis
How is rubeola treated?
- The World Health Organization recommends Vitamin A for all children with measles, regardless of their country of residence
What is the vaccine for rubeola?
- Live attenuated vaccine included in measles-mumps-rubella (MMR) vaccine
- Generally given at 12-15 months with a booster given at 4-6 years
What are the classic findings with rubeola?
- Rubeola classic findings: coryza, cough, conjunctivitis, Koplik spots
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Rubella
What causes rubella?
- RNA virus
What are the signs and symptoms of rubella?
- Mild fever prodrome for 1-2 days
- Rash begins on face and spreads quickly to trunk (“shower distribution”). As it spreads to trunk, it clears on the face.
- Lymphadenopathy: Retroauricular, posterior cervical, and suboccipital
- Conjunctivitis may be present
How is rubella treated?
- Supportive; usually lasts about 3 days
What are the complications of rubella?
- Progressive panencephalitis (very rare):
• Insidious behavior change
• Deteriorating school performance
• Later, dementia and multifocal neurologic deficits - Thrombocytopenia (rare)
What is the vaccine for rubella?
- Live attenuated vaccine included in MMR vaccine
- Generally given at 12-15 months with a booster given at 4-6 years
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Roseola
What causes roseola?
- Human herpes virus types 6 and 7
- By the age of 4 years almost all are immune
- Peak age is 6-24 months
What are the signs and symptoms of roseola?
- High fever; high fever seen with roseola often triggers febrile seizures.
- Mild upper respiratory symptoms
- Cervical and suboccipital lymphadenopathy
- Maculopapular rash that spreads to the neck, face and proximal extremities
- Fever resolves before rash
What is the treatment for roseola?
- Supportive (anti-pyretics, increase oral fluid intake, rest)
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Fifths disease
What causes fifths disease?
- Parvovirus B19
- Attacks red blood cell precursors
- Transmitted in respiratory secretions
What are the signs and symptoms of fifths disease?
- Prodrome: 1 week of low grade fever, headache, malaise, myalgia, and mild upper respiratory symptoms
- “Slapped cheeks”, circumoral pallor
- Rash spreads rapidly to trunk and extremities in ornamental “lace-like” pattern
- Arthritis (knee) rare in children
How is fifths disease diagnosed?
- Clinical (serum parvovirus B19 immunoglobulin M is available, e.g., for arthritis cases)
- Parvovirus B19 serology may be offered to women of child bearing age to determine their susceptibility to infection (teachers)
How is fifths disease treated?
- Supportive (anti-pyretics, increase oral fluid intake, rest)
- Intravenous immune globulin (IVIG) should be considered for immunocompromised patients
What are the complications of fifths disease?
- Transient aplastic crisis in patients with chronic hemolysis including sickle cell disease (SCD), thalassemia, hereditary spherocytosis, pyruvate kinase deficiency
- Chronic anemia/pure red cell aplasia in immunocompromised hosts
- Hydrops fetalis: generalized edema due to fetal congestive heart failure (caused by fetal edema)
