Q 1:
A 2-year-old child was recently adopted from India. She appears to be healthy, and there are no abnormal symptoms. Her weight and height are at 25th percentile for age. Her examination is normal. On screening, you find a positive TB skin test using purified protein derivative (PPD) with 20 mm induration. She has a history of receiving a BCG vaccination at birth. Your management plan is to do which of the following?
(A) Obtain a chest x-ray and treat only if this is abnormal.
(B) Obtain a chest x-ray and initiate prophylactic treatment with isoniazid (INH).
(C) Repeat the test in 3–6 months.
(D) Attribute the positive PPD to the BCG vaccination and do serial yearly x-rays.
(E) Obtain sputum cultures.
Answer :
(B)
Generally, the interpretation of tuberculin skin test (TST) is the same regardless of BCG status.
Induration >5 mm is considered positive in children in close contact with known or suspected cases of tuberculosis disease or children suspected to have tuberculosis disease.
Induration >10 mm is considered positive in children at greater risk of disseminated disease (age <4 years; other medical conditions such as lymphoma, diabetes, chronic renal failure, or malnutrition) or children at greater risk of exposure to tuberculosis disease (born in, or parents born in high-prevalence regions, travel to these regions, exposure to adults at high risk, such as HIV infected, homeless, or drug abusers).
Induration >15 mm is positive in children >4 years without any risk factors.
Radiographic evaluation of all children with positive TST is recommended. Latent tuberculosis infection is
defined as an infection in a person with a positive TST, no physical findings of the disease, and a chest radiograph that is either normal or reveals only granulomas or calcifications in the
lungs or regional lymph nodes.
Children with latent tuberculosis infection should receive prophylaxis, usually 9 months of INH. Those with
symptoms, signs, and/or radiographic manifestations are said to have tuberculosis disease.
There is no benefit to repeating the test in 3–6 months, and it will delay treatment. Sputum cultures are difficult to obtain in younger children.
Gastric aspirate specimens obtained with a nasogastric tube are preferred. Culture material should be obtained in children with evidence of the disease in order to obtain information on drug susceptibility and resistance patterns.
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Q 2:
A parent brings in a 5-year-old boy being treated for acute lymphocytic leukemia (ALL). He states a friend who is staying with them at their home has just come down with chicken pox. Your patient has not had chicken pox or received immunization with varicella vaccine. What is the appropriate treatment?
(A) acyclovir given IV
(B) varicella vaccine
(C) varicella immune globulin (VZIG)
(D) varicella vaccine and VZIG
(E) acyclovir given IV for 7 days, varicella vaccine, and VZIG
Answer :
(E)
Children with chicken pox may be infectious for 1 or 2 days before the appearance of the rash.
Once skin lesions have crusted, the patient is no longer infectious. Susceptible individuals can
contract chicken pox from patients with zoster.
In the cases of both chicken pox and zoster, transmission is thought to occur by the respiratory
route rather than by direct contact. The virus can travel long distances in the air and remain viable.
Transmission from one hospital patient to other susceptible hospitalized patients has been reported to occur through air vents. VZIG should be given within 3 or 4 days of exposure to varicella-susceptible individuals who are immunocompromised.
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Q 3
A 3-month-old infant is brought to your office in the winter with a history of 1 day of vomiting, followed by 3 days of diarrhea. She has had six to eight stools per day, which are loose and foul smelling. On examination, she looks well. Which of the following viruses is the most likely cause of her illness?
(A) adenovirus
(B) enterovirus
(C) human herpesvirus, type 6
(D) respiratory syncytial virus
(E) rotavirus
Answer :
(E)
Because many childhood viral illnesses have seasonal presentations, the etiologic agent may be suspected on the basis of clinical and seasonal presentation. Yearly winter outbreaks of bronchiolitis and pneumonia are associated with respiratory syncytial virus. Summer outbreaks of gastroenteritis are associated with
enterovirus, while winter outbreaks are associated with rotavirus. Although adenovirus can cause diarrhea, it more commonly causes respiratory symptoms. Human herpes virus type 6
is the etiologic agent in roseola infantum.
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Q 4:
A 10-year-old boy comes to your office in the winter with a sore throat he has had for 2 days. In addition, he has had fever, headache, and abdominal pain. He does not have any allergies to medications. On examination, he has a temperature of 38.6°C, an erythematous pharynx, and tender cervical adenopathy. Arapid screening test for group Astreptococcus is performed and is positive. Which of the following would
be the most appropriate antimicrobial agent?
(A) erythromycin
(B) penicillin
(C) trimethoprim-sulfamethoxazole
(D) azithromycin
(E) cefaclor
Answer:
(B)
Penicillin remains the drug of choice for treatment of streptococcal pharyngitis. Amoxicillin,
macrolides, and cephalosporins are acceptable alternatives.
Q 5:
The same child returns to your office the next day. He has taken the medication you prescribed. He is feeling a little better. His fever has resolved, but he has developed a rash. His examination is unchanged, except that he is afebrile and has a fine, papular rash over his body, which is accentuated in his axilla and groin. Which of the following is the most likely cause of his rash?
(A) allergic reaction to the antibiotic
(B) rash from the antibiotic seen in patients with mononucleosis
(C) scarlet fever
(D) serum sickness
(E) viral exanthem typical of enterovirus
(C)
Scarlet fever is caused by toxins made by group A Streptococci. It is usually seen in patients with strep throat. The rash is papular and described as sandpaper like. Sometimes it is easier to feel it than to see it. An allergic rash would be urticarial. More than 80% of patients with EBV infection develop a maculopapular
rash if given amoxicillin.
This patient’s clinical course is not typical for EBV which presents more gradually, and patients often have posterior cervical adenopathy and splenomegaly.
Patients with serum sickness often have urticarial rashes, sometimes progressing to angioedema. They may also have arthritis, myalgias, and lymphadenopathy. The rash in enteroviral infections is typically macular
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Q 6:
A 4-year-old child presents to your office in July with a history of a low-grade fever (38.1°C) and “sores” in his mouth for 2 days. He has been refusing to eat but has been drinking an adequate amount of liquids. On examination, he is afebrile and seems well hydrated. He has ulcers on his tongue and posterior pharynx,
which are 4 mm in diameter. You also note a few vesicles on his hands and feet, which are 3–4 mm in size and mildly tender. Which of the following is the most likely diagnosis?
(A) herpes simplex virus (HSV)
(B) coxsackie virus
(C) aphthous ulcers
(D) Behçet syndrome
(E) traumatic ulcers
Answer
(B)
Coxsackie A16 is the major cause of hand, foot, and mouth disease. This is a summer enteroviral illness presenting with classic lesions of the hand, feet, and mouth. Herpetic gingivostomatitis is the most common cause of stomatitis in children aged 1–3 years.
There is often a high fever, fetor oris, refusal to eat, and irritability. The lesions are initially vesicular, and soon form ulcers ranging from 2 to 10 mm in diameter. The tongue, cheek, and gums are usually involved, and there may be submaxillary lymphadenitis.
Aphthous ulcerations (canker sores) are painful ulcerations, which present as erythematous, indurated papules that erode to form circumscribed necrotic ulcers with gray fibrinous exudates and erythematous
halo. They are 2–10 mm in diameter, heal spontaneously, and often recur. Behçet syndrome is a multisystem disorder characterized by recurrent oral and genital ulceration, iritis or uveitis, as well as other cutaneous, arthritic, neurologic, vascular, and gastrointestinal (GI) manifestations. It is rare in children. Traumatic
oral ulcers may be seen in chronic cheek biters but do not involve extremities.
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Q 7:
A10-year-old boy comes to the office with fever and chills for 5 days and myalgia. He has recently returned from a 2-week vacation to New England with his family. On physical examination he has mild splenomegaly. Which of the following is the most likely cause of his symptoms?
(A) Kawasaki disease
(B) pneumococcus
(C) babesiosis
(D) leptospirosis
(E) psittacosis
Answer :
(C)
Kawasaki disease is an acute vasculitis of unknown etiology. Humans contract brucellosis by direct contact with infected animals or by drinking unpasteurized milk. Babesiosis is transmitted by ticks. Leptospirosis is
obtained from exposure to the urine of infected animals. Psittacosis is obtained from exposure to bird feces.
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Q 8:
A 6-year-old girl has a low-grade fever, headache, and nasal congestion. She has a flushed face and has developed a lacy reticular rash on the trunk and extensor surface of her arms and legs. Palms and soles are spared. Her mother has been ill with a low-grade fever and some joint stiffness and pain. Which of the following is the most likely diagnosis?
(A) rubella
(B) measles
(C) scarlet fever
(D) roseola infantum
(E) erythema infectiosum (fifth disease)
(E)
Erythema infectiosum is a common childhood viral exanthem caused by parvovirus B19.
It was the fifth in a classification system of childhood exanthems; the others were rubella, measles, scarlet fever, atypical scarlet fever, and roseola infantum. The rash classically presents early with flushed cheeks or a “slapped cheek” appearance. It is followed by development of a macular erythematous rash on trunk and
extremities, which then shows central clearing, developing a lacy, reticulated appearance.
The infection is often not clinically apparent. Adult and older adolescents, especially females, may
develop arthropathy. The symptoms are usually self-limited. Parvovirus B19 is clinically significant
in people with hemolytic anemias because it may induce a transient aplastic crisis.
Immunocompromised individuals are also at risk for chronic infections accompanied by anemia, neutropenia, and thrombocytopenia. It may also induce fetal demise in case of primary infection of pregnant women.
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Q 9:
A 3-year-old boy was bitten while teasing a neighborhood cat. On examination, there are two puncture wounds on the right hand and some superficial scratch marks. There is erythema, warmth, and induration around the puncture sites. Which of the following organisms most likely caused the infection?
(A) Pasturella multicoda
(B) Bartonella henselae
(C) Eikenella corrodens
(D) Peptostreptococcus species
(E) alpha Streptococci
Answer:
(A)
P. multicoda and S. aureus are organisms commonly associated with cat bites. The cat’s sharp teeth and claws predispose the victim to puncture wounds. Wound infections are more common in cat bites than dog bites. E. corrodens,
Peptostreptococcus species, and alpha Streptococci are more common with human bites. B. henselae
causes cat-scratch disease, which presents with subacute lymphadenitis.
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Q 10:
A 7-year-old boy presents with a rash. His mother states that he was well until 3 days ago when he developed fever and malaise. The next day, the rash started as papules on the trunk, which rapidly changed to vesicles. The lesions have spread all over the body. On physical examination, he has no fever and seems well. You note numerous vesicles all over the body, some of which have crusted over. Which of the following is the most likely diagnosis?
(A) chicken pox
(B) Kawasaki disease
(C) measles
(D) rubella
(E) staphylococcal scalded skin syndrome
Answer
(A)
This is a typical presentation of chickenpox. A prodrome of fever and malaise is followed by the rapid eruption of papules that turn to vesicles and crust over. The rash in measles, rubella, and Kawasaki disease are macular or maculopapular. In staphylococcal scalded skin syndrome, a diffuse, tender erythroderma
develops.
