Regarding pneumonia in children, which ONE of the following is INCORRECT?
Answer: B: Bacterial pneumonia beyond the neonatal period generally has a sudden onset with associated high fever (often temperature >39°C). Cough may or may not be present, but children often appear relatively toxic with tachypnoea disproportionate to the fever. Confined rales or wheezes and localised decreased breath sounds commonly occur in older children, although the physical examination in a younger child may be completely unrevealing.
S. pneumoniae is the most common bacterial agent causing pneumonia in children. Risk factors for developing infection from S. pneumoniae include immune deficiency, chronic renal disease, functional or anatomic asplenia, and Aboriginal or Torres Strait Islander decent.
S. aureus pneumonia is less common and tends to cause a more severe pneumonia, with more than 70% of all cases occurring in the first year of life. Children with foreign body aspiration, immunosuppression, or skin infections may be at increased risk for S. aureus pneumonia. Progression of the disease is rapid, and empyema (90%), pneumatocele (50%), pneumothorax (25%) and bacteremia are common complications. H. influenzae incidence has decreased by 90% since the introduction of immunization but it still causes clinically important respiratory disease (mostly non-type B strains). Most cases now occur in older children. H. influenzae pneumonia has a higher incidence of associated pleural effusions (25–75%) and bacteremia (75–95%). Other foci of infection are more common and include meningitis, epiglottitis, septic arthritis, pericarditis, soft tissue infection, and otitis media.
Group A streptococcal pneumonia may occur sporadically and may occur as a complication of varicella. It is typically a severe illness with rapid progression to toxicity and a high fatality rate. M. pneumonia accounts for 10 to 20% of all pneumonias and traditional teaching was that it affected 5–18 year olds. However, it clearly plays a significant role in younger children but is still rare in infants <1 year old. Classically, the onset is gradual and insidious, but some patients also may present with abrupt onset of symptoms similar to its bacterial counterpart. Prodromal symptoms include fever, headache and malaise followed several days later by a nonproductive, hacking cough. Patients also may present with pertussis-like illness. Other symptoms of infection may include hoarseness, sore throat and chest pain; coryza is unusual. Children with mycoplasmal pneumonia generally appear nontoxic. Patients may have rales, with wheezing occurring less often. Pharyngitis, cervical lymphadenopathy, conjunctivitis and otitis media may occur occasionally. Rash is present in 10% of patients and may be urticarial, erythema multiforme, maculopapular or vesicular. Mycoplasma is generally a benign and self-limited infection but does play a significant role in exacerbating asthma, and can be the inciting infection leading to bronchiectasis. The radiographic findings typically are more impressive than the physical exam; involvement is usually unilateral and in the lower lobes. The radiographic findings may include lobar consolidation, scattered segmental infiltrates or interstitial disease. Pleural effusions may occur but are uncommon. The WBC count is usually normal; the erythrocyte sedimentation rate tends to be elevated. Mycoplasma infection is often diagnosed clinically and treated empirically. Diagnosis may be confirmed with acute and convalescent antibody titers; however, patients may take 4–6 weeks to seroconvert, and some patients may fail to mount an immune response. Culture is not routinely available; PCR diagnosis from throat swabs is available at selected labs.
Complications are varied but unusual and include haemolytic anaemia, myopericarditis, neurologic disease (meningoencephalitis, Guillain–Barré syndrome, transverse myelitis, cranial neuropathy), arthritis and rash.
Reference:
Regarding acute pneumonia in children, which ONE of the following is INCORRECT?
Answer: D: A well-appearing child with cough and rales may be diagnosed clinically and treated as an outpatient. A child who appears ill or in whom the diagnosis is unclear requires further evaluation.
An arterial blood gas (ABG) should be considered in a child with severe respiratory distress. Serum electrolytes, blood urea nitrogen, and creatinine are useful in assessing the degree of dehydration and guiding fluid management when clinically relevant.The leukocyte count may be helpful in differentiating aetiology – peripheral WBC counts >15,000/mm3 , with predominance of mature and immature granulocytes, suggest bacterial infection, with pneumococcal pneumonia typically producing the highest WBC counts. Normal to elevated WBC counts with lymphocytosis may be seen in viral infections, and eosinophilia suggests chlamydial disease. Increased WBC counts with extreme lymphocytosis typically are associated with pertussis. BC is not very useful because they are positive in only 1 to 10% of cases of bacterial pneumonia.
Sputum cultures may be useful in adolescents but are not useful in younger children because contamination by organisms of the upper respiratory tract is common. Bacterial cultures of upper respiratory secretions are of no value as they reflect only colonization.
Patients with pleural effusions should have lateral decubitus radiographs to assess effusion size and loculation. Ultrasound is a useful ED modality to confirm fluid in the chest cavity. CT scan is useful to provide greater detail of effusions and lung abnormalities in critically ill children with complicated pneumonia. Thoracentesis for diagnostic and therapeutic purposes is important. Although most suggestive of bacterial infection, parapneumonic effusions also occur with mycoplasmal and occasionally with viral infections. Bronchoscopy with bronchoalveolar lavage may be useful in a severely ill child. Nasopharyngeal viral cultures, antigen detection for specific viral or bacterial agents, and serum antibodies for specific agents may be helpful in determining certain aetiologic agents. Skin testing for tuberculosis should be considered for patients with lobar pneumonia, pulmonary effusions or hilar adenopathy, especially in immunocompromised children or children who have recently immigrated from less developed countries.
Occasonally dehydration can result in a normal CXR, with rehydration revealing an obvious consolidation. Bacterial pathogens usually have alveolar infiltrates in a lobar distribution but may produce diffuse interstitial infiltrates. Viral and chlamydial infections tend to appear as diffuse interstitial infiltrates with associated hyperinflation and atelectasis. Chest radiographs also identify multilobar disease, pleural effusions, pneumatoceles and pneumothorax. Hilar adenopathy may indicate tuberculosis or malignancy. Children without comorbid conditions, who are without fever, unilateral wheezing or tachypnea, are unlikely to have pneumonia and a chest radiograph is unnecessary. Further, a Cochrane review demonstrated that for non-ill-appearing children with <14 days of symptoms and clinical signs of pneumonia, chest radiography does not reduce subsequent hospitalization rate, nor duration of symptoms. Routine chest radiography is not beneficial in ambulatory children over 2 months with acute lower respiratory infections.
References:
When reviewing the leading causes of mortality and morbidity in neonates, which ONE of the following is INCORRECT?
Answer: D: When reviewing neonatal morbidity and mortality registries, most infant deaths were due to four causes (classified according to the International Classification of Diseases):
Birth weight is classified as small for gestational age (SGA), intra-uterine growth restriction (IUGR), low birth weight (<2500 g) and very low birth weight (<1500 g). SGA infants have a birth weight <10th percentile for gestational age, whereas IUGR is defined as a fetus whose estimated weight is below the 10th percentile for its gestational age and whose abdominal circumference is below the 2.5th percentile. At term, the cutoff birth weight for IUGR is 2500 g.
Approximately 70% of fetuses with a birthweight below the 10th percentile for gestational age are constitutionally small; in the remaining 30%, the cause of IUGR is pathologic. GBS infection occurs in neonates born to women colonised with Streptococcus agalactiae. There are two main types of GBS disease; early-onset disease (occurs during the first week of life) and late-onset disease (occurs from the first week through three months of life). For early-onset disease, GBS most commonly causes sepsis, pneumonia and sometimes meningitis. A strong index of suspicion coupled with a rigorous guideline approach is required to decrease the incidence of early onset GBS disease. Most birth suites have protocols designed to identify GBS positive women who are eligible for parenteral antibiotics if they have prolonged rupture of membranes beyond 12 hours. Neonates born to these mothers are observed carefully. Typically, if a mother who tested positive for GBS received antibiotics during labour, the baby will be observed to assess their need for septic screening because of concerns about early-onset disease. Similar illnesses are associated with late-onset GBS disease but meningitis is more common with late-onset GBS disease than with early-onset GBS disease. Late onset disease is more difficult to screen for, although most sepsis/fever algorithms have a low threshold for screening for bacterial illness in a <3-month-old child. Treatment is with parenteral antibiotics, usually ampicillin and gentamicin.
TTN is a benign condition usually occurring in term neonates born after a caesarean section who develop an oxygen requirement with moderate respiratory distress. It usually has its onset at 6–24 hours after birth and may last for up to 72–96 hours. Its aetiology is uncertain, but it is postulated that the usual forces at play during a vertex vaginal delivery are absent from a caesarean birth, with residual fluid retention in the interstitium of the neonatal lung with resultant respiratory distress. It usually resolves after a few days.
A 10-day-old breastfed boy has been jaundiced for 2 days. No associated symptoms of vomiting or lethargy are present, and the stool pattern is unchanged. Examination reveals a well-looking baby with a weight of 2650 g. The baby was born at 35 weeks’ gestational age by spontaneous vertex delivery with a birth weight of 2700 g.
Which ONE of the following is INCORRECT?
Answer: B: Jaundice occurs in most newborn infants and is usually benign, but because of the potential toxicity of bilirubin, newborn infants must be risk stratified to identify those who might develop severe hyperbilirubinemia and, in rare cases, acute bilirubin encephalopathy or kernicterus. The following are risk factors for development of severe hyperbilirubinaemia and acute bilirubin encephalopathy:
1- Major risk factors include:
2- Minor risk factors include:
Indications for formal testing of serum bilirubin levels includes those babies with risk factors for progression to severe hyperbilirubinaemia, progressive jaundice, and babies who appear unwell, that is lethargy, poor feeding, dehydration, failure to thrive or evidence of sepsis. The total serum bilirubin should be plotted on the treatment nomogram for jaundiced babies to assess their need for admission for phototherapy.
Refer to answer 4 for a further discussion on the causes of jaundice.
Answer: D: GBS and gram-negative bacilli predominate in neonates. Ureaplasma urealyticum and Listeria monocytogenes may cause illness in infants younger than 3 months. This is the rationale for empiric neonatal antibiotic cover (for fever without source) with ampicillin and gentamicin with penicillins preferred over cephalosporins in covering listeria.
S. pneumoniae is the leading bacterial cause of pneumonia in all age groups beyond the newborn period, although the spectrum of invasive pneumococcal disease is changing after the introduction of Prevenar (PCV7), which is a heptavalent protein conjugate vaccine against the seven leading invasive strains of S. pneumoniae. A drastic reduction in all invasive pneumococcal disease has been seen between 2001–2005, with staphylococcus increasing in frequency as an invasive respiratory organism.
Respiratory syncytial virus (RSV) and parainfluenza are the most common viral agents in infants younger than 1 year. Viruses that may be responsible for neonatal pneumonia include rubella, CMV and HSV. Other viral agents include influenza, adenovirus, rhinovirus, enterovirus, measles, varicella and EBV. Chlamydia trachomatis is a unique cause of pneumonia in infants 3–19 weeks old. Bordetella pertussis classically occurs in children younger than 1 year but also occurs in older children and adolescents. M. pneumoniae is one of the most common causes of pneumonia among children older than 5 years and may play a role in younger children but the incidence is much less. Chlamydia pneumoniae is more common in children older than 5 years but also may cause infection in younger children.
An immunocompromised host is susceptible to all the aforementioned causes of pneumonia, as well as mixed and opportunistic infections including bacterial, viral (CMV, varicella), protozoan (Pneumocystis carinii), and fungal disease. Pseudomonas aeruginosa, Legionella pneumophila, P. carinii, and rickettsial infections need mention as well. The incidence of M. tuberculosis has in recent years increased with the co-infection of hosts with HIV disease, as well as resurgence in developed countries among the poor and dispossessed.
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