Regarding DKA in children, which ONE of the following is TRUE?
Answer: A: Young or partially treated children and pregnant adolescents may present in DKA with near-normal glucose values (‘euglycaemic ketoacidosis’), where ketosis and abnormal acid–base measurement satisfy part of the diagnostic criteria. Relative normoglycaemia may be seen in patients who were given or took insulin before being seen in the ED, those who were starving or had reduced food intake, and those who have impaired gluconeogenesis from liver failure.
In a study of children with DKA where their WCC was reviewed, it was found that neither the absolute WBC count, nor the differential or the presence of leukocytosis were associated with bacterial infections. Leukocytosis was common regardless of the absence of infection, the presence of a presumed virali nfection, or the presence of a bacterial infection. The mechanism for this postulated to be due to the general adrenergic drive present in DKA.
A serum measurement of beta-hydroxybutyrate is the preferred method of measuring ketones in children with suspected or confirmed DKA. The nitroprusside method for measuring ketones in the urine only measures acetoacetic acid and acetone, not betahydroxybutyrate, the dominant acid in DKA. Because beta-hydroxybutyrate is converted to acetoacetic acid during successful treatment of DKA, acetoacetic acid levels rise, which may lead to confusion as to whether the acidosis is improving or worsening. Recent studies indicate that advances in point of care ‘fingerprick’ ketone measurement are more accurate than traditional urine ketone assessment.
Hypocalcaemia is usually not a feature of DKA. The differentiation of DKA from ethylene glycol (EG) is largely based on the clinical progression of EG poisoning through various stages, as well the specific finding of an osmolality gap in the first stage of EG poisoning. Measurement of EG in serum or urine will confirm the diagnosis.
Urinalysis may be diagnostic with calcium oxalate crystalluria, highly suggestive of EG poisoning. Fluorescein is added to many commercial antifreeze preparations hence fluorescence of urine or gastric contents with a Wood lamp supports EG poisoning early after ingestion.
References:
A 6-month-old boy presents with a 2-day history of cough and coryza on the background of four previous episodes of respiratory illness. He was born at 32 weeks’ gestation with a birth weight of 2000 g. His current weight is 3000 g. He is sweaty but appears well, is interactive and saturating at 94% on room air. He is apyrexial with mild subcostal recession and diffuse bilateral crepitations and wheeze. HR is 140 and air entry symmetrical.
Which ONE of the following is the BEST answer?
Answer: D: This 4-month-old boy (by corrected age) presents with typical features suggestive of bronchiolitis. However, he also has chronic failure to thrive (FTT) (babies gain on average 20–30g per day for the first 2–3 months of life) and this, coupled with recurrent respiratory tract illnesses, suggests that he has an underlying disorder. His tachycardia, sweaty appearance and FTT is suggestive of heart failure and possible cardiac pathology, hence his need for CXR.
Bacterial pneumonia is a clinical diagnosis; this child appears well, interactive and is apyrexial (i.e. he appears non-toxic). Furthermore, no asymmetrical findings are present – the hallmark of bacterial lobar consolidation in children. The presence of wheeze makes bacterial lobar pneumonia very unlikely.
Bronchiolitis is a clinical diagnosis based on typical features including cough, tachypnoea, feeding difficulties and inspiratory crackles – wheezing may be associated but is not an essential feature. The upper age for bronchiolitis is limited to 12 months of age in the Australasian and English literature, whereas European and North American publications include cases up to age of 3 years – this may explain ‘bronchodilator response’ in some studies. The differential diagnosis should always be considered and include:
A risk assessment should always be performed on children with bronchiolitis to identify those in which a severe course of illness is anticipated. These risk factors include:
Routine NPA (nasopharyngeal aspirate) testing is of little clinical value in the well bronchiolitic. There is some value in doing this test where patients are being admitted to an inpatient ward; cohorting patients with the same viruses may decrease the rate of nosocomial spread. Routine suctioning and toilet of the nasal passage with saline is common practice, but it has not been studied in any prospective or randomized trials to assess if it is beneficial.
A CXR is not routinely indicated in children with bronchiolitis. Radiography may be useful when the hospitalized child does not improve at the expected rate, if the severity of disease requires further evaluation, or if another diagnosis is suspected. Although many infants with bronchiolitis have abnormalities that show on chest radiographs, data are insufficient to demonstrate that chest radiograph abnormalities correlate well with disease severity.
Further, obtaining a CXR could affect the emergency clinician’s decision to start antibiotics. This child needs a CXR to ascertain why he has had recurrent respiratory illnesses, FTT and to evaluate specifically for heart failure.
Reference:
A 7-month-old child presents to the ED with respiratory distress, hypoxia and cardiomegaly on CXR. Regarding the evaluation of suspected congenital heart disease in the ED, which one of the following is INCORRECT?
Answer: B: This child requires an ordered approach to aid diagnosis and management. The ‘hyperoxia test’ essentially trials whether high-dose oxygen makes a differences to the saturations recorded on pulse oxymetry. If it does, this likely reflects a pulmonary cause, rather than a pure cardiac lesion. Classic congenital heart disease does not respond to the hyperoxia test.
The initial evaluation involves a systematic approach with three major components. First, consider two major groups based on the presence or absence of cyanosis, which can be determined by examination aided by pulse oximetry. Second, these two groups can be further subdivided according to whether the chest radiograph shows evidence of increased, normal, or decreased pulmonary vascular markings. Finally, the ECG can be used to determine whether right, left or biventricular hypertrophy exists. The character of the heart sounds and the presence and character of any murmurs further narrow the differential diagnosis. The final diagnosis is then confirmed by echocardiography, CT or MRI, or cardiac catheterization.
During the examination of a child, to differentiate a pathological murmur from an innocent one, which ONE of the following principles is TRUE?
Answer: D: Children often present to the ED with innocent murmurs when auscultation is carried out under non-basal circumstances (high cardiac output because of fever, infection, anxiety).
Features suggestive of pathologic murmurs include diastolic murmurs, pansystolic, grade III or higher, harsh, located at the left upper sternal border, and associated with an early or midsystolic click or an abnormal second heart sound.
The most common innocent murmur is a medium pitched, vibratory or ‘musical,’ short systolic ejection murmur along the left lower and midsternal border with no significant radiation to the apex, base or back. The intensity of the murmur often changes with respiration and position and may be attenuated in the sitting or prone position.
Innocent pulmonic murmurs are also common and occur due to turbulence during ejection into the pulmonary artery. They are higher pitched, blowing, brief early systolic murmurs of grade I–II in intensity and are best detected in the second left parasternal space with the patient in the supine position.
A venous hum is another common innocent murmur heard during childhood due to turbulence of blood in the jugular venous system; they have no pathologic significance and may be heard in the neck or anterior portion of the upper part of the chest. It usually has a soft humming sound heard in both systole and diastole; it can be exaggerated or made to disappear by varying the position of the head, or it can be decreased by lightly compressing the jugular venous system in the neck. These manoeuvres are sufficient to differentiate a venous hum from the murmurs produced by a patent ductus arteriosus.
A 2-year-old child presents with tachypnoea, respiratory distress and signs of pulmonary oedema. Cardiomegaly is present on the CXR with associated increased vascularity in the lung fields. The child is pink in room air with saturations of 93%.
Which ONE of the following is TRUE?
Answer: B: This child presents with classic features of heart failure. The child is acyanotic and appears to have increased blood flow to the lungs (on CXR and clinically evidenced by pulmonary oedema). The most common lesions in this group are those that cause left-to-right shunting: atrial septal defect, ventricular septal defect (VSD), AV septal defects (AV canal), and patent ductus arteriosus. There is communication between the systemic and pulmonary sides of the circulation, which results in shunting of fully oxygenated blood back into the lungs. The direction and magnitude of the shunt across such a communication depend on the size of the defect, the relative pulmonary and systemic pressure and vascular resistances, and the compliances of the two chambers connected by the defect.
A large VSD will have little shunting and few symptoms during the initial weeks of life but as pulmonary vascular resistance declines in the next several weeks, the volume of the left-to-right shunt increases, and symptoms begin to appear, usually at 2–4 months of age. Fluid leaks into the interstitial space and alveoli and causes pulmonary oedema. If left untreated, pulmonary vascular resistance eventually begins to rise and, by several years of age, the shunt volume will decrease and eventually reverse to right to left (Eisenmenger physiology, where pulmonary hypertension supercedes with resultant cyanosis and fixed split second heart sound).
Additional lesions that impose a volume load on the heart include regurgitant lesions and the cardiomyopathies. Regurgitation through the AV valves is most commonly encountered in patients with partial or complete AV septal defects (AV canal, endocardial cushion defects). In these lesions, the combination of a left-to-right shunt with AV valve regurgitation increases the volume load on the heart and often leads to more severe symptoms. Isolated regurgitation through the tricuspid valve is seen in mild to moderate forms of Ebstein’s anomaly.
In contrast to left-to-right shunts, heart muscle function is decreased in the cardiomyopathies. Cardiomyopathies may affect systolic contractility or diastolic relaxation, or both. Decreased cardiac function results in increased atrial and ventricular filling pressure, and pulmonary oedema occurs secondary to increased capillary pressure. The major causes of cardiomyopathy in infants and children include viral myocarditis, metabolic disorders and genetic defects.
TOF is a cyanotic lesion that results from pulmonary outflow tract obstruction and results in cyanotic spells with decreased pulmonary blood flow. Patients with TOF do not present with pulmonary oedema. The other components of TOF include an over-riding aorta, VSD and right ventricular (RV) hypertrophy.
Click to expand