Regarding typical and incomplete (atypical) KD, which ONE of the following is the best option?
Answer: B: Infants <1 year or children >5 years of age are more likely to have incomplete KD than those between one and 4 years of age. Children with incomplete KD are also at risk for cardiovascular sequelae. Cervical lymphadenopathy is the cardinal manifestation most often absent in children with either complete or incomplete KD. Adenopathy is missing in up to 90% of children with incomplete disease versus 40–50% of those who met criteria for KD. Rash is not present in 50% of children with incomplete disease compared with 7–10% of children with typical KD. Peripheral extremity changes are absent in approximately 40% of incomplete KD cases. In comparison, only 15% of those with typical KD fail to develop palmar erythema, dorsal oedema or periungual desquamation. Mucous membrane changes are most characteristic of KD and present in more than 90% of children with either typical or incomplete disease.
The current approach to treatment is outlined in guidelines published by the American Heart Association and American Academy of Pediatrics, which strongly favour treatment with intravenous immunoglobulin and aspirin, even in doubtful cases. The reason for this is that the treatment is safe, and the complications of coronary artery aneurysms in untreated ‘doubtful’ or incomplete cases are truly disastrous. Children with a variety of other febrile conditions may receive IVIG treatment using these above mentioned guidelines. All children with incomplete KD, or fever >5 days who are young, should have a full lab work-up, including CRP and ESR, and one should have a low threshold to progress to urgent echocardiography to further evaluate the risk of coronary artery complications.
The following steps summarize the approach to fever >5 days and suspected incomplete KD:
The message is clear: take care in assessing the patient but have a low threshold to treat if you think the diagnosis could be KD.
References:
Regarding UTI in children, which ONE of the following is CORRECT?
Answer: D: A suprapubic aspirate (SPA) is the recommended gold standard test for diagnosing a UTI in children, particularly those who are young (<6 months) or unwell. It has high sensitivity and specificity and reliably rules out UTI in the setting of an unwell child with a fever without a source. The current recommended practice is to perform SPA with ultrasound guidance. The presence of five or more WBC/high-power field suggests an infection. The presence of 10 or more WBC/µL is also consistent with infection. Any growth of organisms is deemed to confirm a UTI as the bladder is meant to be sterile. An exception to this is culture positive Staphylococcus epidermidis, which usually represents a false positive from skin contamination. A catheter specimen of urine is the next best alternative (and favoured in the US), but is not as accurate and requires a pure growth of >1000 CFU to confirm a UTI. Midstream clean-catch urine specimens are adequate for older children who can provide them. More than 100,000 CFU/mL in a midstream clean-catch urine specimen is defined as a UTI.
A bag specimen is not reliable for the exclusion or diagnosis of UTI. It has a high false positive (60%) and a high false negative (15%) and should not be used to exclude UTI if the pretest likelihood of UTI is high, or when no obvious focus of infection has been found.
A urine specimen that is found to be positive on dipstick for nitrite, leukocyte esterase or blood may indicate a UTI. Dipstick tests have sensitivities approaching 85–90%. Dipstick tests should not be used as a rule-out test due to their high false negative rate of up to 20%. This may be due to a number of reasons, including infections with nitrite negative organisms, or very early infections where a sufficient inflammatory reaction has not yet resulted in a leukocytosis. Dipstick tests also produce false positive results in many other disorders including renal diseases, URTI and sterile pyuria (for example with abdominal pathology or KD.)
A renal ultrasound is usually performed in young children after a first UTI, especially those under 4 years of age. The main purpose of ultrasound is to exclude urinary tract obstruction or anatomical abnormality, in addition to assessment of previous renal scarring from possible vesicoureteric reflux. Unwell children or those under the age of 6 months require an inpatient ultrasound to exclude renal abscess or anatomical abnormality such as posterior urethral valves. Most other children <4 years should have their imaging as outpatients.
MCUG is utilized to visualize vesicoureteric reflux disease. The requirement to diagnose vesicoureteral reflux (VUR) is controversial and individual paediatricians have their preference for ordering or omitting this test. It may be done in children under 6 months of age (especially boys), and may be necessary for older children according to circumstances. MCUG should not be arranged from the ED, and discussion of the pros and cons of this with the parents can be undertaken at outpatient review.
Regarding meningitis in children, which ONE of the following is CORRECT?
Answer: B: Bonsu et al studied the use of peripheral WBC counts as a screen for need for LP in infants 3–89 days old. Of the 22 cases of bacterial meningitis, 41% had peripheral WBC counts between 5000 and 15,000 (low risk according to Philadelphia and Rochester criteria), and 64% had peripheral WBC counts between 5000 and 20,000 (low risk according to Boston criteria). They concluded that LPs of febrile infants should not be omitted based on the results of peripheral WBC counts.
The common causes of bacterial meningitis in children 1 month to 12 years of age are N. meningitidis, S. pneumoniae and H. influenzae type b. Specific host defense defects due to altered immunoglobulin production in response to encapsulated pathogens result in increased risk of bacterial meningitis (e.g. IgG subclass deficiency). Defects of the complement system (C5–C8) have been associated with recurrent meningococcal infection. Splenic dysfunction (sickle cell anaemia) or asplenia (due to trauma, or congenital defect) is associated with an increased risk of pneumococcal, H. influenzae type b (to some extent) and, rarely, meningococcal sepsis and meningitis. Congenital or acquired CSF leak across a mucocutaneous barrier, such as cranial or midline facial defects (cribriform plate), or CSF leakage through a rupture of the meninges due to a basal skull fracture into the cribriform plate or paranasal sinus, is associated with an increased risk of pneumococcal meningitis. The risk of bacterial meningitis caused by S. pneumoniae in children with cochlear implants is more than 30 times the risk in the general population.
Meningococcal routine vaccination in Australia only involves protection against meningococcal C. Infections by strains A, C, W135 and Y are vaccine preventable in older children and adults. They are polysaccharide vaccines that give short-term protection against serogroups A, C, W135 and Y and are mainly used for travellers to regions where serogroup A and W135 infections are prevalent, but they can also be used in outbreak control. The B strain currently causes most cases of Neisseria related meningitis and there is no vaccine against this serotype.
Regarding the clinical manifestation of meningitis in children, which ONE of the following is TRUE?
Answer: D: Meningitis presents in two patterns:
Meningeal irritation is manifested as nuchal rigidity, back pain, Kernig’s sign (flexion of the hip 90 degrees with subsequent pain with extension of the leg) and Brudzinski’s sign (involuntary flexion of the knees and hips after passive flexion of the neck while supine). However, Kernig’s and Brudzinski’s signs are not reliable in those younger than 12–18 months. Increased ICP is suggested by headache, emesis, bulging fontanel or diastasis (widening) of the sutures, oculomotor (anisocoria, ptosis) or abducens nerve paralysis, hypertension with bradycardia, apnoea or hyperventilation, decorticate or decerebrate posturing, stupor, coma or signs of herniation. Papilloedema is uncommon in uncomplicated meningitis and suggests a more chronic process such as intracranial abscess, subdural empyema or occlusion of a dural venous sinus. Cranial neuropathies of the ocular, oculomotor, abducens, facial and auditory nerves may also be due to focal inflammation. Around 10–20% of children with bacterial meningitis have focal neurologic signs. Seizures (focal or generalized) occur in 20–30% of patients with meningitis.
Reference:
Regarding CSF findings in suspected meningitis in children, which ONE of the following is INCORRECT?
Answer: C: Many organisms other than the typical bacterial agents cause meningitis syndromes: Mycobacterium tuberculosis, Nocardia spp, Treponema pallidum (syphilis) and Borrelia burgdorferi (Lyme disease); fungi, such as those endemic to specific geographic areas (Coccidioides, Histoplasma and Blastomyces) and those responsible for infections in compromised hosts (Candida, Cryptococcus and Aspergillus); parasites, such as Toxoplasma gondii and those that cause cysticercosis; and, most frequently, viruses (enteroviruses – coxsackie, echo, entero, herpes viruses, varicella, Epstein-Barr virus (EBV), CMV, influenza, measles, mumps and rubella).
Focal infections of the CNS including brain abscess and parameningeal abscess (subdural empyema, cranial and spinal epidural abscess) may also be confused with meningitis. In addition, noninfectious illnesses can cause generalized inflammation of the CNS. Relative to infections, these disorders are uncommon and include malignancy, collagen vascular syndromes and exposure to toxins.
Careful examination of the CSF may indicate the specific cause with specific stains (Kinyoun carbol fuchsin for mycobacteria, India ink for fungi), cytology, antigen detection (Cryptococcus), serology (syphilis, West Nile virus, arboviruses), viral culture (enterovirus) and polymerase chain reaction (HSV, enterovirus and others). PCR of the CSF has a sensitivity of 95 to 100% for HSV type 1, EBV and enterovirus. There is a wide range of variability in the sensitivity (54 to 100%) for PCR testing for tuberculous meningitis, with a specificity of 94–100%, and it could replace acid-fast bacillus smear and culture as the test of choice. PCR is also sensitive for acute neurosyphilis but not for more chronic forms.
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