Can the pattern of vertebral marrow oedema differentiate intervertebral disc infection from degenerative changes?

AIM: To evaluate whether various patterns of bone marrow oedema could be used to discriminate between infection and degenerative change. MATERIALS AND METHODS: Seventy patients with imaging features suspicious for discitis and available clinical follow-up were blindly reviewed for vertebral marrow oedema on sagittal short-tau inversion recovery (STIR) images according to the following patterns: I, vertebra oedema is adjacent to the intervertebral space and sharply-marginated; II, vertebral oedema is adjacent to the intervertebral space but not sharply marginated from normal marrow or involves the entire vertebral body; and III, vertebral oedema is distant from the endplate with intervening hypointense marrow signal. RESULTS: Of 45 patients with a clinical diagnosis of discitis, pattern II was the most common oedema pattern (64%). Approximately 20% and 9% of discitis patients showed patterns I and III, respectively. In patients with degenerative changes, 44% patients showed pattern I, 32% showed pattern II, and 24% showed pattern III. Pattern II had a sensitivity, specificity, and positive predictive value of 0.64, 0.68, and 0.78 for diagnosing spine infection, respectively. CONCLUSIONS: Although bone marrow oedema in infective discitis most often extends from the disc space and has indistinct margins, the oedema may also have sharp margins or be remote from the involved intervertebral space. Bone marrow oedema patterns of infective discitis overlap with those of degenerative disease and are not sufficiently reliable to exclude infection in cases with magnetic resonance imaging findings suggestive of discitis.

3D T2 MR Imaging-Based Measurements of the Posterior Cervical Thecal Sac in Flexion and Extension for Cervical Puncture.

BACKGROUND AND PURPOSE: The current standard technique for cervical puncture involves prone positioning with neck extension. The purpose of this study was to compare measurements of the posterior cervical thecal sac during neck flexion and extension in supine and prone positions by using high-resolution MR imaging to help determine the optimal positioning for cervical puncture. MATERIALS AND METHODS: High-resolution T2-weighted MR imaging was performed of the cervical spine in 10 adult volunteers 18 years of age and older. Exclusion criteria included the following: a history of cervical spine injury/surgery, neck pain, and degenerative spondylosis. Images of sagittal 3D sampling perfection with application-optimized contrasts by using different flip angle evolutions were obtained in the following neck positions: supine extension, supine flexion, prone extension, and prone flexion. The degree of neck flexion and extension and the distance from the posterior margin of the spinal cord to the posterior aspect of the C1-C2 thecal sac were measured in each position. RESULTS: The mean anteroposterior size of the posterior C1-C2 thecal sac was as follows: 4.76 mm for supine extension, 3.63 mm for supine flexion, 5.00 mm for prone extension, and 4.00 mm for prone flexion. Neck extension yielded a larger CSF space than flexion, independent of supine/prone positioning. There was no correlation with neck angle and thecal sac size. CONCLUSIONS: The posterior C1-C2 thecal sac is larger with neck extension than flexion, independent of prone or supine positioning. Given that this space is the target for cervical puncture, findings suggest that extension is the ideal position for performing the procedure, and the decision for prone-versus-supine positioning can be made on the basis of operator comfort and patient preference/ability.

Enlargement of the proximal pituitary stalk associated with spontaneous recovery from multiple pituitary hormone deficiencies.

We report the case of a child with multiple pituitary hormone deficiencies and a truncated pituitary stalk on MR imaging who had recovery of normal secretion of pituitary hormones in early adulthood. Follow-up MR imaging examination after recovery revealed marked enlargement of the proximal pituitary stalk. The case of our patient helps to explain the mechanism whereby some patients experience recovery of hormonal function.

Acute liver failure caused by isoniazid in a child receiving carbamazepine.

We report a case of a 10-year-old boy, being treated for seizures with carbamazepine, who developed acute liver failure within four days of initiation of therapy for suspected tuberculosis with isoniazid, rifampin, pyrazinamide, and ethambutol. Isoniazid-induced liver disease was diagnosed. The likely role of carbamazepine and rifampin in potentiating the hepatotoxicity of isoniazid, and the importance of early recognition of isoniazid-induced liver disease, are discussed.

Quadriplegia complicating Escherichia coli meningitis in a newborn infant: case report and review of 22 cases of spinal cord dysfunction in patients with acute bacterial meningitis.

We report a case of Escherichia coli meningitis complicated by spinal cord dysfunction in a neonate. This very rare complication of bacterial meningitis was probably caused by ischemia of the cord resulting from vasculitis. We review the 22 other reports of patients with this complication and discuss its pathogenesis.

Hepatosplenic cat-scratch disease and abdominal pain.

BACKGROUND: There have been several recent reports that cat-scratch disease (CSD) causes a multiplicity of atypical clinical syndromes. We recently diagnosed hepatosplenic CSD in a child who was seen with fever and abdominal pain. We report this case and 10 other patients with hepatosplenic CSD and highlight the importance of abdominal pain in this clinical entity. METHODS: This was a retrospective review of charts of patients with a diagnosis of cat-scratch disease at Egleston Children's Hospital between January, 1985, and June, 1996. From these cases patients with hepatosplenic CSD were selected for study. RESULTS: Seven children (64%) had significant abdominal pain, and in three children abdominal pain was their chief complaint. All children in the study had pathologic evidence of CSD or elevated titers of antibodies to Bartonella henselae. Ultrasound examination showed that all children had microabscesses in the spleen, and eight had abscesses in the liver. CONCLUSIONS: One of the most remarkable findings in this large series of cases of hepatosplenic CSD was that 64% of the patients complained of abdominal pain. All children in this study received antibiotics. It was our clinical impression that once antibiotics had been started, the patients appeared to improve very quickly. With an increased index of suspicion, the use of B. henselae serology and an abdominal ultrasound examination, the diagnosis of this underrecognized disease might be more readily made.

Evolution of extended-spectrum beta-lactam resistance (SHV-8) in a strain of Escherichia coli during multiple episodes of bacteremia.

Nine isolates of Escherichia coli were recovered from seven blood cultures over a period of 3 months from a 19-month-old female with aplastic anemia. Initial isolates were susceptible to extended-spectrum cephalosporins, including ceftazidime (MIC, < or = 0.25 microgram/ml), but gradually became resistant to this drug (MICs, > or = 128 micrograms/ml) and other cephalosporins and the monobactam aztreonam. Molecular typing methods, including plasmid profile analysis, pulsed-field gel electrophoresis, and arbitrarily primed PCR, indicated that the nine isolates were derived from a common ancestor. Dot blot hybridization and PCR analysis of total bacterial DNA using blaSHV- and blaTEM-specific DNA probes and primers identified the presence of a blaTEM beta-lactamase gene in all of the isolates and a blaSHV gene in the isolates with elevated ceftazidime MICs. Isoelectric focusing analysis of crude lysates showed that all nine isolates contained an enzyme with a pI of 5.4 corresponding to the TEM-1 beta-lactamase, and those isolates containing an SHV-type beta-lactamase demonstrated an additional band with a pI of 7.6. The first of the ceftazidime-resistant isolates appeared to hyperproduce the SHV enzyme compared to the other resistant isolates. DNA sequencing revealed a blaSHV-1 gene in the first ceftazidime-resistant isolate and a novel blaSHV gene, blaSHV-8, with an Asp-to-Asn substitution at amino acid position 179 in the remaining four isolates. Three of the ceftazidime-resistant isolates also showed a change in porin profile. The patient had received multiple courses of antimicrobial agents during her illness, including multiple courses of ceftazidime. This collection of blood isolates from the same patient appears to represent the in vivo evolution of resistance under selective pressure of treatment with various cephalosporins.

Neonatal Torulopsis glabrata fungemia.

Torulopsis glabrata is a yeastlike fungus that has recently become recognized as an important opportunistic pathogen. Only four cases of T glabrata infection in neonates have been reported. We report two cases of fungemia caused by this organism in premature infants. Both patients were treated with amphotericin B and survived the fungemia, but one patient later died of bacterial sepsis. Both patients had been treated with surfactant, artificial ventilation, intravascular catheters (arterial and venous), broad spectrum antibiotics, and hyperalimentation, which appear to be risk factors for T glabrata fungemia. A review of the literature indicates that T glabrata is susceptible to amphotericin B and 5-fluorocytosine and is resistant to fluconazole. In addition, it is less susceptible to ketoconazole, clotrimazole, and itraconazole than is Candida albicans. We recommend that T glabrata infections be treated initially by reducing iatrogenic risk factors and beginning amphotericin B therapy. If necessary, 5-fluorocytosine should be added to the drug regimen.

Antibiotic resistance in bacteria.

Antibiotic resistance in bacteria has emerged as a medical catastrophe. This results from the speed at which bacteria multiply and are spread, and the ease with which they can change their genetic material or acquire new genes. They exert biochemical resistance by preventing entry of the drug, by rapidly extruding the drug, or by enzymatically inactivating the drug or altering its molecular target. The presence of antibiotics in the internal environments of human beings and animals provides a selective pressure for any resistant organisms to become predominant. Examples of antibiotic resistance in several important human pathogens are Streptococcus pneumoniae, enterococci, staphylococci, enteric bacilli, Haemophilus influenzae, Neisseria gonorrhoeae, Neisseria meningitidis, and Mycobacterium tuberculosis.

Infective endocarditis in neonates.

We studied retrospectively the predisposing factors and signs of infective endocarditis (IE) in neonates and infants younger than 3 months of age, and we suggest diagnostic criteria. The charts of 16 infants less than 3 months of age, diagnosed with IE during a 5-year period, were reviewed for possible maternal and infant risk factors and for pathognomonic clinical and laboratory features. No apparent maternal risk factors were noted. Infant risk factors were congenital heart disease (4), patent ductus arteriosus (PDA) (5), and the use of central venous catheters (14). The main clinical findings were cardiac murmurs (12), petechiae (2), skin abscesses (7), arthritis (2), hepatomegaly (9), and splenomegaly (2). Echocardiography revealed a mass or vegetation in nine patients. Of the 27 microorganisms isolated from blood, the most common were staphylococci (15) and Candida sp. (6). Urine cultures were positive in six patients and cerebrospinal fluid cultures were positive in one. Other laboratory findings were not of diagnostic value. We conclude that the main risk factors for neonatal IE are central venous catheters and congenital heart disease, including PDA. The main causative microorganisms are staphylococci and Candida sp. The main investigations of diagnostic value are blood and urine cultures and echocardiography. We propose the diagnostic categories of definite, probable, and possible cases of neonatal IE, based primarily on clinical, blood culture, and echocardiographic data.

Third generation cephalosporin-resistant gram-negative bacilli in the feces of hospitalized children.

In view of the widespread use of third generation cephalosporins in hospitalized infants, we attempted to determine whether their use was associated with the emergence of resistance in fecal Gram-negative bacilli. Stools from infants hospitalized for varying durations were cultured on MacConkey agar containing 4 micrograms/ml of cefotaxime. All isolates growing on this medium were identified and their susceptibilities to 29 antimicrobial agents were determined. Sixty-five infants were studied of whom 44 were receiving a third generation cephalosporin, 7 another antibiotic and 14 no antibiotic. Thirty-one strains resistant to third generation cephalosporins (minimal inhibitory concentrations > or = 16 micrograms/ml) to cefotaxime, ceftriaxone or ceftazidine) were isolated from 26 infants. The proportions of infants with resistant strains were not significantly different whether they were: (1) receiving a third generation cephalosporin or not; (2) hospitalized for longer or shorter than 2 days or not; (3) older or younger than 3 months or not. Notably 8 infants harbored resistant strains within 24 hours of admission. The commonest resistant strains isolated belonged to the genera Enterobacter (10), Citrobacter (6), Serratia (3), Cedecea (3) and Chromobacterium (3). In conclusion hospitalized infants had a high incidence of fecal colonization with Gram-negative bacilli resistant to third generation cephalosporins. These bacteria were predominantly those known to produce broad spectrum beta-lactamases. This colonization was not necessarily associated with the infant receiving such antibiotics or with prolonged hospitalization.

Hemolysis and infection: categories and mechanisms of their interrelationship.

Different cause-and-effect relationships between hemolytic and infectious processes are categorized in a clinically useful manner as follows: infections causing hemolysis by invasion of red blood cells (RBCs), by hemolysins, or by immune mechanisms; oxidative damage to RBCs during infections; hemolysis secondary to infection-induced pathologic processes; hemolytic effects of antimicrobial therapy; and predisposition of an individual to infection caused by an underlying hemolytic disorder or therapy for that disorder. The mechanisms of these interrelationships are discussed in detail.

Spread of non-typable multiply resistant Haemophilus influenzae in a South African hospital.

In July 1987 non-typable Haemophilus influenzae strains resistant to both ampicillin and chloramphenicol were isolated from the endotracheal aspirate of two children with pneumonia at Baragwanath Hospital, Johannesburg, South Africa. A study was therefore undertaken to determine the carriage rates of Haemophilus influenzae strains in the nasopharynx of children and staff in the index ward and in three control wards. Using a disc diffusion and an agar dilution method the susceptibility was determined of 100 isolates to ampicillin, chloramphenicol, erythromycin, rifampicin, amoxicillin/clavulanic acid, gentamicin, cefaclor, cefotaxime, tetracycline, sulphamethoxazole, trimethoprim and trimethoprim/sulphamethoxazole (1:19). The overall carriage rate of Haemophilus influenzae on admission was 76%. In the index ward, children carrying multiply resistant strains differed from the other children in that there was a longer mean duration of hospitalization, a lower proportion of males, and a higher proportion who had previously received antibiotics. All ampicillin resistant strains were shown to produce beta-lactamase. Only four isolates belonged to serotype b, of which three were ampicillin resistant and chloramphenicol sensitive while one was resistant to both drugs. Nasopharyngeal spread of resistant non-typable strains of Haemophilus influenzae was demonstrated to affect the management of paediatric patients in the hospital.

Infective endocarditis in black South African children: report of 10 cases with some unusual features.

Ten black South African children with infective endocarditis seen over a 2-year period are reported. In five cases, including two neonates, the infection was nosocomial and in five cases it occurred in children with previously normal hearts. Of the bacteria isolated from nine cases, five were Staphylococcus aureus (all from nosocomial cases), one was Haemophilus influenzae and three were corynebacteria. The unusual aspects of this series are discussed, with an emphasis on preventing nosocomial cases and on making the diagnosis in children without underlying heart disease.