Are ESR/CRP ratios helpful in differentiating West Nile encephalitis from non-West Nile virus meningitis/encephalitis?

West Nile encephalitis (WNE) may mimic other acute central nervous system infections in endemic areas. The laboratory diagnosis of WNE often takes several days. We review our recent experience of WNE to determine if the erythrocyte sedimentation rate/C-reaction protein ratio would be helpful in the early/presumptive diagnosis of WNE in hospitalized adults.

Ehrlichia chaffeensis presenting with bilateral anterior thigh pain (Louria's sign).

Bilateral anterior thigh pain may indicate bacteremia (Louria's Sign). We present a case of Ehrlichiosis due to Ehrlichia chaffeensis whose predominant presenting symptom was localized bilateral anterior thigh pain.

Recurrent fever of unknown origin (FUO): aseptic meningitis, hepatosplenomegaly, pericarditis and a double quotidian fever due to juvenile rheumatoid arthritis (JRA).

BACKGROUND: Fever of unknown origin (FUO) has been defined as a fever of ≥101°F that persists for 3 weeks or more. It is not readily diagnosed after 1 week of intensive in-hospital testing or after intensive outpatient or inpatient testing. Fevers of unknown origin may be caused by infectious diseases, malignancies, collagen vascular diseases, or a variety of miscellaneous disorders. The relative distribution of causes of FUOs is partly age-related. In the elderly, the preponderance of FUOs is attributable to neoplastic and infectious etiologies, whereas in children, collagen vascular diseases, neoplasms, and viral infectious disease predominate. The diagnostic approach to FUOs depends on a careful analysis of the history, physical findings, and laboratory tests. Most patients with FUOs exhibit localizing findings that should direct the diagnostic workup and limit diagnostic possibilities. The most perplexing causes of FUOs involve those without specific diagnostic tests, e.g., juvenile rheumatoid arthritis (JRA) or adult Still's disease. In a young adult with FUO, if all of the cardinal symptoms are present, JRA may present either a straightforward or an elusive diagnosis, if key findings are absent or if the diagnosis goes unsuspected. METHODS: We present a 19-year-old man with a recurrent FUO. His illness began 3 years before admission and has recurred twice since. In the past, he did not manifest arthralgias, arthritis, or a truncal rash. On admission, he presented with an FUO with hepatosplenomegaly, aseptic meningitis, and pericarditis. An extensive diagnostic workup ruled out lymphoma and leukemia. Moreover, a further extensive workup eliminated infectious causes of FUO appropriate to his clinical presentation, ie, tuberculosis, histoplasmosis, brucellosis, Q fever, typhoid fever, Epstein-Barr virus, infectious mononucleosis, cytomegalovirus, human herpes virus (HHV)-6, babesiosis, ehrlichiosis, viral hepatitis, and Whipple's disease. RESULTS: The diagnosis of JRA was based on the exclusion of infectious and neoplastic disorders in a young adult with hepatosplenomegaly, aseptic meningitis, pericarditis, and a double quotidian fever. With JRA, tests for rheumatic diseases are negative, as they were in this case. The only laboratory abnormalities in this patient included elevated serum transaminases, a mildly elevated erythrocyte sedimentation rate, and a moderately elevated level of serum ferritin. CONCLUSION: Diagnostic fever curves are most helpful in cases where the diagnosis is most elusive, as was the case here. Relatively few disorders are associated with a double quotidian fever, ie, visceral leishmaniasis, mixed malarial infections, right-sided gonococcal acute bacterial endocarditis, and JRA. Because the patient received antipyretics during the first week of admission, fever was not present. After infectious disease consultation during week 2 of hospitalization, antipyretics were discontinued, and a double quotidian fever was present, which provided the key diagnostic clue in this case.

Respiratory syncytial virus (RSV) community-acquired pneumonia (CAP) in a hospitalized adult with human immunodeficiency virus (HIV) mimicking influenza A and Pneumocystis (carinii) jiroveci pneumonia (PCP).

BACKGROUND: Respiratory syncytial virus (RSV) is an important cause of lower respiratory tract infections in young children, the elderly, and immunocompromised hosts, but RSV is a rare cause of community-acquired pneumonia (CAP) in hospitalized adults with human immunodeficiency virus (HIV). In patients with HIV, CAP is most frequently attributable to the usual bacterial respiratory pathogens that cause CAP in immunocompetent hosts, eg, Streptococcuspneumoniae or Hemophilus influenzae. Adults with HIV are also predisposed to intracellular CAP pathogens, ie, Mycoplasmatuberculosis, Salmonella spp., Pneumocystis (carinii) jiroveci (PCP), cytomegalovirus, and Legionella spp. This year, co-circulating in the community during influenza season were strains of human seasonal influenza A (H3N2) and swine influenza A (H1N1). During the influenza season, in adults hospitalized with HIV, the diagnostic possibilities should include influenza-like illnesses, eg, human parainfluenza virus types 3 and 4, human metapneumovirus, and pertussis. CASE REPORT: We present an adult with HIV, hospitalized for an influenza-like illness during influenza season. The differential diagnosis of CAP in this patient included influenza A and PCP. CONCLUSION: We report on an adult patient with HIV with CAP that mimicked influenza and PCP, and was attributable to RSV.

Legionella pneumophila community-acquired pneumonia (CAP) in a post-splenectomy patient with myelodysplastic syndrome (MDS).

Legionnaire's disease is a cause of community-acquired pneumonia (CAP) in normal hosts, but those with impaired cell-mediated immunity (CMI) and T-lymphocyte function are particularly predisposed to Legionella species CAP. Myelodysplastic syndrome (MDS) is a disorder of the elderly that is associated with impaired CMI. Cases of MDS or Legionella species CAP are rare. Splenectomized patients primarily have impaired humoral immunity and B-lymphocyte function, and, to a lesser extent, some decrease in CMI. For this reason, Legionnaire's disease has rarely been reported in splenectomized patients. We believe this to be the first reported case of Legionella pneumophila CAP in an asplenic patient with MDS.

Cryptococcal pneumonia in a patient with presumptive sarcoidosis and selective immunoglobulin A deficiency.

Sarcoidosis is a multisystem granulomatous disease of unknown cause associated with impaired T-lymphocyte function and impaired cell-mediated immunity. Decreased cell-mediated immunity predisposes one to intracellular pathogens (eg, cryptococci).

Transthoracic echocardiography (TTE): sufficiently sensitive screening test for native valve infective endocarditis (IE).

We recently reviewed our experience with paired transthoracic echocardiogram (TTE) and transesophageal echocardiogram (TEE) studies for the diagnosis of native valve infective endocarditis. In patients with normal heart valves, we demonstrated that a normal TTE effectively rules out infective endocarditis and a TTE is unnecessary. In patients with abnormal heart valves, a TEE did not enhance the diagnostic yield in most patients (12/15). We reviewed 87 paired TTEs and TEEs, that is, TEE with a preceding TTE performed for the evaluation of native valve IE. Of 87 paired echocardiograms, 72 of 87 had normal TTEs and TEEs, with no evidence of a vegetation indicative of infective endocarditis. A total of 15 of 87 TTEs had thickened/calcified valves without a definite vegetation. Of these, only 3 of 15 were subsequently shown to have a vegetation indicative of endocarditis by TEE. In patients with possible native valve infective endocarditis, before blood culture results are known, a negative TTE was sufficiently specific to rule out native valve infective endocarditis. Our data showed that the negative predictive value of a normal TTE in the evaluation of possible native valve endocarditis is 90% or greater. In those with some valve abnormality (ie, thickened/calcified heart valves), subsequent TTE did not materially increase vegetation detection.