Fever of unknown origin: subacute thyroiditis versus typhoid fever.

Fever of unknown origin (FUO) is not infrequently a diagnostic dilemma for clinicians. Common infectious causes include endocarditis and abscesses in adults, and noninfectious causes include neoplasms and certain collagen vascular diseases, for example, polymyalgia rheumatica, various vasculitides, and juvenile rheumatoid arthritis (adult Still's disease). Subacute thyroiditis is a rare cause of FUO. Among the infectious causes of FUO, typhoid fever is relatively uncommon. We present a case of FUO in a traveler returning from India whose initial complaints were that of left-sided neck pain and angle of the jaw pain, which initially suggested the diagnosis of subacute thyroiditis. After an extensive FUO workup, when typhoid fever is a likely diagnostic possibility, an empiric trial of anti- Salmonella therapy has diagnostic and therapeutic significance. The presence of relative bradycardia, and response to quinolone therapy, was the basis of the clinical diagnosis of typhoid fever as the explanation for this patients FUO. This case illustrates the diagnostic difficulties in assessing patients with FUO with few diagnostic findings.

Haemophilus parainfluenzae mitral prosthetic valve endocarditis in an intravenous drug abuser.

Haemophilus species are an infrequent cause of subacute bacterial endocarditis. Of the Haemophilus species causing endocarditis, H. aphrophilus and H. parainfluenzae are more frequent causes of subacute bacterial endocarditis than H. influenzae. H. parainfluenzae requires growth factor V (nicotinamide adenine dinucleotide) and grows very slowly on routine culture media. H. parainfluenzae is a rare cause of "culture negative" endocarditis because it is a slow-growing organism. We present a case of a 42-year-old intravenous drug abuser with H. parainfluenzae mitral prosthetic valve endocarditis. To the best of our knowledge, this is the first case of mitral prosthetic valve endocarditis caused by H. parainfluenzae in an intravenous drug abuser.

West Nile viral encephalitis mimicking hepatic encephalopathy.

West Nile encephalitis (WNE) has become endemic in the United States since 1999. The clinical spectrum of WNE includes aseptic meningitis, meningoencephalitis, or encephalitis with or without flaccid paralysis. The severity of WNE ranges from asymptomatic serum conversion to severe neurologic deficits or a fatal outcome. Several systemic disorders may present with encephalitis as part of the clinical presentation, for example, Legionnaires' disease, neoplasms with metastases to the central nervous system, Mycoplasma meningoencephalitis, brucellosis, Listeria, Rocky Mountain spotted fever, ehrlichiosis, and malaria. The most common infectious causes of encephalitis that need to be differentiated from WNE include herpes simplex virus 1, meningoencephalitis, and enteroviral meningoencephalitis. We present a case of apparent hepatic encephalopathy secondary to pancreatic carcinoma with liver involvement that presented as hepatic encephalopathy mimicking WNE. We conclude that patients presenting with encephalitis in the summer months should have serum/cerebrospinal fluid serologic studies sent for WNE even if an alternate explanation seems to explain the clinical syndrome.

Salmonella paratyphi A enteric fever mimicking viral meningitis.

Enteric fevers are caused by invasive strains of Salmonella. Classic enteric fever is caused by S. typhi and usually less severe enteric fevers are caused by S. paratyphi A, B, or C. We present a case of S. paratyphi A enteric fever aseptic meningitis. Headache was so prominent in the case presented that a lumbar puncture was performed to rule out meningitis. Rose spots were not apparent in this dark-skinned patient. Our patient did not have increased serum transaminases and did not have leukopenia, which are common findings in enteric fever. The absence of these findings and the relative bradycardia may be explained by the antimicrobial therapy the patient received before admission. After ruling out malaria, clinicians should suspect enteric fever in patients recently returning from endemic areas, in patients presenting with acute fevers without localizing signs.