EUH Resident Report: Conditions exhibiting fever without tachycardia/causes of fever with relative bradycardia

Bottom line:

Conditions exhibiting fever without tachycardia/causes of fever with relative bradycardia (listed in alphabetical order):  babesiosis, beta blockers, brucellosis (combination of signs is not common), central nervous system (CNS) lesions, Chagas’ disease, Coxiella burnetii, cytomegalovirus heterophile-negative mononucleosis, dengue fever, digitalis, drug fever, Ehrlichia canis, factitious fever, legionella, leptospirosis, lymphomas, acute malaria, meningococcemia and meningitis, mycoplasma, pheochromocytoma, pneumonia caused by Chlamydia sp., pneumonia caused by mycoplasma (combination of signs is not common), psittacosis, Q fever, respiratory syncytial virus (RSV), acute rheumatic fever, Rift Valley fever, Rocky Mountain spotted fever, Salmonella typhimurium, sepsis, typhoid fever (combination of signs is rare; also known as enteric fever), typhus, viral hemorrhagic fevers, yellow fever

References:

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Review of endocarditis due to HASEK (Haemophilus species, Actinobacillus, Cardiobacterium, Eikenella and Kingella species)

Raza, Sania S, Omer WSultan, and Muhammad RSohail. “Gram-negative bacterial endocarditis in adults: state-of-the-heart.” Expert review of anti-infective therapy 8.8 (2010):879-85.

 

Diantamoeba fragilis as a cause of gastrointestinal (GI) clinical symptoms such as diarrhea

Bottom line: Numerous reports from all over the world describe associations between diantamoeba fragilis and various GI symptoms, such as diarrhea.

Evidence:
Stark D, Barratt J, Roberts T, Marriott D, Harkness J, Ellis J. A review of the clinical presentation of dientamoebiasis. Am J Trop Med Hyg. 2010 Apr;82(4):614-619.
This review article states in its abstract, “Among 750 symptomatic and asymptomatic patients, Dientamoeba fragilis was detected at a prevalence of 5.2% and more common than Giardia intestinalis. Most infected patients presented with diarrhea and abdominal pain with symptoms greater than 2 weeks duration being common.”

Above article cites the following three articles.

Norberg A, Nord CE, Evengård B. Dientamoeba fragilis–a protozoal infection which may cause severe bowel distress. Clin Microbiol Infect. 2003 Jan;9(1):65-68.
This is a retrospective study of 87 patients diagnosed as being infected with the protozoan Dientamoeba fragilis. “A majority of the patients had symptoms of diarrhea, abdominal pain and flatus. The diarrhea varied from watery to loose, blood being reported only sporadically. Most patients had traveled outside Europe and had no other parasites in their stools. This study indicates potential pathologic properties in D. fragilis, and prospective studies are recommended.”

Johnson EH, Windsor JJ, Clark CG.  Emerging from obscurity: biological, clinical, and diagnostic aspects of Dientamoeba fragilis.  Clin Microbiol Rev. 2004 Jul;17(3):553-570. The opening lines of this review article’s abstract state, “Ever since its first description in 1918, Dientamoeba fragilis has struggled to gain recognition as a significant pathogen. There is little justification for this neglect, however, since there exists a growing body of case reports from numerous countries around the world that have linked this protozoal parasite to clinical manifestations such as diarrhea, abdominal pain, flatulence, and anorexia.”

Grendon JH, DiGiacomo RF, Frost FJ. Descriptive features of Dientamoeba fragilis infections. J Trop Med Hyg. 1995 Oct;98(5):309-315.
Abstract states, “A total of 237 cases of Dientamoeba fragilis were identified by a state public health laboratory in 1985 and 1986. Dientamoeba fragilis was the only parasite found in about two-thirds of the cases….Seventy-nine per cent of 70 interviewed D. fragilis cases reported symptoms associated with infection; nearly 80% had diarrhoea or loose stools.”

How do ACE inhibitors act to protect kidney function in the setting of HIV-associated nephropathy?

Bottom line:  ACE inhibitors protect kidney function by decreasing glomerular capillary pressure and by reducing exposure to proteins which could cause proliferation of mesangial cells and matrix.

Summary:  According to Goodman & Gilman’s Pharmacological Basis of Therapeutics [AccessMedicine], ACE inibitors mitigate glomerular injury by decreasing arterial blood pressure and dilating renal efferent arterioles, both of which decrease glomerular capillary pressure.  ACE inhibitors also increase “permeability selectivity of the filtering membrane” which then reduces exposure of the mesangium to proteins, which could stimulate mesangial cell and matrix production.  Reduced intrarenal levels of AngII can also inhibit mesangial cell growth.

Is klebsiella a typical pathogen associated with emphysematous cystitis?

Bottom line:  Klebsiella pneumonia is one of the gas-forming organisms most frequently associated with emphysematous cystitis.

SummaryAmano M, Shimizu T.  Emphysematous cystitis: a review of the literature.  Intern Med. 2014;53(2):79-82.

Emphysematous cystitis is a rare disease where microbes form gas inside the bladder wall and lumen.  Based on review of several case series, the authors identify the two major causative organisms:  Escherichia coli (60%) and Klebsiella pneumonia (10-20%).  This review addresses epidemiology, symptoms, diagnosis, treatment, and prevention.

What are the incidence, risk factors, etiology or mechanism of infection for group b streptococcal bacteremia?

Bottom line:  The incidence of invasive GBS disease is increasing and is associated with advanced age, black race, and diabetes. GBS accounts for about 1.3% of endocarditis cases in the U.S.

Summary: Skoff TH, et al. Increasing burden of invasive group B streptococcal disease in nonpregnant adults, 1990-2007. Clin Infect Dis. 2009 Jul 1;49(1):85-92. doi: 10.1086/599369.
This is a population-based study of group b streptoccus (GBS) disease in non-pregnant adults in selected counties in 10 US states. A case was defined as isolation of GBS from a normally sterile site in a non-pregnant adult age 18 and older who was a resident of the surveillance area.  Invasive GBS disease occurred more frequently in patients who are black or who have diabetes.
During 2007, 607 cases of GBS bacteremia without focus were identified. This translated into about 2.8 cases of GBS bacteremia per 100,000 during that year.
Also, age seems to play a role in GBS septicemia as the frequency was 43.2% in patients age 65 and older compared to those of the 18-39 (36.9%) or 40-64 (35.9%) age groups (p=0.017)

Bor DH, et al. Infective Endocarditis in the U.S., 1998–2009: A Nationwide Study. PLoS One. 2013; 8(3): e60033.
A study of 382,153 patients hospitalized with infective endocarditis from 1998 to 2009 in the US, 1.3% were caused by GBS.