Sandbox:Preeti

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Preeti Singh, M.B.B.S.[2]

			Pathophysiology	Symptoms	History	Physical Examination	Laboratory Findings
							Immunochemistry	Blood work	Biospy/CT/CXR
Infections	Bacterial	Syphilis	Syphilis is caused by a spirochete, Treponema pallidum. It has an average incubation period of 3 - 12 weeks. Spirochete penetrates intact mucous membrane or microscopic dermal abrasions and rapidly enters systemic circulation with the central nervous system being invaded during the early phase of infection. The histopathological hallmark findings are endarteritis and plasma cell-rich infiltrates reflecting a delayed-type of hypersensitivity reaction to the spirochete.	Primary syphilis Mononuclear leukocytic infiltration, macrophages, and lymphocytes Swelling and proliferation of small blood vessels Secondary syphilis Swelling and dilatation of blood vessels in the dermis Epidermal hyperplasia and neutrophilic infiltration Inflammatory cell infiltrate, predominantly plasma cell Tertiary syphilis Small vessel inflammation (endarteritis obliterans) Granulomatous lesions (gumma) containing central necrosis, inflammatory cells, such as lymphocytes, macrophages, plasma cells and fibroblasts.			A presumptive diagnosis of syphilis is possible with the use of two types of serologic tests. Nontreponemal tests (e.g., venereal disease research laboratory (VDRL) and rapid plasma reagent test) and Treponemal tests (e.g., fluorescent treponemal antibody absorbed (FTA-ABS) tests, the T. pallidum passive particle agglutination (TP-PA) assay, various enzyme immunoassays, and chemiluminescence immunoassays).		Darkfield examinations and tests to detect T. pallidum.
		Brucellosis	humans could be infected by eating undercook meat or raw dairy products, inhalation of the bacteria and direct contact of bacteria with skin wounds or mucous membranes. Following transmission, white blood cells phagocyte the pathogen and transports it via hematologic or lymphatic route to different organs specially to those of the reticuloendothelial system.	Fever Rash Abdominal pain weightloss Painful lymphadenopathy hepatosplenomegaly arthritis			Relative lymphocytosis positive titer of anti-brucella antibodies on serological testing There are two types of serological tests, based on: Antibody production against lipopolysaccharide Antibody production against other bacterial antigens		Brucella is most commonly isolated from blood cultures (blood cultures are positive between the 7th and 21st day)
	Viral	infectious mononucleosis
		cytomegalovirus
		human immunodeficiency virus
		cat scratch fever
	Mycobacterial	tuberculosis	Mostly in endemic areas	Symptoms include productive cough,night sweats, fever and weight loss			Sputum smear positive for acid-fast bacilliand nucleic acid amplification tests (NAAT) is used on sputum or any sterile fluid for rapid diagnosis and is positive for mycobacteria.		CXR and CT demonstrates cavities in the upper lobe of the lung
	Parasitic	toxoplasmosis
Autoimmune	Systemic lupus erythematosus
	Sjögren's syndrome
	Hydantoin derivatives
	Sarcoidosis		More common in African-American females Often asymptomatic except for enlarged lymph nodes Associated with restrictive lung disease Erythema nodosum Lupus pernio (skin lesions on face resembling lupus) Bell palsy Epithelioid granulomas containing microscopic Schaumann and asteroid bodies						On CXR bilateral adenopathy and coarse reticular opacities are seen. CT of the chest demonstrates extensive hilar and mediastinal adenopathy Additional findings on CT include fibrosis (honeycomb, linear, or associated with bronchial distortion), pleural thickening, and ground-glass opacities. Biopsy of lung shows non-caseatinggranuloma
Neoplasms	Hodgkin's disease
	Chronic lymphocytic leukemia
	Small cell carcinoma of the lung
	Malignant histiocytosis
	Melanoma
	Germ cell neoplasms
Other conditions	Reactive lymphoid hyperplasia
	Lymphomatoid granulomatosis
	Dermatopathic lymphadenopathy
	Angioimmunoblastic lymphadenopathy
	Giant lymph node hyperplasia (Castleman disease)