BRUCELLOSIS

Question 1

Organism

Answer 1

Brucella are aerobic, non-spore-forming, non-motile, gram-negative coccobacilli

Question 2

Etiology

Answer 2

🌚Brucellosis is an important zoonotic disease that result either from direct contact with an infected animal or by consumption of their meat or products (especially unpasteurized milk products),
😡 it also may occur by inoculation through cuts or conjunctiva, or by inhalation of infectious aerosols.

Question 3

Pathology

Answer 3

😁The major virulence factor for Brucella appears to be the smooth lipopolysaccharide (LPS) of its cell wall which makes it more resistant to killing by PMN
😃 because these organisms are facultative intracellular pathogens, they can survive and replicate within the mononuclear phagocytic cells of the RES resulting in granuloma formation.

Question 4

Clinical menifestation

Answer 4

😰 The incubation period is 2-4 wk.

😆Hx. Symptoms are usually non-specific & vague e.g. fever, night sweats, anorexia, headache, fatigue, arthralgia, rash, abdominal pain, diarrhea, vomiting, cough, and pharyngitis.

😆Some patients may present with only FUO

😆but the most consistent part of hx is the direct contact with an infected animal or by consumption of their meat or products.

🧐🧐Ex. Pyrexia, pallor, skin rash, arthritis (especially spine), LAP, & hepatosplenomegaly.

Question 5

Investigations

Answer 5

 CBP; Pancytopenia, i.e. anemia, neutropenia, & thrombocytopenia.

 Culture of blood or any tissue of the RES (e.g. liver, spleen, lymph nodes, or BM) is the gold standard in Dx,

 Serology; Serum Agglutination Test (SAT) or Brucella Agglutination Test (BAT)

 ELISA is more sensitive but less specific than SAT.

 PCR is very sensitive & specific.

Question 6

TX

Answer 6

 Children < 8 yr are usually treated with Trimethiprim (10 mg/kg)- Selphamethoxolon(50 mg/kg) + Rifampin (15-20 mg/kg).

 Children > 8 yr are usually treated with Doxycycline (2-4 mg/kg) + Rifampin [or Streptomycin (20-30 mg/kg) or Gentamicin (3-5 mg/kg)].

All drugs should be given for 6 wk except Aminoglycosides for 2 wk.

 Patients with Cxs e.g. osteomyelitis, endocarditis, or meningitis should be treated with Doxycycline + Gentamicin +/_ Rifampin for 4-6 mo (except gentamicin for 1-2 wk).

Note: Patients should be complaint with this prolong therapy to reduce the relapse rate.