Friday, August 5, 2011

Pyrexia of unknown origin "PUO"

n      Definition:
n      A case presented with pyrexia as a predominant clinical feature of 10 days or longer duration without an obvious cause.
n      It may be acute (if pyrexia persists for few days) or chronic (if pyrexia persists for 3 weeks or longer).
n      I- Infective:
n      A) Non specific e.g:
n      Cryptic abscesses in liver, abdomin, pelvis and retroperitoneal or mediastinal sites.
n      Infective endocarditis.
n      Urinary tract infection.
n      Ear, sinus or dental infections.
n      Osteomyelitis.
n      B) Specific      e.g:
n      Bacterial: T.B., brucellosis, typhoid F., leptospirosis (Weil’s disease), secondary syphilis.
n      Viral: viral hepatitis, glandular fever, yellow fever, CMV, HIV.
n      Rickettsial: typhus and Q fever.
n      Chlamydial and Bortonella: psittacosis and cat scratch fever.
n      Fungal: candidiasis, histoplasmosis, cryptococcosis and aspergillosis.
n      Protozoal: malaria, amaebiasis, toxoplasmosis, trypanosomiasis and leishmaniasis.
n      Helminthic: filariasis and fasciola.
n      II- Non-infective:
n      Haematological: e.g leukemia, purpura, haemolytic anaemia and lymphoma.
n      Autoimmune and collagen: e.g rheumatic fever, rheumatoid arthritis, SLE, polyarteritis nodosa, dermatomyositis and ulcerative colitis.
n       Endocrine: e.g thyrotoxicosis and familial mediteranean fever.
n      Malignancy: sarcoma, carcinoma, hepatoma and hypernephroma.
n      Miscellaneous:
n      Liver cirrhosis and alcoholic hepatitis.
n      Gout (rare).
n      Granulomas e.g sarcoidosis, Crohn's disease.
n      Drug reaction.
n      CNS abnormalities e.g infiltration of heat regulating center in hypothalamus by neoplasm or granuloma (rare).
n      Malingering.
Laboratory Diagnosis
n      Haematological:
n      Hb for anaemia.
n      Platelets for purpura.
n      WBCs: total and differential count.
n      Neutrophilia in pyrogenic infection.
n      Neutropenia in malaria; typhoid; leishmaniasis and SLE.
n      Lymphocytosis in viral infection, typhoid and brucellosis.
n      Monocytosis in TB; atypical monocytes in IMN.
n      Blast cells in leukemia.
n      Thin and thick blood film in malaria; filaria; trypanosomiasis.
n      ESR: > 100 mm/h in T.B; collagen and malignancy.
n      Microbiological:
n      Blood culture for typhoid, brucellosis, leptospirosis and infective endocarditis.
n      Urine and stool culture for UTI, gastrointestinal infections, salmonellosis, brucellosis, leptospirosis. In sterile pyuria: T.B. of genitourinary tract is suspected.
n      Throat swab if rheumatic fever is suspected, negative culture not exclude rheumatic fever.
n      Bone marrow culture for typhoid, brucellosis, T.B.
n      Serology:
n      Paired serum samples are required to look for rising antibody titer four folds. Occasionally, a single high titer maybe suggestive of recent infection e.g IgM for toxoplasma.
n      Some serological tests for diagnosing PUO:
n      Widal test for typhoid (diagnostic titre > 1/80).
n      Brucella agglutination and CFT (diagnostic titre >1/80).
n      ASO titre for rheumatic fever (diagnostic titre > 250 Todds U/ml).
n      Latex co-agglutination to detect Ag as Streptococcal, Staph. species, Neisseria, Candida and Rota viruses.
n      ELISA techniques for detection of microbial antigens e.g. Chlamydial Ag, HB Ag & HIV Ag and microbial antibodies e.g. CMV Ab, HBAb and T.B. (IgA, IgG, IgM).
n      Fluorescent treponemal antibody, fluorescent amaebic antibody and fluorescent leishmanial antibody test.
n      PCR technique for HCV-RNA, HBV-DNA, T.B-DNA, CMV & HSV.

n      3) Biochemical:
n      Liver function tests.
n      Thyroid function tests.
n      Alpha Feto Protein (AFP) for hepatoma.
n      Uric acid for gout.
n      C) Biopsy:
n      Bone marrow, lymph nodes, liver and transbronchial lung biopsies for culture and cytology.
n      D) Skin tests: e.g
n      Mantoux test for TB.
n      Kveim test for sarcoidosis.
n      Histoplasmin test for Histoplasmosis.
n      Frei test for Chlamydia (lymphogranuloma venereum).

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