Stacy E. F. Melanson, Author at Neurology Advisor

Stacy E. F. Melanson

All articles by Stacy E. F. Melanson

Respiratory Alkalosis: Arterial Blood pH Increased with Decreased Arterial pCO and Decreased Arterial H2CO3-

Differential Diagnosis Hyperventilation in response to hypoxemia from a variety of causes Hyperventilation without hypoxemia as a stimulus, as in anxiety and CNS disorders that increase the respiratory rate Suggested Additional Lab Testing Follow arterial pH, pco2, and h2co3 as the disorder worsens or resolves.

Respiratory Acidosis: Low Arterial Blood pH with Increased Arterial pCO2 and Arterial H2CO3- Increased

Differential Diagnosis Neuromuscular disorders that decrease breathing, as produced by brain stem injury, myasthenia gravis, and poliomyelitis If sufficiently severe, multiple non-neuromuscular causes of impaired ventilation, perfusion, or gas diffusion produced by embolism, infection, selected cancers, asthma, bronchitis, and emphysema. Suggested Additional Lab Testing Serial blood gases to assess arterial pH, arterial pco2 and arterial…

Positive Serologic Test for Hepatitis C Virus (HCV)

Differential Diagnosis Hepatitis C virus infection False-positive serologic test for hepatitis C Suggested Additional Lab Testing Acute hepatitis C Elevated liver function tests are expected with positive tests for anti-HCV by a variety of methods. Result may not become positive until 12-16 weeks after exposure. Patients are typically positive for HCV RNA within 4 weeks…

Positive Serologic Test for Hepatitis B Virus (HBV)

Differential Diagnosis Hepatitis B virus infection False-positive serologic test for hepatitis B virus Suggested Additional Lab Testing Acute hepatitis B Patient is positive for IgM antibody to HBV core antigen. Patient is usually positive for hepatitis B surface antigen and hepatitis B virus e antigen. Presence of the e antigen indicates a high degree of…

Positive Serologic Test for

Differential Diagnosis Gastric ulcer Duodenal ulcer Suggested Additional Lab Testing For gastric ulcer: Endoscopy to visualize the ulcer; biopsy of the lesion is recommended to determine if patient has gastric adenocarcinoma. Rapid urease test of biopsy material (CLO test) verifies the presence of active infection. For duodenal ulcer disease: Urea breath test is a sensitive…

Positive Screening Test for HIV

Differential Diagnosis Patient has an HIV infection. Screening test is a false-positive; there is no HIV infection. Suggested Additional Lab Testing Western blot Most important test for patient with a positive HIV screening test Will determine if patient has antibodies to specific HIV-associated proteins Will confirm or refute a diagnosis of HIV infection. CD4 count…

Positive Anti-Nuclear Antibody (ANA) Test

Differential Diagnosis Systemic lupus erythematosus (SLE): when active, usually a homogenous pattern on ANA or less commonly speckled, rim, or nucleolar when present in high enough titer to be clinically significant Sjögren syndrome: common ANA pattern is speckled; less commonly homogenous Scleroderma or systemic sclerosis: ANA pattern is most commonly speckled, followed by centromeric and…

Monoclonal Protein on Serum Protein Electrophoresis (M Component)

Differential Diagnosis Multiple myeloma Waldenstrom macroglobulinemia Monoclonal gammopathy of unknown significance (MGUS) Low concentration of monoclonal immunoglobulins (LCMI) Heavy chain disease Suggested Additional Lab Testing For multiple myeloma: In addition to SPEP followed by immunofixation, quantitative serum immunoglobulin should be performed, because the M component must be greater than3 g/dL in the serum. Bone marrow…

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