associated with longer duration of diabetes, poorer glycemic control, higher BP, advanced retinopathy and neuropathy, subsequent renal failure , and increased vascular damage and risk for cardiovascular disease.
Blood ammonia is increased in 90% of patients but does not reflect the degree of coma. Normal level in comatose patient suggests another cause of coma. Not reliable for diagnosis but may be useful to follow individual
AST:ALT ratio >1 associated with AST <300 U/L will identify 90% of patients with alcoholic liver disease; is particularly useful for differentiation from viral hepatitis, in which increase of AST and ALT are about the same.
Anemia in >50% of patients may be macrocytic (folic acid or vitamin B12 deficiency), microcytic (iron deficiency), mixed, or hemolytic.
In acute alcoholic hepatitis, GGT level is usually higher than AST level. GGT is often abnormal in alcoholics even with normal liver histology. Is more useful as index of occult alcoholism
-In patients with signs of acute pancreatitis, pancreatitis is highly likely (clinical specificity = 85%) when lipase ≥5× URL, if values change significantly with time, and if amylase and lipase changes are concordant.
-Lipase should always be determined whenever amylase is determined. New methodology improves clinical utility.
Creatine kinase (CK) is the test of choice. It is more specific and sensitive than AST and LD and more discriminating than aldolase (ALD) but AST is more significantly associated with inflammatory myopathy and more useful in these cases
Some metabolic disorders
Prolonged exercise; peak 24 hours after extreme exercise (e.g., marathon); smaller increases in well-conditioned athletes
Wilms tumors with rhabdomyomatous features (CK-MB may also be increased
causing abnormally increased release of calcium from membrane of sarcoplasmic reticulum
triggered by various inhalational [e.g., ether] and local anesthetic agents, muscle relaxants [e.g., succinylcholine, tubocurarine]
causing hyperthermia, muscle rigidity, and 70% fatality
Combined metabolic and respiratory acidosis is the most consistent abnormality and is diagnostic in the presence of muscle rigidity or rising temperature. pH is often <7.2, BE >-10, hypoxia, and arterial pCO2 of 70 to 120 torr. Immediate arterial blood gas analysis should be performed.
Inflammatory mono- or polyarticular arthritis due to deposition of calcium pyrophosphate dehydrate crystals in joints
Joint fluid contains crystals identified as calcium pyrophosphate dehydrate, inside and outside of WBCs, and macrophages that are differentiated from urate crystals under polarized light, which distinguishes them from gout.
Crystals may also be identified by other means (e.g., chemical, x-ray diffraction).
Iron overload (e.g., hemosiderosis, idiopathic hemochromatosis).
Can be used to monitor therapeutic removal of excess storage iron. Transferrin saturation is more sensitive to detect early iron overload in hemochromatosis
serum ferritin is used to confirm diagnosis and as indication to proceed with liver biopsy.
Ratio of serum ferritin (in ng/mL) to alanine aminotransferase (ALT) (in IU/L) >10 in iron-overloaded thalassemic patients but averages ≤2 in viral hepatitis; ratio decreases with successful iron chelation therapy.