The sensitivity is higher in patients with interstitial nephritis induced by methicillin or when the Hansels stain is used. However, a 2013 study showed that the sensitivity and specificity of urine eosinophil testing are 35.6% and 68% respectively. Isosthenuria
Blood in the urine and occasional RBC casts
Sterile pyuria: white blood cells and no bacteria. About 50% of patients with AIN have pyuria. Nephrotic-range amount of protein in the urine may be seen with NSAID-associated AIN. Low grade proteinuria may be seen in a majority of other causes of AIN. White blood cell (WBC) casts: Fewer than one in five patients with AIN have WBC casts in urine. Pathology
While non-invasive patient evaluation (physical examination, blood and urine testing, imaging studies) can be suggestive, the only way to definitively diagnosis interstitial nephritis is with a tissue diagnosis obtained by kidney biopsy. Pathologic examination will reveal the presence of interstitial edema and inflammatory infiltration with various white blood cells, including neutrophils, eosinophils, and lymphocytes. Generally, blood vessels and glomeruli are not affected. Electron microscopy shows mitochondrial damage in the tubular epithelial cells, vacuoles in the cytoplasm, and enlarged endoplasmic reticulum. Gallium scan
The sensitivity of an abnormal gallium scan has been reported to range from 60% to 100%. A study of Gallium scan in 76 patients [23 with AIN, 8 with biopsy-proven AIN] showed an AUC of 0.75.
More research is needed to determine the precise effects of HMB on muscle strength and function in various populations.In severe cases of muscular atrophy, the use of an anabolic steroid such as methandrostenolone may be administered to patients as a potential treatment although use is limited by side effects. A novel class of drugs, called selective androgen receptor modulators, is being investigated with promising results. They would have fewer side effects, while still promoting muscle and bone tissue growth and regeneration. These effects have yet to be confirmed in larger clinical trials. Outcomes
Outcomes of muscle atrophy depend on the underlying cause and the health of the patient. Immobility or bed rest in populations predisposed to muscle atrophy, such as the elderly or those with disease states that commonly cause cachexia, can cause dramatic muscle atrophy and impact on functional outcomes. In the elderly, this often leads to decreased biological reserve and increased vulnerability to stressors known as the "frailty syndrome." Loss of lean body mass is also associated with increased risk of infection, decreased immunity, and poor wound healing. The weakness that accompanies muscle atrophy leads to higher risk of falls, fractures, physical disability, need for institutional care, reduced quality of life, increased mortality, and increased healthcare costs. Other animals
Inactivity and starvation in mammals lead to atrophy of skeletal muscle, accompanied by a smaller number and size of the muscle cells as well as lower protein content.