Which clinical manifestation is typical for a client with diabetes insipidus?

In diabetes insipidus, one of the hallmark clinical manifestations is decreased urine osmolarity. This condition occurs due to a deficiency of antidiuretic hormone (ADH), which is crucial for regulating water retention by the kidneys. When there is insufficient ADH, the kidneys are unable to concentrate urine effectively, leading to the excretion of large volumes of dilute urine.

As a result, the urine produced has low osmolarity, reflecting the inability of the renal tubules to reabsorb water appropriately. This dilution of urine is what differentiates diabetes insipidus from conditions where fluid balance is impaired due to other factors, such as diabetes mellitus, wherein one may see increased blood glucose levels and consequently, osmotic diuresis.

The other manifestations mentioned in the options do not align with the primary characteristics of diabetes insipidus. For instance, increased blood glucose levels pertain to diabetes mellitus rather than diabetes insipidus. Similarly, decreased serum sodium might suggest overhydration or other specific pathological conditions, while increased specific gravity is typically indicative of concentrated urine, which again does not occur in diabetes insipidus. Thus, decreased urine osmolarity is the key clinical manifestation that correctly characterizes this disorder.