A male client with type 1 diabetes mellitus (DM) develops a gangrenous toe and is admitted for possible amputation. Which pathophysiological consequence of DM has contributed to this client's complication?

A. Severely decreased GFR:

In stage 4 chronic kidney disease (CKD), the glomerular filtration rate (GFR) is indeed severely decreased. Stage 4 CKD is characterized by a GFR between 15 and 29 mL/min/1.73 m² according to the Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines. At this stage, there is significant kidney damage, resulting in a substantial reduction in kidney function and GFR. Clients with stage 4 CKD require close monitoring and management to prevent further progression of kidney disease and associated complications.

B. Mildly decreased GFR:

This choice is incorrect. Stage 4 CKD is not associated with a mildly decreased GFR. A mildly decreased GFR would typically be indicative of earlier stages of CKD. In stage 4 CKD, the reduction in GFR is severe, falling below 30 mL/min/1.73 m².

C. Kidney damage with increased GFR:

This interpretation is inaccurate. In stage 4 CKD, kidney damage leads to a progressive decline in GFR, rather than an increase. An increased GFR is not typical of advanced CKD stages; instead, it may occur in conditions such as hyperfiltration in early stages of diabetic nephropathy.

D. Moderately decreased GFR:

This option is also incorrect. Stage 4 CKD is not associated with a moderately decreased GFR. A moderately decreased GFR would typically be indicative of stage 3 CKD, where the GFR ranges from 30 to 59 mL/min/1.73 m². In stage 4 CKD, the reduction in GFR is more severe, falling below 30 mL/min/1.73 m².

A. Myocardial infarction one year ago:

A myocardial infarction (MI) that occurred one year ago is not directly related to the current acid-base imbalance described in the scenario. While a history of MI may have implications for the client's overall cardiovascular health and management, it is not the most likely cause of the acid-base imbalance indicated by the laboratory results.

B. Occasional use of antacids:

Occasional use of antacids is unlikely to cause the acid-base imbalance described in the scenario. Antacids primarily work by neutralizing gastric acid and are not typically associated with significant alterations in acid-base status, especially when used intermittently.

C. Chronic renal insufficiency:

Chronic renal insufficiency is the most likely cause of the acid-base imbalance indicated by the laboratory results. A low hemoglobin level suggests anemia, which can occur in chronic kidney disease due to decreased erythropoietin production. An elevated creatinine clearance indicates impaired kidney function, as the kidneys are clearing creatinine at a faster rate than normal. Decreased urine specific gravity suggests the kidneys' inability to concentrate urine properly, which is a common finding in renal insufficiency. Renal insufficiency can lead to metabolic acidosis due to the kidneys' decreased ability to excrete acid and regulate bicarbonate levels.

D. Shortness of breath with exertion:

Shortness of breath with exertion, a symptom commonly seen in COPD exacerbations, is unlikely to directly cause the acid-base imbalance described in the scenario. While respiratory distress can lead to respiratory acidosis, which is characterized by elevated carbon dioxide levels and decreased pH, the laboratory results indicate metabolic rather than respiratory acidosis.