# Brittle Diabetes Following Partial Pancreatectomy: A Case of Type 3c Diabetes Mellitus Complicated by Type 4 Renal Tubular Acidosis

## TL;DR

A patient with a history of partial pancreatectomy developed brittle diabetes and type 4 RTA, highlighting the need for accurate diagnosis and tailored treatment.

## Contribution

This case report highlights the rare co-occurrence of brittle T3cDM and type 4 RTA, emphasizing diagnostic and management challenges.

## Key findings

- Brittle diabetes is rare in T3cDM and requires individualized therapy.
- Type 4 RTA complicates diabetes management by linking hyperkalemia and hypoglycemia risks.
- Multidisciplinary care is essential for managing overlapping glucose and potassium regulation issues.

## Abstract

Type 3c diabetes mellitus (T3cDM), or pancreatogenic diabetes, is an under-recognized subtype of diabetes resulting from exocrine pancreatic disease or surgery. It is frequently misclassified as type 1 or type 2 diabetes, leading to inappropriate management. Brittle diabetes, characterized by severe glycemic variability and insulin sensitivity, is rare in T3cDM. Type 4 renal tubular acidosis (RTA), or hyperkalemic distal RTA, is another underdiagnosed complication of diabetic kidney disease. We report a unique case of transition to T3cDM presenting as brittle diabetes in a patient with a history of partial pancreatectomy, complicated by type 4 RTA.

This case highlights the clinical challenge of managing brittle diabetes in the context of T3cDM, a condition that often goes unrecognized in patients with a history of pancreatic surgery. The concurrent diagnosis of type 4 RTA complicated glucose and electrolyte management, as insulin is both therapeutic for hyperkalemia and a risk for hypoglycemia in brittle diabetes. Awareness of this overlap is essential, as both conditions require individualized therapy that departs from traditional inpatient diabetes management.

Clinicians should maintain a high index of suspicion for T3cDM in patients with pancreatic pathology and unstable glycemic profiles. Accurate diagnosis is key to appropriate treatment and prevention of complications. Additionally, type 4 RTA should be considered in diabetics with unexplained hyperkalemia despite preserved renal function. A multidisciplinary approach is essential for managing the complex interplay between glucose and potassium regulation in such patients.