Differential Diagnosis for General Weakness in a 77-year-old
Single Most Likely Diagnosis
- Chronic Kidney Disease (CKD) with Acute Exacerbation: The patient's eGFR of 37 indicates stage 3 CKD. Rising CRP suggests an inflammatory process, which could be due to an infection or other causes of acute kidney injury (AKI) superimposed on CKD, leading to general weakness. Mild hypokalemia and hyperglycemia can be seen in the context of CKD and AKI.
Other Likely Diagnoses
- Sepsis: Given the rising CRP and general weakness, sepsis should be considered, especially in an elderly patient. Sepsis can lead to AKI, which would explain the low eGFR, and can also cause hypokalemia and hyperglycemia due to stress response and potential insulin resistance.
- Diabetic Ketoacidosis (DKA) or Hyperosmolar Hyperglycemic State (HHS): Although the hyperglycemia is described as mild, in the context of rising CRP and general weakness, DKA or HHS should be considered, especially if the patient has diabetes. These conditions can lead to significant weakness and can complicate CKD.
- Infection (e.g., Urinary Tract Infection, Pneumonia): Infections are common in the elderly and can present with non-specific symptoms such as general weakness. The rising CRP supports an infectious process, which could be contributing to the patient's condition.
Do Not Miss Diagnoses
- Acute Coronary Syndrome (ACS): Although less likely given the information, ACS (including myocardial infarction) can present atypically in the elderly with symptoms such as general weakness rather than chest pain. It's crucial to consider ACS due to its high mortality if missed.
- Abdominal Aortic Aneurysm (AAA): An AAA can cause general weakness if it is leaking or ruptured, leading to hypovolemic shock. This is a life-threatening condition that requires immediate intervention.
- Spinal Cord Compression: This can cause weakness, especially if it involves the lower thoracic or lumbar spine, affecting the patient's mobility and strength. It's a medical emergency that requires prompt diagnosis and treatment.
Rare Diagnoses
- Endocrine Disorders (e.g., Addison's Crisis): Although rare, adrenal insufficiency can cause general weakness, hypokalemia, and hyperglycemia. It's a life-threatening condition if not recognized and treated promptly.
- Neuromuscular Disorders (e.g., Myasthenia Gravis): These disorders can cause fluctuating weakness, which might be mistaken for general weakness. They are less likely but should be considered in the differential diagnosis due to their significant impact on the patient's quality of life and the availability of specific treatments.