Renal Dysfunction
Also written as HRS.
Heart failure may be precipitated by hypertension, myocardial infarction, arrhythmia, infection, anaemia or renal dysfunction.
What our notes say
- Heart failure may be precipitated by hypertension, myocardial infarction, arrhythmia, infection, anaemia or renal dysfunction. (Year 4 Internal Medicine: Exam Revision Roadmap)
- Chronic: Recurrent hospitalisations, worsening heart failure, renal dysfunction, poor quality of life. (Pulmonary oedema and ARDS)
- | Serum urea & creatinine | Detects renal dysfunction causing toxicity or acidosis | Hyperkalaemia induces sine waves, blocks, arrest | (Arrhythmias and ECG interpretation)
- | Electrolytes | Sodium, potassium, chloride, bicarbonate. | Imbalances can occur due to vomiting, diarrhoea, or renal dysfunction. | (Malaria, including severe malaria)
- Jaundice: May indicate underlying liver disease contributing to renal dysfunction or severe hemolysis. (Approach to renal disease)
- Confirm renal dysfunction – eGFR < 15 ml/min/1.73 m² (CKD‑5) or acute rise in serum creatinine ≥ 0.3 mg/dl within 48 h (AKI). (Indications for dialysis)
Study material on Renal Dysfunction
Practice questions on Renal Dysfunction
A 72-year-old man presents with back pain and confusion. X-ray shows punched-out lytic skull lesions. Serum electrophoresis shows an IgG M protein spike. Urine shows Bence Jones proteins. Bone marrow has >30% plasma cells. Creatinine is markedly elevated. Which mechanism BEST explains his renal dysfunction?
- IgG deposition causing membranous nephropathy
- Hypocalcaemia causing renal vasoconstriction
- Obstructive casts of Bence Jones proteins in distal tubules causing tubular necrosis
- Lymphomatous infiltration of the renal parenchyma
Answer: C. This is multiple myeloma. Renal dysfunction results primarily from obstructive proteinaceous casts — composed mostly of Bence Jones proteins (free light chains) along with Tamm-Horsfall protein and albumin — forming in the distal convoluted tubules and collecting ducts. Adjacent epithelial cells become necrotic from the toxic effects of Bence Jones proteins. It is hypercalcaemia (not hypocalcaemia) that also contribu