GeriQBank · Topic
Renal ageing, AKI, CKD, fluid, electrolyte and acid–base disorders.
Set twice
Causes and treatment of acute kidney injury in an elderly male High-Yield Points A. Definition and Why the Old Kidney Is Vulnerable AKI is an abrupt, potentially reversible fall in glomerular filtration over hours to days, with…
Hyperkalaemia is a serum potassium above 5.0–5.5 mEq/L; it is life-threatening above 6.5 mEq/L or with any ECG change. Total body potassium is lower in the old because of reduced muscle mass and poor dietary intake, so a normal or high…
Set once
Renal function declines predictably with age, so drugs and their active metabolites that are cleared by the kidney are eliminated more slowly, have longer half-lives, and accumulate to toxic steady-state concentrations. Serum creatinine…
Definition: a primary fall in serum bicarbonate with a fall in blood pH, compensated by hyperventilation and a fall in pCO₂. Normal bicarbonate is 22–26 mEq/L; expected compensation is a fall in pCO₂ of about 1.2 mmHg for every 1 mEq/L…
Water balance has dual control. The hypothalamus and posterior pituitary handle water retention through ADH, while the renin–angiotensin–aldosterone axis handles sodium retention and blood pressure. ADH (arginine vasopressin) is made in…
Definitions. Hyponatremia is serum sodium <135 mEq/L. Clinically significant hyponatremia is <130 mEq/L; severe hyponatremia is <120 mEq/L. Levels of 130–135 mEq/L are usually asymptomatic. Step 1 — confirm true hypotonic hyponatremia.…
Hyponatraemia is a serum sodium below 135 mEq/L and is the commonest electrolyte disorder in hospitalised patients, associated with increased morbidity, mortality, length of stay and cost. Severity: mild 130–134 mEq/L, moderate 125–129…
Peritoneal dialysis (PD) uses the peritoneum as a semipermeable membrane: solutes are removed by diffusion down a concentration gradient into the dialysate, and water by osmosis (ultrafiltration) driven by an osmotic agent. The…
Chronic kidney disease is predominantly a disease of older adults — its incidence rises steadily with age and it is at least 10 times commoner at 75 and over than at 15–45. The commonest causes of end-stage renal disease in old age are…
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Definition and the trajectory with age. GFR is the volume of plasma filtered by the glomeruli per unit time, expressed as mL/min/1.73 m². It peaks at approximately 140 mL/min/1.73 m² in the third decade and then declines at about 8…
Age alone is not a contraindication. The indications and the incidence of complications of renal biopsy are the same for older and younger adults. However, when a complication does occur in an older adult it is generally more serious —…
The ageing kidney is the substrate for every disturbance. GFR peaks at about 140 mL/min/1.73 m² in the third decade and then falls by roughly 8 mL/min/1.73 m² per decade; effective renal plasma flow falls proportionally more (10% per…
Recurring question — asked ×3. Extra scaffolding provided below. Definition, severity and significance. Serum sodium <135 mEq/L; mild 130–134, moderate 125–129, severe or profound <125 mEq/L. It is the commonest electrolyte abnormality…
Definition. A euvolaemic, hypotonic hyponatraemia caused by non-osmotic, non-physiological release of antidiuretic hormone (arginine vasopressin), with continued renal water reabsorption despite plasma hypo-osmolality. It is now often…
Definitions and the ageing background. Hypokalaemia = serum K⁺ <3.5 mEq/L (severe <2.5); hypomagnesaemia = serum Mg²⁺ <1.7 mg/dL. Total body potassium is lower in healthy older people, and the potassium-controlling ATPases of the…
First — confirm the value and assess urgency simultaneously. Exclude pseudohyperkalaemia by repeating with a properly taken sample: causes are a tight or prolonged tourniquet, fist clenching, haemolysis, difficult venepuncture, delayed…
Recurring question — asked ×4. Extra scaffolding and full evaluation flow chart provided below. Definition and thresholds. Hypercalcaemia is defined by an elevation of calcium above 10.6 mg/dL, and values above 11.0 mg/dL should be…
Definition and the ageing kidney. Metabolic acidosis is a primary fall in serum bicarbonate (<22 mEq/L) with a low arterial pH (<7.35). The ageing kidney handles an acute acid load poorly — older people acidify the urine more slowly and…
Recurring question — asked ×2. Extra scaffolding provided below. Recognise and stage first. AKI is defined by a rise in serum creatinine of ≥0.3 mg/dL within 48 hours, or ≥1.5 times baseline within 7 days, or urine output <0.5 mL/kg/h…
Recurring question — asked ×2. Extra scaffolding provided below. Definition and burden. CKD is a syndrome characterised by progressive and generally irreversible deterioration of renal function due to a reduction in nephron mass,…
elderly in our country Recurring question — asked ×2. Extra scaffolding provided below. The textbook threshold. As CKD progresses and creatinine clearance falls to about 25 mL/min the full picture of uraemia appears; when the GFR falls…
Age itself is not a contraindication to dialysis or transplantation. Older patients can be treated effectively with either haemodialysis (HD) or peritoneal dialysis (PD), and most studies confirm that survival on PD and HD is similar in…
Definition — the acute nephritic syndrome. Abrupt onset of haematuria with dysmorphic red cells and red cell casts, proteinuria (usually sub-nephrotic), hypertension, oedema and oliguria, with a rising creatinine. When crescents involve…
Definition. Nephrotic syndrome is proteinuria >3.5 g/24 h with hypoalbuminaemia (<3 g/dL), oedema and hyperlipidaemia. It accounts for about 50% of all renal biopsy indications in older adults. Commonest causes in old age. Membranous…
Definition. Inflammation of the renal tubulointerstitium with relative sparing of glomeruli and vessels. It presents either as acute interstitial nephritis (AIN) causing acute kidney injury, or as chronic interstitial nephritis causing…
Definition. Diabetic nephropathy is persistent albuminuria with progressive decline in GFR in a person with diabetes, usually accompanied by retinopathy and hypertension, in the absence of another renal disease. It is one of the…