Living Donor: Genetically related (sibling, parent) or unrelated (spouse, friend). Better outcomes, shorter wait times.
Deceased Donor: From brain-dead donors. Organs allocated based on factors like blood type, tissue match (HLA), and waiting time.

Thorough medical and psychosocial evaluation to ensure fitness for surgery and adherence to immunosuppression.
Contraindications: Active malignancy, active infection, severe irreversible extra-renal disease (e.g., severe heart failure, lung disease), substance abuse, non-adherence.

The donor kidney is usually placed in the iliac fossa.
Renal artery and vein are anastomosed to the recipient's iliac vessels.
Ureter is implanted into the bladder. The native kidneys are usually left in place.

Graft Rejection:
- Hyperacute: Within minutes/hours. Pre-formed antibodies. Rare with modern cross-matching.
- Acute: Days to months post-transplant. T-cell or antibody-mediated. Treatable with increased immunosuppression.
- Chronic: Gradual decline in graft function over years. Multifactorial.
Infections: Increased risk due to immunosuppression (CMV, EBV, fungal, bacterial).
Malignancy: Increased risk of skin cancers, post-transplant lymphoproliferative disorder (PTLD).
Cardiovascular disease: Remains a major cause of death.
Drug Toxicity: Nephrotoxicity (calcineurin inhibitors), diabetes, hypertension, hyperlipidemia.
Surgical Complications: Vascular thrombosis, ureteral obstruction/leak.

A group of disorders characterized by a normal anion-gap (hyperchloremic) metabolic acidosis due to a defect in renal acid excretion or bicarbonate reabsorption, despite relatively normal GFR.

1. Type 1 (Distal) RTA

Defect: Impaired hydrogen ion ($H^+$) secretion in the distal nephron (collecting duct).
Features:
- Inability to acidify urine: Urine pH consistently $>5.5$ despite systemic acidosis.
- Hypokalemia (due to increased distal K+ secretion).
- Nephrocalcinosis and kidney stones (due to increased urine calcium and decreased citrate).
- Bone demineralization (osteomalacia/rickets).
Causes: Autoimmune diseases (Sjögren's, SLE), drugs (amphotericin B, lithium), genetic.
Treatment: Oral bicarbonate (sodium bicarbonate or sodium citrate) to correct acidosis and prevent complications.

2. Type 2 (Proximal) RTA

Defect: Impaired bicarbonate ($HCO_3^-$) reabsorption in the proximal tubule.
Features:
- Initial bicarbonate wasting, but urine can be acidified ($<5.5$) when serum bicarbonate is low enough