Renal Replacement Therapy (Haemodialysis, Peritoneal Dialysis) — DCE Clinical Case

Approach — what the examiner is testing

This is not "look at a fistula". It tests whether you can confirm the access is functioning, hunt its complications systematically — especially steal, which the stem is pointing at — and complete the volume and cardiovascular survey that the fistula sits inside. The examiner watches the order (inspection before palpation before auscultation — never palpate away a bruit you have not described), the compression test for steal, and whether you synthesise rather than list [1].

Before touching the patient: look at both arms exposed to the shoulder and the chest wall. The access history is written on the skin — previous fistula scars (which level, which side), old catheter exit scars on the chest, and collateral chest-wall veins that whisper central vein stenosis from catheters past [1] [4].

Examination sequence

General inspection. Comfort at rest, fluid status visible from the end of the bed (ankle oedema, sacral oedema if recumbent), scleral pallor for the anaemia of kidney failure, and a scan for the dialysis vintage signs — parathyroidectomy scar, multiple access scars, and the wasted shoulders and thenar gutters of the long-term patient [5] [6].

The access arm — inspection. Describe the fistula you see: a matured vein at the wrist anastomosis with a well-healed scar. Then hunt, and say what you are hunting: aneurysmal dilatation (from years of buttonhole or rope-ladder needling), skin changes over the aneurysm (thinning, shiny skin, scabbing — pre-rupture signs that demand urgent access review), erythema or discharge (infection is uncommon in fistulas but catastrophic when it lands), collateral veins over the shoulder and chest wall (downstream or central stenosis), and the hand — colour, temperature, trophic change, fingertip ulcers, nail changes [1].

The access arm — palpation. Feel the thrill at the anastomosis and track it along the vein: a continuous, machinery-like buzz means flow; a pulse with a weak or systolic-only thrill suggests stenosis (classically juxta-anastomotic); a water-hammer pulse at the anastomosis suggests downstream stenosis. Assess augmentation: the fistula should plump further when the arm is elevated then lowered, and outflow should augment when the vein is occluded distally. Then the test the stem demands — compress the fistula and re-examine the hand: in steal syndrome, occluding the fistula restores hand warmth and relieves symptoms, which is as close to a diagnostic bedside manoeuvre as this examination offers [1].

The access arm — auscultation. A continuous bruit with systolic accentuation over the anastomosis and outflow vein. Absent bruit with a strong pulse suggests thrombosis; a harsh, high-pitched, systolic-only bruit localises stenosis. State what you heard and where [1].

The hand for steal, formally. Compare temperature and capillary refill between hands; test sensation in median, ulnar and radial distributions; look for trophic change. Severity matters: cool hand without tissue loss is mild steal and observed; pain at rest, neurological deficit or tissue loss is severe steal and a vascular-surgery conversation (banding, distal revascularisation with interval ligation, or ligation) — name the ladder [1].

Fluid status — the dialysis examination's second half. JVP (harder with a fistula on the left if central veins are stenosed — say so if the waveforms are obscured), blood pressure lying and standing, lung bases for crepitations, peripheral and sacral oedema. Remember the dialysis-day caveat aloud: examination findings depend on where he sits in the interdialytic interval — a Monday morning examination after the long break is a different volume state to a post-dialysis Friday [3].

Cardiovascular survey. Displaced apex and fourth sound for the LVH and cardiomyopathy the dialysis life builds; auscultate for flow murmurs and for the pericardial rub you never want to find; and note the heart is the organ that decides his prognosis — cardiovascular disease is the leading cause of death on dialysis, amplified by every episode of intradialytic hypotension and myocardial stunning [6] [3].

If there is a PD catheter instead (or as well). Inspect the exit site with the catheter immobilised: erythema, discharge, crusting, exuberant granulation tissue, cuff extrusion, and the tunnel for tenderness or swelling — exit-site and tunnel infections track directly with peritonitis and catheter loss. Then the PD abdomen: hernias (umbilical, inguinal, incisional — raised intra-abdominal pressure finds every weakness), leaks, and fluid status as before [2] [7].

Finish. Offer fundoscopy (hypertensive and diabetic change stages his end-organ disease), a urine output question (residual function changes every management decision), and the transplant question — where is he on work-up, because the fistula, however good, is meant to be a bridge [6].

Presentation template (deliver this to the examiner)

"Mr Doyle has a left radiocephalic fistula with a well-healed scar, no aneurysm, no skin changes and no erythema. On palpation there is a continuous thrill at the anastomosis tracking along the outflow vein with good augmentation; auscultation confirms a continuous bruit with systolic accentuation. The left hand is one degree cooler than the right with borderline capillary refill, and — the key finding — compressing the fistula restores hand warmth, indicating mild dialysis access-associated steal syndrome without trophic change. He is euvolaemic today with a clear chest and a non-displaced apex, noting this is a post-dialysis-day examination. My synthesis: a functioning fistula with early steal, currently mild. I would document flow surveillance and duplex assessment of the access circuit, monitor the steal clinically, escalate to vascular surgery if he develops rest pain, neurological deficit or tissue loss, and complete the review with his volume target, intradialytic blood-pressure record and transplant status." [1] [3]

If you find an aneurysm with skin changes

Say immediately that a fistula aneurysm with thin, shiny, scabbed or ulcerated skin is a pre-rupture emergency — it needs same-week (often same-day) access surgery review, needling must avoid the thinned segment, and the patient must know to apply direct pressure and present immediately if it bleeds. This is one of the few access findings that outranks the rest of the examination [1].

Probing questions

"How do you distinguish steal from carpal tunnel syndrome in a dialysis patient?" — "By distribution and provocation. Steal is global hand ischaemia — cold, painful, the whole hand, worse during dialysis when perfusion pressure falls, and relieved when I compress the fistula. Carpal tunnel from dialysis-related amyloid — beta-2 microglobulin deposition over years of vintage — is median-territory numbness and thenar wasting, usually bilateral in the long-term patient, without temperature change and without any response to fistula compression. Both can coexist, which is why I test sensation by nerve territory even when the ischaemic picture is obvious." [1] [5]

"His thrill disappears overnight. What happened and what do you do?" — "A lost thrill and bruit is a thrombosed fistula until proven otherwise — the thrill is flow, and no thrill means no flow. That is an urgent access emergency: thrombectomy or declotting within a day or two can salvage the circuit, and every hour of delay lowers the salvage rate. While that is arranged, his dialysis need does not pause — the question becomes whether he can wait for salvage or needs a temporary catheter, which is exactly the bridge use a catheter is for." [1]

"Why do we bother with fistulas at all when a catheter works immediately?" — "Because immediacy is the catheter's only advantage, and it is paid for weekly. Catheters carry the highest rates of bacteraemia with its metastatic sequelae, they scar and stenose the central veins that future access depends on, and registry data linked access type to outcomes strongly enough to drive the global fistula-first culture. A fistula asks for 6–12 weeks of maturation and accepts a real failure-to-mature rate; in exchange it gives the best patency, the lowest infection risk and the lowest mortality association. The modern framing is the ESKD Life-Plan — the right access for the right patient at the right time — but for a patient with years of dialysis ahead, that plan almost always spells fistula, created early." [1] [4]

"He asks why his blood pressure pills were stopped before dialysis days." — "Because his heart and his fistula share one vulnerability: perfusion pressure. Dialysis acutely reduces myocardial blood flow — the stunning work — and ultrafiltration drops pressure further; a full antihypertensive load on a dialysis morning can convert that into symptomatic hypotension, cramps, stunning and a steal flare in his hand. So we time agents around sessions, target dry weight cautiously, cool the dialysate, and treat recurrent intradialytic hypotension as cardiac protection, not a nuisance." [3] [6]