12.11.28 Renal teaching

Pyelonephritis

  • Presentation

    • High fever

    • Loin pain

    • N + V

    • Preceeding cystitis?

    • Unilateral symptoms

  • Differential for loin pain

    • AAA

    • Musculoskeletal

  • Management

    • IV Gent

      • VS Gram -ve organisms

      • 3-5 ml/kg slow IV

      • Check levels

    • IV augmentin

      • 2:1 amoxicillin and clavulanic acid

      • Broad-spectrum (Gram +ve and -ve)

Alpha blockers

  • To treat BPH

  • Options: doxazosin, terazosin, alfuzosin, tamsulosin, silodosin

  • Side-effects:

    • Relax iris dilator muscles and can cause intraoperative floppy iris syndrome (IFIS) during cataract surgery

      • Even if only taken once

    • Orthostatic hypotension, ejaculation changes, nasal congestion, weakness

AKI

  • Definition

    • >50 % rise of creatinine

  • Causes

    • Pre-renal

      • Vascular disease

    • Renal

      • Afferent arteriole

        • NSAIDs

          • Effect is much more noticable when volume depleted

      • Efferent arteriole

        • ACEi

        • ARBs

      • Toxins

        • Gentamycin (monitor very closely!)

        • Contrast (oxidising agent)

          • Protect by ADEQUATELY HYDRATING

          • NAC might also help

            • 600 mg BD, orally, 1 day before procedure

      • Rhabdomyolysis

        • Myoglobin is toxic to tubular epithelial cells

          • NB Looks life haematuria on urine dip

      • Baseline chronic kidney injury

      • Hypoxia

        • Very energy-requiring => First to go

    • Post-renal

      • Obstruction

  • AKIN classification

Urine electrolytes

  • Pre-renal problem

    • Kidneys still working => Hold on to stuff

    • Low sodium, low FeNa, High osmolality

  • ATN

    • Kidneys broken => Let everything out

    • Sodium >20, FeNa > 2%, Osmolality <250 mOsM

Managing electrolyte abnormalities

  • Water deficit

    • Calculate based on fractional rise in sodium, assuming 60% of body weight is fluid

  • Don't correct plasma sodium by more than 8 mM per day, unless it's recently changed very quickly the other way

    • CPM => Dysarthria, Dysphagia, Falling GCS

  • Correcting serum sodium has no effect on mortality

    • It's a symptom of something underlying, which you need to fix

  • Fluid assessment

    • Best thing is POSTURAL CHANGE in pulse and BP

  • Hyponatraemia

    • Hypovolemic

      • Give saline

    • Euvolemic

      • Check cortisol

      • Check thyroid

      • Check urine osmolality

      • Only then can you diagnose SIADH

        • Then fluid-restrict to treat

    • Hypervolemic

      • Treat the cause (heart, kidney or liver failure)

Anion gap

  • Calculation

    • Na + K - Cl - HCO3

    • Normal range 8-17 mM

  • Normal anion gap acidosis

    • Loss of HCO3 (together with counter-ion)

    • Or reduced acid excretion (renal tubular acidosis)

  • High anion gap acidosis

    • Some new acidic thing is there

    • Lactate, ketones, salicilate, methanol, etc.

Things raising urea

  • GI bleed

  • Steroids

  • Catabolic states

  • Protein

  • Tetracycline

Acute glomerulonephritis

  • Streptococcal stuff

    • IgA nephropathy happens while you're still ill (and is quite common)

    • Post-Strep GN happens 2-3 weeks later

      • It's the ANTIGEN that sticks to the basement membrane

      • Antibodies come along later and attack it

  • Goodpastures

    • Goodpasture's DISEASE = Anti-GBM antibodies

      • Tends to occur once and never come back

    • Goodpasture's SYNDROME = Lung and Kidney involvement with an aetiology?

  • Wegener's granulomatosis is supposed to be called granulomatosis with polyangiitis

    • As he was a Nazi

  • Investigations

    • Complement, anti-dsDNA for SLE

    • ASOT for post-Strep

    • ANCA for vasculitides

  • Classification scheme

    • Is is primary or secondary?

      • Secondary causes: Diabetes, Amyloid, SLE, RA, Myeloma

    • Irrespective of the cause, what's the clinical syndrome? (There are 5)

      • Nephrotic syndrome

      • Nephritic syndrome

      • Asymptomatic urinary abnormalities

      • Rapidly progressive glomerulonephrotis

      • Chronic kidney disease

    • What is the histopathology and pathogenesis underlying the clinical syndrome?

      • MCD, FSGS, membranous nephropathy, etc.

SLE

  • 10 times more common in female

  • 10 times more common in African Americans

Henoch–Schönlein purpura

  • Classic triad

    • Purpura

    • Arthritis

    • Abdominal pain

  • 40% have kidney involvement

    • Microscopic or frank haematuria

Notes

  • BPH is a HISTOLOGICAL diagnosis

  • 1/3 of TURPs are carried out because of acute retention

  • You can lose 50% of your kidney function before creatinine rises

  • Metformin => Lactic acidosis

    • Lactate uptake by the liver is diminished with metformin administration

      • Lactate is a substrate for hepatic gluconeogenesis, a process that metformin inhibits

    • Normally fine, but can build up if renal function is impaired (e.g. dehydration for surgery + ACEi)

    • Mortality of 30-50%

  • Diuretics don't help to prevent AKI

    • Can be useful in managing complications

  • Check the CK

  • londonaki.net

  • Trimethoprim is required for creatinine excretion

  • Using mannitol for TURP can => Hyperosmotic hyponatraemia

  • Trimethoprim is a mild potassium-sparing diuretic

  • Need to give lots (10-15 mg) of salbutamol to move potassium

    • And 40% of people don't respond

  • Unexplained haematuria in an elderly patient is RCC until proven otherwise

  • Source of blood in urine

    • Normal morphology => Urological cause

    • Warped/dysmorphic => Renal cause

  • Murmur in an IVDU is VALVE INFECTION

    • i.e. Infective endocarditis

    • Can cause post-infective glomerulonephritis