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