Acute tubulointerstitial nephritis Flashcards Preview

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Flashcards in Acute tubulointerstitial nephritis Deck (17)
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1
Q

Define tubulointerstitial nephritis

A

Inflammatory diseases of the kidney that mostly do NOT involve the glomeruli, includes tubulo-interstitial and interstitial nephritis broadly.

but, Tubulointerstitial nephritis is a term used mostly for bacterial infections when the renal pelvis is prominently involved, as a part of Pyelonephritis.

2
Q

Define Acute Interstitial Nephritis

A

Non-bacterial inflammation of the interstitium and tubules, with inflammatory cell infiltrate, causing rapid decline in kidney function that is usually reversible.

Causes include drugs, irradiation, viruses, and immune reactions, and is the result of
An Type 1 Immune Hypersensitivity reaction, with prominent Eosinophil infiltration of the kidney, and
eosinophils in the urine.

Acute Interstitial nephritis

Analgesic Papillary necrosis.

3
Q

Causes of acute interstitial nephritis

A

Causes:
Drugs- 75%

Infections - cause tubulointerstitial nephritis/pyelonephritis 5-10%

Systemic diseases
Sarcoidosis
SLE
Wegener’s

Acute transplant rejection

Irradiation

4
Q

Symptoms, presentation of acute tubulo-interstitial nephritis

A

Can often be asymptomatic
Patients are usually normotensive, with no edema.

Bilateral flank pain from swelling and stretching of renal capsule

Oliguria in 50%

In drug induced type, occurs 3-21 days after drug.
Fever,
Hives/macropapular rash
Joint pain

5
Q

Lab findings in acute interstitial nephritis

A

Causes a rapid onset AKI: azotemia and lowered GFR, with leukocyte casts in the urine.

Interstitial nephritis is the most common intra-renal cause of AKI, so may be brown necrotic casts in the urine as well.

Blood:
Eosinophilia and increased IgE if drug induced
Mild proteinuria, not nephrosis
Sterile urine culture (unles acute pyelonerphritis)
Viral seroulogy if caused by viruses.

Urine:
Leukocyte casts are the main finding, with eiosinophiluria in drug induced form (not sensitive or speciftc though)
Only few/normal RBC levels, and no RBC casts. RBC casts would suggest a glomerulonephritis instead.

Ultrasound:
Kidneys may be normally sized, or enlarged with cortical edema.

6
Q

Diagnosing Acute interstitial nephritis

A

Symptoms + Luekocyte casts in urine, but not totally sure its AIN = Renal biopsy

Differential diagnosis:
GN
ATN
outflow obstruction

7
Q

Acute interstitial nephritis histology

A

Interstitial edema

Leukocyte infiltration, including lymphocytes, eiosinophils, and monocytes

AIN often causes Acute Tubular Necrosis, so this may be seen as well

Chronic interstitial nephritis will cause interstitial fibrosis.

granulomas may be seen if its due to sarcoidosis.

8
Q

Treating acute interstitial nephritis

Prognosis

A

Remove offending drug or treat underlying disease
Treat symptoms
Treat with steroid therapy if no improvement occurs within 2-4 days after removing the offending drug.

Azotemia should be evaluated for dialysis
Treat hypertension and electrolyte disturbances
Give diuretics if there is volume overload

Prognosis:
50% recovery in 2-6 weeks
40% will have chronic renal insufficiency
10% will have progress to total failure and end stage renal disease

9
Q

Causes of acute pyelonephritis

A

Almost always from an ascending UTI infection

In rare cases hematogenous from infective endocarditis or in immunocompromised patients.

10
Q

Presentation of acute pyelonephritis

A

Acute pyelonephritis is a very serious infection that is organ-threatening and possible life-threatening.

Fever/chills
Flank pain
Nausea, vomiting
Macroscopic hematuria ~40%
Painful urination - UTI

In elderly:
confusion, mental change
decompensation of HF
constipation

11
Q

What is a complicated vs uncomplicated pyelonephritis

A

Uncomplicated:
A non-pregnant adult, without other risk factors, typically an E. Coli infection

People in whom it is always complicated:
Infants
Elderly
Preggos
Immunocompromised/suppressed patients

Risk factors:

  • Anatomical abnormality of the kidney or ureters
  • Vesicoureteric reflux
  • Ureter obstructions - Prostate hyperplasia, Obstruction,
  • Catheters, or other foreign bodies in the urinary tract.

-difficullt/uncommon infectious agent: Klebsiella, Proteus, Enterococci, Pseudomonas, Yeast

12
Q

Laboratory values for Acute pyelonephritis

A

Leukocytosis, elevated CRP, systemic signs of inflammation

Decreased kidney function, Azotemia

Urine:

  • Significant sedimentation:
    • Pyuria
    • White cell casts
    • Bacteria
    • Possible macroscopic hematuria, but RBCs are isomorphic
    • Take urine sample for CULTURE before giving antibiotics. Will have positive urine culture.
    • Positive leukocyte esterase and nitrile tests- on a urine dipstick.
13
Q

Acute pyelonephritis diagnosis and management

A

Symptoms and urine/blood labs should indicate,

Perform Ultrasound and/or CT scan to rule out tract obstruction.

Biopsy is not usually needed.

14
Q

Acute pyelonephritis complications

A

Abscess formation
Perirenal abscesses
Sepsis, multi-organ failure

Interstitial nephritis
AKI
Chronic pyelonephritis/chronic interstitial nephritis
Chronic insufficiency
ESRD
15
Q

Treating acute pyelonephritis

A

Supportive fever, and treat infectious agent.

Remove catheters

Surgical abscess drainage

Targeted antibiotics based on culture sensitivity. Usually 10-14 day antibiotic treatment.

Empiric antibiotics:
Beta-lactams,
Fluoroquinolones,
Aminoglycosides,
TMP-SMX.
16
Q

What can aristolochic acid cause?

A

A rapidly progressive interstitial fibrosis, especially of the renal cortex.
1) Aristolochic acid nephropathy
2) Drastically increased incidence of uroepithelial cancer of the renal pelvis, ureters, and bladder
Two variants:

Chinese herb nephropathy

  • found in some herbs and herbal diet pills
  • Mechanism is unclear and there is NOT any significant inflammation.
  • Causes a severely fibrotic, hypocellular kidney disease

Balkan endemic nephropathy

  • Caused by contamination wheat crops with seeds of the Aristolochia plant
  • Causes same disease with slower progression
17
Q

Treatment for aristolochic acid nephropathy

A

Stop the exposure, but this is usually too late and does Not Halt the progression of the disease

Corticosteroids mildly slow GFR loss

Treat for chronic kidney disease as normal and
Continuously monitor for cancer.
Consider elective/preventative bilateral nephroureterectomy