Tubular and Interstitial Diseases Flashcards
What two major processes lead to clinical manifestations in acute kidney injury?
- Ischemic or toxic tubular injury
- Inflammation of the tubules and interstitium
What is ischemic ATI due to?
- Due to decreased or interrupted blood flow
What is nephrotoxic ATI due to?
- May be caused by endogenous agents
What are present and considered pathognomonic of ATI? What is the association?
- Abundance of the “extreme” coarsely granular casts
- Associated with a greater likelihood of dialysis requiring acute kidney injury
What is responsible for the color of the casts seen in ATI?
- Mitochondrial pigments or lipofuscin
When is the initiation phase of AKI?
- Lasts 36 hours
What is seen in the initiation phase of AKI?
- Dominated by the inciting medical, surgical, or obstetric event
- Only renal involvement sign is a slight decline in urine output with a rise in BUN
What is the maintenance phase characterized by?
- Sustained decreases in urine output to between 40 and 400 mL/day
- Salt and water overload
- Rising BUN concentrations
- Hyperkalemia
- Metabolic acidosis
- Other manifestations of uremia
What is seen in the recovery phase of AKI?
- Steady increase in urine volume that may reach up to 3L /day
- Tubules are still damaged, so large amounts of water, sodium, and potassium are lost in the flood of urine
What is a big clinical problem in the recovery phase of AKI?
- Hypokalemia due to potassium loss
How are tubulointerstitial disorders distinguished from glomerular diseases?
- Absence of nephritic or nephrotic syndrome
- Presence of defects in tubular function such as impaired ability to concentrate urine, evidenced clinically by:
1. Polyuria or nocturia
2. Salt wasting
3. Diminished ability to excrete acids
4. Isolated defects in tubular reabsorption or secretion
What is acute pyelonephritis?
- Generally caused by bacterial infection and is associated with UTI
- Suppurative inflammatory process involving the kidney that is the result of bacterial and sometimes viral infection
What is chronic pyelonephritis?
- More complex disorder
- Bacterial infection plays a dominant role, but other factors predispose to repeat episodes of acute pyelonephritis
What are some associations with acute pyelonephritis?
- Urinary tract obstruction
- Instrumentation
- VUR
- Pregnancy
- Gender and age
- Pre Existing renal lesions
- Diabetes
- Immunosuppression and immunodeficiency
How does acute pyelonephritis present?
- CVA tenderness
- Systemic features (fever, elevated WBC)
- Dysuria, frequency, urgency
How can uncomplicated E. coli cystitis be treated?
- With a single dose of antibiotics or a 3 day course of TMP/SMZ or nitrofurantion
What is a viral pathogen that causes pyelonephritis in kidney allografts?
- Polyomavirus
What is polyomavirus infection characterized by?
- Nuclear enlargement and intranuclear inclusions visible by light microscopy in tubular epithelial cells