The Kidney Strikes Back (interstitial nephritis)
This is the MOST common cause of TIN in adult and pediatric patients.
What are medications! Can you name some of the most common medications or classes causing TIN?
For the medication Bicitra, 1 mL of oral solution contains ____ mEq of bicarbonate and _____ mEq of sodium.
what is 1 (for both)
This synthetic analog of antidiuretic hormone is the most commonly used first-line pharmacological treatment for monosymptomatic nocturnal enuresis in children.
What is desmopressin?
This conventional synthetic DMARD is conditionally recommended over leflunomide, sulfasalazine, and hydroxychloroquine for oligoarticular JIA when escalation beyond NSAIDs and IAGCs is needed.
What is methotrexate?
This is the mean onset of symptoms for medication-induced TIN.
What is 10 days
TIN typically develops within a few weeks of exposure of the medication; Drug-induced TIN is thought to be an immune or allergic reaction in the kidney and can be associated with systemic signs of a hypersensitivity reaction, including fever, rash, arthritis, and eosinophilia; NSAID-induced TIN may have fewer extrarenal symptoms compared with other medications.
RTA is caused by the inability of the renal tubule to retain ____ or to secrete _____ in the presence of normal GFR.
What is bicarbonate (HCO3) and hydrogen ions (H+)
Before prescribing desmopressin for nocturnal enuresis, clinicians warn families to limit evening fluid intake to avoid the dangerous complication of ___________
What is hyponatremia
This strategy is strongly recommended for systemic JIA once inactive disease is attained to minimize long-term toxicity.
What is tapering and discontinuing glucocorticoids?
This treatment, although commonly used in TIN, remains controversial due to conflicting evidence on its long-term impact on kidney recovery.
Bonus question - when would you consider their use?
What is corticosteroids
Interstitial fibrosis on biopsy and no improvement in kidney function after 5 to 7 days of conservative therapy (NOT in cases of self-limiting drug induced TIN)
Most forms of RTA in adults is secondary to other diseases versus in pediatric RTAs it is primarily due to this defect
What is genetic defect (in a protein involved in the processes of HCO3 and H+ physiology)
This class of drugs is often combined with desmopressin in patients who fail monotherapy, and works by inhibiting detrusor muscle overactivity.
What are anticholinergic agents
PJP prophylaxis should be considered at this dose/duration of prednisone equivalents
What is patients expected to be on high-dose corticosteroids (≥ 2 mg/kg/day prednisolone equivalent if < 7.5 kg or ≥ 15 mg/day of prednisolone equivalent) for more than 28 days
In a study of drug-induced TIN, delaying this essential management step was associated with worse kidney outcomes.
What is removal of the offending agent
This electrolyte abnormality is the distinguishing feature in type 4 RTA
What is hyperkalemia
This agent is the only anticholinergic FDA-approved for pediatric use in treating nocturnal enuresis.
What is oxybutynin?
This condition, often triggered by infection and requiring urgent treatment, is associated with systemic JIA and can present with high ferritin and cytopenias.
What is macrophage activation syndrome (MAS)?
These severe infections can be the etiology of granulomatous TIN
What are Mycobacterium tuberculosis, histoplasmosis, candidiasis, and toxoplasmosis
Pediatric patients with this type of RTA will need much greater amount of alkali supplementation than others.
What is type 2 proximal RTA
Overview:
Type 1 - Distal RTA; distal tubule cannot excrete acid
Type 2 - Proximal RTA; proximal tubule cannot reabsorb bicarbonate
Type 4 - Hyperkalemic RTA; Pseudohypoaldosteronism or hypoaldosteronism (most common in adults)
Which formulation of desmopressin is NOT recommended for nocturnal enuresis treatment
What is the intranasal formulation
In systemic JIA, these two biologic agents are conditionally recommended as first-line monotherapy due to their cytokine-specific targets.
What are IL-1 and IL-6 inhibitors?