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Renal Tubular Acidosis (RTA) - Gold Medal Level (MD Pediatrics)

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SECTION 1: PATHOPHYSIOLOGY (5 marks)

Background - Normal Acid-Base Homeostasis

1. Proximal tubule: Reabsorbs ~80% of filtered HCO3- (4500 mEq/day) via apical Na+/H+ exchanger (NHE-3) and basolateral Na+-HCO3- cotransporter (NBCe1); carbonic anhydrase II (cytoplasmic) and IV (luminal) are essential.
2. Distal nephron (cortical collecting duct): Secretes daily fixed acid load (~1 mEq/kg/day) via H+-ATPase (proton pump) and H+/K+-ATPase on type A intercalated cells; buffers excreted as NH4+ and titratable acid.

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Type 1 - Classic Distal RTA (dRTA)

• Autosomal dominant: Missense mutation in AE1 gene (Cl-/HCO3- exchanger, Band 3 protein) - mistargeted to apical membrane; usually mild
• Autosomal recessive with sensorineural deafness (rdRTA1): Mutations in ATP6V1B1 encoding B1-subunit of H+-ATPase - H+-ATPase critical for cochlear/endolymph pH
• Autosomal recessive without deafness (rdRTA2): Mutations in ATP6V0a4
• Type 3 (mixed proximal + distal): Carbonic anhydrase II deficiency (CA2 gene) = Guibaud-Vainsel syndrome (osteopetrosis + cerebral calcification + mixed RTA)

• Loss of electrogenic H+ secretion → compensatory K+ secretion to maintain electronegativity in distal nephron
• Impaired H+/K+-ATPase (normally reabsorbs K+ in exchange for H+)
• Secondary hyperaldosteronism (stimulated by acidosis-induced ECF volume depletion)

• Chronic acidosis → mobilization of bone calcium → hypercalciuria
• Decreased tubular citrate reabsorption (citrate is an important inhibitor of calcium precipitation) → hypocitraturia
• Alkaline urine pH → calcium phosphate precipitation

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Type 2 - Proximal RTA (pRTA)

1. Reduced proximal HCO3- reabsorption → HCO3- floods distal nephron → bicarbonaturia
2. Distal nephron becomes overwhelmed but can still acidify urine below pH 5.5 once serum HCO3- falls to a new steady-state level
3. New steady state reached at HCO3- ~15-18 mEq/L - acidosis is NOT progressive (unlike dRTA)
4. During bicarbonaturia: alkaline urine; once HCO3- falls to threshold: urine pH can be <5.5

• Isolated pRTA: Mutations in SLC4A4 gene encoding NBCe1 (basolateral Na+-HCO3- cotransporter) - autosomal recessive, associated with ocular abnormalities (glaucoma, band keratopathy, cataracts)
• Rare dominant form: Mutation in apical NHE-3

• Baseline: Mild hypokalemia from secondary hyperaldosteronism
• With NaHCO3 therapy: Massive increase in distal Na+ and HCO3- delivery → dramatic increase in renal K+ wasting. This is critical pediatric pearl - always add K+ supplementation when treating pRTA.

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Type 4 - Hyperkalemic RTA (Generalized Distal Nephron Dysfunction)

1. Hyporeninemic hypoaldosteronism (most common in adults - diabetes + mild CKD)
2. Hypoaldosteronism (Addison's disease, bilateral adrenalectomy, heparin therapy)
3. Pseudohypoaldosteronism (PHA) type 1: Aldosterone resistance
   • Autosomal recessive (PHA1a): Loss-of-function mutations in ENaC subunits (α, β, or γ) - severe, multi-organ (kidney, lung, sweat glands)
   • Autosomal dominant (PHA1b): Mineralocorticoid receptor mutations - milder, renal limited
4. PHA type 2 / Gordon syndrome: WNK kinase pathway mutations → NaCl cotransporter overactivation → hyperkalemia, hypertension, acidosis
5. Voltage defect disorders: Obstructive uropathy, sickle cell disease, drugs (NSAIDs, ACE inhibitors, ARBs, calcineurin inhibitors, K+-sparing diuretics, trimethoprim, pentamidine)

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Type 3 RTA (Mixed)

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SECTION 2: DIAGNOSTIC APPROACH (5 marks)

Step-by-Step Framework

• Serum: Na+, K+, Cl-, HCO3-, BUN, creatinine, glucose
• Anion gap = Na+ - (Cl- + HCO3-); normal = 8-12 mEq/L
• Rule out: GI HCO3- loss (diarrhea), renal failure (GFR <40 mL/min), DKA, TPN

• UAG = Urine (Na+ + K+) - Urine Cl-
• UAG estimates urinary NH4+ (the predominant unmeasured cation)
• Positive UAG (>0 to +20) = reduced NH4+ excretion = renal cause (RTA) ← kidneys failing to excrete acid
• Negative UAG (<0) = adequate NH4+ excretion = extrarenal cause (diarrhea, fistula, alkali loss)
• Caveat: UAG is unreliable when urine Na+ <20 mEq/L (volume depletion); use urine osmolar gap [= measured Uosm - 2(UNa+UK) - U-urea/2.8 - U-glucose/18] instead; NH4+ ≈ 0.5 × urine osmolar gap

• Urine pH >5.5 (during spontaneous acidosis) → Type 1 (dRTA) or early in Type 2 (pRTA) (when HCO3- is still above threshold)
• Urine pH <5.5 → ability to acidify urine is intact → consider Type 2 (below threshold), Type 4, or extrarenal cause

• Urine pH >5.5 + positive UAG + low K+ → Distal RTA (Type 1)
• Urine pH >5.5 + positive UAG + high K+ → Type 4 / generalized tubular defect / ureteral obstruction
• Urine pH <5.5 + low K+ → do bicarbonate infusion → if FeHCO3- >15% → Proximal RTA (Type 2)
• Urine pH <5.5 + high K+ → Hypoaldosteronism / PHA / CKD / Gordon syndrome

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Specific Confirmatory Tests

For Distal RTA (Type 1):

• Administer oral NaHCO3 to raise urine pH >7.5
• Normal: Urine pCO2 - Blood pCO2 >20 mmHg (H+ secretion generates CO2 as buffers are titrated)
• dRTA: U-B pCO2 <20 mmHg (classic secretory defect) or normal (backleak defect - hence useful for differentiating subtypes)

• NH4Cl 0.1 g/kg orally → normally urine pH falls to <5.3 within 4-6 hours
• dRTA: Urine pH remains >5.5 despite systemic acidosis
• Contraindicated in hepatic disease - use furosemide + fludrocortisone as alternative (safer, more convenient)

• Furosemide 40 mg + fludrocortisone 1 mg orally → maximizes distal Na+ delivery and aldosterone effect
• Normal: Urine pH <5.3 within 3 hours
• dRTA: Failure to acidify; Type 4: Also fails but due to different mechanism

For Proximal RTA (Type 2):

• Infuse NaHCO3 to normalize serum HCO3- (~24 mEq/L)
• FeHCO3- = (U-HCO3- × P-Cr) / (P-HCO3- × U-Cr) × 100
• FeHCO3- >15-20% = proximal RTA (massive bicarbonaturia when serum HCO3- is at normal level)
• FeHCO3- <5% = distal RTA (distal tubule can handle the HCO3-)
• During infusion: Urine pH becomes alkaline in pRTA (hallmark)
• Limitation: Worsens hypokalemia - monitor closely

• Urine glucose (with normal plasma glucose)
• Urine amino acids (generalized aminoaciduria)
• Urine phosphate (tubular maximum for phosphate/GFR = TmP/GFR - low in Fanconi)
• Urine uric acid (hypouricemia + uricosuria)
• Low-molecular-weight proteins (β2-microglobulin, retinol-binding protein)

For Type 4 RTA:

• Plasma aldosterone level (low in hypoaldosteronism, normal/high in PHA)
• Plasma renin activity (low in hyporeninemic hypoaldosteronism)
• Transtubular K+ gradient (TTKG) = (U-K+ / P-K+) / (U-osm / P-osm)
  • TTKG <5 in a hyperkalemic patient = impaired tubular K+ secretion (renal origin)
  • TTKG >7-10 = adequate collecting duct K+ secretion (non-renal hyperkalemia)
  • TTKG response to mineralocorticoid administration: if TTKG rises → hypoaldosteronism; if no rise → PHA (end-organ resistance)
• Fractional excretion of K+ (FEK+) <25% in hyperkalemia → renal K+ retention

Additional Investigations (Pediatric Workup):

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Summary Comparison Table

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SECTION 3: MANAGEMENT (5 marks)

General Principles

1. Treat the underlying cause where possible (e.g., cysteamine for cystinosis, discontinue offending drugs)
2. Alkali therapy is the cornerstone - replaces ongoing bicarbonate losses and corrects acidosis
3. Monitor serum electrolytes, urine calcium, renal function, growth velocity, and bone density
4. Goal: Serum HCO3- ≥20-22 mEq/L (children), normalize growth, prevent/treat nephrocalcinosis and bone disease

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Type 1 - Distal RTA Management

• Children: 2-4 mEq/kg/day (up to 5 mEq/kg/day in infants)
• Adults: 1-2 mEq/kg/day NaHCO3

• Potassium citrate is preferred in dRTA because:
  1. Corrects hypokalemia simultaneously
  2. Increases urinary citrate → inhibits nephrocalcinosis/stone formation
  3. Citrate is metabolized to HCO3- in the liver
• Sodium bicarbonate can worsen hypokalemia initially (intracellular shift of K+ as pH corrects)
• Shohl's solution (sodium citrate + citric acid): Each 1 mL = 1 mEq base; useful in children
• K-citrate (Urocit-K): 5-10 mEq/tablet

• If severe hypokalemia with flaccid paralysis: IV potassium FIRST, then alkali (alkali alone will worsen hypokalemia, risking respiratory muscle paralysis)
• Aim serum K+ ≥3.0 mEq/L before starting alkali in acute setting

• Nephrocalcinosis: Adequate alkali + K-citrate (prevents progression; established deposits may not reverse)
• Rickets/osteomalacia: Correction of acidosis alone usually sufficient; Vitamin D/calcium supplementation if deficient
• Growth failure: Corrects with adequate alkali therapy (catch-up growth expected)
• Hearing loss (rdRTA1): Hearing aids / cochlear implant as needed - acidosis correction does not reverse deafness

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Type 2 - Proximal RTA Management

• Children with isolated pRTA: 5-10 mEq/kg/day (may need up to 10-15 mEq/kg/day)
• Adults: Often needs only small doses; some cases of acquired pRTA resolve with treatment of cause

• Phosphate 25-50 mg/kg/day in divided doses (3-5 times daily)
• Add activated Vitamin D (calcitriol 0.25-0.5 mcg/day) to prevent secondary hyperparathyroidism from phosphate loading

• Induce mild volume contraction → stimulates proximal HCO3- reabsorption → less alkali required
• Used as adjunct, not primary therapy

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Type 4 - Hyperkalemic RTA Management

• Dietary K+ restriction (<1 mEq/kg/day)
• Sodium bicarbonate (shifts K+ intracellularly + corrects acidosis)
• Loop diuretics (furosemide): First-line in many cases; corrects hyperkalemia and mild acidosis together
• Ion exchange resins (sodium/calcium polystyrene sulfonate, patiromer)
• Discontinue causative medications (NSAIDs, ACEi/ARBs, calcineurin inhibitors, K+-sparing diuretics)

• Fludrocortisone 0.1-0.2 mg/day orally
• Increases Na+ reabsorption via ENaC → creates electronegativity → promotes K+ and H+ secretion
• Effective in true hypoaldosteronism and hyporeninemic hypoaldosteronism
• Not effective in PHA (end-organ resistance)

• No response to fludrocortisone
• High-dose sodium supplementation (to overcome ENaC dysfunction)
• May improve with age (extrarenal manifestations - pulmonary involvement may be life-threatening in neonates)

• Milder; may respond partially to supraphysiologic fludrocortisone
• Often improves spontaneously with age

• Low-dose thiazide diuretics - highly effective (corrects the NaCl cotransporter overactivation)

• NaHCO3 0.5-1 mEq/kg/day - relatively small doses needed
• Acidosis often corrects with hyperkalemia treatment alone

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Alkali Replacement Formulations (Key Table for Exams)

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High-Yield Pediatric Pearls (Gold Medal Level)

1. dRTA most feared complication = nephrocalcinosis → renal failure; K-citrate (not NaHCO3) is preferred to prevent stone disease
2. pRTA treatment paradox: The more you treat pRTA, the more K+ is lost - always co-administer KCl
3. Acute severe dRTA with flaccid paralysis: IV K+ FIRST before any alkali
4. Cystinosis is the most common cause of Fanconi syndrome in children; diagnose with WBC cystine levels; treat with cysteamine
5. Type 3 RTA = osteopetrosis + brain calcifications + mixed RTA = CA2 gene deficiency (Guibaud-Vainsel)
6. rdRTA1 (ATP6V1B1): Always check audiogram - sensorineural deafness is present
7. Endemic dRTA (northeastern Thailand): H+/K+-ATPase abnormality
8. Growth failure in children with RTA is reliably corrected with adequate alkali therapy - catch-up growth is a major treatment endpoint
9. Amphotericin B causes dRTA by backleak mechanism (not secretory defect) → U-B pCO2 may be normal
10. Topiramate causes pRTA (carbonic anhydrase inhibitor) - affects 15-25% of patients on this anticonvulsant
11. UAG pitfall: Unreliable when urine Na+ <20 mEq/L; use urine osmolar gap instead
12. TTKG interpretation: TTKG <5 in a hyperkalemic patient = renal K+ retention = Type 4 RTA; if TTKG rises with fludrocortisone → hypoaldosteronism; if no rise → PHA

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Recent Updates (PubMed 2022-2026)

• A 2023 review in Nature Reviews Nephrology (PMID 37016093) provides updated molecular pathophysiology of dRTA, emphasizing the role of H+-ATPase subunit mutations and genotype-phenotype correlations in hereditary forms - confirming that ATP6V1B1 mutations carry a greater risk of deafness and more severe hypokalemia than ATP6V0a4 mutations.
• Current consensus maintains that potassium citrate is preferred over sodium bicarbonate in dRTA for its dual benefit on hypokalemia and nephrocalcinosis prevention.
• Genetic testing panels (next-generation sequencing) are now the gold standard for confirming hereditary RTA in children, replacing solely clinical/biochemical classification.

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Approach to Proteinuria in a Child (10 Marks - MD Pediatrics)

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I. DEFINITION AND NORMAL VALUES

• Age 6 months - 2 years: Upper normal = 0.5 mg/mg
• Older children and adolescents: Upper normal = 0.2 mg/mg
• Nephrotic-range proteinuria: UP:UC ≥3.0 mg/mg

• Detects albumin only (misses tubular/overflow proteinuria)
• False positive: Alkaline urine (pH ≥7.0), concentrated urine, contamination with blood, vaginal/seminal secretions, mucus
• False negative: Dilute urine, Bence Jones proteins, low-MW tubular proteins
• Always confirm dipstick with spot UP:UC or 24-hour urine on repeat first morning void

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II. PHYSIOLOGICAL BASIS AND MECHANISMS

1. Fenestrated endothelium - size restriction
2. Glomerular basement membrane (GBM) - size + charge selectivity (glycosaminoglycans - negatively charged, repel anionic albumin)
3. Podocytes + slit diaphragm - composed of nephrin, podocin, CD2AP, α-actinin-4; genetic mutations cause steroid-resistant nephrotic syndrome

Types of Proteinuria:

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III. CLASSIFICATION BY DURATION

A. Transient Proteinuria (Most Common, Benign)

• Accounts for the majority of proteinuria detected on random screening
• Causes: Fever, vigorous exercise, dehydration, emotional stress, cold exposure, seizures, congestive heart failure, recent epinephrine use
• Management: No workup needed; resolves with resolution of precipitating factor
• Confirm: Repeat dipstick when child is well and afebrile - should be negative

B. Orthostatic (Postural) Proteinuria

• Occurs in 3-5% of healthy adolescents; accounts for majority of persistent asymptomatic proteinuria in school-age children
• Proteinuria present in upright position, absent in recumbent position
• Mechanism: Postulated alteration in renal hemodynamics in upright posture; rarely associated with "nutcracker phenomenon" (compression of left renal vein between aorta and superior mesenteric artery)
• Amount: Generally <1 g/day (UP:UC <1.0)
• Prognosis: Kidney biopsy shows normal or non-specific findings; excellent long-term prognosis; self-limiting in most cases

1. Child empties bladder at bedtime (discard)
2. Collect first morning void immediately on waking (recumbent sample) - urine protein absent or minimal
3. Collect second urine after 2 hours of upright activity (upright sample) - proteinuria present
4. Diagnosis confirmed if: Recumbent UP:UC <0.1 + upright UP:UC elevated

C. Persistent Proteinuria (Requires Full Evaluation)

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IV. DIAGNOSTIC APPROACH (STEP-BY-STEP)

Step 1: Confirm and Quantify Proteinuria

• First morning void (FMV) on 3 separate occasions (minimizes orthostatic contribution)
• Spot UP:UC ratio on FMV = gold standard for screening/quantification in children; correlates with 24-hour urine protein excretion
• 24-hour urine protein (if available): >4 mg/m²/hr = significant; >40 mg/m²/hr = nephrotic range
• Sulphosalicylic acid (SSA) test: Detects all proteins including LMW (Bence Jones); semi-quantitative; if SSA positive but dipstick negative → overflow/tubular proteinuria

Step 2: Rule Out Transient and Orthostatic Proteinuria

• Repeat FMV urine dipstick when child is well
• Perform split urine collection (as above) to confirm/exclude orthostatic proteinuria
• If transient or orthostatic → reassure; follow up annually
• If persistent and fixed (present even in recumbent sample) → proceed to full evaluation

Step 3: Characterize the Proteinuria

• Age (nephrotic syndrome: peak 1-8 years; FSGS common >8 years)
• Duration and amount of edema (periorbital = often first sign, mistaken for allergy)
• Haematuria (suggests GN - IgAN, PIGN, Alport, MPGN, HSP nephritis, lupus)
• Oliguria, hypertension (nephritis)
• Recurrent infections (hypogammaglobulinemia from urinary Ig loss in NS)
• Systemic symptoms: joint pains, rash, fever (SLE, HSP, vasculitis)
• Family history: hereditary nephritis (Alport), Finnish-type NS, polycystic kidney disease
• Drug history: NSAIDs, captopril, penicillamine, gold, lithium, heroin
• Recent URTI/skin infection (2-3 weeks prior → PIGN)
• Hearing loss (Alport syndrome - X-linked COL4A5 mutation)

• Blood pressure (hypertension → nephritis/FSGS/advanced NS)
• Edema: periorbital, pedal, ascites, pleural effusion (anasarca in NS)
• Growth parameters (chronic kidney disease)
• Rash: malar rash (SLE), purpura (HSP)
• Arthritis (SLE, HSP)
• Ophthalmology: anterior lenticonus (Alport)
• Ear: sensorineural deafness (Alport)

Step 4: Classify as Nephrotic vs. Non-Nephrotic

Step 5: Laboratory Workup

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V. WHEN TO REFER AND WHEN TO BIOPSY

Indications for Renal Biopsy in a Child with Proteinuria:

1. Age <1 year (congenital NS - consider Finnish-type, diffuse mesangial sclerosis, genetic cause)
2. Steroid-resistant NS (no remission after 4-6 weeks of prednisolone at standard dose)
3. Steroid-dependent or frequently relapsing NS - to guide immunosuppressive choice
4. Nephritic + nephrotic syndrome (haematuria + hypertension + low complement + heavy proteinuria)
5. NS with persistent low complement (rules out PIGN after 6-8 weeks)
6. Persistent non-nephrotic proteinuria (>1 g/day) with deteriorating GFR
7. Suspected systemic disease (SLE, vasculitis) - for WHO/ISN-RPS class determination
8. Family history of hereditary nephritis with haematuria + proteinuria
9. NS in children >10 years (higher risk of non-MCNS histology)
10. Proteinuria + renal impairment at presentation (to exclude RPGN)

• Age <1 year or >10 years
• Family history of kidney disease
• Extrarenal disease (arthritis, rash, anaemia)
• Chronic systemic illness
• Hypertension or pulmonary oedema (volume expansion)
• Acute kidney injury at presentation
• Active urine sediment (RBC casts, dysmorphic RBCs)

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VI. DIAGNOSTIC ALGORITHM (STRUCTURED FLOWCHART)

DIPSTICK ≥1+ PROTEINURIA ON RANDOM SAMPLE
            ↓
    Repeat on FIRST MORNING VOID × 3 occasions
            ↓
    ┌────────────────┬────────────────┐
Negative/Trace        1+ or more (persistent)
    ↓                       ↓
Transient           EXCLUDE ORTHOSTATIC:
(reassure,            Two-sample split collection
 no workup)              ↓
                ┌────────────────┐
            Negative in        Positive in
            recumbent          recumbent
                ↓                   ↓
           ORTHOSTATIC         FIXED PERSISTENT
           PROTEINURIA         PROTEINURIA
           (reassure,        ← FULL EVALUATION →
           annual follow-up)
                                   ↓
                    ┌──────────────────────────────┐
               QUANTIFY:                    CHARACTERIZE:
               UP:UC / 24-hr urine          Nephrotic vs. Non-nephrotic
                    ↓                              ↓
        ┌───────────────────────┐    ┌─────────────────────────┐
    NEPHROTIC (UP:UC ≥3)      NON-NEPHROTIC (UP:UC 0.2-3)
    + Albumin <2.5 g/dL        Haematuria? Hypertension?
        ↓                               ↓
    1-8 yrs, no           Yes: GN screen (C3/C4, ANA, ANCA, ASO)
    atypical features       No: Tubular screen (β2-MG, UPEP)
        ↓                               ↓
    EMPIRIC STEROIDS           Nephrology referral + biopsy
    (prednisolone 2 mg/kg/day)   if indicated
        ↓
    STEROID RESPONSIVE?
    Yes: MCNS (90% children 1-8 yr)
    No: BIOPSY (FSGS, MPGN, MN, genetic NS)

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VII. MANAGEMENT OVERVIEW

Transient and Orthostatic Proteinuria:

• Reassurance; no treatment needed
• Annual follow-up for orthostatic proteinuria (rare progression to fixed proteinuria)

Idiopathic Nephrotic Syndrome (First Presentation):

• Prednisolone 2 mg/kg/day (max 60 mg/day) for 6 weeks, then 1.5 mg/kg alternate day × 6 weeks (total 12 weeks per ISKDC modified protocol; Indian Association of Pediatric Nephrology [ISPN/Bagga] protocol extends initial daily phase to 12 weeks)
• Dietary salt restriction, fluid restriction if oedematous
• Diuretics (spironolactone + furosemide) if severe oedema - cautiously; risk of hypovolaemia
• Penicillin prophylaxis (pneumococcal risk in NS)
• Pneumococcal vaccine (before steroids if possible)
• Monitoring: BP, urine protein, serum albumin, lipids, weight, height

Persistent Non-Nephrotic Proteinuria:

• Treat underlying cause
• ACE inhibitors (enalapril) or ARBs - antiproteinuric effect (reduce intraglomerular pressure + direct effect on podocyte slit diaphragm); first-line for all causes of significant persistent proteinuria
• BP target: <50th centile for age/sex/height (or <130/80 mmHg in adolescents)
• Low-sodium, moderate-protein diet
• Nephrology referral for biopsy guidance

Tubular Proteinuria:

• Treat underlying disorder (cysteamine for cystinosis, remove offending drug)
• Generally does not respond to ACE inhibitors

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VIII. RECENT UPDATES (2022-2026)

1. Bravo WC, Pediatrics in Review 2026 (PMID 42219187): Confirms that in children, proteinuria is most often transient or orthostatic. The paper emphasises that the differential diagnosis of proteinuria differs fundamentally based on glomerular vs. tubular origin, and that persistent proteinuria is both a sign of underlying pathology and a modifiable risk factor for CKD progression.
2. Genetic causes of NS: Next-generation sequencing panels for podocyte genes (NPHS1, NPHS2, WT1, LAMB2, TRPC6, INF2, CD2AP) are increasingly recommended before biopsy in infantile/congenital NS and steroid-resistant NS to guide prognosis and avoid immunosuppression in genetic forms.
3. Alport syndrome - 2024 ERKNet/ERA/ESPN guideline (PMID 39673454): Recommends early ACE inhibitor therapy (even pre-proteinuric stage if microscopic haematuria present) to delay progression to ESRD. Genetic testing (COL4A3/A4/A5) is now standard first-line investigation.
4. KDIGO albuminuria categories (A1/A2/A3) now preferred over older "microalbuminuria/macroalbuminuria" terminology.
5. SGLT2 inhibitors: Emerging evidence for antiproteinuric role in adolescents with CKD/diabetic nephropathy, though paediatric-specific trials are still ongoing.

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IX. HIGH-YIELD SUMMARY TABLE (Exam-Oriented)

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