Nephritic syndrome - Revision history

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Ostermayer: Created page with "Nephritic syndrome is a clinical syndrome resulting from '''glomerular inflammation (glomerulonephritis)''', characterized by '''hematuria''' (with dysmorphic RBCs and RBC casts), '''hypertension''', '''oliguria''', '''edema''', and '''subnephrotic proteinuria'''.Nephritic Syndrome. ''StatPearls''. NCBI. 2023. It is distinguished from Nephrotic syndrome primarily by the presence of '''hematuria and active urinary sediment'''. The EM physi..."

2026-03-18T01:48:40Z

Created page with "Nephritic syndrome is a clinical syndrome resulting from '''glomerular inflammation (glomerulonephritis)''', characterized by '''hematuria''' (with dysmorphic RBCs and RBC casts), '''hypertension''', '''oliguria''', '''edema''', and '''subnephrotic proteinuria'''.<ref name="StatPearls">Nephritic Syndrome. ''StatPearls''. NCBI. 2023.</ref> It is distinguished from Nephrotic syndrome primarily by the presence of '''hematuria and active urinary sediment'''. The EM physi..."

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Nephritic syndrome is a clinical syndrome resulting from '''glomerular inflammation (glomerulonephritis)''', characterized by '''hematuria''' (with dysmorphic RBCs and RBC casts), '''hypertension''', '''oliguria''', '''edema''', and '''subnephrotic proteinuria'''.<ref name="StatPearls">Nephritic Syndrome. ''StatPearls''. NCBI. 2023.</ref> It is distinguished from [[Nephrotic syndrome]] primarily by the presence of '''hematuria and active urinary sediment'''. The EM physician encounters nephritic syndrome as '''"cola-colored" urine in a child 1-3 weeks after a sore throat''' (post-streptococcal GN), '''acute renal failure with hypertension and pulmonary edema''', or '''hemoptysis with renal failure''' (pulmonary-renal syndrome). The key ED tasks are to '''recognize the syndrome via urinalysis''', '''manage life-threatening complications''' (hypertensive emergency, hyperkalemia, pulmonary edema, AKI), '''identify rapidly progressive glomerulonephritis (RPGN)''' as a true emergency requiring immediate nephrology involvement, and '''initiate targeted serologic workup'''.

==Background==
*Nephritic syndrome is a '''pattern of glomerular disease''', not a single diagnosis — many diseases present this way
*'''Children:''' post-streptococcal glomerulonephritis (PSGN) is the most common cause
*'''Adults:''' IgA nephropathy, lupus nephritis, ANCA-associated vasculitis, and infection-associated GN are more common
*The distinction between nephritic and nephrotic syndromes is fundamental to the ED evaluation of renal disease:

{| class="wikitable"
|-
! Feature !! '''Nephritic syndrome''' !! '''[[Nephrotic syndrome]]'''
|-
| Primary mechanism || '''Glomerular inflammation''' || Podocyte injury (permeability defect)
|-
| Hematuria || '''Prominent''' (dysmorphic RBCs, RBC casts) || Absent or minimal
|-
| Proteinuria || '''Subnephrotic''' (<3.5 g/day) || '''Nephrotic-range''' (>3.5 g/day)
|-
| Edema || Mild-moderate (volume overload) || '''Severe''' (hypoalbuminemia)
|-
| Hypertension || '''Prominent''' (salt/water retention) || Variable
|-
| Serum albumin || Normal or mildly low || '''Markedly low''' (<3.0 g/dL)
|-
| Hyperlipidemia || Absent || '''Present'''
|-
| Urine sediment || '''Active:''' RBC casts, dysmorphic RBCs, WBCs || '''Bland:''' oval fat bodies, fatty casts; no RBC casts
|-
| Renal function || Often '''impaired''' (elevated creatinine) || Usually preserved early
|}

*Some diseases (MPGN, lupus nephritis, FSGS) can present with '''overlap features''' of both syndromes

==Clinical features==
===Classic acute nephritic syndrome===
*'''Hematuria:''' "cola-colored," "tea-colored," or "smoky" urine (gross hematuria); or microscopic hematuria
*'''Edema:''' periorbital (especially on waking), lower extremity; mild to moderate
*'''Hypertension:''' from sodium/water retention and intravascular volume expansion; may be '''severe'''
*'''Oliguria:''' reduced urine output (<400 mL/day in adults; <0.5 mL/kg/hr in children)
*'''Proteinuria:''' present but usually subnephrotic
*'''Malaise, fatigue, anorexia, nausea'''
*'''Flank or abdominal pain''' (especially in children)
*Onset is often '''abrupt''' (days to 1-2 weeks)

===Post-streptococcal glomerulonephritis (PSGN) — the prototype===
*'''Most common cause in children''' (ages 5-12 years); declining incidence in developed countries<ref name="GN">Glomerulonephritis. ''StatPearls''. NCBI. 2023.</ref>
*'''Latent period:''' 1-2 weeks after pharyngitis; 3-6 weeks after skin infection (pyoderma/impetigo)
*'''Not present during the infection''' — symptoms appear after a latent period (distinguishes from IgA nephropathy, which is synpharyngitic)
*'''Gross hematuria''' in >50% of cases; "smoky" or "cola-colored" urine
*'''Edema and hypertension''' from salt/water retention
*'''Low C3 complement''' (returns to normal within 6-8 weeks — failure to normalize suggests MPGN or C3 glomerulopathy)
*Usually '''self-limited''' in children (>95% recover completely); adults have worse prognosis

===IgA nephropathy (Berger disease) — the most common GN worldwide===
*'''Synpharyngitic hematuria:''' gross hematuria occurring '''within 1-2 days''' of an upper respiratory infection (NOT after a latent period — key distinction from PSGN)<ref name="Wiki_Neph">Nephritic syndrome. ''Wikipedia''. 2025.</ref>
*Recurrent episodes of gross hematuria
*Between episodes: persistent microscopic hematuria ± proteinuria
*'''Normal complement levels''' (unlike PSGN)
*May overlap with [[Henoch-Schönlein purpura]] (IgA vasculitis) — systemic form with palpable purpura, arthritis, abdominal pain, and GN

===Rapidly progressive glomerulonephritis (RPGN) — the EM emergency===
*'''Defines >50% loss of renal function within 3 months'''
*Nephritic sediment + '''rapidly rising creatinine''' over days to weeks
*Pathologic hallmark: '''crescent formation''' in glomeruli on biopsy
*'''Three immunologic categories:'''

{| class="wikitable"
|-
! Type !! Mechanism !! Classic disease !! Key lab findings
|-
| '''Type I (anti-GBM)''' || Anti-glomerular basement membrane antibodies || '''Goodpasture syndrome''' (anti-GBM + pulmonary hemorrhage) || Anti-GBM antibodies positive; complement normal
|-
| '''Type II (immune complex)''' || Immune complex deposition || Lupus nephritis, PSGN (severe), IgA nephropathy, MPGN, endocarditis-related || ANA, anti-dsDNA (lupus); low complement (C3, C4); cryoglobulins
|-
| '''Type III (pauci-immune)''' || ANCA-associated vasculitis (minimal immune deposits) || '''Granulomatosis with polyangiitis (GPA)''', '''microscopic polyangiitis (MPA)''' || '''ANCA positive''' (c-ANCA/PR3 for GPA; p-ANCA/MPO for MPA); complement normal
|}

*'''RPGN is a true nephrology emergency''' — delay in treatment leads to irreversible ESKD
*Requires '''immediate nephrology consultation''', renal biopsy, and aggressive immunosuppression ± plasma exchange

===Pulmonary-renal syndrome===
*'''Hemoptysis + nephritic syndrome''' = pulmonary-renal syndrome until proven otherwise
*Causes: '''Goodpasture syndrome''' (anti-GBM), '''GPA''', '''MPA''', lupus, cryoglobulinemia
*May present with '''diffuse alveolar hemorrhage''' (DAH): hemoptysis, dyspnea, bilateral infiltrates on CXR, dropping hemoglobin
*'''Life-threatening''' — requires ICU admission, urgent nephrology and pulmonology consultation

==Differential diagnosis==
===By complement level (high-yield ED approach)===

====Low C3 (hypocomplementemic)====
*'''Post-streptococcal GN''' (low C3; C4 normal or slightly low; normalizes by 6-8 weeks)
*'''Lupus nephritis''' (low C3 AND C4)
*'''MPGN / C3 glomerulopathy''' (persistently low C3)
*'''Endocarditis-associated GN''' (low C3; blood cultures positive)
*'''Cryoglobulinemic GN''' (low C3 and C4; hepatitis C associated)

====Normal complement====
*'''IgA nephropathy'''
*'''ANCA-associated vasculitis (GPA, MPA)'''
*'''Anti-GBM disease (Goodpasture)'''
*'''Henoch-Schönlein purpura'''
*'''Hereditary nephritis (Alport syndrome)'''

===Non-glomerular causes of hematuria to exclude===
*'''Urinary tract infection''' (positive urine culture; normal RBC morphology)
*'''Nephrolithiasis''' (flank pain; isomorphic RBCs; no casts)
*'''Trauma'''
*'''Urologic malignancy''' (adults; painless hematuria)
*'''Menstrual contamination'''
*'''Exercise-induced hematuria'''

===Key to glomerular vs non-glomerular hematuria===
*'''Glomerular:''' dysmorphic RBCs (acanthocytes), '''RBC casts''' (virtually pathognomonic), proteinuria, brown/cola-colored urine, no clots
*'''Non-glomerular:''' normal/isomorphic RBCs, no casts, pink/red urine, may have clots

==Evaluation==
===ED workup===
*'''Urinalysis with microscopy:''' the '''single most important test'''<ref name="AcuteGN">Acute Glomerulonephritis Workup. ''Medscape''. 2024.</ref>
**'''RBC casts:''' virtually pathognomonic for glomerulonephritis
**'''Dysmorphic RBCs''' (acanthocytes — best seen with phase-contrast microscopy; >30% dysmorphic is highly specific for glomerular origin)
**Proteinuria (usually 1-3+ on dipstick)
**Sterile pyuria (WBCs without bacteria)
*'''BMP/CMP:'''
**'''Creatinine''' (elevated = impaired GFR; trending creatinine is critical for identifying RPGN)
**'''Potassium''' (hyperkalemia from impaired excretion — potentially life-threatening)
**'''Bicarbonate''' (metabolic acidosis)
**'''BUN''' (elevated; disproportionately elevated BUN:creatinine ratio in prerenal azotemia)
*'''CBC:''' anemia (dilutional or from chronic disease); thrombocytopenia (TTP-HUS, SLE)
*'''Spot urine protein:creatinine ratio:''' quantifies proteinuria; helps distinguish nephritic (<3.5) from nephrotic (>3.5)
*'''Albumin:''' usually near-normal (mildly low at most); if markedly low, consider nephrotic overlap
*'''Blood pressure:''' frequently elevated; may be severely hypertensive

===Targeted serologic workup (initiate from ED based on clinical suspicion)===
{| class="wikitable"
|-
! Test !! What it identifies
|-
| '''C3, C4 complement''' || Low C3: PSGN, lupus, MPGN, endocarditis GN; Low C3+C4: lupus, cryoglobulinemia
|-
| '''ASO titer, anti-DNase B''' || Post-streptococcal GN (ASO elevated after pharyngitis; anti-DNase B after skin infection)
|-
| '''ANA, anti-dsDNA''' || Lupus nephritis
|-
| '''ANCA''' (c-ANCA/PR3, p-ANCA/MPO) || ANCA-associated vasculitis (GPA, MPA)
|-
| '''Anti-GBM antibodies''' || Goodpasture syndrome / anti-GBM disease
|-
| '''Blood cultures''' || Endocarditis-associated GN
|-
| '''Hepatitis B, C serologies''' || Hepatitis-associated GN, cryoglobulinemia, MPGN
|-
| '''Cryoglobulins''' || Cryoglobulinemic GN (often hepatitis C-associated)
|-
| '''HIV''' || HIV-associated nephropathy
|-
| '''Serum IgA''' || Elevated in ~50% of IgA nephropathy (nonspecific)
|}

===Imaging===
*'''Renal ultrasound:''' assess kidney size (normal or enlarged in acute GN; small in chronic GN), exclude obstruction
*'''Chest X-ray:''' if dyspnea (pulmonary edema, pulmonary hemorrhage/DAH), cough, hemoptysis
*'''CT head:''' if hypertensive encephalopathy suspected (altered mental status, seizures, visual changes)
*'''Echocardiography:''' if endocarditis suspected

===Renal biopsy===
*'''Not an ED procedure''' — arranged by nephrology
*Indicated for most adults with nephritic syndrome (PSGN in children with typical presentation usually does not require biopsy)
*'''Urgent biopsy indications:''' suspected RPGN, rapidly deteriorating renal function, unclear diagnosis

==Management==
===Life-threatening emergencies (manage first)===

====Hypertensive emergency====
*May present with '''encephalopathy, seizures, visual changes, pulmonary edema'''
*'''Salt and water restriction'''
*'''Loop diuretics:''' furosemide 1-2 mg/kg IV (children) or 40-80 mg IV (adults) — first-line for volume-overload hypertension
*'''IV antihypertensives''' if diuretics insufficient: nicardipine infusion, labetalol, or hydralazine
*Avoid ACE inhibitors/ARBs in the '''acute''' setting with AKI and hyperkalemia (may worsen both)
*Target: gradual reduction; do not lower BP >25% in the first hour

====Hyperkalemia====
*'''Impaired renal excretion''' → dangerous hyperkalemia
*Manage per standard [[Hyperkalemia]] protocols: calcium gluconate (cardiac membrane stabilization), insulin + dextrose, albuterol, sodium bicarbonate, kayexalate/patiromer, dialysis if refractory

====Pulmonary edema / volume overload====
*'''IV furosemide''' (high-dose may be needed with impaired GFR)
*'''Oxygen, positive pressure ventilation''' (CPAP/BiPAP or intubation) if severe
*'''Fluid and sodium restriction'''
*'''Dialysis''' if refractory pulmonary edema unresponsive to diuretics

====Pulmonary hemorrhage (pulmonary-renal syndrome)====
*'''ICU admission'''
*'''Urgent nephrology and pulmonology consultation'''
*'''Plasma exchange (plasmapheresis):''' especially for anti-GBM disease (removes pathogenic antibodies)
*'''Pulse IV methylprednisolone''' (1 g daily for 3 days) ± cyclophosphamide — initiated by specialist
*'''Intubation and mechanical ventilation''' if significant hemorrhage/respiratory failure
*'''Type and crossmatch''' — transfuse for significant anemia from hemorrhage

===General ED management of acute nephritic syndrome===
*'''Fluid restriction:''' limit to insensible losses + urine output
*'''Sodium restriction'''
*'''Loop diuretics:''' for edema and hypertension
*'''Monitor:''' urine output, blood pressure, electrolytes (especially potassium), creatinine q6-12 hours
*'''Treat underlying infection:''' antibiotics for endocarditis; note that PSGN treatment targets the ''complication'' (not the strep infection itself — the GN is post-infectious; antibiotics do not alter the course of GN but may eradicate ongoing streptococcal infection)
*'''Hold nephrotoxic medications:''' NSAIDs, aminoglycosides, contrast dye

===Disease-specific treatment (nephrology-directed)===
*'''PSGN:''' supportive care; usually self-limited; antibiotics only to eradicate residual streptococcal infection
*'''Lupus nephritis:''' corticosteroids ± mycophenolate mofetil or cyclophosphamide
*'''ANCA-associated vasculitis:''' pulse steroids + cyclophosphamide or rituximab; plasma exchange for severe disease
*'''Anti-GBM disease:''' plasma exchange + steroids + cyclophosphamide — '''true emergency; outcomes are time-dependent'''
*'''IgA nephropathy:''' ACE inhibitor/ARB; immunosuppression for severe/progressive disease
*'''Endocarditis-associated GN:''' treat the endocarditis; immunosuppression is '''contraindicated''' (would worsen infection)

==Disposition==
*'''Admit:'''
**Hypertensive emergency or severely elevated blood pressure
**Hyperkalemia
**Pulmonary edema or respiratory distress
**Rapidly rising creatinine (suspect RPGN) — '''urgent nephrology consult'''
**Pulmonary hemorrhage / pulmonary-renal syndrome — '''ICU'''
**Significant AKI (creatinine >2x baseline, oliguria, need for dialysis)
**New-onset nephritic syndrome in adults (most require biopsy and specialist evaluation)
*'''Consider discharge with close follow-up (48-72 hours):'''
**Child with classic PSGN presentation: mild edema + mild hypertension + stable renal function + no hyperkalemia + confirmed strep history
**Ensure '''nephrology or pediatric nephrology follow-up''' within 48-72 hours
**Return precautions: decreased urine output, worsening edema, headache, visual changes, seizures, difficulty breathing
*'''Always obtain nephrology consultation''' for: RPGN, pulmonary-renal syndrome, unclear diagnosis, adults with nephritic syndrome, renal failure requiring dialysis

==See Also==
*[[Nephrotic syndrome]]
*[[Focal segmental glomerulosclerosis]]
*[[Acute kidney injury]]
*[[Hyperkalemia]]
*[[Hypertensive emergency]]
*[[Post-streptococcal glomerulonephritis]]
*[[IgA nephropathy]]
*[[Lupus nephritis]]
*[[Goodpasture syndrome]]
*[[Henoch-Schönlein purpura]]
*[[Pulmonary embolism]]

==External Links==
*[https://www.ncbi.nlm.nih.gov/books/NBK562240/ StatPearls — Nephritic Syndrome]
*[https://www.ncbi.nlm.nih.gov/books/NBK560644/ StatPearls — Glomerulonephritis]
*[https://pmc.ncbi.nlm.nih.gov/articles/PMC6188440/ PMC — Clinical Presentation & Management of Glomerular Diseases]
*[https://emedicine.medscape.com/article/239278-workup Medscape — Acute Glomerulonephritis Workup]
*[https://www.msdmanuals.com/professional/genitourinary-disorders/glomerular-disorders/overview-of-nephritic-syndrome MSD Manual — Overview of Nephritic Syndrome]

==References==
<references/>

[[Category:Renal]]

← Older revision		Revision as of 09:36, 22 March 2026
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	*The EM physician encounters nephritic syndrome as "cola-colored" urine in a child 1-3 weeks after a sore throat (post-streptococcal GN), acute renal failure with hypertension and pulmonary edema, or hemoptysis with renal failure (pulmonary-renal syndrome)		*The EM physician encounters nephritic syndrome as "cola-colored" urine in a child 1-3 weeks after a sore throat (post-streptococcal GN), acute renal failure with hypertension and pulmonary edema, or hemoptysis with renal failure (pulmonary-renal syndrome)
	*The key ED tasks are to recognize the syndrome via urinalysis, manage life-threatening complications (hypertensive emergency, hyperkalemia, pulmonary edema, AKI), identify '''rapidly progressive glomerulonephritis (RPGN)''' as a true emergency requiring immediate nephrology involvement, and initiate targeted serologic workup		*The key ED tasks are to recognize the syndrome via urinalysis, manage life-threatening complications (hypertensive emergency, hyperkalemia, pulmonary edema, AKI), identify '''rapidly progressive glomerulonephritis (RPGN)''' as a true emergency requiring immediate nephrology involvement, and initiate targeted serologic workup
	*Nephritic syndrome is a ~~'''~~pattern of glomerular disease~~'''~~, not a single diagnosis — many diseases present this way		*Nephritic syndrome is a pattern of glomerular disease, not a single diagnosis — many diseases present this way
	* Children: post-streptococcal glomerulonephritis (PSGN) is the most common cause		* Children: post-streptococcal glomerulonephritis (PSGN) is the most common cause
	* Adults: IgA nephropathy, lupus nephritis, ANCA-associated vasculitis, and infection-associated GN are more common		* Adults: IgA nephropathy, lupus nephritis, ANCA-associated vasculitis, and infection-associated GN are more common
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	\|}		\|}

	*Some diseases (MPGN, lupus nephritis, FSGS) can present with ~~'''~~overlap features~~'''~~ of both syndromes		*Some diseases (MPGN, lupus nephritis, FSGS) can present with overlap features of both syndromes

	==Clinical features==		==Clinical features==
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	* Hematuria "cola-colored," "tea-colored," or "smoky" urine (gross hematuria); or microscopic hematuria		* Hematuria "cola-colored," "tea-colored," or "smoky" urine (gross hematuria); or microscopic hematuria
	* Edema periorbital (especially on waking), lower extremity; mild to moderate		* Edema periorbital (especially on waking), lower extremity; mild to moderate
	* Hypertension from sodium/water retention and intravascular volume expansion; may be ~~'''~~severe~~'''~~		* Hypertension from sodium/water retention and intravascular volume expansion; may be severe
	* Oliguria reduced urine output (<400 mL/day in adults; <0.5 mL/kg/hr in children)		* Oliguria reduced urine output (<400 mL/day in adults; <0.5 mL/kg/hr in children)
	* Proteinuria present but usually subnephrotic		* Proteinuria present but usually subnephrotic
	* Malaise, fatigue, anorexia, nausea		* Malaise, fatigue, anorexia, nausea
	* Flank or abdominal pain (especially in children)		* Flank or abdominal pain (especially in children)
	*Onset is often ~~'''~~abrupt~~'''~~ (days to 1-2 weeks)		*Onset is often abrupt (days to 1-2 weeks)

	===Post-streptococcal glomerulonephritis (PSGN) — the prototype===		===Post-streptococcal glomerulonephritis (PSGN) — the prototype===
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	* Edema and hypertension from salt/water retention		* Edema and hypertension from salt/water retention
	* Low C3 complement (returns to normal within 6-8 weeks — failure to normalize suggests MPGN or C3 glomerulopathy)		* Low C3 complement (returns to normal within 6-8 weeks — failure to normalize suggests MPGN or C3 glomerulopathy)
	*Usually ~~'''~~self-limited~~'''~~ in children (>95% recover completely); adults have worse prognosis		*Usually self-limited in children (>95% recover completely); adults have worse prognosis

	===IgA nephropathy (Berger disease) — the most common GN worldwide===		===IgA nephropathy (Berger disease) — the most common GN worldwide===
	* Synpharyngitic hematuria: gross hematuria occurring ~~'''~~within 1-2 days~~'''~~ of an upper respiratory infection (NOT after a latent period — key distinction from PSGN)<ref name="Wiki_Neph">Nephritic syndrome. ''Wikipedia''. 2025.</ref>		* Synpharyngitic hematuria: gross hematuria occurring within 1-2 days of an upper respiratory infection (NOT after a latent period — key distinction from PSGN)<ref name="Wiki_Neph">Nephritic syndrome. ''Wikipedia''. 2025.</ref>
	*Recurrent episodes of gross hematuria		*Recurrent episodes of gross hematuria
	*Between episodes: persistent microscopic hematuria ± proteinuria		*Between episodes: persistent microscopic hematuria ± proteinuria
Line 63:		Line 63:
	===Rapidly progressive glomerulonephritis (RPGN) — the EM emergency===		===Rapidly progressive glomerulonephritis (RPGN) — the EM emergency===
	* Defines >50% loss of renal function within 3 months		* Defines >50% loss of renal function within 3 months
	*Nephritic sediment + ~~'''~~rapidly rising creatinine~~'''~~ over days to weeks		*Nephritic sediment + rapidly rising creatinine over days to weeks
	*Pathologic hallmark: ~~'''~~crescent formation~~'''~~ in glomeruli on biopsy		*Pathologic hallmark: crescent formation in glomeruli on biopsy
	* Three immunologic categories:		* Three immunologic categories:

Line 79:		Line 79:

	*'''RPGN is a true nephrology emergency''' — delay in treatment leads to irreversible ESKD		*'''RPGN is a true nephrology emergency''' — delay in treatment leads to irreversible ESKD
	*Requires ~~'''~~immediate nephrology consultation~~'''~~, renal biopsy, and aggressive immunosuppression ± plasma exchange		*Requires immediate nephrology consultation, renal biopsy, and aggressive immunosuppression ± plasma exchange

	===Pulmonary-renal syndrome===		===Pulmonary-renal syndrome===
	*~~'''~~Hemoptysis + nephritic syndrome~~'''~~ = pulmonary-renal syndrome until proven otherwise		*Hemoptysis + nephritic syndrome = pulmonary-renal syndrome until proven otherwise
	*Causes: ~~'''~~Goodpasture syndrome~~'''~~ (anti-GBM), ~~'''~~GPA~~'''~~, ~~'''~~MPA~~'''~~, lupus, cryoglobulinemia		*Causes: Goodpasture syndrome (anti-GBM), GPA, MPA, lupus, cryoglobulinemia
	*May present with ~~'''~~diffuse alveolar hemorrhage~~'''~~ (DAH): hemoptysis, dyspnea, bilateral infiltrates on CXR, dropping hemoglobin		*May present with diffuse alveolar hemorrhage (DAH): hemoptysis, dyspnea, bilateral infiltrates on CXR, dropping hemoglobin
	*'''Life-threatening''' — requires ICU admission, urgent nephrology and pulmonology consultation		*'''Life-threatening''' — requires ICU admission, urgent nephrology and pulmonology consultation

Line 113:		Line 113:

	===Key to glomerular vs non-glomerular hematuria===		===Key to glomerular vs non-glomerular hematuria===
	* Glomerular dysmorphic RBCs (acanthocytes), ~~'''~~RBC casts~~'''~~ (virtually pathognomonic), proteinuria, brown/cola-colored urine, no clots		* Glomerular dysmorphic RBCs (acanthocytes), RBC casts (virtually pathognomonic), proteinuria, brown/cola-colored urine, no clots
	* Non-glomerular normal/isomorphic RBCs, no casts, pink/red urine, may have clots		* Non-glomerular normal/isomorphic RBCs, no casts, pink/red urine, may have clots

Line 122:		Line 122:
	==Evaluation==		==Evaluation==
	===ED workup===		===ED workup===
	* Urinalysis with microscopy the ~~'''~~single most important test~~'''~~<ref name="AcuteGN">Acute Glomerulonephritis Workup. ''Medscape''. 2024.</ref>		* Urinalysis with microscopy the single most important test<ref name="AcuteGN">Acute Glomerulonephritis Workup. ''Medscape''. 2024.</ref>
	** RBC casts: virtually pathognomonic for glomerulonephritis		** RBC casts: virtually pathognomonic for glomerulonephritis
	** Dysmorphic RBCs (acanthocytes — best seen with phase-contrast microscopy; >30% dysmorphic is highly specific for glomerular origin)		** Dysmorphic RBCs (acanthocytes — best seen with phase-contrast microscopy; >30% dysmorphic is highly specific for glomerular origin)
Line 178:		Line 178:

	====Hypertensive emergency====		====Hypertensive emergency====
	*May present with ~~'''~~encephalopathy, seizures, visual changes, pulmonary edema~~'''~~		*May present with encephalopathy, seizures, visual changes, pulmonary edema
	* Salt and water restriction		* Salt and water restriction
	* Loop diuretics furosemide 1-2 mg/kg IV (children) or 40-80 mg IV (adults) — first-line for volume-overload hypertension		* Loop diuretics furosemide 1-2 mg/kg IV (children) or 40-80 mg IV (adults) — first-line for volume-overload hypertension
	* IV antihypertensives if diuretics insufficient: nicardipine infusion, labetalol, or hydralazine		* IV antihypertensives if diuretics insufficient: nicardipine infusion, labetalol, or hydralazine
	*Avoid ACE inhibitors/ARBs in the ~~'''~~acute~~'''~~ setting with AKI and hyperkalemia (may worsen both)		*Avoid ACE inhibitors/ARBs in the acute setting with AKI and hyperkalemia (may worsen both)
	*Target: gradual reduction; do not lower BP >25% in the first hour		*Target: gradual reduction; do not lower BP >25% in the first hour

Line 224:		Line 224:
	**Hyperkalemia		**Hyperkalemia
	**Pulmonary edema or respiratory distress		**Pulmonary edema or respiratory distress
	**Rapidly rising creatinine (suspect RPGN) — ~~'''~~urgent nephrology consult~~'''~~		**Rapidly rising creatinine (suspect RPGN) — urgent nephrology consult
	**Pulmonary hemorrhage / pulmonary-renal syndrome — ~~'''~~ICU~~'''~~		**Pulmonary hemorrhage / pulmonary-renal syndrome — ICU
	**Significant AKI (creatinine >2x baseline, oliguria, need for dialysis)		**Significant AKI (creatinine >2x baseline, oliguria, need for dialysis)
	**New-onset nephritic syndrome in adults (most require biopsy and specialist evaluation)		**New-onset nephritic syndrome in adults (most require biopsy and specialist evaluation)
	* Consider discharge with close follow-up (48-72 hours):		* Consider discharge with close follow-up (48-72 hours):
	**Child with classic PSGN presentation: mild edema + mild hypertension + stable renal function + no hyperkalemia + confirmed strep history		**Child with classic PSGN presentation: mild edema + mild hypertension + stable renal function + no hyperkalemia + confirmed strep history
	**Ensure ~~'''~~nephrology or pediatric nephrology follow-up~~'''~~ within 48-72 hours		**Ensure nephrology or pediatric nephrology follow-up within 48-72 hours
	**Return precautions: decreased urine output, worsening edema, headache, visual changes, seizures, difficulty breathing		**Return precautions: decreased urine output, worsening edema, headache, visual changes, seizures, difficulty breathing
	* Always obtain nephrology consultation for: RPGN, pulmonary-renal syndrome, unclear diagnosis, adults with nephritic syndrome, renal failure requiring dialysis		* Always obtain nephrology consultation for: RPGN, pulmonary-renal syndrome, unclear diagnosis, adults with nephritic syndrome, renal failure requiring dialysis