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Nephritic Syndrome, Emergency Medicine

Basics

Description

- Poststreptococcal glomerulonephritis (PSGN): - A postinfectious cause of acute nephritic syndrome, resulting from group A ²-hemolytic streptococci - Considered a nonsuppurative complication (antibiotic treatment does not prevent this complication) - Occurs when immune complexes create hump-shaped subepithelial deposits in renal glomeruli - Most commonly affects patients between ages 3 and 15 yr but can occur at any age - Incidence of nephritis is 5 " 10% after pharyngitis and 25% after skin infections. - Consider PSGN in the setting of new-onset proteinuria, RBC casts, edema, and any recent infection. - Latent period between infection and onset of nephritis helps differentiate between PSGN and IgA nephropathy: - 1 " 3 wk in pharyngeal infection - 2 " 4 wk in cutaneous infection

- Other infectious sources of glomerulonephritis (GN): - Sepsis, pneumonia, endocarditis, viruses, HIV - Pulmonary, intra-abdominal, or cutaneous infections - Syphilis, leprosy, schistosomiasis, and malaria - Goal: Treat underlying infection.

- IgA nephropathy (IgA-N) - Most common cause of AGN (>25%) worldwide - Antibody " antigen causes immune complex deposition of IgA and C3 - Complement levels are usually normal. - IgA-N has different presentations: - Gross hematuria following upper respiratory infection (URI) - Microscopic hematuria with proteinuria - Hematuria during viral illness or after exercise - Prognosis is related to serum creatinine, BP, and proteinuria. - 50% of patients with proteinuria may develop progressive renal disease. - ACE inhibitors or angiotensin-receptor blockers (ARBs) may help

  • Acute glomerulonephritis (AGN) is acute inflammatory damage to glomerulus, associated with:Abrupt onset of hematuria with or without RBC castsAcute renal failure manifested by edema, hypertension, azotemia, decline in urine outputVariable proteinuriaActive urine sediment (RBC casts)
  • Exact mechanism of AGN unclear:Combination of autoimmune reactivity to specific antigens at renal glomeruliCharacterized by crescent formation secondary to nonspecific injury at the glomerular wall

Etiology

  • Poststreptococcal glomerulonephritis (PSGN):A postinfectious cause of acute nephritic syndrome, resulting from group A ²-hemolytic streptococciConsidered a nonsuppurative complication (antibiotic treatment does not prevent this complication)Occurs when immune complexes create hump-shaped subepithelial deposits in renal glomeruliMost commonly affects patients between ages 3 and 15 yr but can occur at any ageIncidence of nephritis is 5 " 10% after pharyngitis and 25% after skin infections.Consider PSGN in the setting of new-onset proteinuria, RBC casts, edema, and any recent infection.Latent period between infection and onset of nephritis helps differentiate between PSGN and IgA nephropathy:1 " 3 wk in pharyngeal infection2 " 4 wk in cutaneous infectionRenal biopsy is usually not necessary for diagnosis.Low complement (C3) for 6 " 8 wkCan progress to severe renal failure if underlying infection goes untreatedPrognosis:Excellent; >95% recover spontaneously with normalization of renal function within 6 " 8 wk, even with dialysis.Hematuria usually resolves in 3 " 6 mo.Transient nephrotic phase in 20% of patients during resolution of illnessEnd-stage renal disease occurs <5%Rapidly progressive glomerulonephritis (RPGN) is rare, occurring in <1% cases.Most cases resolve spontaneously with no long-term sequelae.
  • Other infectious sources of glomerulonephritis (GN):Sepsis, pneumonia, endocarditis, viruses, HIVPulmonary, intra-abdominal, or cutaneous infectionsSyphilis, leprosy, schistosomiasis, and malariaGoal: Treat underlying infection.
  • Hepatitis virus " related glomerular disease:Can present with either nephritic or nephrotic symptomsCauses membranoproliferative GNComplements remain low indefinitely (compared to PSGN)
  • Noninfectious causes of GN (due to immune complex formation):Systematic lupus erythematosus, Henoch " Sch Άnlein purpura, vasculitis, Wegener granulomatosisGoodpasture syndrome
  • IgA nephropathy (IgA-N)Most common cause of AGN (>25%) worldwideAntibody " antigen causes immune complex deposition of IgA and C3Complement levels are usually normal.IgA-N has different presentations:Gross hematuria following upper respiratory infection (URI)Microscopic hematuria with proteinuriaHematuria during viral illness or after exercisePrognosis is related to serum creatinine, BP, and proteinuria.50% of patients with proteinuria may develop progressive renal disease.ACE inhibitors or angiotensin-receptor blockers (ARBs) may help
  • RPGN:Certain patients with AGN may progress rapidly to renal failure.Hallmarks are crescents on renal biopsy.
  • Hereditary nephritis

Diagnosis

Signs and Symptoms

  • Hematuria:Abrupt onset gross hematuria in 30 " 40% (coffee- or cola-colored urine)
  • Edema:Periorbital edemaGeneralized edema more common in infants and children
  • Infectious source or recent infection: Upper respiratory tract or skin common, e.g., PSGN
  • Symptoms of congestive heart failure:40% occurrence in patients >60 yrRare in children
  • Arthritis, arthralgias, and various skin rashes: PSGN, systemic disease
  • Nonspecific manifestations:MalaiseWeaknessAnorexiaNausea/vomiting

History

  • Recent URI or skin or other infection
  • Change in urine color

Physical Exam

Essential Workup

Urinalysis with sediment evaluation to detect:

  • RBCs, proteinuria, and RBC casts
  • RBC casts are diagnostic of an active glomerular inflammation.

Diagnosis Tests & Interpretation

Lab

  • CBC:Anemia (seen in more chronic cases of GN or other systemic disease)Acute leukocytosis (may suggest infectious process)
  • Basic metabolic panel:Assess baseline renal functionCheck for electrolyte abnormalitiesGFR will be normal or nearly normal
  • Urinalysis:RBCs +/ ’ casts, protein
  • Serum albumin
  • Cultures (throat, skin, urine, blood):As clinically suspected for infectious sourceStreptozyme
  • Serum complement level (C3): Decreased in infectious endocarditis, shunt nephritis, and PSGN
  • Streptococcal antibodies:Antistreptolysin (ASO), antistreptokinase (ASK), antideoxyribonuclease B (ADNase B), antinicotinyl adenine dinucleotidase (ANADase), and antihyaluronidase (AH)ASO more reactive in pharyngeal infectionsADNase B, ANADase, and AH more reactive in cutaneous infectionsASK elevated in recent hemolytic Streptococcus infectionsTiters do not correlate with prognosis of disease
  • Urine osmolality, sodium, creatinine
  • 24-hr urine collection:Proteinuria initially present in 5% of children, 20% of adults with PSGN

Imaging

  • Renal ultrasound: Kidney size abnormality
  • Chest radiograph: Cardiomegaly, pulmonary edema, infection

Diagnostic Procedures/Surgery

Renal biopsy:

  • Generally not done for PSGN, as symptoms typically resolve after a brief illness
  • Recommended if atypical features of PSGN, persistently abnormal complement levels, persistent hypertension, and proteinuria >3 g/d
  • Facilitates diagnosis for other causes of nephritis

Differential Diagnosis

  • (See "Glomerulonephritis " for further information on types of GN)
  • Renal:Primary glomerular disease
  • Systemic:Goodpasture syndromeVasculitisHenoch " Sch Άnlein purpura
  • Other (rare):Hemolytic-uremic syndromeThrombotic thrombocytopenic purpuraAcute hypersensitivity interstitial nephritisSerum sickness

Treatment

Pre-Hospital

Support ABCs

Initial Stabilization/Therapy

ABCs

Ed Treatment/Procedures

  • Antibiotics for streptococcal infection:Penicillin (erythromycin, if penicillin allergic)
  • Restrict salt and fluid intake
  • Administer loop diuretics (furosemide)
  • Restore urine flow in oliguric patients:
  • Treat pulmonary edema:OxygenMorphineLoop diuretics
  • Stabilize BP to decrease proteinuria, retard progression of GN:ACEIs, ARBsHypertensive emergency: Nitroprusside or other titratable antihypertensive medication
  • Hemodialysis for:Severe hyperkalemiaFluid overloadUremiaSevere acidosisCorrect electrolyte abnormalities

Medication

  • Erythromycin: 250 " 500 mg (peds: 30 " 50 mg/kg/d) PO q6h for 7 " 10 days
  • Furosemide: 20 " 80 mg (peds: 1 " 6 mg/kg) PO daily/BID
  • Lisinopril (ACEI): 10 " 40 mg (peds: >6 yr: 0.07 mg/kg) PO daily
  • Losartan (ARB): 25 " 100 mg (peds: >6 yr: 0.7 mg/kg) PO daily
  • Mannitol: 12.5 " 100 g (peds: 0.25 " 0.5 g/kg) IV:May use single or repeat dosing; consider test dosing 1st.
  • Morphine sulfate: 0.1 mg/kg/dose IV q4h
  • Nitroprusside: 0.3 " 4 Όg/kg/min IVTitrate to goal mean arterial pressure for hypertensive emergency.
  • Penicillin:Benzathine penicillin: 1.2 million U (peds: 0.3 " 0.9 million U, based on weight) IM as single dosePenicillin VK: 250 " 500 mg (peds: <12 yr 25 " 50 mg/kg/d) PO q6 " 8h for 10 days
  • Other agents, including fish oil ( -3 fatty acids for anti-inflammatory effects) and immunosuppressive agents (glucocorticoids, cyclophosphamide), may be used in consultation with specialists.

Follow-Up

Disposition

Admission Criteria

  • Evidence of infectious cause for GN
  • Oliguria, anuria
  • Uremia
  • Elevated creatinine
  • Edema
  • Electrolyte abnormalities
  • Severe hypertension
  • CHF

Discharge Criteria

Mild cases of clinical nephritis in healthy patients with:

  • No comorbid illness
  • Strict supervision/monitoring of symptoms, diet, urine output, and medication
  • Close follow-up with PMD and nephrology referral

Issues for Referral

Nephrology:

Follow-Up Recommendations

  • Adherence to antibiotic and antihypertensive therapy, as indicated
  • Restrict salt and fluid intake.

Pearls and Pitfalls

  • Diagnosis is confirmed by biopsy showing characteristic crescent formation within renal glomeruli.
  • Must obtain thorough history of ongoing or recent infections as possible etiology of nephritis
  • IgA nephropathy is most common cause of nephritis.
  • Patients require aggressive management of BP and volume status.

Additional Reading

  • Ikee R, Kobayashi S, Saigusa T, et al. Impact of hypertension and hypertension-related vascular lesions in IgA nephropathy. Hypertens Res. 2006;29(1):15 " 22.
  • Kanjanabuch T, Kittikowit W, Eiam-Ong S. An update on acute postinfectious glomerulonephritis worldwide. Nat Rev Nephrol. 2009;5:259 " 269.
  • Kunz R, Friedrich C, Wolbers M, et al. Meta-analysis: Effect of monotherapy and combination therapy with inhibitors of the renin angiotensin system on proteinuria in renal disease. Ann Intern Med. 2008;148(1):30 " 48.

See Also (Topic, Algorithm, Electronic Media Element)

  • Acute Renal Failure
  • Glomerulonephritis
  • Nephrotic Syndrome

Codes

ICD9

  • 580.0 Acute glomerulonephritis with lesion of proliferative glomerulonephritis
  • 580.9 Acute glomerulonephritis with unspecified pathological lesion in kidney
  • 583.2 Nephritis and nephropathy, not specified as acute or chronic, with lesion of membranoproliferative glomerulonephritis
  • 583.4 Nephritis and nephropathy, not specified as acute or chronic, with lesion of rapidly progressive glomerulonephritis

ICD10

  • N00.9 Acute nephritic syndrome with unsp morphologic changes
  • N01.9 Rapidly progr nephritic syndrome w unsp morphologic changes
  • N05.9 Unsp nephritic syndrome with unspecified morphologic changes
  • N05.1 Unsp neph syndrome w focal and segmental glomerular lesions
  • N05.0 Unsp nephritic syndrome with minor glomerular abnormality
  • N05.2 Unsp nephritic syndrome w diffuse membranous glomrlneph
  • N05.3 Unsp neph syndrome w diffuse mesangial prolif glomrlneph
  • N05.4 Unsp neph syndrome w diffuse endocaplry prolif glomrlneph
  • N05.5 Unsp nephritic syndrome w diffuse mesangiocap glomrlneph
  • N05.6 Unspecified nephritic syndrome with dense deposit disease
  • N05.7 Unsp nephritic syndrome w diffuse crescentic glomrlneph
  • N05.8 Unsp nephritic syndrome with other morphologic changes
  • N05 Unspecified nephritic syndrome

SNOMED

  • 7724006 Nephritic syndrome (disorder)
  • 19351000 Acute glomerulonephritis (disorder)
  • 236392004 Rapidly progressive glomerulonephritis (disorder)
  • 80321008 Mesangiocapillary glomerulonephritis (disorder)
  • 68544003 Acute post-streptococcal glomerulonephritis (disorder)