22 Sep 2021

5/17/21: Dilated Cardiomyopathy 2/2 TTN Mutation

PGY2 Christina Vu presented a case of a 28 y/o M with no PMH who presents with 4 months of cough and 1 month of progressive dyspnea and b/l LE edema. 

Travel History:

  • Originally from India and works on a cruise ship (2/2020)
  • Departed India by plane to French Polynesia for cruise ship: Australia, New Zealand, Los Angeles
  • Developed cough after 1 month on ship (3/2020): treated with 2 courses of abx (Azithromycin) with no improvement
  • Developed progressive dyspnea and b/l LE edema during the following month (4/2020)

PMH: none

Meds: none

Allergies: NKDA

FH: none

SH: Born and raised in Mumbai, India.  Works as a butler on a Norwegian Cruise ship.  Former social smoker 1-2 cigs/month x4 years.

Vitals: T 37, HR 106, RR 22, BP 90/56, O2 sat 98% on RA

Physical Exam: AA&Ox4, tachycardia, normal S1/S2, no murmurs, normal pulm exam, 2+ b/l LE edema to abdomen

CBC: WBC 6.8>Hb 16.4/Hct 49.1 <Plt 172 (MCV 87.7, RDW 13.2%)

CMP:

Na 131/K 4.3/Cl 90/HCO3 27/BUN 16/Cr 0.7<Glucose 341

ALP 188>T.protein 5.9/Albumin 2.9/AST 26/ALT 32/Tbili 0.3/Dbili 0.2

Ca 9.3, Mg 2.4, Phos 4.1

PT 15.8, INR 1.28, PTT 40.3

Pro-BNP: 1246

Troponin: <0.01

EKG:

CXR:

TTE: LV is mildly dilated.  LV systolic function is severly reduced with EF 10-15%. Severe global hypokinesis.  Grade III diastolic dysfunction.

Infectious workup initiated with negative findings of the following: BCx, Fungal Culture, UA, TB, Viral (COVID-19, HIV, HSV, Norovirus, VZV, CMV, Adenovirus, Parvovirus, EBV, Rubeola, Influenza A/B, Parainfluenza, Adenovirus, RSV, Mycoplasma, Rhinovirus/Enterovirus, Coxsackie), fungal (blasto, cocci, histo, crypto, aspergillus), Parasites (Strongyloides, Trypanosoma, Toxoplasma) and hepatitis panel. 

Urine toxicology negative.

Endocrine studies negative for diabetes, normal TSH.

Rheum Labs:

  • ANA 1:160
  • ANCA negative, dsDNA negative, RF negative, SSA/SSB negative, RNP Smith negative

R Heart Cath/L Heart Cath: severely elevated cardiac filling pressures.  Low cardiac output.

Endomyocardial Biopsy: Negative for viral, giant cell, eosinophilic infiltration, amyloid deposition, or fibrosis. TTN gene mutation was detected.

Treatment: Admitted and started on GDMT and pressors.  The patient was transported back to India per patient’s request after discussion with Cardiologist in India. Several months later, the patient received a heart transplant at India and is now recovering well.

Teaching points:

  • Etiology of Dilated Cardiomyopathy
    • Ischemic
    • Stress-induced – Taskotsubo cardiomyopathy
    • Infectious – Viral (Parvovirus, HSV 6, Coxsackie, Influenza, Adenovirus, Echovirus, CMV), HIV, Chagas, Lyme
    • Genetic – TTN (titin gene) mutation definitely linked to DCM and is involved in 25% of familial cases of idiopathic DCM
    • Toxic – Alcohol, Cocaine, Medications (Anthracyclines, Trastuzumab), Trace Elements
    • Peripartum
    • Tachycardia-mediated
    • Sarcoidosis
    • ESRD
    • Autoimmune
    • Endocrine
    • Malnutrition (Thiamine, Selenium, Carnitine)
    • OSA

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