Protein restriction
Vegetarian diets and, for younger children, breastfeeding are common ways to limit protein intake without endangering tryptophan transport to the brain. Tryptophan
Formulas such as XLys, XTrp Analog, XLys, XTrp Maxamaid, XLys, XTrp Maxamum or Glutarex 1 are designed to provide amino acids other than lysine and tryptophan, to help prevent protein malnutrition. The entry of tryptophan into the brain is crucial in the proper synthesis of the neurotransmitter serotonin in the brain. One way to acutely cause depression, bulimia or anxiety in humans, in order to assess an individuals vulnerability to those disorders, is to supplement with a formula with all or most amino acids except tryptophan. Acute tryptophan depletion is a diagnostic procedure, not a treatment for GA1. The protein synthesis elicited by the amino acids leads circulating amino acids, including tryptophan, to be incorporated into proteins. Tryptophan is thus lowered in the brain as a result of the protein synthesis enhancement, causing circulating tryptophan to drop more than other amino acids. A relative excess of other large neutral amino acids may also compete with tryptophan for transport across the blood–brain barrier through the large neutral amino acid transporter 1. The consequence is acute tryptophan depletion in the brain and a consequent decrease in serotonin synthesis. 5-Hydroxytryptophan, a precursor of serotonin that is not metabolized to glutaryl-CoA, glutaric acid and secondary metabolites, could be used as an adjunct to selective tryptophan restriction, although it has risks.
Several systemic illnesses have been associated with plastic bronchitis:
Cardiac: constrictive pericarditis, congenital heart disease
Pulmonary: asthma, allergic bronchopulmonary aspergillosis, aspergillosis, bronchiectasis, cystic fibrosis, tuberculosis, pneumonia, and bronchocentric granulomatosis
Disorders of lymphatic drainage: lymphangiectasia, lymphangiomatosis
Miscellaneous: acute chest syndrome/sickle cell disease, amyloidosis, rheumatoid arthritis, membranous colitis, inhaled irritants, neoplastic (lymphoma)The most common form of plastic bronchitis follows cardiac surgery for congenital heart disease, especially the Fontan procedure. Systemic blood flow is diverted to pulmonary flow, elevating pressures in the pulmonary venous system, and promoting leaks of proteinaceous and lipid-rich fluids from the lymphatics into the bronchial tree. Diagnosis
The diagnosis of plastic bronchitis is confirmed by recovery of casts that have been coughed up or visualized during a bronchoscopy. There is no specific cytologic, pathologic or laboratory test that is diagnostic for casts due to lymphatic PB. Imaging
Simple chest X-rays may reveal collapse due to airway obstruction. The contralateral lung may be hyperinflated. Casts can be visualized within the major airways using computerized axial tomography scans.Heavy T2-weighted MRI, and, as appropriate, intranodal lymphangiogram and/or dynamic contrast-enhanced MR lymphangiography may be useful for identifying pathological lymphatic tissue or lymphatic flow. Management
Acute therapy for PB is often focused on removal or facilitated expectoration of the casts. This is followed by short and long term efforts to identify and remediate the underlying condition resulting in the excessive airway leakage or inflammation that is causing the casts to form.PB can present as a life threatening emergency when the casts obstruct the major airways resulting in acute respiratory distress.