AApoAIV amyloidosis

What it is

From: Orphanet

A rare nonhereditary systemic amyloidosis characterized by slowly progressive renal dysfunction, increased serum creatinine, mostly normal urine analysis with no significant proteinuria and associated heart disease. Cardiac involvement presents as hypertrophic obstructive cardiomyopathy, left ventricular outflow tract obstruction, coronary artery disease and conduction system abnormalities. Histology reveals medullar amyloid deposits, renal tubular atrophy, interstitial fibrosis, and glomerular sclerosis.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Abnormal renal medulla morphology · Very frequent (99-80%)

Any structural abnormality of the medulla of the kidney.

Elevated circulating creatinine concentration · Very frequent (99-80%)

An increased amount of creatinine in the blood.

Abnormal cardiac ventricular function · Frequent (79-30%)

An abnormality of the cardiac ventricular function.

Chronic kidney disease · Frequent (79-30%)

Functional anomaly of the kidney persisting for at least three months.

Hypertension · Frequent (79-30%)

The presence of chronic increased pressure in the systemic arterial system.

Renal amyloidosis · Frequent (79-30%)

A form of amyloidosis that affects the kidney. On hematoxylin and eosin stain, amyloid is identified as extracellular amorphous material that is lightly eosinophilic. These deposits often stain weakly for periodic acid Schiff (PAS), demonstrate a blue-to-gray hue on the trichrome stain and are typically negative on the Jones methenamine silver (JMS) stain. These tinctorial properties contrast with the histologic appearance of collagen, a major component of basement membranes, mesangial matrix and areas of sclerosis, which demonstrates strong positivity for PAS and JMS (See Figure 1 of PMID:25852856).

Renal interstitial amyloid deposits · Frequent (79-30%)

Deposition of amyloid in the interstitial tissue of the kidney. Amyloid is is made up of 10 nm (on average) fibrils that are most commonly composed of monoclonal light chains (AL), transthyretin (TTR), amd LECT2, or occur in the setting of long standing systemic inflammation.

Abnormality of the gastrointestinal tract · Occasional (29-5%)

An abnormality of the gastrointestinal tract.

Back pain · Occasional (29-5%)

An unpleasant sensation characterized by physical discomfort (such as pricking, throbbing, or aching) localized to the back.

Cardiac conduction abnormality · Occasional (29-5%)

Any anomaly of the progression of electrical impulses through the heart.

Chronic pulmonary obstruction · Occasional (29-5%)

An anomaly that is characterized progressive airflow obstruction that is only partly reversible, inflammation in the airways, and systemic effects or comorbities.

Coronaryartery atherosclerosis · Occasional (29-5%)

Reduction of the diameter of the coronary arteries as the result of an accumulation of atheromatous plaques within the walls of the coronary arteries, which increases the risk of myocardial ischemia.

Diabetes mellitus · Occasional (29-5%)

A group of abnormalities characterized by hyperglycemia and glucose intolerance.

Glomerulosclerosis · Occasional (29-5%)

Accumulation of scar tissue within the glomerulus.

Other findings in the same source

From: Orphanet

Additional reported features include Hyperlipidemia (Occasional (29-5%)); Hypertrophic cardiomyopathy (Occasional (29-5%)); Left bundle branch block (Occasional (29-5%)); Left ventricular hypertrophy (Occasional (29-5%)); Left ventricular outflow tract obstruction (Occasional (29-5%)); Paraproteinemia (Occasional (29-5%)); Paroxysmal nocturnal dyspnea (Occasional (29-5%)); Proteinuria (Occasional (29-5%)); Reduced left ventricular ejection fraction (Occasional (29-5%)); Abnormal lung morphology (Very rare (<4-1%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Adult

Inheritance in the source

From: Orphanet

Not applicable

Frequency and the population described

From: Orphanet

Point prevalence: <1 / 1 000 000; Worldwide; Class only. Reported case(s): 2.0; Worldwide. This is a published case count, not prevalence.

Which doctor should you see?

The suggested department for discussing AApoAIV amyloidosis is Nephrology, with a nephrologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• How is kidney function being assessed over time?
• Are any current medicines or supplements relevant to kidney safety?
• Is there an individual recommendation about fluids, diet or blood pressure?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for AApoAIV amyloidosis. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.