Anti-platelet autoantibodies in a pregnant woman with ITP will attack the patient's own platelets and will also cross the placenta and react against fetal platelets. Therefore, ITP is a significant cause of fetal and neonatal immune thrombocytopenia. Approximately 10% of newborns affected by ITP will have platelet counts <50,000/uL and 1% to 2% will have a risk of intracerebral hemorrhage comparable to infants with neonatal alloimmune thrombocytopenia (NAIT).

No lab test can reliably predict if neonatal thrombocytopenia will occur. The risk of neonatal thrombocytopenia is increased with:

- Mothers with a history of splenectomy for ITP

- Mothers who had a previous infant affected with ITP

- Gestational (maternal) platelet count less than 100,000/uL

It is recommended that pregnant women with thrombocytopenia or a previous diagnosis of ITP should be tested for serum antiplatelet antibodies. A woman with symptomatic thrombocytopenia and an identifiable antiplatelet antibody should be started on therapy for their ITP which may include steroids or IVIG. Fetal blood analysis to determine the platelet count is not generally performed as ITP-induced thrombocytopenia in the fetus is generally less severe than NAIT. Platelet transfusions may be performed in newborns, depending on the degree of thrombocytopenia. It is recommended that neonates be followed with serial platelet counts for the first few days after birth.,

The following medications can induce thrombocytopenia through direct myelosuppression.

- Valproic acid

- Methotrexate

- Carboplatin

- Interferon

- Isotretinoin

- Panobinostat

- H blockers and proton-pump inhibitors

Thrombocytopenia affects a few percent of newborns, and its prevalence in neonatal intensive care units (NICU) is high. Normally, it is mild and resolves without consequences. Most cases affect preterm birth infants and result from placental insufficiency and/or fetal hypoxia. Other causes, such as alloimmunity, genetics, autoimmunity, and infection, are less frequent.

Thrombocytopenia that starts after the first 72 hours since birth is often the result of underlying sepsis or necrotizing enterocolitis (NEC). In the case of infection, PCR tests may be useful for rapid pathogen identification and detection of antibiotic resistance genes. Possible pathogens include viruses (e.g. Cytomegalovirus (CMV), rubella virus, HIV), bacteria (e.g. "Staphylococcus sp.", "Enterococcus sp.", "Streptococcus agalactiae" (GBS), "Listeria monocytogenes", "Escherichia coli", "Haemophilus influenzae", "Klebsiella pneumoniae", "Pseudomonas aeruginosa", "Yersinia enterocolitica"), fungi (e.g. "Candida sp."), and "Toxoplasma gondii". The severity of thrombocytopenia may be correlated with pathogen type; some research indicates that the most severe cases are related to fungal or gram-negative bacterial infection. The pathogen may be transmitted during or before birth, by breast feeding, or during transfusion. Interleukin-11 is being investigated as a drug for managing thrombocytopenia, especially in cases of sepsis or necrotizing enterocolitis (NEC).

The primary treatment for CAMT is bone marrow transplantation.

Bone Marrow/Stem Cell Transplant is the only thing that ultimately cures this genetic disease. Frequent platelet transfusions are required to ensure that platelet levels do not fall to dangerous levels, although this is not always the case. It is known for patients to continue to create very small numbers of platelets over time.

Recent studies have found that the life expectancy of males with XLT is not significantly affected. Individuals with XLT typically experience milder symptoms than those with other "WAS"-related disorders. For this reason, the long term prognosis for individuals with XLT is generally positive as long as symptoms are managed appropriately. Enhanced treatment methods in the past two decades have significantly improved the prognosis as well.

Iatrogenic causes of pancytopenia include chemotherapy for malignancies if the drug or drugs used cause bone marrow suppression. Rarely, drugs (antibiotics, blood pressure medication, heart medication) can cause pancytopenia.

The antibiotics Linezolid and Chloramphenicol can cause pancytopenia in some individuals.

Rarely, pancytopenia may have other causes, such as mononucleosis, or other viral diseases. Increasingly, HIV is itself a cause for pancytopenia.

- Familial hemophagocytic syndrome

- Aplastic anemia

- Gaucher's disease

- metastatic carcinoma of bone

- Multiple Myeloma

- overwhelming infections

- Lymphoma

- myelofibrosis

- Dyskeratosis congenita

- Myelodysplastic syndrome

- Leukemia

- Leishmaniasis

- Severe Folate or vitamin B12 deficiency

- Systemic lupus erythematosus

- Paroxysmal nocturnal hemoglobinuria (blood test)

- Viral infections (such as HIV, EBV--undetermined virus is most common).

- Alimentary toxic aleukia

- Copper deficiency

- Pernicious anemia

- Medication

- Hypersplenism

- Osteopetrosis

- Organic acidurias (Propionic Acidemia, Methylmalonic Aciduria, Isovaleric Aciduria)

- Low dose arsenic poisoning

- Sako disease (Myelodysplastic-cytosis)

- Chronic radiation sickness

- LIG4 syndrome

Increased platelet counts can be due to a number of disease processes:

- Essential (primary)

- Essential thrombocytosis (a form of myeloproliferative disease)

- Other myeloproliferative disorders such as chronic myelogenous leukemia, polycythemia vera, myelofibrosis

- Reactive (secondary)

- Inflammation

- Surgery (which leads to an inflammatory state)

- Hyposplenism (decreased breakdown due to decreased function of the spleen)

- Splenectomy

- Asplenia (absence of normal spleen function)

- Iron deficiency anemia or hemorrhage

Over-medication with drugs that treat thrombocytopenia, such as eltrombopag or romiplostim, may also result in thrombocytosis.

Other causes include the following

- Kawasaki disease

- Soft tissue sarcoma

- Osteosarcoma

- Dermatitis (rarely)

- Inflammatory bowel disease

- Rheumatoid arthritis

- Nephritis

- Nephrotic syndrome

- Bacterial diseases, including pneumonia, sepsis, meningitis, urinary tract infections, and septic arthritis.

The vast majority of causes of thrombocytosis are acquired disorders, but in a few cases, they may be congenital, such as thrombocytosis due to congenital asplenia.

X-linked thrombocytopenia is inherited on the X chromosome. Females that are carriers will have a 50% chance of passing the "WAS" gene mutation on to their male offspring. Female offspring also have a 50% chance of receiving the mutated gene from their mothers and are considered carriers in that event. Males with X-linked thrombocytopenia will not pass the condition to their sons since they pass their Y chromosome on to any male offspring. However, any daughters males with this condition have will be carriers.

The cause for this disorder appears to be a mutation in the gene for the TPO receptor, "c-mpl", despite high levels of serum TPO. In addition, there may be abnormalities with the central nervous system including the cerebrum and cerebellum which could cause symptoms.

The incidence of acute TTP in adults is around 1.7–4.5 per million and year. These cases are nearly all due to the autoimmune form of TTP, where autoantibodies inhibit ADAMTS13 activity. The prevalence of USS has not yet been determined but is assumed to constitute less than 5% of all acute TTP cases. The syndrome's inheritance is autosomal recessive, and is more often caused by compound heterozygous than homozygous mutations. The age of onset is variable and can be from neonatal age up to the 5th–6th decade. The risk of relapses differs between affected individuals. Minimization of the burden of disease can be reached by early diagnosis and initiation of prophylaxis if required.

A normal platelet count is considered to be in the range of 150,000–450,000 per microlitre (μl) of blood for most healthy individuals. Hence one may be considered thrombocytopenic below that range, although the threshold for a diagnosis of ITP is not tied to any specific number.

The incidence of ITP is estimated at 50–100 new cases per million per year, with children accounting for half of that amount. At least 70 percent of childhood cases will end up in remission within six months, even without treatment. Moreover, a third of the remaining chronic cases will usually remit during follow-up observation, and another third will end up with only mild thrombocytopenia (defined as a platelet count above 50,000). A number of immune related genes and polymorphisms have been identified as influencing predisposition to ITP, with FCGR3a-V158 allele and KIRDS2/DL2 increasing susceptibility and KIR2DS5 shown to be protective.

ITP is usually chronic in adults and the probability of durable remission is 20–40 percent. The male to female ratio in the adult group varies from 1:1.2 to 1.7 in most age ranges (childhood cases are roughly equal for both genders) and the median age of adults at the diagnosis is 56–60. The ratio between male and female adult cases tends to widen with age. In the United States, the adult chronic population is thought to be approximately 60,000—with women outnumbering men approximately 2 to 1, which has resulted in ITP being designated an orphan disease.

The mortality rate due to chronic ITP varies but tends to be higher relative to the general population for any age range. In a study conducted in Great Britain, it was noted that ITP causes an approximately 60 percent higher rate of mortality compared to gender- and age-matched subjects without ITP. This increased risk of death with ITP is largely concentrated in the middle-aged and elderly. Ninety-six percent of reported ITP-related deaths were individuals 45 years or older. No significant difference was noted in the rate of survival between males and females.

There has been no general recommendation for treatment of patients with Giant Platelet Disorders, as there are many different specific classifications to further categorize this disorder which each need differing treatments. Platelet transfusion is the main treatment for people presenting with bleeding symptoms. There have been experiments with DDAVP (1-deamino-8-arginine vasopressin) and splenectomy on people with Giant platelet disorders with mixed results, making this type of treatment contentious.

HPS was identified among healthy blood donors in the north-eastern part of the Indian subcontinent, characterized by absent bleeding symptoms, mild to severe thrombocytopenia (platelets rarely <50 X 109/L)with giant platelets (Mean platelet volume 10fL) and normal platelet aggregation studies with absent MYH9 mutation.

In the blood donors with HPS authors found a statistically higher MPV, RDW and a lower platelet count and platelet biomass.

At present the diagnosis of HPS is made by ascertaining the ethnicity of the patient, as well as assessing for conditions causing acquired thrombocytopenias, and after also excluding the known inherited giant platelet disorders(IGPD) and other congenital thrombocytopenias. Unfortunately some patients with IGPD are treated inappropriately with corticosteroids, immunoglobulin infusions and even splenectomy.

It is extremely important to recognize Harris platelet syndrome, as one third the population of certain parts of Indian subcontinent is affected.

Harris platelet syndrome (HPS) is the most common inherited giant platelet disorder.

Many of the further classifications of Giant Platelet Disorder occur as a result of being genetically passed down through families as an autosomal recessive disorder, such as in Bernard-Soulier syndrome and Grey Platelet syndrome. To get this disorder both of the parents have to have it for it to be passed down to the child. It has to be transmitted in an autosomal recessive pattern. There chromosome number is 17.

Evans syndrome is rare, serious, and has a reported mortality rate of 7%.

It has been observed that there is a risk of developing other autoimmune problems and hypogammaglobulinemia, with recent research finding that 58% of children with Evans syndrome have CD4-/CD8- T cells which is a strong predictor for having autoimmune lymphoproliferative syndrome.

High platelet levels do not necessarily signal any clinical problems, and are picked up on a routine full blood count. However, it is important that a full medical history be elicited to ensure that the increased platelet count is not due to a secondary process. Often, it occurs in tandem with an inflammatory disease, as the principal stimulants of platelet production (e.g. thrombopoietin) are elevated in these clinical states as part of the acute phase reaction.

High platelet counts can occur in patients with polycythemia vera (high red blood cell counts), and is an additional risk factor for complications.

A very small segment of patients report symptoms of erythromelalgia, a burning sensation and redness of the extremities that resolves with cooling and/or aspirin use.

Scientific literature sometimes excludes thrombocytosis from the scope of thrombophilia by definition, but practically, by the definition of thrombophilia as an increased predisposition to thrombosis, thrombocytosis (especially primary thrombocytosis) is a potential cause of thrombophilia. Conversely, secondary thrombocytosis very rarely causes thrombotic complications.

Untreated, severe aplastic anemia has a high risk of death. Modern treatment, by drugs or stem cell transplant, has a five-year survival rate that exceeds 85%, with younger age associated with higher survival.

Survival rates for stem cell transplant vary depending on age and availability of a well-matched donor. Five-year survival rates for patients who receive transplants have been shown to be 82% for patients under age 20, 72% for those 20–40 years old, and closer to 50% for patients over age 40. Success rates are better for patients who have donors that are matched siblings and worse for patients who receive their marrow from unrelated donors.

Older people (who are generally too frail to undergo bone marrow transplants), and people who are unable to find a good bone marrow match, undergoing immune suppression have five-year survival rates of up to 75%.

Relapses are common. Relapse following ATG/ciclosporin use can sometimes be treated with a repeated course of therapy. In addition, 10-15% of severe aplastic anemia cases evolve into MDS and leukemia. According to a study, for children who underwent immunosuppressive therapy, about 15.9% of children who responded to immunosuppressive therapy encountered relapse.

Milder disease can resolve on its own.

In 2003, the incidence of Rh(D) sensitization in the United States was 6.8 per 1000 live births; 0.27% of women with an Rh incompatible fetus experience alloimmunization.

The disease is marked by an inappropriate and ineffective T cell activation that leads to an increased hemophagocytic activity. The T cell activated macrophages engulf erythrocytes, leukocytes, platelets, as well as their progenitor cells. Such finding is common in the syndrome, which is also referred to as hemophagocytic lymphohistiocytosis (HLH). Along with pancytopenia, HLH is characterized by fever, splenomegaly, and hemophagocytosis in bone marrow, liver, or lymph nodes.

Secondary TTP is diagnosed when the patient's history mentions one of the known features associated with TTP. It comprises about 40% of all cases of TTP. Predisposing factors are:

- Cancer

- Bone marrow transplantation

- Pregnancy

- Medication use:

- Antiviral drugs (acyclovir)

- Certain chemotherapy medications such as gemcitabine and mitomycin C

- Quinine

- Oxymorphone

- Quetiapine

- Bevacizumab

- Sunitinib

- Platelet aggregation inhibitors (ticlopidine, clopidogrel, and prasugrel)

- Immunosuppressants (ciclosporin, mitomycin, tacrolimus/FK506, interferon-α)

- Hormone altering drugs (estrogens, contraceptives, hormone replacement therapy)

- HIV-1 infection

The mechanism of secondary TTP is poorly understood, as ADAMTS13 activity is generally not as depressed as in idiopathic TTP, and inhibitors cannot be detected. Probable etiology may involve, at least in some cases, endothelial damage, although the formation of thrombi resulting in vessel occlusion may not be essential in the pathogenesis of secondary TTP. These factors may also be considered a form of secondary aHUS; patients presenting with these features are, therefore, potential candidates for anticomplement therapy.

Complications of HDN could include kernicterus, hepatosplenomegaly, inspissated (thickened or dried) bile syndrome and/or greenish staining of the teeth, hemolytic anemia and damage to the liver due to excess bilirubin. Similar conditions include acquired hemolytic anemia, congenital toxoplasma and syphilis infection, congenital obstruction of the bile duct and cytomegalovirus infection.

- High at birth or rapidly rising bilirubin

- Prolonged hyperbilirubinemia

- Bilirubin Induced Neuorlogical Dysfunction

- Cerebral Palsy

- Kernicterus

- Neutropenia

- Thrombocytopenia

- Hemolytic Anemia - MUST NOT be treated with iron

- Late onset anemia - Must NOT be treated with iron. Can persist up to 12 weeks after birth.

Gray platelet syndrome (GPS), or platelet alpha-granule deficiency, is a rare congenital autosomal recessive bleeding disorder caused by a reduction or absence of alpha-granules in blood platelets, and the release of proteins normally contained in these granules into the marrow, causing myelofibrosis.

GPS is primarily inherited in an autosomal recessive manner, and the gene that is mutated in GPS has recently been mapped to chromosome 3p and identified as "NBEAL2". "NBEAL2" encodes a protein containing a BEACH domain that is predicted to be involved in vesicular trafficking. It is expressed in platelets and megakaryocytes and is required for the development of platelet alpha-granules. "NBEAL2" expression is also required for the development of thrombocytes in zebrafish.

GPS is characterized by "thrombocytopenia, and abnormally large agranular platelets in peripheral blood smears." The defect in GPS is the failure of megakaryocytes to package secretory proteins into alpha-granules. Patients with the GPS are affected by mild to moderate bleeding tendencies. Usually these are not major bleeds but there has been some life threatening cases. Also Women will tend to have heavy, irregular periods. Myelofibrosis is a condition that usually comes with the Gray Platelet syndrome.

In terms of treatment/management, bleeding events can be controlled by platelet transfusion.

Most heterozygotes, with few exceptions, do not have a bleeding diathesis. BSS presents as a bleeding disorder due to the inability of platelets to bind and aggregate at sites of vascular endothelial injury. In the event of an individual with mucosal bleeding tranexamic acid can be given.

The affected individual may need to avoid contact sports and medications such as aspirin, which can increase the possibility of bleeding. A potential complication is the possibility of the individual producing antiplatelet antibodies

Considered a rare to very rare autoimmune disorder it has had few studies with cohorts often less than 30.