Differential diagnosis of immunodeficiency in an adolescent with weight loss and recurrent infection

Malnutrition, primary immunodeficiency, cytomegalovirus (CMV) infection, human immunodeficiency virus (HIV) infection, and diabetes mellitus are among the possible causes of immunodeficiency in an adolescent with weight loss and recurrent infection. Malnutrition can suppress the immune system and is often associated with anorexia nervosa, which can be characterized by a very low body mass index (BMI), lanugo hair growth, hypothermia, bradycardia, and hypotension. Primary immunodeficiency syndromes, which are usually inherited as single-gene disorders, tend to present in infancy or early childhood with poor growth and weight gain and recurrent, prolonged, severe, or atypical infections. Cytomegalovirus (CMV) is a herpes virus that can cause serious complications in immunocompromised individuals or congenital cases, but is usually asymptomatic in immunocompetent individuals. Human immunodeficiency virus (HIV) infection can result in immunodeficiency by infecting and destroying CD4 cells, and should be suspected in individuals with prolonged, severe, or recurrent infections, particularly if they are a member of a high-risk group. Diabetes mellitus, especially type I, can also cause dysfunction of the immune system and increase the risk of infection. However, in an adolescent with a low BMI, type II diabetes would be very unlikely.

In cases of anaphylaxis, the most crucial drug to administer is IM adrenaline, even if the patient does not have breathing difficulties. This patient is displaying signs of anaphylaxis, such as tachycardia and hypotension. The recommended site for administering IM adrenaline is the anterolateral aspect of the middle third of the thigh. If the patient responds well to the first dose, they may be discharged after two hours of symptom resolution.

IV chlorphenamine is no longer part of the initial management for anaphylaxis. Instead, non-sedating oral antihistamines are preferred after initial treatment. IV chlorphenamine may be used later in management if IM adrenaline is insufficient, and it can be continued orally or by injection for 24-48 hours to prevent relapse.

IV hydrocortisone was previously recommended as an adjuvant drug in the management of acute anaphylaxis. However, due to the lack of evidence and delayed onset of action, it is no longer recommended in the initial management of anaphylaxis.

Oral chlorphenamine is not the first-line treatment for anaphylaxis due to its sedating properties. Non-sedating oral antihistamines, such as cetirizine, are preferred in the management of allergic reactions and in stabilized patients after acute anaphylaxis has resolved (2021 Resus Council Guidelines). If the patient’s urticaria symptoms persist, a non-sedating antihistamine may be prescribed.

Anaphylaxis is a severe and potentially life-threatening allergic reaction that affects the entire body. It can be caused by various triggers, including food, drugs, and insect venom. The symptoms of anaphylaxis typically occur suddenly and progress rapidly, affecting the airway, breathing, and circulation. Common signs include swelling of the throat and tongue, hoarse voice, respiratory wheeze, dyspnea, hypotension, and tachycardia. In addition, around 80-90% of patients experience skin and mucosal changes, such as generalized pruritus, erythematous rash, or urticaria.

The management of anaphylaxis requires prompt and decisive action, as it is a medical emergency. The Resuscitation Council guidelines recommend intramuscular adrenaline as the most important drug for treating anaphylaxis. The recommended doses of adrenaline vary depending on the patient’s age, ranging from 100-150 micrograms for infants under 6 months to 500 micrograms for adults and children over 12 years. Adrenaline can be repeated every 5 minutes if necessary, and the best site for injection is the anterolateral aspect of the middle third of the thigh. In cases of refractory anaphylaxis, IV fluids and expert help should be sought.

Following stabilisation, patients may be given non-sedating oral antihistamines to manage persisting skin symptoms. It is important to refer all patients with a new diagnosis of anaphylaxis to a specialist allergy clinic and provide them with an adrenaline injector as an interim measure before the specialist assessment. Patients should also be prescribed two adrenaline auto-injectors and trained on how to use them. A risk-stratified approach to discharge should be taken, as biphasic reactions can occur in up to 20% of patients. The Resus Council UK recommends a fast-track discharge for patients who have had a good response to a single dose of adrenaline and complete resolution of symptoms, while those who require two doses of IM adrenaline or have a history of biphasic reaction should be observed for at least 12 hours following symptom resolution.

Hypersensitivity Reactions: Types and Examples

Hypersensitivity reactions are immune responses that can cause tissue damage and inflammation. There are four types of hypersensitivity reactions, each with different mechanisms and clinical presentations.

Type I hypersensitivity reaction is an immediate hypersensitivity reaction mediated by IgE in response to an innocuous environmental antigen. Examples of such reactions are allergic rhinitis and systemic urticaria.

Type II hypersensitivity reaction is an antibody-mediated reaction. Cellular injury may result from complement activation, antibody-dependent cell-mediated cytotoxicity or phagocytosis. Examples include incompatible blood transfusions, haemolytic disease of the newborn and autoimmune haemolytic anaemias.

Type III hypersensitivity reaction is an immune complex-mediated reaction. Immune complexes are lattices of antibody and antigen. When these are not cleared from the circulation, they may trigger an inflammatory response. An example of this type of reaction is extrinsic allergic alveolitis, otherwise known as ‘bird fancier’s lung’, a hypersensitivity pneumonitis caused by exposure to bird droppings.

Type IV hypersensitivity reaction is a delayed hypersensitivity reaction involving T helper cells that become activated upon contact with an antigen, which results in a clonal expansion over 1–2 weeks. Repeated exposure to the antigen results in cytokine release from sensitised T-cells, leading to macrophage-induced phagocytosis.

Anaphylaxis is a type I-mediated hypersensitivity reaction, involving the release of inflammatory mediators (such as histamine), which precipitate vasodilatation and oedema. Anaphylaxis is characterised by the rapid onset of respiratory and circulatory compromise.

Understanding the different types of hypersensitivity reactions is important for diagnosis and treatment. Treatment may involve removal of the source of hypersensitivity, immunosuppressive therapy, or administration of epinephrine in the case of anaphylaxis.

Vaccination Schedule for Infants in the UK

In the UK, infants are recommended to receive a series of vaccinations to protect them from various diseases. Here is a breakdown of the vaccination schedule and when each vaccine is given.

UK Infant Vaccination Schedule

MMR, Hib/Men C, Men B, and Pneumococcal Vaccines

At one year of age, infants are given the MMR, Hib/Men C, and the third dose of both the Men B and pneumococcal vaccines.

Pneumococcal, Rotavirus, Men B, and MMR Vaccines

The pneumococcal and rotavirus vaccines are given at eight weeks, while the Men B vaccine is given at 8 weeks, 16 weeks, and one year. The MMR vaccine is given at 12-14 months.

MMR, Rotavirus, and Pneumococcal Vaccines

The MMR vaccine is given at 12-14 months, while the rotavirus and pneumococcal vaccines are given at eight weeks, 16 weeks, and one year.

Rotavirus, MMR, Six-in-One, and Men B Vaccines

The rotavirus and six-in-one vaccines are given at eight weeks, while the Men B vaccine is given at 8 weeks, 16 weeks, and one year. The MMR vaccine is given at 12-14 months.

Six-in-One Vaccine

The six-in-one vaccine is given at eight weeks, 12 weeks, and 16 weeks.

Severe combined immunodeficiency disease (SCID) is a condition that affects both B- and T-cell immunity, making patients more susceptible to viral, bacterial, mycobacterial, or fungal infections. It typically presents at a young age due to the severity of the immunodeficiency. SCID has two major forms: an X-linked recessive mutation in the γ-chain subunit of a cytokine receptor, which is more common in males, and an autosomal recessive mutation in the genes that encode the enzyme adenosine deaminase, which leads to toxic accumulation of nucleotides in differentiating lymphocytes, especially those in the T-cell lineage. Based on the patient’s female gender, young age at presentation, history of infections, and diminished B and T cells with low serum immunoglobulins, autosomal recessive SCID is the most likely diagnosis. Other conditions such as acquired immunodeficiency syndrome (AIDS), di George syndrome (dGS), systemic lupus erythematosus (SLE), and Wiskott–Aldrich syndrome (WAS) have different pathogenic mechanisms and are less likely to be the cause of the patient’s presentation.

Lymph Node Drainage in the Pelvic Region

The lymphatic drainage in the pelvic region is an important aspect of the body’s immune system. There are several lymph nodes in this area that drain different parts of the body. Here is a breakdown of the lymph node drainage in the pelvic region:

1. Inguinal: The inguinal lymph nodes drain the anal canal inferior to the pectinate line. These nodes then drain into the lateral pelvic nodes.

2. External iliac: The external iliac nodes drain the adductor region of the upper thigh, glans, clitoris, cervix, and upper bladder.

3. Inferior mesenteric: The inferior mesenteric nodes drain the sigmoid, upper rectum, and descending colon.

4. Internal iliac: The internal iliac nodes drain the rectum and the part of the anal canal superior to the pectinate line.

5. Superior mesenteric: The superior mesenteric nodes drain parts of the upper gastrointestinal tract, specifically the duodenum and jejunum.

Understanding the lymph node drainage in the pelvic region is important for diagnosing and treating certain conditions. By knowing which lymph nodes drain which parts of the body, healthcare professionals can better identify the source of an infection or cancer and provide appropriate treatment.

The recommended adult dose of adrenaline for anaphylaxis is 500 mcg, which is equivalent to 0.5 ml of a 1 in 1,000 solution.

Anaphylaxis is a severe and potentially life-threatening allergic reaction that affects the entire body. It can be caused by various triggers, including food, drugs, and insect venom. The symptoms of anaphylaxis typically occur suddenly and progress rapidly, affecting the airway, breathing, and circulation. Common signs include swelling of the throat and tongue, hoarse voice, respiratory wheeze, dyspnea, hypotension, and tachycardia. In addition, around 80-90% of patients experience skin and mucosal changes, such as generalized pruritus, erythematous rash, or urticaria.

The management of anaphylaxis requires prompt and decisive action, as it is a medical emergency. The Resuscitation Council guidelines recommend intramuscular adrenaline as the most important drug for treating anaphylaxis. The recommended doses of adrenaline vary depending on the patient’s age, ranging from 100-150 micrograms for infants under 6 months to 500 micrograms for adults and children over 12 years. Adrenaline can be repeated every 5 minutes if necessary, and the best site for injection is the anterolateral aspect of the middle third of the thigh. In cases of refractory anaphylaxis, IV fluids and expert help should be sought.

Following stabilisation, patients may be given non-sedating oral antihistamines to manage persisting skin symptoms. It is important to refer all patients with a new diagnosis of anaphylaxis to a specialist allergy clinic and provide them with an adrenaline injector as an interim measure before the specialist assessment. Patients should also be prescribed two adrenaline auto-injectors and trained on how to use them. A risk-stratified approach to discharge should be taken, as biphasic reactions can occur in up to 20% of patients. The Resus Council UK recommends a fast-track discharge for patients who have had a good response to a single dose of adrenaline and complete resolution of symptoms, while those who require two doses of IM adrenaline or have a history of biphasic reaction should be observed for at least 12 hours following symptom resolution.

Common Medical Tests and Their Uses

Immunoglobulin Measurement: This test measures the levels of immunoglobulin G (IgG), IgA, and IgM proteins in response to infection. Low levels of these proteins can lead to increased susceptibility to infections.

Flow Cytometry: This test is used to differentiate between different T cell populations and count the number of cells in a sample. It works by passing cells through a laser beam and analyzing the amount of light scatter to identify cell size and granularity.

Human Leukocyte Antigen (HLA) Typing: This test matches patients and donors for cord blood or bone marrow transplants by analyzing proteins used by the immune system to differentiate between self and non-self.

Patch Test: This test diagnoses delayed type IV hypersensitivity reactions by applying test substances to the skin and examining it for any inflammatory response.

Polymerase Chain Reaction: This test amplifies DNA segments for functional analysis of genes, diagnosis of hereditary diseases, and detection of infectious diseases.

The preferred treatment for gonococcal infections is a single intramuscular dose of ceftriaxone, with the dosage based on the patient’s weight. This medication is highly effective against susceptible N. gonorrhoeae and more effective than oral cephalosporins. A test of cure is necessary after treatment to ensure the infection has been cleared. Ciprofloxacin should only be used if the organism’s susceptibility to the antibiotic is known. Dual antibiotic use is no longer recommended, but presumptive treatment for chlamydia may be administered if the patient’s sexual history or symptoms suggest co-infection. Intravenous antibiotics are not necessary for uncomplicated cases, but severe cases of pelvic inflammatory disease may require hospitalization and intravenous antibiotics. Penicillin is not indicated for gonorrhoea treatment due to high antimicrobial resistance.

Adrenaline can be administered every 5 minutes during the management of anaphylaxis.

Anaphylaxis is a severe and potentially life-threatening allergic reaction that affects the entire body. It can be caused by various triggers, including food, drugs, and insect venom. The symptoms of anaphylaxis typically occur suddenly and progress rapidly, affecting the airway, breathing, and circulation. Common signs include swelling of the throat and tongue, hoarse voice, respiratory wheeze, dyspnea, hypotension, and tachycardia. In addition, around 80-90% of patients experience skin and mucosal changes, such as generalized pruritus, erythematous rash, or urticaria.

The management of anaphylaxis requires prompt and decisive action, as it is a medical emergency. The Resuscitation Council guidelines recommend intramuscular adrenaline as the most important drug for treating anaphylaxis. The recommended doses of adrenaline vary depending on the patient’s age, ranging from 100-150 micrograms for infants under 6 months to 500 micrograms for adults and children over 12 years. Adrenaline can be repeated every 5 minutes if necessary, and the best site for injection is the anterolateral aspect of the middle third of the thigh. In cases of refractory anaphylaxis, IV fluids and expert help should be sought.

Following stabilisation, patients may be given non-sedating oral antihistamines to manage persisting skin symptoms. It is important to refer all patients with a new diagnosis of anaphylaxis to a specialist allergy clinic and provide them with an adrenaline injector as an interim measure before the specialist assessment. Patients should also be prescribed two adrenaline auto-injectors and trained on how to use them. A risk-stratified approach to discharge should be taken, as biphasic reactions can occur in up to 20% of patients. The Resus Council UK recommends a fast-track discharge for patients who have had a good response to a single dose of adrenaline and complete resolution of symptoms, while those who require two doses of IM adrenaline or have a history of biphasic reaction should be observed for at least 12 hours following symptom resolution.