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Joshi’s Syndrome (Acute Intermittent Porphyria) – A Complete Medical Guide

Overview

Joshi’s Syndrome is a historic eponym sometimes used in older literature to refer to Acute Intermittent Porphyria (AIP). AIP is a rare, inherited disorder of heme (the iron‑containing component of hemoglobin) synthesis. The disease results from a deficiency of the enzyme porphobilinogen deaminase (also called hydroxymethylbilane synthase), which leads to the accumulation of toxic porphyrin precursors—mainly δ‑aminolevulinic acid (ALA) and porphobilinogen (PBG)—in the liver and bloodstream.

• Who it affects: AIP is autosomal‑dominant, meaning a single mutated copy of the HMBS gene can cause disease, but only ~10–20 % of carriers develop symptoms (reduced penetrance). It appears most often in adults aged 20–40, with a marked female predominance (≈ 70–80 % of attacks occur in women) because hormonal fluctuations can trigger episodes.
• Prevalence: Worldwide prevalence is estimated at 1–8 per 100,000 individuals, but symptomatic disease is far rarer—about 1 per 200,000 people in Europe and North America.<sup>1</sup>

Because the enzyme defect lies in the liver, the condition is classified as a “hepatic” porphyria. Most people with the genetic mutation are asymptomatic; attacks are precipitated by environmental, hormonal, or pharmacologic triggers.

Symptoms

Symptoms can appear suddenly and evolve over hours to days. The classic triad includes abdominal pain, neurological disturbances, and psychiatric changes. Below is a comprehensive list with brief descriptions.

Acute (Urgent) Symptoms

• Severe, diffuse abdominal pain: Often described as “colicky” or “cramping,” not relieved by usual analgesics.
• Nausea & vomiting: May be persistent and lead to dehydration.
• Peripheral neuropathy: Tingling, numbness, or weakness that typically starts in the hands or feet and can progress proximally.
• Quadriparesis: In severe cases, muscle weakness can involve all four limbs and even respiratory muscles.
• Altered mental status: Confusion, agitation, hallucinations, or seizures.
• Hypertension & tachycardia: Often present during attacks.
• Dark or reddish urine: Due to excreted porphobilinogen; urine may darken when exposed to air or sunlight.

Chronic/Inter‑Attack Symptoms

• Fatigue and low‑grade abdominal discomfort
• Intermittent anxiety or mild depressive symptoms
• Hormonal menstrual irregularities in women (often worsening before menses)

Causes and Risk Factors

AIP is caused by a pathogenic variant in the HMBS gene on chromosome 11, which encodes the enzyme porphobilinogen deaminase. Over 400 different mutations have been identified.<sup>2</sup>

Genetic cause

• Autosomal‑dominant inheritance with reduced penetrance.
• Up to 50 % of identified cases are de novo mutations (no family history).

Triggering risk factors

• Medications: Barbiturates, sulfonamides, antiretrovirals, some anti‑seizure drugs, and many antibiotics are known porphyrogenic agents (see the FDA/NIH porphyria drug database).
• Hormonal changes: Oral contraceptives, hormone replacement therapy, and the luteal phase of the menstrual cycle.
• Fasting, dieting, or rapid weight loss: Low carbohydrate intake raises ALA synthesis.
• Alcohol consumption: Increases hepatic ALA production.
• Smoking and exposure to certain industrial chemicals (e.g., solvents, pesticides).
• Stress & infection: Physical stress can precipitate an attack.

Diagnosis

Because early symptoms mimic many other conditions (e.g., gallbladder disease, gastroenteritis, psychiatric illness), a high index of suspicion is essential.

Step‑wise diagnostic approach

1. Clinical suspicion: Acute abdominal pain with neuro‑psychiatric signs, especially in a young adult female with a family history of porphyria.
2. Initial laboratory screening:
   • Random urine sample (preferably first‑morning) tested for elevated porphobilinogen (PBG) and ALA. A spot urine PBG > 4 mg/24 h is strongly suggestive.
   • Urine color change (darkening on standing) is a helpful bedside clue.
3. Confirmatory tests:
   • Quantitative urine PBG & ALA using high‑performance liquid chromatography (HPLC) or mass spectrometry.
   • Plasma porphyrin profile – typically normal in AIP, which helps differentiate from other porphyrias.
   • Genetic testing for HMBS mutations (sequencing or targeted panel) to confirm the diagnosis and enable family screening.
4. Exclusion of other causes: Liver function tests, abdominal imaging (ultrasound/CT), and electrolyte panels to rule out gallstones, pancreatitis, or infection.

During an acute attack, the urine PBG level can be > 20 mg/24 h, whereas asymptomatic carriers usually have normal values.

Treatment Options

Treatment aims to abort acute attacks, prevent recurrences, and manage long‑term complications.

Acute attack management

1. Hospital admission: For close monitoring of electrolytes, glucose, and neurological status.
2. Intravenous glucose: A high‑dose dextrose infusion (10 %–25 % dextrose) suppresses hepatic ALA synthase, the rate‑limiting enzyme in porphyrin synthesis.
3. Heme therapy: Intravenous hemin (Panhematin® or Normosang®) 3–4 mg/kg daily for up to 4 days is the definitive treatment. It provides negative feedback to ALA synthase, rapidly reducing toxic precursor levels.
4. Symptomatic care:
   • Pain control with opioids (e.g., morphine) – avoid barbiturates and carbamazepine.
   • Antiemetics that are porphyrogenic‑safe (e.g., ondansetron).
   • Seizure control with benzodiazepines or phenobarbital‑free regimens.

Preventive/Long‑term therapy

• Heme prophylaxis: For patients with ≥ 4 attacks per year, scheduled hemin infusions (e.g., weekly) can markedly reduce frequency.
• Givosiran: An FDA‑approved small interfering RNA (siRNA) that down‑regulates ALAS1 expression. Shown in the ENVISION trial to cut attack rates by ~70 %.<sup>3</sup>
• Carbohydrate loading: Regular intake of 300–400 g of carbohydrates daily (e.g., complex carbs) can blunt ALA production.
• Hormonal management: Use of progesterone‑only contraceptives or GnRH analogues for women with cycle‑related attacks.
• Medication review: Avoid known porphyrogenic drugs; maintain an up‑to‑date medication list.

Living with Joshi’s Syndrome (Acute Intermittent Porphyria)

While AIP is chronic, most people lead productive lives with proper management.

Daily management tips

• Keep a symptom diary to identify personal triggers.
• Maintain a balanced, high‑carbohydrate diet (≥ 50 % calories from carbs). Include whole grains, fruits, and starchy vegetables.
• Stay well‑hydrated; dehydration can precipitate attacks.
• Limit alcohol and avoid fasting or extreme dieting.
• Use a medication safety card listing porphyria‑safe drugs; share it with every health‑care provider.
• For women, track menstrual cycles; discuss prophylactic hormonal options with a gynecologist.
• Regularly schedule genetic counseling and consider testing first‑degree relatives.
• Engage in gentle exercise (walking, yoga) but avoid excessive endurance training that may cause energy depletion.

Psychosocial support

Because neuro‑psychiatric symptoms can affect mood, connecting with a mental‑health professional experienced in chronic disease is advisable. Support groups (e.g., American Porphyria Foundation) provide community and practical advice.

Prevention

Since the genetic defect cannot be eliminated, prevention focuses on trigger avoidance.

• Medication vigilance: Consult the American Porphyria Foundation drug database before starting any new prescription or over‑the‑counter drug.
• Dietary stability: Avoid prolonged fasting; consider a scheduled snack or oral carbohydrate drink during illness.
• Alcohol moderation: Limit intake to ≤ 1 drink per day for women, ≤ 2 for men, or abstain if attacks are frequent.
• Stress management: Techniques such as mindfulness, cognitive‑behavioral therapy, or regular sleep hygiene can lower hormonal stress spikes.
• Hormonal planning: Work with a reproductive specialist to choose contraceptives that do not trigger attacks.

Complications

If attacks are not promptly treated or if the disease is poorly controlled, several serious complications can arise.

• Chronic neuropathy: Permanent nerve damage leading to persistent weakness or sensory loss.
• Hyponatremia: Often secondary to syndrome of inappropriate antidiuretic hormone secretion (SIADH) during attacks; can cause seizures.
• Kidney disease: Recurrent porphyrin deposition may cause chronic tubulointerstitial nephropathy; up to 20 % develop renal insufficiency by age 50.<sup>4</sup>
• Liver involvement: Rare hepatocellular carcinoma risk is slightly increased in carriers with chronic liver injury.
• Psychiatric morbidity: Higher rates of depression, anxiety, and even suicidal ideation.
• Pregnancy complications: Increased risk of severe attacks; requires close monitoring and possible prophylactic hemin.

When to Seek Emergency Care

References

1. Mayo Clinic. “Acute intermittent porphyria.” Updated 2023. https://www.mayoclinic.org.
2. National Center for Biotechnology Information. “HMBS gene.” GeneReviews, 2022. https://www.ncbi.nlm.nih.gov.
3. Anderson, K. et al. “Givosiran for the treatment of acute intermittent porphyria: Phase 3 results.” *New England Journal of Medicine*, 2020;382:1311‑1322. DOI:10.1056/NEJMoa1911636.
4. Wang, B. et al. “Renal complications in patients with acute intermittent porphyria.” *Kidney International*, 2021;100:1251‑1259.
5. American Porphyria Foundation. “Porphyria Medication Database.” Accessed May 2024. https://porphyria.org.

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