| Evidence stratum | Trigger | Primary pathology | Clinical findings and quantitative human data | Key test | Treatment | Evidence limitations |
|---|---|---|---|---|---|---|
| **Stable cesium-salt poisoning** | Usually deliberate oral or intravenous use of nonradioactive CsCl or Cs₂CO₃, commonly as unsupported alternative cancer therapy | Chemical cardiotoxicity: potassium-channel and HCN-channel inhibition, renal/GI potassium loss, delayed repolarization, early afterdepolarizations, and malignant ventricular arrhythmia | Review of **20 case reports**: **5 deaths (25%)**, cardiac arrest in 7, hypokalemia in **10/12** measured patients (median K⁺ 3.05 mmol/L), and QT prolongation reported in **14/20** in the article text; 11 reported QTc values had median **620 ms**. The article’s Figure 3 appears to show a lower QT count, so the explicit textual count is used here. (pqac-00000004, pqac-00000010) | Exposure history; serial ECG/telemetry and QTc; serum K⁺, Mg²⁺, renal function; cesium measurement by ICP-MS/AES-ICP where available | Stop exposure; intensive cardiac monitoring; aggressive K⁺/Mg²⁺ correction; ACLS, cardioversion/defibrillation, lidocaine or pacing as clinically indicated; Prussian blue has been used, but stable-Cs evidence is limited to case reports. (pqac-00000002, pqac-00000005) | Publication and selection bias are substantial; no controlled trials, validated toxic threshold, population incidence, or cesium-specific genetic susceptibility data. Most cases involved gram-scale self-administration, so ordinary environmental trace exposure is not comparable. |
| **Severe internal radioactive cesium contamination: Goiânia, 1987** | Rupture of a **50.9-TBq ¹³⁷CsCl** teletherapy source, causing ingestion, skin contamination, and external irradiation | Internal β/γ irradiation distributed broadly through soft tissues, combined in many victims with external/cutaneous exposure; sufficiently high dose can cause hematopoietic acute radiation syndrome (ARS) | Of **112,000 screened**, **249** had external and/or internal contamination; **20 developed hematopoietic ARS** and **4 died within four weeks**. These figures describe one accident cohort, not disease incidence or prevalence. (pqac-00000003) | Radiation survey and decontamination assessment; whole-body gamma counting; urine/fecal bioassay; CBC with serial lymphocyte counts; cytogenetic biodosimetry and committed-dose reconstruction | Insoluble Prussian blue; 46 internally contaminated people received **3–10 g/day** as adults/adolescents or **1–3 g/day** as children in the reported reconstruction; treat ARS, infection, hemorrhage, electrolyte abnormalities, and cutaneous injury concurrently. (pqac-00000003, pqac-00000015) | Outcomes cannot be attributed solely to internal ¹³⁷Cs because external irradiation and skin contamination co-occurred; treatment was not randomized, and dose reconstruction was complex. |
| **Low-dose residual radiocesium exposure: Fukushima retrospective study, 2024** | Environmental ¹³⁴Cs/¹³⁷Cs intake after the 2011 Fukushima accident, varying with evacuation timing and location | Low-level internal radiation exposure detectable retrospectively; not equivalent to acute cesium poisoning or ARS | Whole-body-counter analysis of **1,145 adults** found 90th-percentile committed effective doses ranging from **0.04 mSv** in one lower-exposure group to **0.16 mSv** in the highest reported group. Participants were exposure cohorts, **not diagnosed poisoning cases**. (pqac-00000024) | Whole-body counting for ¹³⁴Cs/¹³⁷Cs plus biokinetic back-calculation of committed effective dose and reconstruction of evacuation behavior | Exposure control, food/environmental monitoring, and individualized radiological assessment; these reported dose levels do not themselves establish an indication for Prussian blue | Retrospective measurements began months after release and required modeling; temporary re-entry or surface contamination may have affected some results. The study does not estimate cesium-poisoning incidence or demonstrate clinical illness from the measured doses. (pqac-00000024, pqac-00000026) |


*Table: Comparison of chemically toxic stable cesium-salt poisoning, severe internal ¹³⁷Cs contamination, and low-dose Fukushima radiocesium exposure. The strata are separated to prevent conflating cardiac poisoning, radiation injury, and detectable exposure without diagnosed disease.*